Effect of supplementation of phytogenic feed additives (powdered vs. encapsulated) on performance and nutrient digestibility in broiler chickens

Effect of supplementation of phytogenic feed additives (powdered vs. encapsulated) on performance and nutrient digestibility in broiler chickens A. Hafeez,∗ K. M¨ anner,∗ C. Schieder,† and J. Zentek∗ ∗

Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universit¨ at Berlin, K¨ onigin-Luise-Str. 49, 14195 Berlin, Germany; and † BIOMIN Holding GmbH, Erber Campus 1, 3131 Getzersdorf, Austria

Key words: phytogenic feed additives, essential oils, feed conversion, amino acids, digestibility 2015 Poultry Science 00:1–8 http://dx.doi.org/10.3382/ps/pev368

INTRODUCTION

production of digestive secretions as well as immune status in birds (Brenes and Roura, 2010, Reisinger et al., 2011). Addition of PFAs may promote production performance and productivity of birds mainly by improving feed conversion (Windisch et al., 2008). Inclusion of PFAs in broiler diet resulted in improved daily weight gain (Ciftci et al., 2005) and feed conversion ratio (Jamroz and Kamel, 2002; Hong et al., 2012) as well as higher apparent ileal digestibility (AID) of protein, fat, calcium, and phosphorus (Amad et al., 2011, Mountzouris et al., 2011). Inclusion of plant extracts and essential oils, respectively, also improved apparent total digestibility of crude protein when added to a broiler finisher diet (Hernandez et al., 2004). The impact of PFAs on the intestinal microbiota is considered essential for the biological effects; however, the exact mode of action is still not clear. Relief from microbial activity in the small intestine may enhance the activity of digestive enzymes (Windisch et al., 2008). However, the addition of herbal essential oils to feed is normally done at levels below the range found in in vitro studies [0.03 to 2.0% (v/v)] to have antimicrobial activity

In the recent past, antibiotic feed additives have extensively been used as growth promoters in poultry diets. However, after the ban of antibiotics for this purpose in the European Union in 2006, non-antibiotic substances with growth promoting potential including organic acids, probiotics and botanical products have received more attention. Botanical products, also known as phytogenic feed additives (PFA’s), have inconsistent effects on poultry performance mainly due to differences in their botanical origin, processing, and composition. Herbs, spices, essential oils and oleoresins contain a huge variety of chemical substances. Most of the properties of PFAs are considered to be related to essential oils, which may stimulate blood circulation, reduce load of pathogenic bacteria, and enhance

 C 2015 Poultry Science Association Inc. Received August 24, 2015. Accepted October 14, 2015. 1 Corresponding author: [email protected]

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efficiency during finisher phase was improved in treatment ME-100 relatively to control and P-150 treatments (P = 0.035). At d 21 in trial 2, the apparent ileal digestibility of crude protein was higher in ME-100 treatment in comparison with control and P-150 treatments (P < 0.001). Apparent ileal absorption (AIA) of phosphorus was higher in ME-100 treatment than control treatment (P = 0.028). AID of cysteine was higher in both phytogenic additive supplemented treatments in comparison with control treatment (P = 0.001). In conclusion, inclusion of a powdered phytogenic additive characterized by menthol and anethole at 150 mg/kg had no effect but only a tendency towards improved performance and AIA of phosphorus, whereas essential oils addition in encapsulated form characterized by caravacol, thymol, and limonene at 100 mg/kg improved performance as well as apparent ileal digestibility of nutrients in broilers, possibly due to improved secretion of digestive enzymes.

