Processing diets containing corn distillers’ dried grains with solubles in growing broiler chickens: effects on performance, pellet quality, ileal amino acids digestibility, and intestinal microbiota

Processing diets containing corn distillers’ dried grains with solubles in growing broiler chickens: effects on performance, pellet quality, ileal amino acids digestibility, and intestinal microbiota J. S. Kim,∗,1 A. R. Hosseindoust,∗,1 Y. H. Shim,† S. H. Lee,‡ Y. H. Choi,∗ M. J. Kim,∗ S. M. Oh,∗ H. B. Ham,∗ A. Kumar,∗ and B. J. Chae∗,2 ∗

College of Animal Life Sciences, Kangwon National University, Chuncheon, 24341, Republic of Korea; SAJOBIOFEED, 1685-18 Hamyeong-ro, Hampyeong-eup, Hampyeong-gun, Jeollanam-do, Korea 57136; and ‡ Department of Swine and Poultry Science, Korea National College of Agriculture and Fisheries, Jeonju 54874, Korea †

creased the digestibility of CP, and tended to decrease digestibility of DM (P = 0.056) and gross energy (P = 0.069). Expanded pellet feeding decreased (P < 0.05) the ileal digestibility of isoleucine, lysine, methionine, phenylalanine, threonine, cysteine, and glutamine compared with mash diet. Processed feed increased (P < 0.01) pH in the gizzard and duodenum; however, processing decreased pH in ileum. The addition of DDGS to the diet reduced pH in the duodenum. The population of Lactobacillus spp. was lower in the duodenum of birds fed the EP diet compared to the mash diet. Processed feed increased the colonization of Clostridium spp. in the gizzard. These results indicated that SP and EP in broiler diet had a potential to improve BW gain, but EP compromised amino acid digestibility. In addition, DDGS supplementation (20%) decreased pellet quality and CP digestibility in broiler chickens; however, the growth performance and feed intake were not affected.

ABSTRACT The present study investigated the effects of feed form and distillers’ dried grains with solubles (DDGS) on growth performance, nutrient digestibility, and intestine microbiota in broilers. A total of 720 broilers (Ross 308; average BW 541 ± 6 g) was randomly allotted to 6 treatments on the basis of BW. There were 6 replicates in each treatment with 20 birds per replicate. Birds were fed 3 different feed forms (mash, simple pellet, and expanded pellet) and DDGS (0 or 20% of diet) in a 3 × 2 factorial arrangement. Simple pellet (SP) and expanded pellet (EP) fed birds showed an increase in BW gain (P < 0.05). The interaction between feed processing and DDGS level was observed on pellet hardness (P < 0.01). The lowest (P < 0.01) pellet durability index (PDI) and hardness were observed in the diet with DDGS. Values for PDI and hardness were higher for EP compared with SP (P < 0.01). Simple pellet decreased ileal digestibility of CP compared to mash feed. The inclusion of DDGS de-

Key words: feed processing, mash, pellet, expansion, amino acids 2018 Poultry Science 0:1–8 http://dx.doi.org/10.3382/ps/pey075

INTRODUCTION

minerals (Pederson et al., 2014). DDGS is not a new feed material and has been used in the feed industry for decades; however, an increased global production of ethanol along with the popularity of corn used as a feedstock for ethanol production is increasing the availability of distiller by-products. Regarding the proper nutritive value of DDGS as well as low price in the industry, it can always be considered as a low-cost feed resource. The concentration of nutrients in DDGS is higher than the original resource due to starch removal (Belyea et al., 2010). However, it is well known in the industry that the bulkiness and handling characteristics of DDGS are the major feed processing (FP) barriers to the use of this product in pelleted feed. Therefore, the livestock industry must have more detailed information on the characteristics of these by-products and their effects on the animal performance, feed quality, and FP procedure.

With the continuation of increased prices for cereal grains, there is a push for nutritionists to discover inexpensive alternatives. The availability of bio-processed products, combined with their low cost, has made their application as feed sources for broiler chickens more economical. Distillers’ dried grains with solubles (DDGS) is an excellent alternative due to the presence of high nutritive components such as protein, fat, fiber, and  C 2018 Poultry Science Association Inc. Received March 3, 2017. Accepted March 7, 2018. 1 These two are equal first authors. 2 Corresponding author: [email protected] The protocol for the present experiment was approved by the Institutional Animal Care and Use Committee of Kangwon National University, Chuncheon, Republic of Korea.

1 Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018

2

KIM ET AL.

