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Effects of whole wheat incorporated into pelleted diets on the growth performance and intestinal function of broiler chickens
Accepted Manuscript Title: Effects of whole wheat incorporated into pelleted diets on the growth performance and intestinal function of broiler chickens ´ L. Author: F. Husv´eth L. P´al E. Galamb K.C. Acs Bustyah´azai L. W´agner F. Dublecz K. Dublecz PII: DOI: Reference:
S0377-8401(15)30030-4 http://dx.doi.org/doi:10.1016/j.anifeedsci.2015.09.021 ANIFEE 13384
To appear in:
Animal
Received date: Revised date: Accepted date:
2-4-2015 24-7-2015 22-9-2015
Feed
Science
and
Technology
´ Please cite this article as: Husv´eth, F., P´al, L., Galamb, E., Acs, K.C., Bustyah´azai, L., W´agner, L., Dublecz, F., Dublecz, K.,Effects of whole wheat incorporated into pelleted diets on the growth performance and intestinal function of broiler chickens, Animal Feed Science and Technology (2015), http://dx.doi.org/10.1016/j.anifeedsci.2015.09.021 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Effects of whole wheat incorporated into pelleted diets on the
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growth performance and intestinal function of broiler chickens
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F. Husvéth , L. Pál , E. Galamb , K. C. Ácsb, L. Bustyaházai ,
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L. Wágner , F. Dublecz , K. Dublecz
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Department of Animal Science, Georgikon Faculty, Pannon
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UBM Feed Ltd., Fő u. 130, H-2085 Pilisvörösvár, Hungary
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University, Deák F. u. 16, H-8360 Keszthely, Hungary
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Highlights
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Whole wheat in the diet may improve feed conversion efficiency
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in broiler chickens.
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Upper part of digestive tract is stimulated by whole wheat increasing gizzard weight.
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This stimuli result in higher activities of pancreatic enzymes in the small intestine.
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Corresponding author. Tel.: +36 30 9365 862; fax: +36 83 545 143 E-mail address: [email protected]
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Intestinal viscosity and histological properties of small intestine is not influenced.
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Whole wheat inclusion in the diet decreases feeding costs by reducing grinding.
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Abstract
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An experiment was carried out to study the effect of postpelleting
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dietary inclusion of whole wheat at the expense of ground wheat in
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different
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characteristics of broiler chickens. In the starter phase all chickens
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were fed the same corn–wheat based diet without whole grain. At 11
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days of age chickens were allotted into three groups and fed the
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following diets containing different percentages of whole wheat in the
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growing and finishing periods. Control: without whole wheat grain;
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treatment A: 5, 10 and 15% whole wheat in growing I (12–18 d),
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growing II (19–28 d) and finishing (29–40 d of age) periods,
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respectively; treatment B: 5, 20 and 30% whole wheat, respectively, in
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the same phases as for treatment A. Body weight and feed
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consumption of chickens were measured during the experiment. At 40
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d of age a total of 12 chickens (6 female and 6 male) were slaughtered
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from each treatment group and dissected to measure the carcass,
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breast fillet, thigh, abdominal fat and gizzard weights, respectively.
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Small intestinal content was analysed for trypsin, α-amylase and lipase
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activities and viscosity. Histological examination of the jejunum was
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performed to determine the size and density of villi and crypts in the
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mucosa.
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performance
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proportions
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Only slight differences were shown between the treatments in
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the weight gain of the chickens. At 40 d of age female chickens fed
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higher proportion of whole wheat (treatment B) had lower body weight
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than those fed the control diet without whole wheat (P<0.05). However,
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no differences were found in the body weight of male chickens between
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the treatments at the end of the experiment. Chickens fed the diet
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containing lower percentages of whole wheat (treatment A) showed
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significantly better feed conversion ratio than chickens both in the
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control group and the group fed a higher level of whole wheat
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(treatment B) both in the whole experimental period and in growing
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phase II (19–24 d). No significant differences were found between the
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treatment groups in carcass weight, breast fillet, thigh and abdominal
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weights. Compared to the control, chickens fed diets containing whole
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wheat increased gizzard weight by 46.2 and 62.2%, respectively,
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depending on the inclusion levels of whole wheat. Relative to the
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control group, higher trypsin, α-amylase or lipase activities were
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detected in the small intestinal contents of chickens fed both lower and
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higher levels of whole wheat (P<0.05), but no differences were shown
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in the viscosity of the intestinal contents between dietary treatments.
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Whole wheat feeding did not have any significant effects on the
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parameters measured and on the histological structure of the small
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intestine.
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As the results indicate, whole wheat supplementation of the
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pelleted diet of broiler chickens may have advantageous effects on
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broiler chicken production by increasing the efficiency of digestion. This
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proves that some costs of grinding can be spared without any harmful
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effects on performance.
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Keywords: Whole wheat; Broiler chicken; Performance; Digestive
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physiology
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1. Introduction
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As evidenced from several scientific publications, there is a steadily
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growing interest in the feeding of whole wheat with different poultry
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species, including broiler chcikens. This interest has primarily been
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fuelled by the possibility to save wheat grinding costs and to improve
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gizzard function and the efficiency of digestion. Feeding of whole wheat
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helps the chicken to develop a bigger and stronger gizzard, which has
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a beneficial effect on the function of the entire digestive tract. The
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gizzard is a dynamic organ with a size closely correlated with the fibre
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content and particle size of the ration (Svihus, 2011). The increase of
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gizzard size results from the increased frequency and strength of
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gizzard contractions aimed at appropriately reducing the size of feed
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particles when whole wheat is fed (Roche, 1981). Ross 208 broiler
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chickens fed whole wheat grains at an inclusion level of 5 to 50% were
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found to have significantly larger gizzards expressed in relation to their
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body size (Engberg et al., 2004). When fed at inclusion levels up to
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20% or 30% of the ration, whole wheat did not decrease the body
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weight gain of chickens significantly as compared to the control, while it
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improved the feed conversion ratio.
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According to the research results reported so far, the feeding of
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whole wheat has ambiguous effects on the development and function
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of the different digestive tract segments too (Jones and Taylor, 2001;
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Wu and Ravindran, 2004; Amerah and Ravindran, 2008). According to
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some reports, the feeding of whole wheat resulted in a decrease of the
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relative size of digestive tract segments. When feeding whole wheat
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grains, Taylor and Jones (2004) observed a 16% decrease in the
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relative size of the duodenum while the relative size of the jejunum did
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not change. In broilers fed a ration containing 200 g/kg whole wheat
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grains, Wu et al. (2004) did not find any difference in the height of the
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intestinal villi, the depth of the mucosal glands (crypts of Lieberkühn)
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and the number of mucus-producing glandular cells (goblet cells) in the
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ileum. On the other hand, Gabriel et al. (2008) observed increased
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villus to crypt ratio and surface area in the duodenum of broiler
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chickens fed whole wheat, due to the decrease in crypt depth. Based
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upon these findings, the authors suggest that the morphological
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changes occurring in the small intestine of broiler chickens fed whole
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wheat result in an improved efficiency of digestion and absorption.
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Supporting the assumption of the above-cited researchers, Engberg et
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al. (2004) reported that, up to an inclusion level of 300 g/kg in the diet,
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the feeding of whole wheat increased the relative weight of not only the
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gizzard but also of the pancreas in broiler chickens. The increased
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efficiency of digestion significantly increases the metabolisable energy
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(MEn) content of the feed, presumably due to the higher digestibility of
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nutrients including amino acids (Biggs and Parsons, 2009).
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The efficiency of digestion in the small intestine is markedly
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influenced by the viscosity of digesta. Only few data are available on
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the effect of feeding whole wheat grains on the viscosity of the
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intestinal content. Feed mixtures formulated with ground wheat were
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found to increase the viscosity of digesta as compared to feeds
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containing whole wheat (Yasar, 2003). In contrast, Engberg et al.
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(2004) found that the feeding of whole wheat increased the viscosity in
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ileal contents as compared with pellet-fed birds.
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There are few and contradictory data in the literature on the effect of
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whole wheat feeding on the digestion of nutrients in the digestive tract.
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In the trials conducted by Engberg et al. (2004) with broiler chickens,
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the feeding of whole wheat did not exert a significant influence on
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chymotrypsin, trypsin and lipase activities measured in the pancreatic
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tissue, but caused a close-to-significant decrease (P=0.054) in the
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activity of amylase.
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As can be seen from the foregoing, the feeding of whole wheat has
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numerous beneficial effects in broiler chicken nutrition. It is also
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evident, however, that the relevant reports are often contradictory and
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there are hardly any published results on certain physiological and
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nutritional issues. Therefore, our aim was to conduct an experiment to
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study the effect of whole wheat incorporated into pelleted diets on the
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growth performance of broilers as well as on the morphology and
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functions of the digestive system. During these trials, we studied the
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effect of whole wheat added to grower and finisher diets of different
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phases at varying inclusion levels on the body weight and feed
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conversion efficiency of broiler chickens, the weight of the gizzard, the
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activities of digestive enzyme in the small intestine, the viscosity of
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digesta and the histiological structure of the intestine. The influence of
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feeding whole wheat on the digestibility of certain nutrients and on
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caecal function will be reported in a forthcoming paper.
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2. Materials and methods
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The protocol of the animal experiment was approved by the Food
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Chain Safety and Animal Health Directorate of the Government Office
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of Zala County (permission number: ZAI/100/1479-003/2014).
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2.1. Experimental birds and their keeping conditions The trial included a total of 624 Ross 308 day-old broiler chicks,
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which were sexed and vaccinated against Newcastle Disease,
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Infectious Bronchitis and Infectious Bursal Disease in the “Levente
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Telep hatchery I” of Gallus Poultry Breeding and Hatcheries Ltd. of
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Devecser before transportation to the experimental farm of our
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Department. The day-old chicks were housed in a closed room, where
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the optimal environmental conditions were provided by an automatic,
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computer-controlled system. The room contained 2 × 1 m pens with 1.7
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m2 useful ground-space (after deducting the area occupied by the
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feeders and drinkers). The pens were bedded with chopped wheat
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straw as deep litter. Seventeen female and 17 male day-old chicks (a
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total of 34 chicks per pen) were placed in each pen, where they were
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raised together up to 40 days of age. The chicks were fed from self-
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feeders and drinking water was provided from automatic drinkers ad
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libitum. Temperature, lighting and other environmental conditions of the
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room were controlled according to the specifications of the Ross Broiler
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Management Manual (Aviagen Broiler Breeders, 2009). From week 2
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till week 5 the chicks received a selenium supplementation (Reaszelén
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Combi, Pharmotéka Bt.; 0.25 g/kg body weight) via the drinking water
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once a week.
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2.2. Feeding and experimental treatments
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In the 40-day trial period the following phases were used: days 0–11:
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starter diet, days 12–18: grower I diet, days 19–28: grower II diet, days
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29–40: finisher diet. Starter diets were fed in mash form, grower and
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finisher diets as pellets. From day 0 to day 10, all the experimental
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chicks received a starter feed of identical composition, without whole
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wheat. Starting from the grower phase, three experimental treatments
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were established, by adding to the diet different amounts of whole
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wheat seeds at the expense of ground wheat, at the following ratios.
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Control: the diets did not contain whole wheat in any of the phases. In
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the case of treatment „A‟ the inclusion levels of whole wheat seeds
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were 5% in the grower I diet, 10% in the grower II diet, and 15% in the
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finisher diet. The whole wheat contents of diets treatment „B‟ were 5%
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in the grower I diet, 20% in the grower II diet and 30% in the finisher
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diet. The experimental diets were pelleted and then the whole wheat
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seeds were mixed to them. During mixing a liquid enzyme mix
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(Phyzyme®: phytase; Axtra™: xylanase + glucanase, Table 2) was
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sprayed onto the surface of the pellets and the whole wheat seeds. The
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diameter of the pellets was 3 mm in all phases while their length varied
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between 3 and 5 mm depending on the phase of rearing. The specific
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gravity of the pellet prepared in this way was nearly identical with that
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of the whole wheat seeds, which markedly reduced the possibility of
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segregation of the two constituents through sedimentation. The
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composition and the nutrient content of the diets by treatment and
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growing phase are presented in Tables 1 and 2.