ABSTRACT Inclusion of phytogenic feed additives (PFA) in feed may enhance performance of broilers. Levels of essential oils in powdered form (characterized by menthol and anethole) at 150 mg/kg (P-150) and matrix-encapsulated form (characterized by carvacrol, thymol, and limonene) at 100 mg/kg (ME-100) were supplemented in diet to investigate their effect on performance (trial 1) and apparent ileal digestibility (AID) of nutrients (trial 2) in broilers. A total of 480 1-day-old broilers (Cobb 500) were used in trial 1 and 120 broilers in trial 2. Broilers were distributed in 24 pens with 8 pens per treatment (trial 1) and 6 pens with 2 pens per treatment (trial 2), with 20 birds per pen. Feed and water were offered ad libitum throughout the experimental periods in both trials. In trial 1, body weight of birds at d 42 and overall body weight gain from d 1 to d 42, was higher in treatment ME-100 than birds in control treatment (P = 0.023 and P = 0.024, respectively). Feed

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MATERIAL AND METHODS The animal trial was performed in accordance with the Animal Welfare Act of Germany approved by the local state office of occupational health and technical safety (Landesamt f¨ ur Gesundheit und Soziales, LaGeSo, no. A 0100/13).

Experimental Design Trial 1 (for evaluation of performance parameters in broilers) lasted for 42 d whereas trial 2 (for determination of nutrient digestibility) took 21 d. A total of 600 male broiler chicks (Cobb 500) purchased from a commercial hatchery (Cobb Germany Avimex GmbH, Wiedemar-Wiesenena) were used for trial 1 (n = 480) and trial 2 (n = 120). These studies were designed to in-

vestigate the effect of two phytogenic products at their recommended dose levels (BIOMIN Holding GmbH, Getzersdorf, Austria). The first phytogenic additive was a powdery mixture based on a defined mixture of essential oils, plant extracts, herbs and spices, characterized by menthol and anethole. The second phytogenic additive was a matrix-encapsulated phytogenic additive characterized by carvacrol, thymol, and limonene. In both trials, broilers were assigned to 3 treatments including a diet without feed additives (Control), a diet with a PFA characterized by menthol and anethole (150 mg/kg; P-150) and a diet with an encapsulated PFA characterized by carvacrol, thymol, and limonene (100 mg/kg; ME-100). The test substances were added at the expense of Sipernat (fine, loose powdered with approximately 99% silicon dioxide; SiO2 ). Each treatment included 160 birds (trial 1) and 40 birds (trial 2). One pen comprised of 20 birds in any experiment. Broilers were distributed into 24 pens with 8 pens per treatment (trial 1) and 6 pens with 2 pens per treatment (trial 2). In the basal starter, grower and finisher diets, the corresponding amounts of the essential oils (150 mg/kg of diet in powdered form or 100 mg/kg of diet in granulated form) were added at the expense of Sipernat (fine, loose powdered with approximately 99% SiO2 ). After preparing the control and experimental diets (P-150 and ME-100), all three diets were pelleted with a pellet mill using a 2.5 mm dye. The temperature in the conditioner was adjusted to about 50◦ C, which was corresponding to a temperature in the ring dye of about 56◦ C. All diets were manufactured in the feed mill owned by the institute (registration number: DEBE-100001). Representative samples (3 × 1,000 g) from each diet batch manufactured for the trials were collected before and after pelleting, labeled, and identified for confirming the nutritional composition and the addition of the phytogenic additives. During both trials, standard husbandry practices for broilers were followed. After trial 1 was completed, trial 2 was carried out in the same house. Softwood shaving was used as bedding material in pens with 1.20 × 1.75 m2 dimensions. House temperature was maintained at 33◦ C for the first week which was gradually reduced by 3◦ C per week until it reached 24◦ C. Climate was controlled in the house. Ventilation was 0.3 m/s (1 to 18 d of age) and 1.0 m/s (19 d of age onwards) with 50 to 65% relative humidity. Full time light was provided for the first 5 d, which was then reduced and maintained at 16 hours of light per d for the rest of the period. Throughout both trials, feed and water were offered ad libitum. Broilers were fed starter (01 to 14 d of age), grower (15 to 28 d of age) and finisher (29 to 42 d of age) diets. All three types of basal diets were formulated according to recommendations of the German Society of Nutritional Physiology (GfE, 1999). For the determination of nutrient digestibility, grower diet of trial 2 was supplemented with titanium dioxide (TiO2 ,