FP is costly but it provides an opportunity to enhance the feed quality and improve broiler performance. Pelletizing is the most common method to improve starch utilization, reduce feed wastage, and destroy pathogens and anti-nutritive factors and thus improve bird performance by agglomerating smaller feed particles in a mechanical high-temperature process (Abdollahi et al., 2013; Svihus 2014). Diet form influences feed digestibility and the utilization of nutrients in animals. Serrano et al. (2012) found that feeding broilers pelleted and reground corn-based diets resulted in 6% increase in bird performance compared with broilers fed similar unprocessed diets. In the pelleting process, the addition of DDGS to the diet resulted in reducing pellet quality (Denstadli et al 2010). Loar et al. (2010) suggested that the maximum inclusion of DDGS should not be more than 15% in the grower diet. The quality of expanded pellet (EP) is higher than that of simple pellet (SP) (Lundblad et al., 2011). Therefore, expanding might be a better processing method to use DDGS in the diet due to the higher gelatinization, better pellet quality, and, to some extent, breaking the nonstarch polysaccharides (NSP) bonds (Lundblad et al., 2011; Zaefarian et al., 2015). The high NSP and low energy contents of corn DDGS limit its use in the diet of broilers (Oryschak et al., 2010). The influence of feed expansion in regard to voluntary feed intake and total tract apparent digestibility of nutrients in broilers is the subject of debate. There is a conflicting report stating that high temperature gelatinizes starch but denaturizes amino acids (AA) as well. Starch gelatinization is widely accepted as a thermo-mechanical interaction to improve pellet quality by increasing the accessibility of glucosidic linkage to enzymes (Briggs et al., 1999). Gelatinized starch can entangle and fold different particles as an adhesive or binding agent to form feed (Zaefarian et al., 2015). The excessive increase in the temperature of pellets may compromise the availability of nutrients, particularly the accessibility of AA (MartinezAmezcua et al., 2007). On the other hand, in the expanding process, the pellet quality might be higher due to a higher temperature, which negatively stimulates more protein denaturation (Briggs et al., 1999), causes the degradation of cell wall components, and holds the strands of fiber, hence contributing to the adhesion between particles in the pellets. Starch and protein are not the only feed constituents that can be affected in a high-temperature pelleting process. As the temperature increases, the rate of vitamins and other active micro-ingredients changes in the diet. To maximize the profit, it seems a reliable temperature must be reached in order to keep the benefits of gelatinization and minimize the loss of nutrients. The hypothesis tested in this research was that DDGS in the diet could negatively affect pellet quality and growth performance. In addition, it was hypothesized that the application of high temperature in the expansion process may diminish the negative effects of dietary DDGS on pellet quality. This experiment was carried out to obtain further

knowledge on the effects of dietary DDGS in the SP or EP process on the physical quality of pellets, growth performance, and microbiota of broiler chickens.

MATERIAL AND METHODS The protocol for the present experiment was approved by the Institutional Animal Care and Use Committee of Kangwon National University, Chuncheon, Republic of Korea.

Birds, Diets, and Management This experiment was designed to evaluate the interaction between feed types (FT) and DDGS on the growth performance of broilers. A total of 720 broilers (Ross 308; average BW 541 ± 6 g and 14 d old) was randomly assigned based on BW and sex to 6 dietary treatments. A randomized complete block design with a 3 × 2 factorial arrangement of treatments was used to investigate the response of broiler chickens to 2 levels of DDGS (0 and 20% of diet), in mash, SP, and EP forms. Each treatment had 6 replicate pens with 20 broilers (10 males and 10 females) per pen. Prior to the experiment, the birds were fed a standard broiler starter diet with standard management from d 1 to 14. The diets were formulated to be isonitrogenous (21% CP) and isocaloric (ME based). The analysis of the average composition (dry basis) of DDGS in the current study showed 5,266 kcal gross energy (GE), 29.8% CP, 0.88% lysine, 0.69% methionine, 1.06% threonine, 6.1% ash, 0.21% calcium, and 0.88% phosphorus. The mash diet was formulated to contain 3,150 kcal/kg of ME, 21.0% CP, and 1.1% lysine, supplemented with vitamins, minerals, and AA to meet or exceed the nutrient requirements (Table 1) listed in Ross 308 nutrition specification (Aviagen, 2014). For the SP diet, the mash diet was steam conditioned to 75◦ C and pelleted using a 220 hp pellet mill (Model 12 type, Matador, Denmark) with a 2.8 mm die in diameter. The EP was produced by subjecting the mash diet to a 300 hp expander (Model M12, Matador, Denmark) with 180 amperes, a gap opening of 39%, and temperature of 105◦ C for 20 s with a 2.8 mm die in diameter. The duration of the experiment was 21 d, and the final BW was approximately 2 kg. The birds were housed in rice hull-covered floor pens. Each pen was provided with a self-feeder and hanging bell drinker to allow free access to feed and water. The room temperature was 23◦ C during the first wk and subsequently lowered to 20◦ C by 1◦ C and 2◦ C decrease in the second and third wk, respectively. The lighting was provided for 23 h/d.

Experimental Procedures The birds were individually weighed at the start of the trial and on d 35. Feed that was not consumed was

Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018

3

FEED PROCESSING IN BROILER CHICKENS DIET Table 1. Ingredient and chemical composition of basal diet (as-fed basis). Dietary DDGS content, % Item Ingredients (% as fed) Corn Wheat Soybean meal (45.0 % CP) Corn gluten Rapeseed meal Animal fat Dicalcium phosphate Limestone Vitamin premix1 Mineral premix2 Salt L -Lysine HCL (78 %) L -Threonine (98.5 %) DL -Methionine (98 %) Choline chloride (25 %) Distillers dried grains with solubles (DDGS) Chromic oxide premix3 Analyzed nutrient composition Gross energy (kcal/kg) Dry matter (%) Crude protein (%) Calcium (%) Phosphorus (%) Lysine (%) Methionine (%) Cysteine (%)

0

20

54.94 5.00 23.37 6.14 2.00 3.31 1.74 0.87 0.10 0.10 0.20 0.75 0.06 0.32 0.10 – 1.0

41.23 5.00 18.01 3.04 2.00 5.48 1.43 1.13 0.10 0.10 0.20 0.92 0.02 0.24 0.10 20.0 1.0