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The diets described above were fed to chicks of six pens per
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treatment. Accordingly, the diet of every treatment was fed to a total of
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204 (102 female and 102 male) chicks.
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2.3. Collection of data and samples
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The health status of the chickens was monitored regularly
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throughout the trial period. In the morning, the dead birds, if any, were
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collected, weighed and the cause of death was determined. On days 1,
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11, 18, 28 and 40 of life chickens were weighed individually. At the time
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of the first three weighings, the female and male chicks could not be
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distinguished phenotypically with high accuracy; therefore, the results
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obtained at those time-points were given for as the average weight of
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mixed sex. At the same time, on day 40 the pullets and cockerels could
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be distinguished reliably and, therefore, the weighing results were given
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separately for the two sexes. Simultaneously with the body weight
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measurements, feed consumption on pen level (n = 6) was also
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measured and feed conversion ratio was calculated. After the weighing on day 40, one female and one male chick per
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pen (a total of 6 female and 6 male birds per treatment) were randomly
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selected and exsanguinated after stunning with CO 2. After removing
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the feathers, the carcass weight (without head, legs and viscerals) as
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well as the weight of the breast fillet, the thigh and the abdominal fat
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were determined by weighing with gram precision, and expressed as a
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percentage of the liveweight.
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The digestive tract was excised from the carcasses, and then the
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gizzard was separated and weighed. An about 5-cm-long segment was
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excised from the proximal part of the jejunum and the digesta were
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removed from it and collected in a 2-ml plastic test tube to determine
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the activities of digestive enzymes. The digesta samples were stored in
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a deep freezer at –70 °C temperature until the laboratory analyses.
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From the part of the jejunum distal to Meckel‟s diverticulum, an
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approximately 3 cm long segment was excised. In order to remove the
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digesta, the excised intestinal segments were washed in physiological
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phosphate-buffered saline, then they were placed, one by one, into
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approximately 20 ml of 5% formaldehyde solution precooled to 10 °C,
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and were then stored at that temperature until used for histological
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examination.
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In order to measure the viscosity of the digesta, an about 10 cm long
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segment was excised from the ileum at a site proximal to the ileocaecal
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junction, and the digesta present in that segment were collected in a 2-
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ml plastics test tube. The ileal digesta samples were stored in a deep
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freezer at –70 °C temperature until the viscosity measurements.
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2.4. Laboratory analyses Feed analysis. The experimental diets were analysed for moisture
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(ISO, 1999b), crude fiber (ISO, 2000), crude protein (ISO, 2005a),
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crude fat (ISO, 1999b), phosphorus (ISO, 1998), calcium and sodium
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(ISO, 2001) contents and amino acid composition (ISO, 2005b) using
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methods of International Organisation for Standardization (ISO).
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Enzyme activity determinations. The activity of α-amylase was
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determined as described by Dahlqvist (1962), while lipase activity was
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measured by the method elaborated by Schön et al. (1961).Trypsin
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activity was measured by a Boehringer test as described by Kakade et
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al. (1969).
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Measurement of the viscosity of digesta. To measure the viscosity of
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ileal digesta, 2 g of digesta were frozen and stored at –80 °C. After
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defrosted the samples were centrifuged (with 12,000 g for 10 min), and
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the viscosity of the supernatant (0.5 ml) was measured using a
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Brookfield DV II+ viscometer (Brookfield Engineering Laboratories,
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Stoughton, MA, USA) at 25 °C with a CP40 cone and shear rate of 60–
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600s–1.
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Histological examination of the intestine. Histological analysis of the
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small intestinal segment was performed at the Histology Laboratory of
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the Clinical Unit for Poultry Medicine of the University of Veterinary
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Medicine Vienna. The samples were taken from an ileal segment close
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to Meckel‟s diverticulum, and fixed in 5% formalin solution until starting
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the preparatory operations. During the preparation of samples, serial
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water extraction and purification steps were performed, and the
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samples were subsequently embedded in paraffin. The samples (12
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chicks per treatment, 6 female and 6 male birds) were cut into 5 m
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thick sections with a microtome, and fixed on slides. Two slides were
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prepared from all samples. The slides were stained with haematoxylin
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and eosin, then examined with a digital video camera (Olympus DP-26)
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and an Olympus BX43F light microscope fitted up with an Olympus
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Stream Start software. The images were analysed with the help of the
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„Image J‟ software (Version 1.47) developed by the National Institutes
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of Health (Maryland, USA). From the two sections fixed on slides from
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each sample, the intact villus–crypt segments were selected and were
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used for histological analysis. This analysis involved the calculation of
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the villus length, the crypt depth, the basal and apical width of the
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intestinal villus, the width of the muscle layer and the calculation of the
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villus to crypt ratio (Molnar et al., 2015).
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2.5. Statistical analysis
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The results of the experiment were evaluated by one-way analysis of
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variance (ANOVA). To determine statistically significant differences
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caused by the dietary treatments (F-test; P<0.05), Tuky‟s test was
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used. The calculations were made using the IBM SPSS Statistics 20.0
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GL Model Univariate Test statistical programme package.
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3. Results
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3.1. Mortality No animal health problems different from those observed usually
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were found in the course of the trial. During the trial period a total of 23
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chickens (3.2% of the flock) died. There was no connection between
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the distribution of deaths and the experimental treatments. The causes
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of death were sudden death syndrome in 16 cases, ascites in 4 cases,
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leg disorders in 1 case and an unknown reason in 2 cases.
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3.2. Performance
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The average values of the body weights are presented in Table 3.
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There were no major differences in the body weight of chickens fed
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diets containing different levels of whole wheat. A significant difference
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in body weight was found only once, at day 40, when pullets fed diet „B‟
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had lower average weight than control chicks. No significant difference
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in the body weight of the cockerels of the different treatment groups
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was found throughout the trial.
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However, significant differences were found in the feed conversion
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ratio of the chicks (Table 4). During the whole experimental period
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(days 0 to 40) the chickens fed diet „A‟ containing a lower level of whole
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wheat used less (P<0.05) feed for 1 kg liveweight gain, as calculated
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for the entire trial period (40 days), than the control chickens or the
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chickens fed diet „B‟ containing a higher level of whole wheat seeds.
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The beneficial effect of using a lower inclusion level of whole wheat on
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the body weight gain was apparent also in the growing phase between
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19 and 28 days of age. Namely, during that period the chickens fed the
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diet containing 10% whole wheat seeds consumed less (P<0.05) feed
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for 1 kg liveweight gain than the control chickens.
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3.3. Carcass parameters
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No significant differences were found between the treatments in the
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carcass weight of chickens slaughtered at the end of the trial, on day
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40 of life, in the ratios of the valuable meat parts (breast fillet and thigh)
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and in the amount of abdominal fat expressed in percentage of the
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body weight.
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At the same time, the weight of the gizzard increased significantly as
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a result of whole wheat seed supplementation. The highest gizzard
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weights were found in chickens fed a higher level of whole wheat seeds
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(diet „B‟) (Fig. 1). The gizzard weight of chickens of this treatment group
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was 62.2% higher than that of the control chickens not receiving whole
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wheat seed supplementation. The gizzard weight of chickens fed diet
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„A‟ containing a lower level of whole wheat exceeded that of the control
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by 46.4% (P<0.05).
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3.4. Histological structure of the small intestine
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No significant differences associated with the dietary treatments
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were found in the microscopically measured values characterising the
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histological status of the small intestine. In none of the dietary
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treatments did the feeding of whole wheat exert a notable effect on the
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length and width of villi of the intestinal mucosa, on the depth of the
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crypts of Lieberkühn and on the thickness of the smooth muscle layer
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of the mucosa (P>0.05).
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3.5. Enzyme activities and viscosity of the small intestinal digesta
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In chyme samples collected from the proximal segment of the
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jejunum, the measured activity values of pancreatic enzymes (α-
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amylase, lipase and trypsin) were consistently higher (P<0.05) in
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chickens fed the diets supplemented with whole wheat (diets „A‟ and
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„B‟) than in the control chickens (Table 5). For all three enzymes, the
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highest activities were measured in chickens fed the diet containing
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higher levels of whole wheat (diet „B‟); however, all three enzymes had
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higher activities in the digesta of chickens fed a diet with a lower
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inclusion level of whole wheat (diet „A‟) than in the digesta of the control
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chickens. In contrast to these changes in the activity of digestive
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enzymes, in the viscosity of the ileal digesta no differences were found
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between the different treatments (Table 5).
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4. Discussion
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Jones and Taylor (2001) found that in chickens fed whole wheat
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grains mixed to a pelleted diet the incidence of proventricular dilatation
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and mortality due to ascites decreased. In this trial, we could not
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demonstrate a similar phenomenon in chickens fed whole wheat. The
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rate of mortality due to ascites was low and was not connection with the
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dietary treatments. In our study, the most common cause of mortality
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was sudden death syndrome. In fast-growing broilers, this syndrome
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has been proven to account for a substantial proportion of deaths
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(Siddiqui et al., 2009). In the present trial, the growth rate of broilers
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was outstandingly high, exceeding even the average growth rates
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specified in the Ross Broiler Management Manual (Aviagen Broiler
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Breeders, 2009). This fact may explain the rather common occurrence
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of sudden death syndrome as a cause of death in our trial.
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In this trial the only significant difference in the body weights of
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chickens were found at day 40 between the female birds of the control
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and treatment “B” groups. Several research studies have demonstrated
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that whole wheat added to mash or pelleted diets at an inclusion rate of
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5–30% exerted no (Jones and Taylor, 2001; Svihus et al., 2010) or only
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marginal effect (Engberg et al., 2004) on the weight gain of broiler
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chickens. At the same time, a higher inclusion level of whole wheat
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grains may decrease the growth rate of chickens, depending on their
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age (Biggs and Parsons, 2009). In our trial, the body weight gain of
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chickens substantially exceeded the values found in the above-cited
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studies. In sipite of such high growth rate did we did not find significant
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decrease in the body weight gain of cockerels during the 40-day trial. At
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the same time, when the inclusion level of whole wheat in the pelleted
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diet was raised to 30% between days 28 and 40, the average weight of
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the pullets at the end of the trial was slightly (by 86 g, 3.1%) but
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significantly lower than that of the controls. Although the difference
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between the two sexes in the above-mentioned period is difficult to
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explain, the results suggest that female chickens react to a higher
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inclusion level of whole wheat seeds in the diet more sensitively than
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cockerels, and this is reflected in the body weight gain.
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When comparing as hatched birds (17 male and 17 female,
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respectively in a pen), the chickens fed pelleted diets containing lower
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levels of whole wheat, showed significantly better feed conversion ratio
420
throughout the trial (from day 0 to day 40) than did the controls. This
421
favourable effect manifested itself mainly in growing phase II, when the
422
weight of the chickens changed between 800 and 1800 g. In
423
accordance with our findings, Biggs and Parsons (2009) found no
424
change in feed conversion efficiency in 8–21 days old broilers fed diets
425
containing 20% whole wheat. However, the feeding of 35% whole grain
426
resulted in a significantly poorer feed conversion in their experiment. In
427
a growing period similar to growing phase II used in our trial, i.e.
428
between days 16 and 25 of age, Svihus et al. (2010) found a
429
significantly better feed conversion ratio in broiler chickens fed 150 g
430
whole wheat added to every kg of the diet, even if no differences were
431
obtained in the body weight gain. They attributed the more efficient
432
feed conversion obtained to higher AMEn value and improved starch
433
digestibility for diets supplemented with whole wheat.