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(Hammer et al., 1999). Few studies could demonstrate reduced intestinal microbiota, including E. coli and Clostridium perfringens, in broilers (Jamroz et al., 2003; Mitsch et al., 2004; McReynolds et al., 2009). Furthermore, addition of essential oils in broiler diet reduced the microbial load, including Salmonella, in carcasses (Aksit et al., 2006). Addition of phytogenic formulations in broilers diet increased villi length, crypt depth and the number of goblet cells (Reisinger et al., 2011), intestinal mucus production (Jamroz et al., 2006), activities of trypsin and amylase (Lee et al., 2003; Jang et al., 2004), secretion of bile acids (Platel and Srinivasan, 2000; Williams and Losa, 2001), had laxative and spasmolytic effects (Chrubasik et al., 2005) and reduced intestinal as well as fecal urease activities (Nazeer et al., 2002). However, effects may vary, as depth of crypts in ileum was reduced in broilers fed with a diet including garlic and thyme in comparison with a diet supplemented with antibiotic growth promoters (Demir et al., 2005). PFAs can have antioxidative properties, which might help to protect cellular function in the intestine and other tissues (Cuppett and Hall, 1998; Craig, 1999; Nakatani, 2000; Wei and Shibamoto, 2007). It was emphasized that selection of proper plants, active components, and efficacious dietary doses are important for suitability of these substances to influence poultry performance. In recent past, various combinations of PFAs have been tested in poultry diets; however, their biological efficacy presents a scattered picture. Most of the reported data represent effects of combinations of different PFAs, and only a few studies are available on effects of individual plants on performance in broilers. The individual plants and particularly their active ingredient quantities remain a complex question; therefore, effect of plants and herbs as well as their active ingredients cannot be compared individually. The present study was designed to investigate the effect of two phytogenic products at their recommended levels on performance and digestibility of nutrients in broiler chickens.

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POWDERED VS ENCAPSULATED FEED SUPPLEMENTS IN BROILERS Table 1. Feed composition and nutrient content of the basal experimental diet. Item

Starter (1–14 d)

Finisher (29–42 d)

32.95 26.5 30.2 5.08 1.46 1.38 1.20 0.24 0.20 0.23 0.06 0.50

35.06 23.0 32.3 5.08 1.47 1.25 1.20 0.22 0.20 0.20 0.02 0

201 12.0 5.60 9.00 24.0 73.9 12.6

187 10.7 5.00 8.50 23.7 71.2 12.7

919 199 25.7 74.8 57.2 409 40.8 8.70 6.07 1.67

918 182 25.3 74.1 54.4 414 38.2 7.73 6.07 1.63

ME metabolizable energy. 1 Contents per kg premix: 400,000 IU vit. A; 40,000 IU vit. D3 ; 8,000 mg vit. E (a-tocopherole acetate); 300 mg vit. K3; 250 mg vit. B1 ; 250 mg vit. B2 ; 2,500 mg nicotinic acid; 400 mg vit. B6 ; 2,000 mg vit. B12; 25,000 mg biotin; 1,000 mg calcium pantothenate acid; 100 mg folic acid; 80,000 mg choline chloride; 5,000 mg Zn (zinc oxide); 2,000 mg Fe (iron carbonate); 6,000 mg Mn (manganese oxide); 1,200 mg Cu (copper sulfate-pentahydrate); 45 mg J (calcium jodate); 30 mg Co (cobalt- (II)-sulfate-heptahydrate); 35 mg Se (sodium selenite); 130 g Na (sodium chloride); 55 g Mg (magnesium oxide). 2 fine, loose powdered with approximately 99% SiO2. 3 Supplemented in grower diet of trial 2 for digestibility analysis.

Sigma Aldrich, St. Louis, MO) as an inert indigestible marker at 5 g/kg of diet. Table 1 represents the composition of basal starter, grower and finisher diets. The analyzed concentration of nutrients in the grower feed used for the digestibility calculations are given in Table 2.