4417 88.9 20.83 0.871 0.699 1.19 0.53 0.45

4555 89.1 20.74 0.863 0.701 1.16 0.51 0.45

1 Supplied per kg diet: 10,000 IU vitamin A, 4,500 IU vitamin D3 , 65 mg vitamin E, 1.5 mg vitamin B1 , 12 mg vitamin B2 , 3.2 mg vitamin B6 , 0.011 mg vitamin B12 , 3.0 mg vitamin K3 , 18 mg pantothenic acid, 60 mg niacin, 0.18 mg biotin, 1.9 mg folic acid, 18 mg ethoxyquin. 2 Supplied per kg diet: 20 mg Fe, 16 mg Cu, 110 mg Zn, 120 mg Mn, 1.25 mg I, 0.9 mg Co, 0.3 mg Se. 3 Prepared as 2.5 g of chromic oxide added to 7.5 g of corn gluten.

weighed at the end of the experiment, and feed intake was calculated for d 15 to 35. Body weight gain, feed intake, and feed efficiency (G:F) were corrected for the weight of dead birds. Nutrient balance trials were conducted during the last wk of the feeding trial to determine retention of DM, CP and GE. From d 28 onwards, 2 birds from each replicate (one male and one female) were moved into individual cages (one bird/cage) to facilitate the collection of excreta samples. The diets containing 2.5 g/kg chromium as an indigestible marker were given from d 28 onwards. Excreta samples (about 100 g/d per bird) were collected from each bird during d 33 to 35. The excreta samples were dried in a forced-air drying oven at 60◦ C for 72 h and ground in a Wiley labR Mill, Thomas oratory mill (Thomas Model 4 Wiley Scientific, Swedesboro, NJ) using a 1-mm screen. The apparent nutrient retention was calculated as: apparent nutrient retention (%) = 100 − [100 × (% Cr in feed/% Cr in excreta) × (% nutrient in excreta/% nutrient in feed)]. Pellet durability was determined by the method described by Svihus et al. (2004) using a Holmen Pellet Tester (Holmen Pellet Tester, Tekpro Ltd., Norfolk, UK). In this method, 100 g of pellets were circulated through a closed chamber before passing through a 2mm sieve. The pellet durability index (PDI) was calculated as the percentage of pellets remaining after tumbling by dividing the weight of the whole pellets at the

beginning. Pellet hardness was measured by a hardness tester (Handpi-HLD, Taipei, Taiwan) using the method as described by Svihus et al. (2004).

Chemical Analysis Experimental diets and excreta samples were analyzed in triplicate for DM (Method 930.15), CP (Method 990.03), calcium, and phosphorus (Method 985.01) according to AOAC (2007). GE of diets and excreta were measured by a bomb calorimeter (Model 1261, Parr Instrument Co., Moline, IL). Chromium concentration was determined with an automated spectrophotometer (Jasco V-650, Jasco Corp., Tokyo, Japan) according to the procedure of Fenton and Fenton (1979). AA composition of feed samples and ileum contents were determined by HPLC (Waters 486, Waters Corp., Milford, MA) after acid hydrolysis (Knabe et al., 1989). The methionine and cysteine were determined following oxidation with performic acid (Moore, 1963).

Microbial and pH Analysis On the last d of the experiment, 72 birds around the average weight (2 birds per replicate; one male and one female) were selected and euthanized by cervical dislocation to evaluate microbial assay and gastrointestinal

Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018

4

KIM ET AL. Table 2. Effect of processing feed on growth performance and pellet quality of broiler diets with or without distillers’ dried grains with solubles (DDGS) for 21 d. Feed types1 (FT)

DDGS (D) Items

0

20 %

SEM

2

M

P-value 2

SP

EP

SEM

D

FT

542 2030a 1488a 2152 690

541 2032a 1491a 2145 695

1.70 18.3 17.2 38.4 9.6

0.90 0.15 0.13 0.52 0.49

0.84 0.035 0.028 0.065 0.42

0.49 0.12

< 0.01 < 0.01

FT×D

3

Growth performance Initial weight, g Final weight, g Weight gain, g Feed intake, g G:F, g/kg Pellet quality4 PDI %5 Hardness

541 2026 1485 2124 699 93.8 2.98

541 1995 1454 2095 691 87.4 2.29

1.4 14.3 14.1 31.3 7.7 0.49 0.12

541 1970b 1429b 2033 703 – –

89.3 2.35

91.9 2.95

< 0.01 < 0.01

0.74 0.61 0.63 0.64 0.73 0.33 < 0.01

1

Feed types: M = mash, SP = simple pellet, EP = expanded pellet. Standard error of means. 3 Each value represents the mean of 6 replicates (20 birds/replicate). 4 Each value represents the mean of 20 feed samples. 5 PDI: Pellet durability index. a,b Values with different superscripts in the row significantly differ (P < 0.05). 2

(GI) pH trend. The microbiological assay of the gizzard, duodenum, jejunum, ileum (from the Meckel’s diverticulum to the ileo-cecal junction), and cecum chyme was carried out by the procedure described by Lee et al. (2016). In short, 1 g of mixed content was diluted with 9 mL of Butterfields phosphate buffer solution, followed by further serial dilutions in Butterfields phosphate buffer dilution solution. Duplicate plates were then inoculated with 0.1 mL sample and incubated. The microbial groups enumerated were Lactobacillus spp. (MRS agar + 0.02% NaN3 + 0.05% l-cystine hydrochloride monohydrate) and Clostridium spp. (tryptose sulphite cycloserine agar, Oxoid, Hampshire, UK). The microbial populations were log transformed before statistical analysis. The pH of the gizzard, duodenum, jejunum, ileum, and cecum chyme was determined by pH meter (Basic pH Meter PB-11, Sartorius, Germany).