Ac
ce pt
ed
M
an
us
cr
417
434
Our results show that the feeding of whole wheat at a lower inclusion
435
levels of whole wheat (diet „A‟) resulted in a more favourable feed
436
conversion ratio than the diet not containing whole wheat (control diet)
Page 18 of 35
19
or the diet containing whole wheat at higher levels (diet „B‟). This
438
improvement of feed conversion was presumably due to the better
439
intestinal function. Raising the inclusion level of whole wheat resulted in
440
a marked increase in gizzard size. Several research studies of similar
441
nature have demonstrated that the increase of feed particle size,
442
including the feeding of whole grains, substantially increases the size of
443
the gizzard relative to body size as well as gizzard acidity (Svihus,
444
2011). Improved gizzard function in chickens fed diets supplemented
445
with whole wheat results in a more efficient grinding of feed in the
446
gizzard. As a consequence, a chyme of smaller particle size will be
447
propelled into the small intestine (Hetland et al., 2002), which may have
448
a favourable effect on enzymatic digestion taking place in that part of
449
the gut (Amerah et al., 2009). This hypothesis is supported by our own
450
measurement results of α-amylase, trypsin and lipase activity in the
451
small intestinal content. As a result of feeding whole wheat, the
452
activities of all three enzymes were higher in the content of small
453
intestine of chickens fed a diet containing whole wheat than in chickens
454
receiving a diet without whole grain. The mechanism behind the
455
increase in enzyme secretion could be the stimuli of vagus nerve and
456
cholecystokinin by increased gizzard activity (Svihus, 2011). The
457
enzyme activities found in this experiment in the chickens fed whole
458
wheat are supported by the findings of Gabriel et al. (2008), who
459
observed a 12% increase in pancreas weight in chickens fed a diet
460
supplemented with whole wheat. Biggs and Parsons (2009) reported an
461
improvement in amino acid digestibility in chickens fed diets containing
Ac
ce pt
ed
M
an
us
cr
ip t
437
Page 19 of 35
20
10–20% whole wheat, whereas Svihus et al. (2010) observed higher
463
starch digestibility in broiler chickens fed 15% whole wheat. At the
464
same time, Engberg et al. (2004) found that amylase activity decreased
465
in the pancreatic tissue of chickens fed whole wheat grains. However, if
466
besides whole wheat a fibrolytic enzyme (xylanase) was also added to
467
the diet, the activities of chymotrypsin and lipase increased in the
468
pancreatic tissue. This latter finding proves that the feeding of whole
469
wheat has a favourable effect on digestion also when used concurrently
470
with NSP degrading enzymes. In our experiment, all diets contained
471
NSP degrading enzymes. When feeding whole wheat at higher
472
inclusion levels (20–30%), we did not find a better feed conversion
473
despite the bigger gizzard and the higher digestive enzyme activities
474
measured in the digesta. These results suggest that the benefits of
475
feeding whole wheat to broiler chickens are influenced by their
476
inclusion rate in the diets. When fed in quantities exceeding a certain
477
level, whole wheat may induce adverse effects in intensively growing
478
broiler chickens, in addition to its favourable influence exerted on
479
digestion as studied and demonstrated in this trial.
ce pt
ed
M
an
us
cr
ip t
462
The lower average weight measured on day 40 in the case of
481
chickens fed a higher level of whole wheat seeds (diet „B‟) as compared
482
to the control, and the poorer feed conversion obtained for the entire
483
trial period in comparison with chickens fed a lower level of whole
484
wheat (diet „A‟) cannot be explained either by the histological
485
parameters of the intestine determined by us or by the differences in
486
the viscosity of digesta. No differences were found between the dietary
Ac
480
Page 20 of 35
21
treatments either in the viscosity of digesta or in the parameters
488
measured in order to characterise the tissue structure of the gut (size of
489
intestinal villi, depth of the crypts of Lieberkühn, thickness of the muscle
490
layer of the mucosa). Our results regarding the viscosity of digesta are
491
consistent with the findings reported by Svihus and Hetland (2001) as
492
well as Engberg et al. (2004). In the studies of Engberg et al. (2004),
493
the viscosity of digesta of chickens fed whole wheat was higher than
494
that of birds reared on a pelleted diet without whole wheat. These
495
differences,
496
supplementation
497
examinations support the results reported by Wu et al. (2004), who did
498
not find differences in the above-mentioned intestinal parameters in
499
chickens fed whole wheat added to the diet at a rate of 200 g/kg. In
500
contrast, Gabriel et al. (2008) reported that 20-40% whole wheat
501
supplementation resulted in increased duodenal villus to crypt length
502
and surface due to lower crypt depth and smaller crypt area in broiler
503
chickens.
506 507
given.
The
when findings
xylanase of
our
enzyme
histological
ce pt
ed
M
an
was
disappeared
Ac
504 505
however,
us
cr
ip t
487
5. Conclusion
508
Whole wheat added to the diet using appropriate techniques do not
509
markedly affect the performance of intensively reared broiler chickens.
510
In fact, when fed at lower levels (up to 15% in the grower and up to
511
20% in the finisher phase), whole wheat improves feed conversion
Page 21 of 35
22
efficiency, presumably through its favourable influence exerted on the
513
upper part of the digestive tract and the activities of pancreatic
514
enzymes in the small intestine. Although whole wheat grains fed at an
515
inclusion level of 30% may adversely affect growth performance,
516
however, do not cause unfavourable changes in carcass composition
517
or small intestinal tissue structure. According to our results female
518
chicks are more sensitive to the ratio of whole wheat than cockerels. By
519
feeding wheat as whole wheat grains the grinding costs can be reduced
520
markedly, which has a favourable effect on the overall feed costs. The
521
upper limit of the inclusion level of whole wheat grains in the diet shall
522
be determined by carefully weighing the feed cost reduction resulting
523
from the omission of wheat grinding against the potentially lower growth
524
performance obtained at higher inclusion levels of whole wheat.
525
ed
M
an
us
cr
ip t
512
Acknowledgements
527
Authors would like to thank UBM Feed Ltd. for financial support of the
528
experiments, and A. Szekely for cheking the English in the paper.
Ac
529
ce pt
526
Page 22 of 35
23 530
References
531
Amerah, A.M., Ravindran, V., 2008. Influence of method of whole-
533
wheat feeding on the performance, digestive tract development and
534
carcass traits of broiler chickens. Anim. Feed Sci. Technol. 147,
535
326–339.
ip t
532
Amerah, A.M., Ravindran, V., Lentle, R.G., 2009. Influence of wheat
537
hardness and xylanase supplementation on the performance, energy
538
utilization, digestive tract development and digesta parameters of
539
broiler starters. Anim. Prod. Sci. 49, 71–78.
us
an
541
Aviagen Broiler Breeders, 2009. Ross Broiler Management Manual, Aviagen Group, Midlothian, pp. 1–114.
M
540
cr
536
Biggs, P., Parsons, C.M., 2009. The effects of whole grains on nutrient
543
digestibilities, growth performance, and cecal short-chain fatty acid
544
concentrations in young chicks fed ground corn-soybean meal diets.
545
Poult. Sci. 88, 1893-1905.
547
ce pt
546
ed
542
Dahlqvist, A., 1962. A method for the determination of amylase in intestinal content. Scand. J. Clin. Lab. Invest. 14, 145–151. Engberg, R.M., Hedemann, M.S., Steenfeldt, S., Jensen, B.B., 2004.
549
Influence of whole wheat and xylanase on broiler performance and
550
microbial composition and activity in the digestive tract. Poult. Sci.
551
83, 925–938.
Ac
548
552
Gabriel, I., Mallet, S., Leconte, M., Travel. A., Lalles, J.P., 2008. Effect
553
of whole wheat feeding on the development of the digestive tract of
554
broiler chickens. Anim. Feed Sci. Technol. 142, 144–162.
Page 23 of 35
24 555
Hetland, H., Svihus, B., Olaisen, V., 2002. Effect of feeding whole
556
cereals on performance, starch digestibility and duodenal particle
557
size distribution in broiler chickens. Br. Poultr. Sci. 43, 416–423. ISO. 1998. Animal feeding stuffs. Determination of phosphorus content.
559
Spectrometric method (ISO 6491). International Organization for
560
Standardization, Geneva, Switzerland.
ip t
558
ISO. 1999a. Animal feeding stuffs. Determination of moisture and other
562
volatile matter content (ISO 6496). International Organization for
563
Standardization, Geneva, Switzerland.
us
cr
561
ISO. 1999b. Animal feeding stuffs. Determination of fat content (ISO
565
6492). International Organization for Standardization, Geneva,
566
Switzerland.
M
567
an
564
ISO. 2000. Animal feeding stuffs. Determination of crude fibre content. Method
with
intermediate
filtration
569
Organization for Standardization, Geneva, Switzerland.
ed
568
(ISO
6865).
International
ISO. 2001. Animal feeding stuffs. Determination of the contents of
571
calcium, copper, iron, magnesium, manganese, potassium, sodium
572
and zinc. Method using atomic absorption spectrometry (ISO 6896).
573
International Organization for Standardization, Geneva, Switzerland.
Ac
ce pt
570
574
ISO. 2005a. Animal feeding stuffs. Determination of nitrogen content
575
and calculation of crude protein content. Part 1: Kjeldahl method
576
(ISO
577
Geneva, Switzerland.
5983-1).
International
Organization
for
Standardization,
Page 24 of 35
25 578
ISO. 2005b. Animal feeding stuffs. Determination of amino acid content
579
(ISO 13903). International Organization for Standardization, Geneva,
580
Switzerland. Jones, G.P.D., Taylor, R.D., 2001. The incorporation of whole grain into
582
pelleted
broiler
chicken
diets:
production
583
responses. Br. Poult. Sci. 42, 477–483.
and
physiological
ip t
581
Kakade, M.L., Simons, N., Liener, I.E., 1969. An evolution of natural vs.
585
synthetic substrate for measuring the antitryptic activity of soybean
586
samples. Cereal Chem. 46, 518–526.
us
cr
584
Molnar, A. Hess C., Pál L., Wágner L., Husvéth F., Hess M., Dublecz K.
588
2015. Composition of diet modifies colonization of dynamics of
589
Campylobacter jejuni in broiler chickens. J. Appl. Microbiology 118,
590
245-254.
593
M
ed
592
Roche, M., 1981. Feeding behavior and digestive motility of birds. Reprod. Nutr. Dev. 21, 781–788.
Schön, H.B., Rassler, B., Henning, N., 1961. Über die Untersuchung
ce pt
591
an
587
594
der
595
Aktivitätsbestimmungen
596
Carboxipeptidase. Klin. Wschr. 39, 217–222.
598 599 600
Pankreasfunktion. von
Trypsin,
Methoden
zur
Chymotrypsin,
Ac
597
exkretorischen
Siddiqui, M.F.M.F., Patil, M.S., Khan, K.M., Khan, L.A., 2009. Sudden death syndrome – An overview. Veterinary World 2, 444–447. Svihus, B., 2011. The gizzard: function, influence of diet structure and effects on nutrient availability. World‟s Poult. Sci. J. 67, 207–224.
601
Svihus, B., Hetland H., 2001. Ileal starch digestibility in growing broiler
602
chickens fed on a wheat-based diet is improved by mash feeding,
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26 603
dilution with cellulose or whole wheat inclusion. Br. Poult. Sci. 42,
604
633–637. Svihus, B., Sacranie, A, Denstadli, V., Choct, M., 2010. Nutrient
606
utilization and functionality of the anterior digestive tract caused by
607
intermittent feeding and inclusion of whole wheat in diets for broiler
608
chickens. Poult Sci. 89, 2617–2625.
ip t
605
Taylor, R.D. and Jones, G.P.D., 2004. The incorporation of whole grain
610
into pelleted broiler chicken diets. II. Gastrointestinal and digesta
611
characteristics. Br. Poult. Sci. 45, 237–246.
us
cr
609
Wu, Y.B., Ravindran, V., 2004. Influence of whole wheat inclusion and
613
xylanase supplementation on the performance, digestive tract
614
measurement and carcass characteristics of broiler chickens. Anim.