Performance Parameters Parameters for productive performance (body weight, body weight gain, feed intake, and feed conversion ratio) were measured on weekly basis throughout the experimental period of trial 1. Body weight gain of broilers was measured as a difference of weight between two weighing intervals. After correction for feed refusals, feed consumption was calculated using the

Treatment

Dry matter Crude ash Crude protein Crude fat Calcium Phosphorus Alanine Arginine Aspartic acid Cysteine Glutamic acid Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Proline Serine Threonine Tyrosine Valine

Control

P-150

ME-100

918 57.2 202 75.2 8.60 6.30 8.12 11.8 17.3 5.44 21.6 7.31 5.39 7.67 14.2 11.1 5.80 8.98 10.7 9.48 7.49 5.92 8.41

921 57.5 197 74.7 8.80 5.90 8.98 13.3 19.5 6.31 22.8 8.04 6.00 8.58 15.5 13.0 6.49 9.87 11.9 10.5 8.44 6.43 9.26

917 56.9 198 74.5 8.70 6.00 8.56 11.9 18.2 5.77 21.6 7.66 5.47 8.04 14.5 11.7 5.79 9.11 11.0 9.58 7.89 5.90 8.82

following formula:

F eed consumed per period =f eed consumed per pen/ (number of surviving birds × days of the period) +days of died birds alive Feed conversion ratio (FCR) was estimated using the following expression:

F eed conversion per period =f eed consumed f or the period in each replicate/total weight gain f or the period(with weight gain of died or culled chickens)

Collection of Samples At mid growth period of broilers on d 21 (trial 2), 8 chickens per pen (16 per treatment) with body weight close to the pen average were randomly selected, weighed, stunned, and killed by exsanguination. After slaughtering, carcass was immediately dissected. Luminal ileal digesta from the posterior half between Meckel’s diverticulum and 2 cm prior to the ileo-ceco-colonic-junction was collected and stored at –20◦ C before being freeze-dried for chemical analyses. The apparent ileal digestibility (AID) of nutrients was calculated using the following formula:

Apparent Digestibility (%) = 100 − ((concentration of marker in f eed/concentration of marker in

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Ingredients (%) Maize 32.33 Soybean meal (CP 44%) 32.0 Wheat 25.9 Soybean oil 5.08 Limestone 1.48 Monocalcium phosphate 1.40 Premix1 1.20 DL-Methionine 0.26 Sipernat/test products2 0.20 L-Lysine HCL 0.13 L-Threonine 0.02 Titanium dioxide3 0 Calculated chemical composition (g/kg) Crude protein 221 Lysine 12.7 Methionine 5.90 Methionine/Cystine 9.70 Crude fiber 24.5 Crude fat 73.6 ME (MJ/kg) 12.5 Analyzed nutrient content (g/kg) Dry matter 921 Crude protein 222 Crude fiber 24.1 Crude fat 70.7 Crude ash 54.5 Starch 358 Sugars 40.0 Calcium 8.97 Phosphorus (total) 6.83 Sodium 1.67

Grower (15–28 d)

Table 2. Analyzed nutrient contents (g/kg) in grower diet.

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digesta) × (concentration of nutrient in digesta/

Table 3. Effect of supplementation of essential oils in feed on productive performance in broiler chickens.1

concentration of nutrient in f eed) × 100) Sixteen digesta samples per treatment were used to calculate AID of nutrients. Ileal digesta of always two broiler chickens per treatment was pooled; therefore 8 pooled samples were used to calculate AID of amino acids.

Chemical Analysis

Data Analysis Performance parameters and nutrient digestibilities were measured on the basis of pen as experimental unit. The data were analyzed by one-way ANOVA. ShapiroWilk’s test was used for testing normality. The statistical model was including the random effects of animal and the fixed effect of treatment. All treatment least squares means were compared with each other and the Tukey adjustment was used to control for experimentwise error. Differences among least squares means with a probability of P < 0.05 were accepted as statistically significant. For statistical analysis, SPSS 21.0 (SPSS Inc., Chicago, IL) was used.