Statistical Analysis Data generated in this experiment were analyzed as a 3 × 2 factorial arrangement in a completely randomized design, which were analyzed using the Proc-GLM procedure. Pens were considered the experimental unit for growth performance, and broiler chickens were experimental units for measuring the digestibility of nutrients (DM, GE, CP, and AA) and all GI samplings (pH and microbiota). The main effects of FT and DDGS, and their interaction were determined by the mixed procedure of SAS statistical program (SAS Inst., Inc., Cary, NC). P-values ≤ 0.05 were considered statistically significant.

RESULTS Growth Performance Interactions were not observed for FI (Table 2). DDGS levels in the diet did not affect BW gain, FI, or G:F of broilers. At 35 d old, the broilers fed the

SP and EP diets exhibited higher final BW compared with those that received mash diets, which increased by 4.1 and 4.4%, respectively. The reduced final BW of the broilers was reflected in decreased weight gain, with the broilers in the SP and EP treatments exhibiting weight gain values that were 6.5 and 7% higher compared with those in the mash treatment. FI tended to increase (P = 0.065) by the SP and EP treatments. However, there was no significant difference in G:F between the broilers among the treatments.

Pellet Physical Quality The relationship between FT and DDGS levels are shown in Table 2. FP × DDGS interaction was observed on pellet hardness. The lowest (P < 0.01) PDI and hardness were observed in the diet with DDGS. Values for PDI and hardness were higher for EP compared with SP (P < 0.01).

Digestibility of Nutrients and Amino Acids Interactions were not observed in digestibility of nutrients and AA between DDGS and FT (Table 3). DDGS in the diet decreased digestibility of CP and tended to reduce digestibility of DM (P = 0.06) and GE (P = 0.07). Digestibility of DM was unaffected among FT groups. Broiler chickens fed the SP diet had higher (P < 0.05) digestibility of GE compared with the mash diet. The SP treatment reduced the digestibility of CP by 2.9 for SP compared with the mash diet. The digestibility of AA was unaffected by DDGS levels. The reduced CP digestibility of the broilers in processed feed was reflected in decreased AA digestibility, with the broilers in the EP treatments exhibiting decreased digestibility in isoleucine, lysine, methionine, phenylalanine, threonine, cysteine, and glutamine compared with broiler fed mash diet (Table 3).

Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018

5

FEED PROCESSING IN BROILER CHICKENS DIET Table 3. Effect of feed processing on apparent fecal digestibility of nutrients and apparent ileal amino acids (AA) digestibility in broiler diets with or without distillers’ dried grains with solubles (DDGS) at d 35.1 Feed types2 (FT)

DDGS (D) Items Digestibility, % Dry matter Gross energy Crude protein Indispensable AA Arginine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Valine Dispensable AA Alanine Asparagine Cysteine Glutamine Glycine Serine Tyrosine

2

0

20 %

SEM

M

74.2 76.7 68.6a

73.1 75.8 66.9b

0.40 0.34 0.45

73.2 75.5b 69.1a

65.0 61.6 62.9 70.7 69.5 70.7 64.2 45.7 52.3

65.2 61.4 61.8 69.9 68.4 68.6 64.0 44.6 51.8

0.55 0.54 0.55 0.38 0.43 1.32 0.68 0.63 0.55

61.3 59.6 57.2 67.3 51.1 59.6 56.8

60.8 59.1 56.7 67.2 50.4 59.4 56.8

0.43 0.40 0.43 0.44 0.44 0.46 0.30

SP

P-value 3

EP

SEM

D

FT

FT×D

73.8 77.1a 67.1b

73.9 76.0a,b 67.2a,b

0.49 0.42 0.55

0.056 0.069 0.015

0.53 0.034 0.027

0.39 0.81 0.81

66.2 61.8 63.8a 70.7a,b 70.5a 72.6a 65.6a 47.0a 52.3

64.8 61.7 62.8a 71.0a 69.1a,b 71.0a,b 64.8a,b 45.3a,b 52.2

64.2 60.9 60.4b 69.2b 67.4b 65.4b 61.9b 43.2b 51.6

0.68 0.66 0.67 0.47 0.52 1.62 0.83 0.77 0.67

0.77 0.85 0.18 0.17 0.081 0.26 0.81 0.20 0.50

0.12 0.57 < 0.01 0.029 < 0.01 0.010 0.011 < 0.01 0.73

0.61 0.90 0.56 0.85 0.72 0.87 0.91 0.68 0.82

61.4 59.2 58.1a 68.2a 50.8 59.5 56.8

61.5 59.5 56.9a,b 68.1a 51.4 59.4 56.9

60.2 59.3 55.8b 65.5b 49.9 59.7 56.8

0.53 0.49 0.53 0.54 0.54 0.57 0.37

0.39 0.30 0.37 0.87 0.32 0.74 0.94

0.19 0.92 0.020 < 0.01 0.20 0.94 0.96

0.45 0.60 0.74 0.89 0.76 0.43 0.47

1

Each value represents the mean of 6 replicates (2 birds/replicate). Feed types: M = mash, SP = simple pellet, EP = expanded pellet. 3 Standard error of means. a,b Values with different superscripts in the row significantly differ (P < 0.05). 2