615
Feed Sci. Technol. 116, 129–139.
M
an
612
Wu, Y., Ravindran, V., Thomas, D.G., Birtles, M.J., Hendriks, W.H.,
617
2004. Influence of method of whole wheat inclusion and xylanase
618
supplementation on the performance, apparent metabolisable
619
energy, digestive tract measurement and gut morphology of broilers.
620
Br. Poult. Sci. 45, 385–394.
ce pt
ed
616
Yasar, S., 2003. Performance, gut size and ileal digesta viscosity of
622
broiler chickens fed with a whole wheat added diet and the diets with
623
different wheat particle sizes. Int. J. Poult. Sci. 2, 75–82.
Ac
621
624 625 626
Table 1. Dietary treatments
Page 26 of 35
27 Treatments (whole wheat seed % in the diets)
Growing
chickens
phases
(days)
Control
Whole wheat A
Whole wheat B
Starter
0
0
0
12-18
Grower I
0
5
5
19-28
Grower II
0
10
20
29-40
Finisher
0
15
30
us
627
cr
0-11
ip t
Age of
an
628
Table 2. Analysed nutrient composition and viscosity of wheat used in the
630
experiment
M
629
631
Dry matter
ed
Nutrients
g/kg 889.00 115.00
Starch
545.00
ce pt
Crude protein (Nx6.25)
15.10
Crude fibre
31.11
Total arabinoxylan
35.2
Ac
Ether extract
Water soluble arabinoxylan
3.5
Lysine
4.23
Methionine
2.40
P
3.12
Ca
0.61
Page 27 of 35
28 Extract viscosity (mPa·s)
2.94
632 633 634
Table 3. Composition and nutrient content of the diets † (g/kg diet)
Grower I.
Grower II.
0 to 11 d
12 to 18 d
19 to 28 d
29 to40 d
Corn
220.0
231.0
211.9
159.4
Wheat
349.8
359.7
400.0
500.0
Soybean meal
265.0
181.0
148.0
Fullfat soybean
53.0
60.0
70.0
60.0
40.0
50.0
45.0
32.0
43.0
46.0
49.0
0.7
0.0
0.0
0.0
3.6
2.6
2.3
2.1
17.4
16.4
15.6
15.2
3.2
3.3
3.3
3.4
Monocalcium phosphate
12.1
10.3
9.5
8.4
L-Lysine HCl (78%)
4.3
2.9
2.7
2.9
L-Threonine (98%)
1.5
0.9
0.8
0.9
Elancoban® 200 2
0,0
0,0
0.6
0.0
3
0.6
0.6
0.0
0.0
4.5
4.0
4.0
3.5
30.0
M
1
ed
Fractionated sunflower meal, 40%
an
Ingredient
223.0
L-Valine FG DL-Methionine (99%) Calcium carbonate
Ac
Sodium chloride
ce pt
Sunflower oil
Maxiban® G160
UBM Broiler premix 4
Finisher
cr
Starter
us
636
ip t
635
Page 28 of 35
Water/Phytase enzyme mix (10/1) 5
1.0
1.0
1.0
1.0
Water/NSP enzyme mix (10/1) 6
1.3
1.3
1.3
1.3
Dry matter
889.0
890.0
891.0
891.2
Crude protein (Nx6.25)
223.7
210.1
201.4
190.4
Fat
58.3
70.4
74.9
Fibre
38.9
38.6
38.4
AMEn (MJ/kg)
12.2
12.6
12.8
13.1
LYS
14.3
12.4
11.5
10.7
MET
6.9
5.8
us
29
5.5
5.1
MET+CYS
10.7
9.1
8.6
THR
9.6
8.5
8.1
7.6
Ca
10.3
9.5
9.0
8.5
4.9
4.5
4.3
4.0
1.6
1.6
1.6
1.6
879.0
889.0
882.0
882.0
Crude protein (Nx6.25)
219.5
208.0
197.0
187.4
Fat
61.8
77.7
81.5
73.6
35.0
35.4
34.7
34.6
LYS
13.9
10.8
11.8
10.5
MET
7.0
5.7
5.2
5.0
MET+CYS
10.9
8.5
8.6
8.4
THR
9.8
8.5
8.5
7.8
Ac
Analysed nutrients
Fibre
75.4 36.1
cr
an M
ed
Na
ce pt
Available P
Dry matter
9.5
ip t
Calculated nutrients
Page 29 of 35
30 Ca
10.4
9.6
8.9
8.6
P total
6.6
6.3
6.1
5.7
Na
1.7
1.6
1.5
1.6
637 638
†
639
of ground and whole seed wheat as indicated in Table 1.
640
1
641
manufactured by a fractionation technique.
642
2
643
46140 USA).
644
3
645
Greenfield, IN 46140 USA).
646
4
647
Zn, 3000 mg Cu, 15 000 mg Fe, 22 000 mg Mn, 400 mg I, 80 mg Se,
648
3 200 000 IU Vitamin A, Vitamin D 1 160 000 IU, 20 000 mg Vitamin E,
649
Vitamin K3 1000 mg, Vitamin B1 800 mg, Vitamin B2 2000 mg, Vitamin B6
650
1220 mg, Vitamin B12 10 mg, Vitamin B3 15 400 mg, Vitamin B5 4800 mg,
651
Folic acid 540 mg, Biotin 48 mg, Choline chloride 90 000 mg, Betaine 50 000
652
mg.
653
(DSM Nutritional Products Hungary Kft., H-2367-Újhartyán, Japán fasor, 4.)
654
5
655
Nutrition, PO Box 777, Marlborough, Wiltshire, SN8 1XN, United Kingdom).
656
6
657
1,3(4)-beta-glucanase 1520 U/g, Danisco Animal Nutrition, PO Box 777,
658
Marlborough, Wiltshire, SN8 1XN, United Kingdom).
ip t
Composition of diets of all treatments was the same except for the proportion
cr
The sunflower meal with low fibre and high protein content was
us
Monensin-sodium coccidiostat (Elanco, 2500 Innovation Way, Greenfield, IN
an
Narasin and Dicarbazin coccidiostat (Elanco, 2500 Innovation Way,
ce pt
ed
M
Premix composition (kg): 13% Ca, 5.4% Na, 2.3% Cl, 0.15% S, 22 000 mg
Ac
Phyzyme® XP 5000 L (Min. activity: 6-phytase 5000 FTU/g, Danisco Animal
Axtra™ XB 201 (Min. activity: endo-1,4-beta-xylanase 12 200 U/g, endo-
659 660 661 662
Page 30 of 35
31 663
Table 4.
664
Body weight (g) of chickens fed different amounts of whole
665
wheat seed in the diet (the number of animals in brackets) Age (days)
Treatments 11
18
28
40
Control1
49 (204)
369 (204)
818 (203)
1819 (202)
3020 (200)
Whole wheat seed A2
48 (204)
361 (204)
815 (201)
Whole wheat seed B3
48 (204)
365 (204)
814 (202)
Pooled SEM
0.27
2.40
5.6
Significance4
P>0.05
P>0.05
cr
2986 (195)
1782 (197)
2946 (194)
15.1
30.5
P>0.05
P>0.05
an
us
1804 (201)
P>0.05
M
666
ip t
0
1
control (without whole wheat seed); 20, 5,10 and15% 30, 5, 20 and
668
30% whole wheat seed in starter, grower I, grower II and finisher
669
diets, respectively 4Significance among averages in a column
ed
667
672
ments
Table 5. Feed conversion rate of chickens (kg feed/kg body weight gain) fed different amount of whole wheat seed in the diet
Ac
671
ce pt
670
Stages of growing (d)
0-11
12-18
19-28
29-40
0-40
1.13
1.39
1.54 b
2.01
1.61 b
wheat seed A 2
1.15
1.37
1.50 a
1.94
1.57 a
wheat seed B3
1.14
1.40
1.53 ab
2.04
1.60 b
0.01
0.01
0.01
0.05
0.01
l1
d SEM
Page 31 of 35
32 673
1
control (without whole wheat seed); 2 = 0,5,10,15% 3=0,5,20,30%
674
whole wheat seed in starter, grower I, grower II or finisher diets,
675
respectively
676
n = 6 (No. of pens containing chickens fed the same diets)
677
a,b,c
678
superscripts have significant differences (P<0.05)
ip t
= values in the same columns indicated with different
679 Table 6.
681
Carcass characteristics of chickens slaughtered at 40 days
682
of age (% of body weight)
an
us
cr
680
weight4
1
63.90
wheat seed A2
wheat seed B3 SEM
685 686 687
Gizzard weight
18.99
0.69
21.96
19.24
1.01 1.12
63.67
20.98
19.31
0.57
0.55
0.35
Abdominal fat
a
2.00
b
1.82
c
1.70
0.04
0.53
Ac
684
Thighs
21.49
ce pt
64.48
Breast fillet
ed
Carcass
ents
M
683
1
control (without whole wheat seed); 20. 5. 10 and 15%. 30. 5. 20
and 30% whole wheat seed in starter. grower I. grower II and finisher diets, respectively 4carcass weight=body weight after killing
688
without feathers, head, legs and viscera
689
n = 6 male and 6 female chickens
690
a.b.c
691
columns are significantly different (P<0.05)
values marked with different superscripts within the same
692
Page 32 of 35
33 693
Table 7.
694
Histological structure of small intestine (ileum) of chickens
695
slaughtered at 40 days of age
ip t
696 Thickness of
crypt depth
muscularis
ratio
mucosae (µm)
6.08
134.03
137.45
6.05
130.31
130.76
6.38
122.98
7.16
7.00
0.43
7.17
P>0.05
P>0.05
P>0.05
P>0.05
Villus apical
Crypt depth
(µm)
width (µm)
width (µm)
(µm)
821.53
171.98
138.83
139.36
eed A2
797.86
165.52
121.13
eed B3
824.95
170.16
137.59
42.85
8.34
P>0.05
P>0.05
an
M
ed
697
cr
Villus basal
us
Villus height to
Villus height
1
699
and 30% whole wheat seed in starter. grower I. grower II and
700
finisher diets, respectively 4Significance among averages in a
701
column
702
n = 6 male and 6 female chickens
704 705
Ac
703
control (without whole wheat seed); 20. 5. 10 and 15%. 30. 5. 20
ce pt
698
Table 8.
Enzyme activities, protein content and viscosity values of
706
small intestinal contents collected from chickens slaughtered
707
at 40 days of age
708
Page 33 of 35
34 Enzyme activities
Protein
mU/mg protein
ments
concentration
Viscosity (mPa·s)
Lipase
Trypsin
(mg/g digesta)
l1
8.1a
19.02a
21.98a
16.85
3.68
wheat seed A2
9.0b
20.19b
22.80b
17.10
3.92
wheat seed B3
10.4c
21.16c
23.51c
0.10
0.19
0.24
1
711
and 30% whole wheat seed in starter, grower I, grower II and
712
finisher diets, respectively
713
n = 6 male and 6 female chickens
714
a,b,c
715
columns are significantly different (P<0.05)
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values marked with different superscripts within the same
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717
721
0.47
control (without whole wheat seed); 20, 5, 10 and 15%, 30, 5, 20
716
720
0.67
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710
719
3.44
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718
15.76
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d SEM
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α-Amylase
723 724 725 726 727
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S0377-8401(15)30030-4 http://dx.doi.org/doi:10.1016/j.anifeedsci.2015.09.021 ANIFEE 13384
To appear in:
Animal
Received date: Revised date: Accepted date:
2-4-2015 24-7-2015 22-9-2015
Feed
Science
and
Technology
´ Please cite this article as: Husv´eth, F., P´al, L., Galamb, E., Acs, K.C., Bustyah´azai, L., W´agner, L., Dublecz, F., Dublecz, K.,Effects of whole wheat incorporated into pelleted diets on the growth performance and intestinal function of broiler chickens, Animal Feed Science and Technology (2015), http://dx.doi.org/10.1016/j.anifeedsci.2015.09.021 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1
Effects of whole wheat incorporated into pelleted diets on the
2
growth performance and intestinal function of broiler chickens
3 a,*
a
b
b
F. Husvéth , L. Pál , E. Galamb , K. C. Ácsb, L. Bustyaházai ,
5
L. Wágner , F. Dublecz , K. Dublecz
a
a
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Department of Animal Science, Georgikon Faculty, Pannon
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UBM Feed Ltd., Fő u. 130, H-2085 Pilisvörösvár, Hungary
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9
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University, Deák F. u. 16, H-8360 Keszthely, Hungary
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Highlights
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Whole wheat in the diet may improve feed conversion efficiency
18
19
Ac
in broiler chickens.