RESULTS Birds in all treatments were healthy throughout the both experimental period with a low mortality rate (2.7%). Based on casual observation, behavior of broilers and consistency of excreta did not show differences between treatments.

Trial 1 The effect of supplemented PFAs on performance of broiler chickens is presented in Table 3. Body weight of birds at d 42 and overall body weight gain from d 1 to d 42 in treatment ME-100 was higher than birds

Control

P-150

Body weight (g/bird) 01 d 42.6 42.8 14 d 498 494 28 d 1,676 1,709 42 d 3,134a 3,188a,b Body weight gain (g/bird) 01 to 14 d 455 451 15 to 28 d 1,179 1,215 29 to 42 d 1,458 1,478 01 to 42 d 3,091a 3,145a,b Feed intake (g/bird) 01 to 14 d 541 527 15 to 28 d 1,854 1,881 29 to 42 d 2,578 2,623 01 to 42 d 4,973 5,031 FCR2 (g:g) 01 to 14 d 1.19 1.17 15 to 28 d 1.57 1.55 a 29 to 42 d 1.77 1.77a 01 to 42 d 1.61 1.60

ME-100

SEM

P-value

42.7 484 1,702 3,212b

0.203 4.83 9.25 12.4

0.942 0.536 0.321 0.023

442 1,217 1,510 3,169b

4.90 10.4 9.72 12.4

0.545 0.236 0.080 0.024

527 1,873 2,607 5,007

7.21 14.8 19.4 18.6

0.661 0.751 0.654 0.461

1.20 1.54 1.73b 1.58

0.013 0.013 0.008 0.005

0.705 0.564 0.035 0.083

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Data are means of 8 replicates per treatment. FCR = feed conversion ratio (feed intake:body weight gain). a,b Means with different superscripts in a row differ significantly (P < 0.05). 2

Table 4. Effect of supplementation of essential oils in feed on apparent ileal digestibility (%) of nutrients in broiler chickens at 21 d of age.1 Treatment

Dry matter Crude ash Crude protein Crude fat Calcium Phosphorus

Control

P-150

ME-100

SEM

P-value

56.7 40.3 82.3a 92.3 35.3 39.0a

57.4 41.8 83.0a 92.7 35.3 40.3a,b

56.2 42.0 84.8b 92.7 36.8 42.4b

0.583 0.663 0.243 0.233 0.519 0.54

0.716 0.535 < 0.001 0.712 0.428 0.028

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Data are means of 16 replicates per treatment. Means with different superscripts in a row differ significantly (P < 0.05). a,b

in control treatment (P = 0.023 and P = 0.024, respectively) whereas no significant differences were observed for treatment P-150 (P > 0.05). Body weight and body weight gain was not distinctly affected by test treatments during starter, grower and finisher periods (P > 0.05). Feed intake by broilers within all treatments was comparable during all production phases and overall experimental period (P > 0.05). Feed conversion during finisher phase was improved in treatment ME100, which displayed lower FCR in relation to control and P-150 treatments (P = 0.035). During starter and grower phase as well as for overall experimental period, FCR was similar among all treatments (P > 0.05).

Trial 2 Table 4 summarizes the impact of essential oils supplementation in diet on AID of nutrients in broilers. The AID of crude protein was higher in ME-100

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After freeze drying, all experimental diets and ileal digesta were ground to pass through a 0.25-mm screen before analysis. Laboratory measurements were including Weende constituents and additionally starch, total sugars, calcium, phosphorus, and sodium. Analyses were in accordance to the methods issued by VDLUFA (2013) including dry matter: VDLUFA III 3.1; crude ash: VDLUFA III 8.1; crude protein: VDLUFA III 4.1.1 modified according to macro-N determination (vario Max CN); crude fibre: VDLUFA III 6.1.4; crude fat: VDLUFA III 5.1.1; starch: VDLUFA III 7.2.1; total sugars: VDLUFA III 7.1.1; calcium: VDLUFA VII 2.2.2.6; phosphorus: VDLUFA VII 2.2.2.6; and sodium: VDLUFA VII 2.2.2.6. The amino acid determination in diets and ileal digesta was corresponding to the methods issued by VDLUFA III 4.11.1. Titanium dioxide was measured in feed and ileum digesta according to the method described by Short et al. (1996).