Microbiota and pH The results of pH and microbial population in the GI tract at the end of the experiment are presented in Table 4. Birds fed DDGS had significantly lower pH in the duodenum and tended to have lower pH in the gizzard (P = 0.07) compared with the birds fed mash diet. No significant differences were observed for pH of digesta in the jejunum, ileum, or cecum when chickens were fed DDGS. Feeding pellets increased (P < 0.01) the pH in the gizzard and duodenum, and decreased pH in the ileum (P < 0.01). The population of Lactobacillus spp. was not affected by DDGS levels. Generally, FT did not affect the Lactobacillus spp. population in the GI tract of birds except in the duodenum, where the population of Lactobacillus spp. was greater (P < 0.05) in chickens fed a mash diet compared to chickens fed the EP diet. No effect of DDGS on the colonization of Clostridium spp. in the intestine was observed. Compared to birds fed EP and SP diets, the colonization of Clostridium spp. in the gizzard decreased in birds fed a mash diet (P < 0.01).

DISSCUSION The effects of DDGS on the performance and FI of broiler chickens are inconsistent. The results of the current study did not show any significant negative effects on performance of broiler chickens when DDGS was added to the diet. These results agree with the findings of Lumpkins et al. (2004), who fed 18% DDGS in

the diet with no difference in G:F of broiler chickens. However, some recent published data are similar to the older data, which indicated that only a small amount of DDGS can be substituted in the diet without compromising FI and growth performance (Loar et al., 2010; Oryschak et al., 2010; Alizadeh et al., 2016). An increasing FCR was observed when the amount of DDGS increased from 10 to 40% (Denstadli et al., 2010). Weight gain and FI of chickens fed DDGS were numerically lower, but this difference was not significant, indicating that 20% DDGS is a marginal amount, and the higher levels may show significant negative effects on performance. In the present study, weight gain significantly improved in diets using processed feed. The positive relationship between growth performance and processed diet is well recognized in broiler chickens (Abdollahi et al., 2013). Moreover, a reduction in FI and gizzard function in broiler chickens was observed when fed diets with relatively smaller particle size (Xu et al., 2015). Studies have shown that pelleted diet could enhance BW gain and FI of broiler chickens compared to mash diet (Lemme et al., 2006; Brickett et al., 2007; Abdollahi et al., 2010). In another study, Jimenez-Moreno et al. (2016) reported that the pellets improved growth performance of broilers with an increased feed consumption compared with broilers that were fed a mash diet. Expansion processing resulted in a rigid, expanded, and porous structure in starch granules (Blanche and Sun, 2004). Processing methods involving heat, moisture, and shear force generally reduced the

Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018

6

KIM ET AL. Table 4. Effect of feed processing on pH value and bacterial count in different sections of digestive tract from broiler diets with or without distillers’ dried grains with solubles (DDGS) for 21 d.1 Feed types2 (FT)

DDGS (D) Items

0

20 %

pH Gizzard 3.92 3.81 Duodenum 6.59 6.38 Jejunum 6.43 6.46 Ileum 7.33 7.33 Cecum 6.24 6.24 Lactobacillus spp. (log10 cfu/g) Gizzard 7.14 7.08 Duodenum 7.27 7.34 Jejunum 7.57 7.58 Ileum 8.08 8.14 Cecum 8.47 8.43 Clostridium spp. (log10 cfu/g) Gizzard 4.34 4.26 Duodenum 4.64 4.59 Jejunum 5.55 5.51 Ileum 6.32 6.28 Cecum 6.61 6.60

SEM

3

M

SP

P-value 2

EP

SEM

D

FT

FT×D

< 0.01 < 0.01 0.055 < 0.01 0.63

0.90 0.63 < 0.01 0.057 0.16

0.042 0.034 0.038 0.033 0.046

3.52b 6.30b 6.54 7.48a 6.26

4.07a 6.53a 6.38 7.28b 6.20

4.01a 6.63a 6.43 7.25b 6.27

0.051 0.042 0.047 0.041 0.056

0.074 < 0.01 0.61 0.94 0.98

0.064 0.034 0.044 0.069 0.043

7.21 7.4a 7.62 8.2 8.53

7.08 7.31a,b 7.57 8.11 8.41

7.06 7.22b 7.54 8.02 8.41

0.079 0.042 0.054 0.085 0.053

0.51 0.15 0.92 0.50 0.52

0.047 0.067 0.043 0.061 0.042

4.17b 4.58 5.58 6.20b 6.61

4.38a 4.63 5.50 6.31a,b 6.62

4.35a 4.64 5.52 6.39a 6.59

0.04 0.057 0.083 0.053 0.075

0.086 0.48 0.68 0.56 0.97

0.36 0.015 0.56 0.35 0.27

0.74 0.92 0.84 0.98 0.99

< 0.01 0.66 0.75 0.058 0.95

0.79 0.97 0.53 0.41 0.40

1

Each value represents the mean of 6 replicates (2 birds/replicate). Feed types: M = mash, SP = simple pellet, EP = expanded pellet. 3 Standard error of means. a,b Values with different superscripts of the row significantly differ (P < 0.05). 2