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Upper part of digestive tract is stimulated by whole wheat increasing gizzard weight.
20 21
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This stimuli result in higher activities of pancreatic enzymes in the small intestine.
23 24
*
Corresponding author. Tel.: +36 30 9365 862; fax: +36 83 545 143 E-mail address: [email protected]
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Intestinal viscosity and histological properties of small intestine is not influenced.
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Whole wheat inclusion in the diet decreases feeding costs by reducing grinding.
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Abstract
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An experiment was carried out to study the effect of postpelleting
41
dietary inclusion of whole wheat at the expense of ground wheat in
42
different
43
characteristics of broiler chickens. In the starter phase all chickens
44
were fed the same corn–wheat based diet without whole grain. At 11
45
days of age chickens were allotted into three groups and fed the
46
following diets containing different percentages of whole wheat in the
47
growing and finishing periods. Control: without whole wheat grain;
48
treatment A: 5, 10 and 15% whole wheat in growing I (12–18 d),
49
growing II (19–28 d) and finishing (29–40 d of age) periods,
50
respectively; treatment B: 5, 20 and 30% whole wheat, respectively, in
51
the same phases as for treatment A. Body weight and feed
52
consumption of chickens were measured during the experiment. At 40
53
d of age a total of 12 chickens (6 female and 6 male) were slaughtered
54
from each treatment group and dissected to measure the carcass,
55
breast fillet, thigh, abdominal fat and gizzard weights, respectively.
56
Small intestinal content was analysed for trypsin, α-amylase and lipase
57
activities and viscosity. Histological examination of the jejunum was
58
performed to determine the size and density of villi and crypts in the
59
mucosa.
on
the
performance
and
gastrointestinal
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proportions
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Only slight differences were shown between the treatments in
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the weight gain of the chickens. At 40 d of age female chickens fed
62
higher proportion of whole wheat (treatment B) had lower body weight
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4
than those fed the control diet without whole wheat (P<0.05). However,
64
no differences were found in the body weight of male chickens between
65
the treatments at the end of the experiment. Chickens fed the diet
66
containing lower percentages of whole wheat (treatment A) showed
67
significantly better feed conversion ratio than chickens both in the
68
control group and the group fed a higher level of whole wheat
69
(treatment B) both in the whole experimental period and in growing
70
phase II (19–24 d). No significant differences were found between the
71
treatment groups in carcass weight, breast fillet, thigh and abdominal
72
weights. Compared to the control, chickens fed diets containing whole
73
wheat increased gizzard weight by 46.2 and 62.2%, respectively,
74
depending on the inclusion levels of whole wheat. Relative to the
75
control group, higher trypsin, α-amylase or lipase activities were
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detected in the small intestinal contents of chickens fed both lower and
77
higher levels of whole wheat (P<0.05), but no differences were shown
78
in the viscosity of the intestinal contents between dietary treatments.
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Whole wheat feeding did not have any significant effects on the
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parameters measured and on the histological structure of the small
81
intestine.
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As the results indicate, whole wheat supplementation of the
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pelleted diet of broiler chickens may have advantageous effects on
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broiler chicken production by increasing the efficiency of digestion. This
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proves that some costs of grinding can be spared without any harmful
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effects on performance.
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Keywords: Whole wheat; Broiler chicken; Performance; Digestive
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physiology
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1. Introduction
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As evidenced from several scientific publications, there is a steadily
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growing interest in the feeding of whole wheat with different poultry
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species, including broiler chcikens. This interest has primarily been
98
fuelled by the possibility to save wheat grinding costs and to improve
99
gizzard function and the efficiency of digestion. Feeding of whole wheat
100
helps the chicken to develop a bigger and stronger gizzard, which has
101
a beneficial effect on the function of the entire digestive tract. The
102
gizzard is a dynamic organ with a size closely correlated with the fibre
103
content and particle size of the ration (Svihus, 2011). The increase of
104
gizzard size results from the increased frequency and strength of
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gizzard contractions aimed at appropriately reducing the size of feed
106
particles when whole wheat is fed (Roche, 1981). Ross 208 broiler
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chickens fed whole wheat grains at an inclusion level of 5 to 50% were
108
found to have significantly larger gizzards expressed in relation to their
109
body size (Engberg et al., 2004). When fed at inclusion levels up to
110
20% or 30% of the ration, whole wheat did not decrease the body
111
weight gain of chickens significantly as compared to the control, while it
112
improved the feed conversion ratio.
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According to the research results reported so far, the feeding of
114
whole wheat has ambiguous effects on the development and function
115
of the different digestive tract segments too (Jones and Taylor, 2001;
116
Wu and Ravindran, 2004; Amerah and Ravindran, 2008). According to
117
some reports, the feeding of whole wheat resulted in a decrease of the
118
relative size of digestive tract segments. When feeding whole wheat
119
grains, Taylor and Jones (2004) observed a 16% decrease in the
120
relative size of the duodenum while the relative size of the jejunum did
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not change. In broilers fed a ration containing 200 g/kg whole wheat
122
grains, Wu et al. (2004) did not find any difference in the height of the
123
intestinal villi, the depth of the mucosal glands (crypts of Lieberkühn)
124
and the number of mucus-producing glandular cells (goblet cells) in the
125
ileum. On the other hand, Gabriel et al. (2008) observed increased
126
villus to crypt ratio and surface area in the duodenum of broiler
127
chickens fed whole wheat, due to the decrease in crypt depth. Based
128
upon these findings, the authors suggest that the morphological
129
changes occurring in the small intestine of broiler chickens fed whole
130
wheat result in an improved efficiency of digestion and absorption.
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Supporting the assumption of the above-cited researchers, Engberg et
132
al. (2004) reported that, up to an inclusion level of 300 g/kg in the diet,
133
the feeding of whole wheat increased the relative weight of not only the
134
gizzard but also of the pancreas in broiler chickens. The increased
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efficiency of digestion significantly increases the metabolisable energy
136
(MEn) content of the feed, presumably due to the higher digestibility of
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nutrients including amino acids (Biggs and Parsons, 2009).
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The efficiency of digestion in the small intestine is markedly
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influenced by the viscosity of digesta. Only few data are available on
140
the effect of feeding whole wheat grains on the viscosity of the
141
intestinal content. Feed mixtures formulated with ground wheat were
142
found to increase the viscosity of digesta as compared to feeds
143
containing whole wheat (Yasar, 2003). In contrast, Engberg et al.
144
(2004) found that the feeding of whole wheat increased the viscosity in
145
ileal contents as compared with pellet-fed birds.
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There are few and contradictory data in the literature on the effect of
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whole wheat feeding on the digestion of nutrients in the digestive tract.
148
In the trials conducted by Engberg et al. (2004) with broiler chickens,
149
the feeding of whole wheat did not exert a significant influence on
150
chymotrypsin, trypsin and lipase activities measured in the pancreatic
151
tissue, but caused a close-to-significant decrease (P=0.054) in the
152
activity of amylase.
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As can be seen from the foregoing, the feeding of whole wheat has
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numerous beneficial effects in broiler chicken nutrition. It is also
155
evident, however, that the relevant reports are often contradictory and
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there are hardly any published results on certain physiological and
157
nutritional issues. Therefore, our aim was to conduct an experiment to
158
study the effect of whole wheat incorporated into pelleted diets on the
159
growth performance of broilers as well as on the morphology and
160
functions of the digestive system. During these trials, we studied the
161
effect of whole wheat added to grower and finisher diets of different
162
phases at varying inclusion levels on the body weight and feed
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conversion efficiency of broiler chickens, the weight of the gizzard, the
164
activities of digestive enzyme in the small intestine, the viscosity of
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digesta and the histiological structure of the intestine. The influence of
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feeding whole wheat on the digestibility of certain nutrients and on
167
caecal function will be reported in a forthcoming paper.
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2. Materials and methods
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The protocol of the animal experiment was approved by the Food
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Chain Safety and Animal Health Directorate of the Government Office
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of Zala County (permission number: ZAI/100/1479-003/2014).
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2.1. Experimental birds and their keeping conditions The trial included a total of 624 Ross 308 day-old broiler chicks,
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which were sexed and vaccinated against Newcastle Disease,
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Infectious Bronchitis and Infectious Bursal Disease in the “Levente
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Telep hatchery I” of Gallus Poultry Breeding and Hatcheries Ltd. of
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Devecser before transportation to the experimental farm of our
181
Department. The day-old chicks were housed in a closed room, where
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the optimal environmental conditions were provided by an automatic,
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computer-controlled system. The room contained 2 × 1 m pens with 1.7
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m2 useful ground-space (after deducting the area occupied by the
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feeders and drinkers). The pens were bedded with chopped wheat
186
straw as deep litter. Seventeen female and 17 male day-old chicks (a
187
total of 34 chicks per pen) were placed in each pen, where they were
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raised together up to 40 days of age. The chicks were fed from self-
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feeders and drinking water was provided from automatic drinkers ad
190
libitum. Temperature, lighting and other environmental conditions of the
191
room were controlled according to the specifications of the Ross Broiler
192
Management Manual (Aviagen Broiler Breeders, 2009). From week 2
193
till week 5 the chicks received a selenium supplementation (Reaszelén
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Combi, Pharmotéka Bt.; 0.25 g/kg body weight) via the drinking water
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once a week.
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2.2. Feeding and experimental treatments
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In the 40-day trial period the following phases were used: days 0–11:
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starter diet, days 12–18: grower I diet, days 19–28: grower II diet, days
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29–40: finisher diet. Starter diets were fed in mash form, grower and
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finisher diets as pellets. From day 0 to day 10, all the experimental
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chicks received a starter feed of identical composition, without whole
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wheat. Starting from the grower phase, three experimental treatments
204
were established, by adding to the diet different amounts of whole
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wheat seeds at the expense of ground wheat, at the following ratios.
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Control: the diets did not contain whole wheat in any of the phases. In
207
the case of treatment „A‟ the inclusion levels of whole wheat seeds
208
were 5% in the grower I diet, 10% in the grower II diet, and 15% in the
209
finisher diet. The whole wheat contents of diets treatment „B‟ were 5%
210
in the grower I diet, 20% in the grower II diet and 30% in the finisher
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diet. The experimental diets were pelleted and then the whole wheat
212
seeds were mixed to them. During mixing a liquid enzyme mix
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(Phyzyme®: phytase; Axtra™: xylanase + glucanase, Table 2) was
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sprayed onto the surface of the pellets and the whole wheat seeds. The
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diameter of the pellets was 3 mm in all phases while their length varied
216
between 3 and 5 mm depending on the phase of rearing. The specific
217
gravity of the pellet prepared in this way was nearly identical with that
218
of the whole wheat seeds, which markedly reduced the possibility of
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segregation of the two constituents through sedimentation. The
220
composition and the nutrient content of the diets by treatment and
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growing phase are presented in Tables 1 and 2.