Treatment

POWDERED VS ENCAPSULATED FEED SUPPLEMENTS IN BROILERS Table 5. Effect of supplementation of essential oils in feed on apparent ileal digestibility (%) for amino acids in broiler chickens at 21 d of age.1 Treatment P-150

ME-100

SEM

P-value

80.3 86.3 80.5 74.2a 83.8 76.7 81.5 82.2 82.8 85.1 90.5 84.6 83.7 81.2 75.1 77.2 79.8

79.9 86.2 81.4 77.4b 84.3 77.0 82.3 82.5 83.6 84.7 91.8 84.5 84.1 81.4 77.7 76.5 79.5

81 87.3 81.9 77.4b 85.2 77.7 83.1 82.6 83.6 87.1 91.1 85 85 81.8 78.5 77.6 80.2

0.365 0.24 0.374 0.452 0.349 0.331 0.377 0.262 0.371 0.449 0.219 0.234 0.272 0.272 0.690 0.466 0.287

0.473 0.094 0.324 0.001 0.252 0.491 0.246 0.861 0.621 0.058 0.058 0.736 0.205 0.731 0.096 0.647 0.660

1

Data are means of 8 replicates per treatment. Means with different superscripts in a row differ significantly (P < 0.05). a,b

treatment in comparison with control and P-150 treatments (P < 0.001). PFA supplementation affected AID of phosphorus, which was higher in ME-100 treatment than control treatment (P = 0.028) with no significant effect on P-150 treatment (P > 0.05). Dry matter and crude ash content as well as AID of crude fat and calcium were not affected by supplementation of PFA in broilers diet (P > 0.05). The effect of PFAs in broiler diets on AID of amino acids is presented in Table 5. The AID of cysteine was higher in both PFA supplemented diets in comparison with control treatment (P = 0.001). PFA supplementation in broiler diets did not statistically affect the AID of other amino acids under consideration (P > 0.05).

DISCUSSION Due to the high number of different phytogenic formulations with various phytogenic substances available on the market, data of scientific studies cannot be compared that easily. In this study, two formulations were tested, which differed in the combination of plant extracts, herbs and spices and essential oils. This also makes it more difficult to interpret, which plant extract, herb, spice, essential oil or combination is responsible for the data obtained. While interpreting the results, this fact has to be taken into consideration. The present study was designed to investigate the effect of dietary supplementation of PFAs in powdered form characterized by menthol and anethole (150 mg/kg; P-150) and encapsulated form characterized by carvacrol, thymol, and limonene (100 mg/kg, ME-100) on performance (trial 1) and nutrient digestibility (trial 2) in broilers. The results of our first trial indicated that inclusion of a PFA type ME-100 in broiler diets improved body weight and body weight gain in the over-