particle size, changed the crystalline structure, and altered the rate and extent of starch digestion (Zaefarian et al., 2015). However, there was no difference between SP and EP in the present study. This result is in line with another study, which was conducted with broiler chickens and indicated a similar BW and G:F between pelleted and expanded feed (Boroojeni et al., 2014). The efficacy of the expansion process is due to the destruction of anti-nutritional factors, increasing digestibility of starch, and reducing feed-borne pathogens (Abdollahi et al., 2013). However, not all the research reported a higher performance with a heat-processed diet (Lundblad et al., 2011). Regarding heat processing, the beneficial observations are not consistent, because the benefits of high temperature are related to several variables, including the processing time, mechanical influences, food composition, and pellet quality, such as durability and hardness. A possibility for a higher rate of growth of chickens fed pelleted diets in the current study refers to higher digestibility of GE, which might be related to a higher gelatinization rate. Furthermore, another possibility contributes to the higher digestibility of CP and the lower digestibility of GE in chickens fed a mash diet, where the higher digestibility of protein and AA perhaps provided higher amounts of AA than their growth requirement. Therefore, the growth performance of chickens fed a mash diet may be restricted due to an unbalanced nutritional state. In the present experiment, significant effects on PDI and hardness were found, and the quality and hardness of pellets decreased when diets included DDGS. Physical quality of pellets can be evaluated using pellet durability and pellet hardness parameters (Briggs et al., 1999; Abdollahi et al., 2013). Shim et al, (2011)

reported that pellet durability was negatively related to the proportion of DDGS in the feeds. They mentioned that 2 probable factors contributed to reduced pellet quality when DDGS was included in the feeds: higher DDGS levels and higher poultry fat levels. Dietary DDGS inclusion resulted in decreased pellet quality, likely because of the reduction in a starch component in comparison to ground corn, which could result in less starch gelatinization and decreased pellet binding (Svihus 2014; Zaefarian et al., 2015). The wheat flour (50 g/kg diet) added to both diets in the current study also might help to improve pellet quality. The addition of small particle sizes has been demonstrated to be effective in increasing durability of pelleted diets compared to diets with large particle sizes (Briggs et al., 1999; Svihus, 2014). The PDI increases with increasing conditioning temperature, and an expanded diet results in a greater PDI and modified PDI compared to a lowtemperature pelleted diet (Briggs et al., 1999; Lundblad et al., 2011). The present study investigated the effect of different thermal methods, including simple pelleting and expanded pelleting and different DDGS inclusion levels and their interactions on digestibility of protein and both indispensable and dispensable AA in broiler chickens. There was a tendency for lower digestibility of DM, GE, and CP in diets with DDGS inclusion. These results were in line with the work of Denstadli et al. (2010) who reported lower digestibility of starch and energy in broilers fed 10 or 20% DDGS; however, in contrast to the result of the current study, they reported no difference in digestibility of CP for a DDGS-containing diet. Heat processed diets showed significantly higher digestibility of energy and starch in chickens due to the

Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018

FEED PROCESSING IN BROILER CHICKENS DIET

greater accessibility of digestive enzymes to starch after heat processing (Oryschak et al., 2010). A higher digestibility of starch may be a reason for higher digestibility of GE. Lundblad et al, (2011) surveyed the effects of steam conditioning at low and high temperatures on nursery pigs and broiler chickens and reported that expansion processing improved G:F in nursery pigs due to improved digestibility of protein, starch, DM, organic matter, and energy, which was in contrast to the result of the current experiment. Their result on broiler chickens also showed that all hydro-thermal treatments increased starch digestibility; however, steam conditioning before pelleting increased growth rate and feed utilization in broilers. The accessibility of starch to digestive enzymes is greatly attributed to heat and moisture during FP (Briggs et al., 1999; Zaefarian et al., 2015). Changing the crystalline structure of starch and therefore increasing the enzymatic accessibility to starch granules accelerating the digestibility of starch (Svihus 2014). Another possible reason for improving the digestibility of starch is α-amylase inhibitors denaturation in high temperature (Svihus 2014; Zaefarian et al., 2015). Generally, the ileal apparent digestibility of AA was negatively affected by the expansion method. Clear trends were observed regarding ileal digestibility of AA and were supported by the digestibility of CP. It is known that there is a positive relationship between the reaction between AA and other compounds, such as glucose, when the temperature increases (Boroojeni et al., 2014). Lysine was the only AA in DDGS that tended a show a lower digestibility (P = 0.08). From this data, we can conclude that although DDGS can be substituted in the diet of chickens, the lower energy and lower accessibility of lysine content of DDGS has to be considered (Martinez-Amezcua et al., 2007). Lumpkins et al. (2004) suggested that because there is a marginal lysine deficiency in dietary protein with corn origin, the performance of broilers is decreased in comparison to soybean protein. Previous reports indicated that the high temperature of processing decreased the bioavailability of lysine or some other AA in DDGS (Lumpkins and Batal, 2005; Martinez-Amezcua et al., 2007). Thus, digestibility of lysine can be a major concern in the use of DDGS. Expansion is a process that could enhance the denaturation of protein due to the high temperature and high pressure, especially lysine that is in danger of Maillard reaction (Martinez-Amezcua et al., 2007; Boroojeni et al., 2014). Results from the current study presented a statistically significant effect of FT on acidity in the GI tract, which showed higher pH in the proximal (gizzard and duodenum) sections and lower pH at the distal sections (ileum). In line with the present experiment, Huang et al., (2006) also reported that a broiler fed pellets had higher pH in the gizzard than a broiler fed a mash diet, but had lower pH in the cecum. It is known that volatile fatty acids are a product of carbohydrates that have been fermented by microbes, which tend to lower intestinal lumen pH values (Qaisrani