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The diets described above were fed to chicks of six pens per
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treatment. Accordingly, the diet of every treatment was fed to a total of
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204 (102 female and 102 male) chicks.
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2.3. Collection of data and samples
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The health status of the chickens was monitored regularly
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throughout the trial period. In the morning, the dead birds, if any, were
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collected, weighed and the cause of death was determined. On days 1,
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11, 18, 28 and 40 of life chickens were weighed individually. At the time
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of the first three weighings, the female and male chicks could not be
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distinguished phenotypically with high accuracy; therefore, the results
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obtained at those time-points were given for as the average weight of
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mixed sex. At the same time, on day 40 the pullets and cockerels could
235
be distinguished reliably and, therefore, the weighing results were given
236
separately for the two sexes. Simultaneously with the body weight
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measurements, feed consumption on pen level (n = 6) was also
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measured and feed conversion ratio was calculated. After the weighing on day 40, one female and one male chick per
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pen (a total of 6 female and 6 male birds per treatment) were randomly
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selected and exsanguinated after stunning with CO 2. After removing
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the feathers, the carcass weight (without head, legs and viscerals) as
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well as the weight of the breast fillet, the thigh and the abdominal fat
244
were determined by weighing with gram precision, and expressed as a
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percentage of the liveweight.
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The digestive tract was excised from the carcasses, and then the
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gizzard was separated and weighed. An about 5-cm-long segment was
248
excised from the proximal part of the jejunum and the digesta were
249
removed from it and collected in a 2-ml plastic test tube to determine
250
the activities of digestive enzymes. The digesta samples were stored in
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a deep freezer at –70 °C temperature until the laboratory analyses.
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From the part of the jejunum distal to Meckel‟s diverticulum, an
253
approximately 3 cm long segment was excised. In order to remove the
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digesta, the excised intestinal segments were washed in physiological
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phosphate-buffered saline, then they were placed, one by one, into
256
approximately 20 ml of 5% formaldehyde solution precooled to 10 °C,
257
and were then stored at that temperature until used for histological
258
examination.
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In order to measure the viscosity of the digesta, an about 10 cm long
260
segment was excised from the ileum at a site proximal to the ileocaecal
261
junction, and the digesta present in that segment were collected in a 2-
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ml plastics test tube. The ileal digesta samples were stored in a deep
263
freezer at –70 °C temperature until the viscosity measurements.
264 265
2.4. Laboratory analyses Feed analysis. The experimental diets were analysed for moisture
267
(ISO, 1999b), crude fiber (ISO, 2000), crude protein (ISO, 2005a),
268
crude fat (ISO, 1999b), phosphorus (ISO, 1998), calcium and sodium
269
(ISO, 2001) contents and amino acid composition (ISO, 2005b) using
270
methods of International Organisation for Standardization (ISO).
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Enzyme activity determinations. The activity of α-amylase was
272
determined as described by Dahlqvist (1962), while lipase activity was
273
measured by the method elaborated by Schön et al. (1961).Trypsin
274
activity was measured by a Boehringer test as described by Kakade et
275
al. (1969).
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Measurement of the viscosity of digesta. To measure the viscosity of
277
ileal digesta, 2 g of digesta were frozen and stored at –80 °C. After
278
defrosted the samples were centrifuged (with 12,000 g for 10 min), and
279
the viscosity of the supernatant (0.5 ml) was measured using a
280
Brookfield DV II+ viscometer (Brookfield Engineering Laboratories,
281
Stoughton, MA, USA) at 25 °C with a CP40 cone and shear rate of 60–
282
600s–1.
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Histological examination of the intestine. Histological analysis of the
284
small intestinal segment was performed at the Histology Laboratory of
285
the Clinical Unit for Poultry Medicine of the University of Veterinary
286
Medicine Vienna. The samples were taken from an ileal segment close
Page 12 of 35
13
to Meckel‟s diverticulum, and fixed in 5% formalin solution until starting
288
the preparatory operations. During the preparation of samples, serial
289
water extraction and purification steps were performed, and the
290
samples were subsequently embedded in paraffin. The samples (12
291
chicks per treatment, 6 female and 6 male birds) were cut into 5 m
292
thick sections with a microtome, and fixed on slides. Two slides were
293
prepared from all samples. The slides were stained with haematoxylin
294
and eosin, then examined with a digital video camera (Olympus DP-26)
295
and an Olympus BX43F light microscope fitted up with an Olympus
296
Stream Start software. The images were analysed with the help of the
297
„Image J‟ software (Version 1.47) developed by the National Institutes
298
of Health (Maryland, USA). From the two sections fixed on slides from
299
each sample, the intact villus–crypt segments were selected and were
300
used for histological analysis. This analysis involved the calculation of
301
the villus length, the crypt depth, the basal and apical width of the
302
intestinal villus, the width of the muscle layer and the calculation of the
303
villus to crypt ratio (Molnar et al., 2015).
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2.5. Statistical analysis
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The results of the experiment were evaluated by one-way analysis of
307
variance (ANOVA). To determine statistically significant differences
308
caused by the dietary treatments (F-test; P<0.05), Tuky‟s test was
309
used. The calculations were made using the IBM SPSS Statistics 20.0
310
GL Model Univariate Test statistical programme package.
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14 312 313
3. Results
314 315
3.1. Mortality No animal health problems different from those observed usually
317
were found in the course of the trial. During the trial period a total of 23
318
chickens (3.2% of the flock) died. There was no connection between
319
the distribution of deaths and the experimental treatments. The causes
320
of death were sudden death syndrome in 16 cases, ascites in 4 cases,
321
leg disorders in 1 case and an unknown reason in 2 cases.
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3.2. Performance
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The average values of the body weights are presented in Table 3.
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There were no major differences in the body weight of chickens fed
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diets containing different levels of whole wheat. A significant difference
327
in body weight was found only once, at day 40, when pullets fed diet „B‟
328
had lower average weight than control chicks. No significant difference
329
in the body weight of the cockerels of the different treatment groups
330
was found throughout the trial.
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However, significant differences were found in the feed conversion
332
ratio of the chicks (Table 4). During the whole experimental period
333
(days 0 to 40) the chickens fed diet „A‟ containing a lower level of whole
334
wheat used less (P<0.05) feed for 1 kg liveweight gain, as calculated
335
for the entire trial period (40 days), than the control chickens or the
336
chickens fed diet „B‟ containing a higher level of whole wheat seeds.
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The beneficial effect of using a lower inclusion level of whole wheat on
338
the body weight gain was apparent also in the growing phase between
339
19 and 28 days of age. Namely, during that period the chickens fed the
340
diet containing 10% whole wheat seeds consumed less (P<0.05) feed
341
for 1 kg liveweight gain than the control chickens.
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3.3. Carcass parameters
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No significant differences were found between the treatments in the
345
carcass weight of chickens slaughtered at the end of the trial, on day
346
40 of life, in the ratios of the valuable meat parts (breast fillet and thigh)
347
and in the amount of abdominal fat expressed in percentage of the
348
body weight.
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At the same time, the weight of the gizzard increased significantly as
350
a result of whole wheat seed supplementation. The highest gizzard
351
weights were found in chickens fed a higher level of whole wheat seeds
352
(diet „B‟) (Fig. 1). The gizzard weight of chickens of this treatment group
353
was 62.2% higher than that of the control chickens not receiving whole
354
wheat seed supplementation. The gizzard weight of chickens fed diet
355
„A‟ containing a lower level of whole wheat exceeded that of the control
356
by 46.4% (P<0.05).
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3.4. Histological structure of the small intestine
359
No significant differences associated with the dietary treatments
360
were found in the microscopically measured values characterising the
361
histological status of the small intestine. In none of the dietary
Page 15 of 35
16 362
treatments did the feeding of whole wheat exert a notable effect on the
363
length and width of villi of the intestinal mucosa, on the depth of the
364
crypts of Lieberkühn and on the thickness of the smooth muscle layer
365
of the mucosa (P>0.05).
367
3.5. Enzyme activities and viscosity of the small intestinal digesta
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In chyme samples collected from the proximal segment of the
369
jejunum, the measured activity values of pancreatic enzymes (α-
370
amylase, lipase and trypsin) were consistently higher (P<0.05) in
371
chickens fed the diets supplemented with whole wheat (diets „A‟ and
372
„B‟) than in the control chickens (Table 5). For all three enzymes, the
373
highest activities were measured in chickens fed the diet containing
374
higher levels of whole wheat (diet „B‟); however, all three enzymes had
375
higher activities in the digesta of chickens fed a diet with a lower
376
inclusion level of whole wheat (diet „A‟) than in the digesta of the control
377
chickens. In contrast to these changes in the activity of digestive
378
enzymes, in the viscosity of the ileal digesta no differences were found
379
between the different treatments (Table 5).
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4. Discussion
383 384
Jones and Taylor (2001) found that in chickens fed whole wheat
385
grains mixed to a pelleted diet the incidence of proventricular dilatation
386
and mortality due to ascites decreased. In this trial, we could not
Page 16 of 35
17
demonstrate a similar phenomenon in chickens fed whole wheat. The
388
rate of mortality due to ascites was low and was not connection with the
389
dietary treatments. In our study, the most common cause of mortality
390
was sudden death syndrome. In fast-growing broilers, this syndrome
391
has been proven to account for a substantial proportion of deaths
392
(Siddiqui et al., 2009). In the present trial, the growth rate of broilers
393
was outstandingly high, exceeding even the average growth rates
394
specified in the Ross Broiler Management Manual (Aviagen Broiler
395
Breeders, 2009). This fact may explain the rather common occurrence
396
of sudden death syndrome as a cause of death in our trial.
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387
In this trial the only significant difference in the body weights of
398
chickens were found at day 40 between the female birds of the control
399
and treatment “B” groups. Several research studies have demonstrated
400
that whole wheat added to mash or pelleted diets at an inclusion rate of
401
5–30% exerted no (Jones and Taylor, 2001; Svihus et al., 2010) or only
402
marginal effect (Engberg et al., 2004) on the weight gain of broiler
403
chickens. At the same time, a higher inclusion level of whole wheat
404
grains may decrease the growth rate of chickens, depending on their
405
age (Biggs and Parsons, 2009). In our trial, the body weight gain of
406
chickens substantially exceeded the values found in the above-cited
407
studies. In sipite of such high growth rate did we did not find significant
408
decrease in the body weight gain of cockerels during the 40-day trial. At
409
the same time, when the inclusion level of whole wheat in the pelleted
410
diet was raised to 30% between days 28 and 40, the average weight of
411
the pullets at the end of the trial was slightly (by 86 g, 3.1%) but
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significantly lower than that of the controls. Although the difference
413
between the two sexes in the above-mentioned period is difficult to
414
explain, the results suggest that female chickens react to a higher
415
inclusion level of whole wheat seeds in the diet more sensitively than
416
cockerels, and this is reflected in the body weight gain.
ip t
412
When comparing as hatched birds (17 male and 17 female,
418
respectively in a pen), the chickens fed pelleted diets containing lower
419
levels of whole wheat, showed significantly better feed conversion ratio
420
throughout the trial (from day 0 to day 40) than did the controls. This
421
favourable effect manifested itself mainly in growing phase II, when the
422
weight of the chickens changed between 800 and 1800 g. In
423
accordance with our findings, Biggs and Parsons (2009) found no
424
change in feed conversion efficiency in 8–21 days old broilers fed diets
425
containing 20% whole wheat. However, the feeding of 35% whole grain
426
resulted in a significantly poorer feed conversion in their experiment. In
427
a growing period similar to growing phase II used in our trial, i.e.
428
between days 16 and 25 of age, Svihus et al. (2010) found a
429
significantly better feed conversion ratio in broiler chickens fed 150 g
430
whole wheat added to every kg of the diet, even if no differences were
431
obtained in the body weight gain. They attributed the more efficient
432
feed conversion obtained to higher AMEn value and improved starch
433
digestibility for diets supplemented with whole wheat.