all production period (1 to 42 d of age), in comparison with control group whereas no statistical significant differences were observed for the PFA type P-150 group. Furthermore, feed conversion ratio was improved in the PFA supplemented group ME-100 between 29 to 42 d of age compared to control and PFA type P-150 group. Literature reflects versatile effects of dietary inclusion of PFA on feed conversion, body weight gain and feed intake, by having impact on either one or more parameters. Some previous studies are in agreement with our findings and present similar pattern of body weight gain and feed conversion improvement. For instance, supplementation of broiler feed with PFAs comprising essential oils from oregano, anise, and citrus at 80, 125, and 250 mg/kg resulted in linear increase in overall body weight gain and feed conversion ratio and quadratic decrease in overall feed intake in comparison with control group (Mountzouris et al., 2011). In comparison with control group, broiler fed with diet supplemented with anise oil at 400 mg/kg had higher body weight gain and increased feed efficiency throughout the experimental period (Ciftci et al., 2005). Broilers infected with Eimeria tenella at 14 d of age displayed higher body weight gain and feed conversion ratio in a feeding group supplemented with oregano essential oils at 300 mg/kg of wheat soybean meal-based diet compared to the infected non-supplemented controls at 28 d of age (Giannenas et al., 2003). In another study, broiler feed was supplemented with antibiotic growth promoter (avilamycin) at 10 mg/kg, a prebiotic (mannan oligosaccharide) at 1 g/kg diet, an essential oil (oregano) at 1 g/kg diet, a plant extract of hop at 1 g/kg or a mixture of oregano and plant extract of hop at 1 g/kg. In all treatments in comparison with control treatment, body weight and feed conversion ratio were improved from 1 to 21 d of age, and body weight as well as feed consumption were improved for the overall trial period of 42 d (Bozkurt et al., 2009). Another study suggests that inclusion of 0.2% peppermint or thyme (w/w) characterized by menthol and thymol (70 mg/kg diet) in broiler diets improved body weight gain in comparison to a control group from 7 to 21 and from 7 to 35 d of age, whereas feed intake and feed conversion ratio were not affected (Ocak et al., 2008). Amad et al. (2011) used PFA containing essential oils of thyme and anise at 150, 750, and 1,500 mg/kg in broiler diets and reported a linearly improved feed conversion ratio in comparison to the control diet during grower and overall production period with no significant effect on body weight, weight gain and feed intake. Similarly, Jamroz et al. (2005) compared maize, wheat and barley based diets with and without supplementation of a plant extract (100 mg/kg) consisting of capsaicin, cinnamaldehyde, and carvacrol. They reported enhanced feed conversion. However, body weight in the plant extract supplemented groups was similar to the nonsupplemented groups. Various studies have reported that inclusion of PFA in broiler diets enhanced feed conversion ratio mostly due to decreased or constant

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Alanine Arginine Aspartic acid Cysteine Glutamic acid Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Proline Serine Threonine Tyrosine Valine

Control

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between 29 to 42 d of age (Mountzouris et al., 2011) as well as in the present study. In the same context, ingredients used in basal diet, processing techniques, hygiene of stable, environmental factors, and quality of the phytogenic product applied are crucial for the effect of a PFA on poultry performance (Botsoglou et al., 2002; Jang et al., 2004; Ocak et al., 2008; Windisch et al., 2008). In the present study, AID of crude protein was higher in the PFA type ME-100 supplemented group in comparison to control and the PFA type P-150 supplemented group. AID of phosphorus was higher in the PFA type ME-100 group than in the control group, whereas no statistical significant differences were observed for the PFA type P-150 group. Both groups receiving PFAs displayed higher AID of cysteine than the control group. Effects of PFA on nutrient digestibility are inconsistent in broilers. With an increasing dose of PFA in the diet, AID of crude ash, crude protein, crude fat, calcium, and phosphorus was linearly increased for all categories of age including starter, grower, finisher and overall growth period (Amad et al., 2011). Inclusion of PFA in broilers starter diet improved AID of dry matter and starch, whereas apparent fecal digestibility of dry matter and crude protein was enhanced by PFA supplementation in finisher diet (Hernandez et al., 2004). Some other studies reflect no beneficial effect of PFA inclusion in poultry diet on nutrients digestibility. For instance, AID of crude protein, fiber, and amino acids was not affected by supplementation of plant extracts (Jamroz et al., 2005). In comparison with control diet, inclusion of PFA in diet did not consistently affect apparent ileal and apparent total tract digestibility of dry matter, crude protein, and ether extract in broilers (Mountzouris et al., 2011). The mode of action of PFA in broiler diets enhancing nutrient digestibility is still not clear. Various plants extracts, spices and herbs influence the digestive system in poultry by stimulating appetite and digestion as well as exerting antimicrobial effects (Kamel, 2001). It has been reported that supplementation of PFA in broiler feed increased intestinal mucus production (Jamroz et al., 2006), influenced gut morphology (Reisinger et al., 2011), enhanced activities of trypsin and amylase (Lee et al., 2003; Jang et al., 2004), stimulated bile acid secretion and enhanced activity of digestive enzymes (Platel and Srinivasan, 2000; Williams and Losa, 2001). Furthermore, PFA supplementation resulted in increased bile flow, and stimulated the release of digestive enzymes from pancreas and gut mucosa (Platel and Srinivasan, 2004; Jamroz et al., 2005; Jang et al., 2007). Also, in the current experiment, stimulation of digestion and a potential improvement of digestive enzyme activity could explain improved AID of nutrients and enhanced performance of broilers. Additional or other influencing factors including gut microflora, influence on goblet cells, mucus production, and immune function, etc., should not be ignored and might also be involved in the improvement of digestibility and performance results.