7

et al., 2015). The decrease in pH of the gizzard in broiler chickens fed a mash diet is a direct response to secreted hydrochloric acid by the proventriculus (Engberg et al., 2002). Interestingly, our data indicated lower C. perfringens presence in the gizzard when birds were fed a mash diet. The mash diet decreased Clostridium spp. colonization in the gizzard of broilers by decreasing pH, which is in agreement with a previous study (Engberg et al., 2002). Furthermore, pelleted feed has a smaller size of feed particles, and one of the consequences of finely ground material is the potential to trigger proliferation of clostridia (Dahiya et al., 2006). It is well known that lower pH can pierce across the bacterial cell membrane and increase the antibacterial activity of short chain fatty acids (Dahiya et al., 2006). The pelleting of feed in a diet also has reduced the pH of ileum contents due to improved ileal fermentation, which may be explained by the smaller size of feed particles in pellets (Engberg et al., 2002). However, the result was the opposite in the ileum, where the lower ileal pH for EP showed higher C. perfringens. There are 2 possible reasons to support these data. The first reason might be that Clostridium spp. is more sensitive in low pH, and a change in the range of pH in an acidic environment (pH = 3.52 to 4.07 in the gizzard compared to pH = 7.25 to 7.48 in the ileum) could have more severe effects on their population. The second reason can be correlated to the quality of protein. Dahiya et al (2006) reported C. perfringens colonization in broilers’ intestine microflora is related to protein source and level. The high temperature in the expansion process may increase the rate of AA denaturation. The denaturized AA may encourage C. perfringens colonization in the ileum. Therefore, it can be speculated that this potential increase in viable C. perfringens present with increasing the pelletizing temperature is due to AA denaturation. Furthermore, broilers fed a mash diet had higher Lactobacillus spp. bacteria in the duodenum compared with broilers fed the expanded diet.

CONCLUSION Diets containing up to 20% corn DDGS in the grower diet of broiler chickens decreased the pellet physical quality without compromising chickens’ growth performance. FP and, in particular, the SP diet, improved final gain in broiler chickens due to improved digestibility of GE and pellet physical quality. The expansion process improved pellet quality; however, it did not show any performance preference compared with the SP diet. The pH of the GI tract changed when chickens were fed a processed diet, following change in colonization of Clostridium spp.

ACKNOWLEDGEMENTS This study is supported by a 2015 Research Grant from Kangwon National University (No. 520150150).

Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018

8

KIM ET AL.

REFERENCES Abdollahi, M. R., V. Ravindran, T. J. Wester, G. Ravindran, and D. V. Thomas. 2010. Influence of conditioning temperature on the performance, nutrient utilisation and digestive tract development of broilers fed on maize- and wheat-based diets. Br. Poult. Sci. 51:648–657. Abdollahi, M. R., V. Ravindran, and B. Svihus. 2013. Pelleting of broiler diets: An overview with emphasis on pellet quality and nutritional value. Anim. Feed Sci. Technol. 179 :1–23. Alizadeh, M., J. C. Rodriguez-Lecompte, A. Rogiewicz, R. Patterson, and B. A. Slominski. 2016. Effect of yeast-derived products and distillers dried grains with solubles (DDGS) on growth performance, gut morphology, and gene expression of pattern recognition receptors and cytokines in broiler chickens. Poult. Sci. 95:507–517. AOAC. 2007. Official Methods of Analysis of the Association of Official Analytical Chemists International. 18th ed. Gaithersburg, MD, USA. Aviagen, R. 2014. Ross Broiler Management Manual. http://pt. aviagen.com/assets/TechCenter/Ross Broiler/Ross Broiler Manual. 9:350–364. Belyea, R. L., K. D. Rausch, T. E. Clevenger, V. Singh, D. B. Johnston, and M. E. Tumbleson. 2010. Sources of variation in composition of DDGS. Anim. Feed Sci. Technol. 159:122– 130. Blanche, S., and X. Z. Sun. 2004. Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions. Adv. Polym. Technol. 23:277–290. Boroojeni, F. G., A. Mader, F. Knorr, I. Ruhnke, I. R¨ ohe, A. Hafeez, K. M¨ anner, and J. Zentek. 2014. The effects of different thermal treatments and organic acid levels on nutrient digestibility in broilers. Poult. Sci. 93:1159–1171. Brickett, K. E., J. P. Dahiya, H. L. Classen, C. B. Annett, and S. Gomis. 2007. The impact of nutrient density, feed form, and photoperiod on the walking ability and skeletal quality of broiler chickens. Poult. Sci. 86:2117–2125. Briggs, J. L., D. E. Maier, B. A. Watkins, and K. C. Behnke. 1999. Effect of ingredients and processing parameters on pellet quality. Poult. Sci. 78:1464–1471. Dahiya, J. P., D. C. Wilkie, A. G. Van Kessel, and M. D. Drew. 2006. Potential strategies for controlling necrotic enteritis in broiler chickens in post-antibiotic era. Anim. Feed Sci. Technol. 129:60– 88. Denstadli, V., S. Ballance, S. H. Knutsen, B. Westereng, and B. Svihus. 2010. Influence of graded levels of brewers dried grains on pellet quality and performance in broiler chickens. Poult. Sci. 89:2640–2645. Engberg, R. M., M. S. Hedemann, and B. B. Jensen. 2002. The influence of grinding and pelleting of feed on the microbial composition and activity in the digestive tract of broiler chickens. Br. Poult. Sci. 43:569–579. Fenton, T. W., and M. Fenton. 1979. An improved method for chromic oxide determination in feed and feces. Can. J. Anim. Sci.. 59:631–634. Huang, D. S., D. F. Li, J. J. Xing, Y. X. Ma, Z. J. Li, and S. Q. Lv. 2006. Effects of feed particle size and feed form on survival of Salmonella typhimurium in the alimentary tract and cecal S. typhimurium reduction in growing broilers. Poult. Sci. 85:831– 836. Jimenez-Moreno, E., A. de Coca-Sinova, J. M. Gonz´ alez-Alvarado, and G. G. Mateos. 2016. Inclusion of insoluble fiber sources in mash or pellet diets for young broilers. 1. Effects on growth performance and water intake. Poult. Sci. 95:41–52. Knabe, D. A., D. C. LaRue, E. J. Gregg, G. M. Martinez, and T. D. Tanksley Jr. 1989. Apparent digestibility of nitrogen and amino acids in protein feedstuffs by growing pigs. J. Anim. Sci. 67:441– 458.