Ac
ce pt
ed
M
an
us
cr
417
434
Our results show that the feeding of whole wheat at a lower inclusion
435
levels of whole wheat (diet „A‟) resulted in a more favourable feed
436
conversion ratio than the diet not containing whole wheat (control diet)
Page 18 of 35
19
or the diet containing whole wheat at higher levels (diet „B‟). This
438
improvement of feed conversion was presumably due to the better
439
intestinal function. Raising the inclusion level of whole wheat resulted in
440
a marked increase in gizzard size. Several research studies of similar
441
nature have demonstrated that the increase of feed particle size,
442
including the feeding of whole grains, substantially increases the size of
443
the gizzard relative to body size as well as gizzard acidity (Svihus,
444
2011). Improved gizzard function in chickens fed diets supplemented
445
with whole wheat results in a more efficient grinding of feed in the
446
gizzard. As a consequence, a chyme of smaller particle size will be
447
propelled into the small intestine (Hetland et al., 2002), which may have
448
a favourable effect on enzymatic digestion taking place in that part of
449
the gut (Amerah et al., 2009). This hypothesis is supported by our own
450
measurement results of α-amylase, trypsin and lipase activity in the
451
small intestinal content. As a result of feeding whole wheat, the
452
activities of all three enzymes were higher in the content of small
453
intestine of chickens fed a diet containing whole wheat than in chickens
454
receiving a diet without whole grain. The mechanism behind the
455
increase in enzyme secretion could be the stimuli of vagus nerve and
456
cholecystokinin by increased gizzard activity (Svihus, 2011). The
457
enzyme activities found in this experiment in the chickens fed whole
458
wheat are supported by the findings of Gabriel et al. (2008), who
459
observed a 12% increase in pancreas weight in chickens fed a diet
460
supplemented with whole wheat. Biggs and Parsons (2009) reported an
461
improvement in amino acid digestibility in chickens fed diets containing
Ac
ce pt
ed
M
an
us
cr
ip t
437
Page 19 of 35
20
10–20% whole wheat, whereas Svihus et al. (2010) observed higher
463
starch digestibility in broiler chickens fed 15% whole wheat. At the
464
same time, Engberg et al. (2004) found that amylase activity decreased
465
in the pancreatic tissue of chickens fed whole wheat grains. However, if
466
besides whole wheat a fibrolytic enzyme (xylanase) was also added to
467
the diet, the activities of chymotrypsin and lipase increased in the
468
pancreatic tissue. This latter finding proves that the feeding of whole
469
wheat has a favourable effect on digestion also when used concurrently
470
with NSP degrading enzymes. In our experiment, all diets contained
471
NSP degrading enzymes. When feeding whole wheat at higher
472
inclusion levels (20–30%), we did not find a better feed conversion
473
despite the bigger gizzard and the higher digestive enzyme activities
474
measured in the digesta. These results suggest that the benefits of
475
feeding whole wheat to broiler chickens are influenced by their
476
inclusion rate in the diets. When fed in quantities exceeding a certain
477
level, whole wheat may induce adverse effects in intensively growing
478
broiler chickens, in addition to its favourable influence exerted on
479
digestion as studied and demonstrated in this trial.
ce pt
ed
M
an
us
cr
ip t
462
The lower average weight measured on day 40 in the case of
481
chickens fed a higher level of whole wheat seeds (diet „B‟) as compared
482
to the control, and the poorer feed conversion obtained for the entire
483
trial period in comparison with chickens fed a lower level of whole
484
wheat (diet „A‟) cannot be explained either by the histological
485
parameters of the intestine determined by us or by the differences in
486
the viscosity of digesta. No differences were found between the dietary
Ac
480
Page 20 of 35
21
treatments either in the viscosity of digesta or in the parameters
488
measured in order to characterise the tissue structure of the gut (size of
489
intestinal villi, depth of the crypts of Lieberkühn, thickness of the muscle
490
layer of the mucosa). Our results regarding the viscosity of digesta are
491
consistent with the findings reported by Svihus and Hetland (2001) as
492
well as Engberg et al. (2004). In the studies of Engberg et al. (2004),
493
the viscosity of digesta of chickens fed whole wheat was higher than
494
that of birds reared on a pelleted diet without whole wheat. These
495
differences,
496
supplementation
497
examinations support the results reported by Wu et al. (2004), who did
498
not find differences in the above-mentioned intestinal parameters in
499
chickens fed whole wheat added to the diet at a rate of 200 g/kg. In
500
contrast, Gabriel et al. (2008) reported that 20-40% whole wheat
501
supplementation resulted in increased duodenal villus to crypt length
502
and surface due to lower crypt depth and smaller crypt area in broiler
503
chickens.
506 507
given.
The
when findings
xylanase of
our
enzyme
histological
ce pt
ed
M
an
was
disappeared
Ac
504 505
however,
us
cr
ip t
487
5. Conclusion
508
Whole wheat added to the diet using appropriate techniques do not
509
markedly affect the performance of intensively reared broiler chickens.
510
In fact, when fed at lower levels (up to 15% in the grower and up to
511
20% in the finisher phase), whole wheat improves feed conversion
Page 21 of 35
22
efficiency, presumably through its favourable influence exerted on the
513
upper part of the digestive tract and the activities of pancreatic
514
enzymes in the small intestine. Although whole wheat grains fed at an
515
inclusion level of 30% may adversely affect growth performance,
516
however, do not cause unfavourable changes in carcass composition
517
or small intestinal tissue structure. According to our results female
518
chicks are more sensitive to the ratio of whole wheat than cockerels. By
519
feeding wheat as whole wheat grains the grinding costs can be reduced
520
markedly, which has a favourable effect on the overall feed costs. The
521
upper limit of the inclusion level of whole wheat grains in the diet shall
522
be determined by carefully weighing the feed cost reduction resulting
523
from the omission of wheat grinding against the potentially lower growth
524
performance obtained at higher inclusion levels of whole wheat.
525
ed
M
an
us
cr
ip t
512
Acknowledgements
527
Authors would like to thank UBM Feed Ltd. for financial support of the
528
experiments, and A. Szekely for cheking the English in the paper.
Ac
529
ce pt
526
Page 22 of 35
23 530
References
531
Amerah, A.M., Ravindran, V., 2008. Influence of method of whole-
533
wheat feeding on the performance, digestive tract development and
534
carcass traits of broiler chickens. Anim. Feed Sci. Technol. 147,
535
326–339.
ip t
532
Amerah, A.M., Ravindran, V., Lentle, R.G., 2009. Influence of wheat
537
hardness and xylanase supplementation on the performance, energy
538
utilization, digestive tract development and digesta parameters of
539
broiler starters. Anim. Prod. Sci. 49, 71–78.
us
an
541
Aviagen Broiler Breeders, 2009. Ross Broiler Management Manual, Aviagen Group, Midlothian, pp. 1–114.
M
540
cr
536
Biggs, P., Parsons, C.M., 2009. The effects of whole grains on nutrient
543
digestibilities, growth performance, and cecal short-chain fatty acid
544
concentrations in young chicks fed ground corn-soybean meal diets.
545
Poult. Sci. 88, 1893-1905.
547
ce pt
546
ed
542
Dahlqvist, A., 1962. A method for the determination of amylase in intestinal content. Scand. J. Clin. Lab. Invest. 14, 145–151. Engberg, R.M., Hedemann, M.S., Steenfeldt, S., Jensen, B.B., 2004.
549
Influence of whole wheat and xylanase on broiler performance and
550
microbial composition and activity in the digestive tract. Poult. Sci.
551
83, 925–938.
Ac
548
552
Gabriel, I., Mallet, S., Leconte, M., Travel. A., Lalles, J.P., 2008. Effect
553
of whole wheat feeding on the development of the digestive tract of
554
broiler chickens. Anim. Feed Sci. Technol. 142, 144–162.
Page 23 of 35
24 555
Hetland, H., Svihus, B., Olaisen, V., 2002. Effect of feeding whole
556
cereals on performance, starch digestibility and duodenal particle
557
size distribution in broiler chickens. Br. Poultr. Sci. 43, 416–423. ISO. 1998. Animal feeding stuffs. Determination of phosphorus content.
559
Spectrometric method (ISO 6491). International Organization for
560
Standardization, Geneva, Switzerland.
ip t
558
ISO. 1999a. Animal feeding stuffs. Determination of moisture and other
562
volatile matter content (ISO 6496). International Organization for
563
Standardization, Geneva, Switzerland.
us
cr
561
ISO. 1999b. Animal feeding stuffs. Determination of fat content (ISO
565
6492). International Organization for Standardization, Geneva,
566
Switzerland.
M
567
an
564
ISO. 2000. Animal feeding stuffs. Determination of crude fibre content. Method
with
intermediate
filtration
569
Organization for Standardization, Geneva, Switzerland.
ed
568
(ISO
6865).
International
ISO. 2001. Animal feeding stuffs. Determination of the contents of
571
calcium, copper, iron, magnesium, manganese, potassium, sodium
572
and zinc. Method using atomic absorption spectrometry (ISO 6896).
573
International Organization for Standardization, Geneva, Switzerland.
Ac
ce pt
570
574
ISO. 2005a. Animal feeding stuffs. Determination of nitrogen content
575
and calculation of crude protein content. Part 1: Kjeldahl method
576
(ISO
577
Geneva, Switzerland.
5983-1).
International
Organization
for
Standardization,
Page 24 of 35
25 578
ISO. 2005b. Animal feeding stuffs. Determination of amino acid content
579
(ISO 13903). International Organization for Standardization, Geneva,
580
Switzerland. Jones, G.P.D., Taylor, R.D., 2001. The incorporation of whole grain into
582
pelleted
broiler
chicken
diets:
production
583
responses. Br. Poult. Sci. 42, 477–483.
and
physiological
ip t
581
Kakade, M.L., Simons, N., Liener, I.E., 1969. An evolution of natural vs.
585
synthetic substrate for measuring the antitryptic activity of soybean
586
samples. Cereal Chem. 46, 518–526.
us
cr
584
Molnar, A. Hess C., Pál L., Wágner L., Husvéth F., Hess M., Dublecz K.
588
2015. Composition of diet modifies colonization of dynamics of
589
Campylobacter jejuni in broiler chickens. J. Appl. Microbiology 118,
590
245-254.
593
M
ed
592
Roche, M., 1981. Feeding behavior and digestive motility of birds. Reprod. Nutr. Dev. 21, 781–788.
Schön, H.B., Rassler, B., Henning, N., 1961. Über die Untersuchung
ce pt
591
an
587
594
der
595
Aktivitätsbestimmungen
596
Carboxipeptidase. Klin. Wschr. 39, 217–222.
598 599 600
Pankreasfunktion. von
Trypsin,
Methoden
zur
Chymotrypsin,
Ac
597
exkretorischen
Siddiqui, M.F.M.F., Patil, M.S., Khan, K.M., Khan, L.A., 2009. Sudden death syndrome – An overview. Veterinary World 2, 444–447. Svihus, B., 2011. The gizzard: function, influence of diet structure and effects on nutrient availability. World‟s Poult. Sci. J. 67, 207–224.
601
Svihus, B., Hetland H., 2001. Ileal starch digestibility in growing broiler
602
chickens fed on a wheat-based diet is improved by mash feeding,
Page 25 of 35
26 603
dilution with cellulose or whole wheat inclusion. Br. Poult. Sci. 42,
604
633–637. Svihus, B., Sacranie, A, Denstadli, V., Choct, M., 2010. Nutrient
606
utilization and functionality of the anterior digestive tract caused by
607
intermittent feeding and inclusion of whole wheat in diets for broiler
608
chickens. Poult Sci. 89, 2617–2625.
ip t
605
Taylor, R.D. and Jones, G.P.D., 2004. The incorporation of whole grain
610
into pelleted broiler chicken diets. II. Gastrointestinal and digesta
611
characteristics. Br. Poult. Sci. 45, 237–246.
us
cr
609
Wu, Y.B., Ravindran, V., 2004. Influence of whole wheat inclusion and
613
xylanase supplementation on the performance, digestive tract
614
measurement and carcass characteristics of broiler chickens. Anim.
615
Feed Sci. Technol. 116, 129–139.
M
an
612
Wu, Y., Ravindran, V., Thomas, D.G., Birtles, M.J., Hendriks, W.H.,
617
2004. Influence of method of whole wheat inclusion and xylanase
618
supplementation on the performance, apparent metabolisable
619
energy, digestive tract measurement and gut morphology of broilers.
620
Br. Poult. Sci. 45, 385–394.
ce pt
ed
616
Yasar, S., 2003. Performance, gut size and ileal digesta viscosity of
622
broiler chickens fed with a whole wheat added diet and the diets with
623
different wheat particle sizes. Int. J. Poult. Sci. 2, 75–82.
Ac
621
624 625 626
Table 1. Dietary treatments
Page 26 of 35
27 Treatments (whole wheat seed % in the diets)
Growing
chickens
phases
(days)
Control
Whole wheat A
Whole wheat B
Starter
0
0
0
12-18
Grower I
0
5
5
19-28
Grower II
0
10
20
29-40
Finisher
0
15
30
us
627
cr
0-11
ip t
Age of
an
628
Table 2. Analysed nutrient composition and viscosity of wheat used in the
630
experiment
M
629
631
Dry matter
ed
Nutrients
g/kg 889.00 115.00
Starch
545.00
ce pt
Crude protein (Nx6.25)
15.10
Crude fibre
31.11
Total arabinoxylan
35.2
Ac
Ether extract
Water soluble arabinoxylan
3.5
Lysine
4.23
Methionine
2.40
P
3.12
Ca
0.61
Page 27 of 35
28 Extract viscosity (mPa·s)
2.94
632 633 634
Table 3. Composition and nutrient content of the diets † (g/kg diet)
Grower I.
Grower II.
0 to 11 d
12 to 18 d
19 to 28 d
29 to40 d
Corn
220.0
231.0
211.9
159.4
Wheat
349.8
359.7
400.0
500.0
Soybean meal
265.0
181.0
148.0
Fullfat soybean
53.0
60.0
70.0
60.0
40.0
50.0
45.0
32.0
43.0
46.0
49.0
0.7
0.0
0.0
0.0
3.6
2.6
2.3
2.1
17.4
16.4
15.6
15.2
3.2
3.3
3.3
3.4
Monocalcium phosphate
12.1
10.3
9.5
8.4
L-Lysine HCl (78%)
4.3
2.9
2.7
2.9
L-Threonine (98%)
1.5
0.9
0.8
0.9
Elancoban® 200 2
0,0
0,0
0.6
0.0
3
0.6
0.6
0.0
0.0
4.5
4.0
4.0
3.5
30.0
M
1
ed
Fractionated sunflower meal, 40%
an
Ingredient
223.0
L-Valine FG DL-Methionine (99%) Calcium carbonate
Ac
Sodium chloride
ce pt
Sunflower oil
Maxiban® G160
UBM Broiler premix 4
Finisher
cr
Starter
us
636
ip t
635
Page 28 of 35
Water/Phytase enzyme mix (10/1) 5
1.0
1.0
1.0
1.0
Water/NSP enzyme mix (10/1) 6
1.3
1.3
1.3
1.3
Dry matter
889.0
890.0
891.0
891.2
Crude protein (Nx6.25)
223.7
210.1
201.4
190.4
Fat
58.3
70.4
74.9
Fibre
38.9
38.6
38.4
AMEn (MJ/kg)
12.2
12.6
12.8
13.1
LYS
14.3
12.4
11.5
10.7
MET
6.9
5.8
us
29
5.5
5.1
MET+CYS
10.7
9.1
8.6
THR
9.6
8.5
8.1
7.6
Ca
10.3
9.5
9.0
8.5
4.9
4.5
4.3
4.0
1.6
1.6
1.6
1.6
879.0
889.0
882.0
882.0
Crude protein (Nx6.25)
219.5
208.0
197.0
187.4
Fat
61.8
77.7
81.5
73.6
35.0
35.4
34.7
34.6
LYS
13.9
10.8
11.8
10.5
MET
7.0
5.7
5.2
5.0
MET+CYS
10.9
8.5
8.6
8.4
THR
9.8
8.5
8.5
7.8
Ac
Analysed nutrients
Fibre
75.4 36.1
cr
an M
ed
Na
ce pt
Available P
Dry matter
9.5
ip t
Calculated nutrients
Page 29 of 35
30 Ca
10.4
9.6
8.9
8.6
P total
6.6
6.3
6.1
5.7
Na
1.7
1.6
1.5
1.6
637 638
†
639
of ground and whole seed wheat as indicated in Table 1.
640
1
641
manufactured by a fractionation technique.
642
2
643
46140 USA).
644
3
645
Greenfield, IN 46140 USA).
646
4
647
Zn, 3000 mg Cu, 15 000 mg Fe, 22 000 mg Mn, 400 mg I, 80 mg Se,
648
3 200 000 IU Vitamin A, Vitamin D 1 160 000 IU, 20 000 mg Vitamin E,
649
Vitamin K3 1000 mg, Vitamin B1 800 mg, Vitamin B2 2000 mg, Vitamin B6
650
1220 mg, Vitamin B12 10 mg, Vitamin B3 15 400 mg, Vitamin B5 4800 mg,
651
Folic acid 540 mg, Biotin 48 mg, Choline chloride 90 000 mg, Betaine 50 000
652
mg.
653
(DSM Nutritional Products Hungary Kft., H-2367-Újhartyán, Japán fasor, 4.)
654
5
655
Nutrition, PO Box 777, Marlborough, Wiltshire, SN8 1XN, United Kingdom).
656
6
657
1,3(4)-beta-glucanase 1520 U/g, Danisco Animal Nutrition, PO Box 777,
658
Marlborough, Wiltshire, SN8 1XN, United Kingdom).
ip t
Composition of diets of all treatments was the same except for the proportion
cr
The sunflower meal with low fibre and high protein content was
us
Monensin-sodium coccidiostat (Elanco, 2500 Innovation Way, Greenfield, IN
an
Narasin and Dicarbazin coccidiostat (Elanco, 2500 Innovation Way,
ce pt
ed
M
Premix composition (kg): 13% Ca, 5.4% Na, 2.3% Cl, 0.15% S, 22 000 mg
Ac
Phyzyme® XP 5000 L (Min. activity: 6-phytase 5000 FTU/g, Danisco Animal
Axtra™ XB 201 (Min. activity: endo-1,4-beta-xylanase 12 200 U/g, endo-
659 660 661 662
Page 30 of 35
31 663
Table 4.
664
Body weight (g) of chickens fed different amounts of whole
665
wheat seed in the diet (the number of animals in brackets) Age (days)
Treatments 11
18
28
40
Control1
49 (204)
369 (204)
818 (203)
1819 (202)
3020 (200)
Whole wheat seed A2
48 (204)
361 (204)
815 (201)
Whole wheat seed B3
48 (204)
365 (204)
814 (202)
Pooled SEM
0.27
2.40
5.6
Significance4
P>0.05
P>0.05
cr
2986 (195)
1782 (197)
2946 (194)
15.1
30.5
P>0.05
P>0.05
an
us
1804 (201)
P>0.05
M
666
ip t
0
1
control (without whole wheat seed); 20, 5,10 and15% 30, 5, 20 and
668
30% whole wheat seed in starter, grower I, grower II and finisher
669
diets, respectively 4Significance among averages in a column
ed
667
672
ments
Table 5. Feed conversion rate of chickens (kg feed/kg body weight gain) fed different amount of whole wheat seed in the diet
Ac
671
ce pt
670
Stages of growing (d)
0-11
12-18
19-28
29-40
0-40
1.13
1.39
1.54 b
2.01
1.61 b
wheat seed A 2
1.15
1.37
1.50 a
1.94
1.57 a
wheat seed B3
1.14
1.40
1.53 ab
2.04
1.60 b
0.01
0.01
0.01
0.05
0.01
l1
d SEM
Page 31 of 35
32 673
1
control (without whole wheat seed); 2 = 0,5,10,15% 3=0,5,20,30%
674
whole wheat seed in starter, grower I, grower II or finisher diets,
675
respectively
676
n = 6 (No. of pens containing chickens fed the same diets)
677
a,b,c
678
superscripts have significant differences (P<0.05)
ip t
= values in the same columns indicated with different
679 Table 6.
681
Carcass characteristics of chickens slaughtered at 40 days
682
of age (% of body weight)
an
us
cr
680
weight4
1
63.90
wheat seed A2
wheat seed B3 SEM
685 686 687
Gizzard weight
18.99
0.69
21.96
19.24
1.01 1.12
63.67
20.98
19.31
0.57
0.55
0.35
Abdominal fat
a
2.00
b
1.82
c
1.70
0.04
0.53
Ac
684
Thighs
21.49
ce pt
64.48
Breast fillet
ed
Carcass
ents
M
683
1
control (without whole wheat seed); 20. 5. 10 and 15%. 30. 5. 20
and 30% whole wheat seed in starter. grower I. grower II and finisher diets, respectively 4carcass weight=body weight after killing
688
without feathers, head, legs and viscera
689
n = 6 male and 6 female chickens
690
a.b.c
691
columns are significantly different (P<0.05)
values marked with different superscripts within the same
692
Page 32 of 35
33 693
Table 7.
694
Histological structure of small intestine (ileum) of chickens
695
slaughtered at 40 days of age
ip t
696 Thickness of
crypt depth
muscularis
ratio
mucosae (µm)
6.08
134.03
137.45
6.05
130.31
130.76
6.38
122.98
7.16
7.00
0.43
7.17
P>0.05
P>0.05
P>0.05
P>0.05
Villus apical
Crypt depth
(µm)
width (µm)
width (µm)
(µm)
821.53
171.98
138.83
139.36
eed A2
797.86
165.52
121.13
eed B3
824.95
170.16
137.59
42.85
8.34
P>0.05
P>0.05
an
M
ed
697
cr
Villus basal
us
Villus height to
Villus height
1
699
and 30% whole wheat seed in starter. grower I. grower II and
700
finisher diets, respectively 4Significance among averages in a
701
column
702
n = 6 male and 6 female chickens
704 705
Ac
703
control (without whole wheat seed); 20. 5. 10 and 15%. 30. 5. 20
ce pt
698
Table 8.
Enzyme activities, protein content and viscosity values of
706
small intestinal contents collected from chickens slaughtered
707
at 40 days of age
708
Page 33 of 35
34 Enzyme activities
Protein
mU/mg protein
ments
concentration
Viscosity (mPa·s)
Lipase
Trypsin
(mg/g digesta)
l1
8.1a
19.02a
21.98a
16.85
3.68
wheat seed A2
9.0b
20.19b
22.80b
17.10
3.92
wheat seed B3
10.4c
21.16c
23.51c
0.10
0.19
0.24
1
711
and 30% whole wheat seed in starter, grower I, grower II and
712
finisher diets, respectively
713
n = 6 male and 6 female chickens
714
a,b,c
715
columns are significantly different (P<0.05)
M
ed
values marked with different superscripts within the same
Ac
722
ce pt
717
721
0.47
control (without whole wheat seed); 20, 5, 10 and 15%, 30, 5, 20
716
720
0.67
an
710
719
3.44
us
709
718
15.76
cr
d SEM
ip t
α-Amylase
723 724 725 726 727
Page 34 of 35
35
Ac
ce pt
ed
M
an
us
cr
ip t
728
Page 35 of 35