Lee, S. H., A. R. Hosseindoust, J. S. Kim, Y. H. Choi, J. H. Lee, I. K. Kwon, and B. J. Chae. 2016. Bacteriophages as a promising anti-pathogenic option in creep-feed for suckling piglets: Targeted to control Clostridium spp. and coliforms faecal shedding. Livest. Sci. 191:161–164. Lemme, A., P. J. A. Wijtten, J. van Wichen, A. Petri, and D. J. Langhout. 2006. Responses of male growing broilers to increasing levels of balanced protein offered as coarse mash or pellets of varying quality. Poult. Sci. 85:721–730. Loar, R. E., J. S. Moritz, J. R. Donaldson, and A. Corzo. 2010. Effects of feeding distillers dried grains with solubles to broilers from 0 to 28 days posthatch on broiler performance, feed manufacturing efficiency, and selected intestinal characteristics. Poult. Sci. 89:2242–2250. Lumpkins, B. S., A. B. Batal, and N. M. Dale. 2004. Evaluation of distillers dried grains with solubles as a feed ingredient for broilers. Poult. Sci. 83:1891–1896. Lumpkins, B. S., and A. B. Batal. 2005. The bioavailability of lysine and phosphorus in distillers dried grains with solubles. Poult. Sci. 84:581–586. Lundblad, K. K., S. Issa, J. D. Hancock, K. C. Behnke, L. J. McKinney, S. Alavi, E. Prestløkken, J. Fledderus, and M. Sørensen. 2011. Effects of steam conditioning at low and high temperature, expander conditioning and extruder processing prior to pelleting on growth performance and nutrient digestibility in nursery pigs and broiler chickens. Anim. Feed Sci. Technol. 169:208–217. Martinez-Amezcua, C., C. M. Parsons, V. Singh, R. Srinivasan, and G. S. Murthy. 2007. Nutritional characteristics of corn distillers dried grains with solubles as affected by the amounts of grains versus solubles and different processing techniques. Poult. Sci. 86:2624–2630. Moore, S. 1963. On the determination of cystine as cysteric acid. J. Biol. Sci. 38:235–237. Oryschak, M., D. Korver, M. Zuidhof, X. Meng, and E. Beltranena. 2010. Comparative feeding value of extruded and nonextruded wheat and corn distillers dried grains with solubles for broilers. Poult. Sci. 89:2183–2196. Pedersen, M. B., S. Dalsgaard, K. B. Knudsen, S. Yu, and H. N. Lærke. 2014. Compositional profile and variation of distillers dried grains with solubles from various origins with focus on nonstarch polysaccharides. Anim. Feed Sci. Technol. 197:130–141. Qaisrani, S. N., M. M. van Krimpen, R. P. Kwakkel, M. W. A. Verstegen, and W. H. Hendriks. 2015. Diet structure, butyric acid, and fermentable carbohydrates influence growth performance, gut morphology, and cecal fermentation characteristics in broilers. Poult. Sci. 94:2152–2164. Serrano, M. P., D. G. Valencia, J. M. Ndez, and G. G. Mateos. 2012. Influence of feed form and source of soybean meal on growth performance of broilers from 1 to 42 d of age: Floor pen study. Poult. Sci. 91:2838–2844. Shim, M. Y., G. M. Pesti, R. I. Bakalli, P. B. Tillman, and R. L. Payne. 2011. Evaluation of corn distillers dried grains with solubles as an alternative ingredient for broilers. Poult. Sci. 90:369– 376. Svihus, B., K. H. Kløvstad, V. Perez, O. Zimonja, S. Sahlstr¨ om, R. B. Sch¨ uller, W. K. Jeksrud, and E. Prestløkken. 2004. Physical and nutritional effects of pelleting of broiler chicken diets made from wheat ground to different coarsenesses by the use of roller mill and hammer mill. Anim. Feed Sci. Techo. 117:281–293. Svihus, B. 2014. Starch digestion capacity of poultry. Poult. Sci. 93:2394–2399. Xu, Y., C. R. Stark, P. R. Ferket, C. M. Williams, and J. Brake. 2015. Effects of feed form and dietary coarse ground corn on broiler live performance, body weight uniformity, relative gizzard weight, excreta nitrogen, and particle size preference behaviors. Poult. Sci. 94:1549–1556. Zaefarian, F., M. R. Abdollahi, and V. Ravindran. 2015. Starch digestion in broiler chickens fed cereal diets. Anim. Feed Sci. Technol. 209:16–29.

Downloaded from https://academic.oup.com/ps/advance-article-abstract/doi/10.3382/ps/pey075/4959878 by East Carolina University user on 04 April 2018