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feed intake and unchanged or negligible weight gain (Windisch et al., 2008; Brenes and Roura, 2010). This fact was supported by Brenes and Roura (2010), who reviewed the mode of action of essential oils in poultry nutrition and categorized potential properties including sensorial effects (oronasal sensing and digestive conditioning), antioxidant (preventing tissue oxidation) and antimicrobial activity as well as the likely influence on the modulation of gut microbiota. The literature suggests that supplementation of Origanum vulgare ssp. hirtum at 300, 500, and 700 mg/kg in broiler diet improved feed intake and feed conversion ratio; however, no effect was observed on body weight and body weight gain (Calislar et al., 2009). Another study reported that graded supplement of oregano at 2, 4, 10, and 20 g/kg and its essential oil at 0.1, 0.2, 0.5, and 1 g/kg in broiler diets resulted in improved feed conversion and reduced daily feed intake (Halle et al., 2004). Some studies demonstrated that inclusion of PFAs in poultry diet may not have any beneficial effect. Supplementation of wheat-soybean mealbased diet with oregano oil at 50 and 100 mg/kg had no effect on growth performance of broilers (Botsoglou et al., 2002). Feed supplemented at 200 mg/kg with essential oils extracted from oregano, cinnamon, and pepper or at 5,000 mg/kg with Labiatae extract from sage, thyme, and rosemary did not affect feed intake and feed conversion ratio in broilers (Hernandez et al., 2004). Growth performance of broilers was not improved when maize-soybean based feed was supplemented with thymol, cinnamaldehyde, as well as a commercial phytogenic preparation at 100 mg/kg (Lee et al., 2003). Two commercial PFA products containing 5% carvacrol, 3% cinnamaldehyde, and 2% Capsicum oleoresin supplemented at 50, 100, 200, and 500 mg/kg of diet had no effect on growth performance of broilers (Muhl and Liebert, 2007). Body weight gain, feed intake, and feed efficiency were not affected from 1 to 42 d of age in broilers when feed was supplemented with oregano powder at 1 g/kg, fructooligosaccharides at 0.5 g/kg, Ouillaia saponaria at 0.1 g/kg, garlic powder at 1 g/kg, and thyme powder at 1 g/kg of diet (Demir et al., 2005). The differences in efficacy of PFAs on performance of broiler chickens might be attributed to their types used in various studies. Furthermore, the concentration of active substances and their biological activity in different type of PFAs could be another reason for variable findings. Herbs and spices, their essential oils and active substances, influence broiler performance as well as production of endogenous secretions; however, the differences in their efficacy are related to their terpene composition (Cross et al., 2007). Similarly the results of some studies reveal age dependent effects of PFAs on broiler performance. For instance, feed conversion ratio was improved due to PFA supplementation in broiler diets after the first week of age (Ciftci et al., 2005), after 14 d of age (Giannenas et al., 2003), between 21 to 41 d of age (Jamroz et al., 2005), between 14 to 21 and 28 to 35 d of age (Hernandez et al., 2004) and

POWDERED VS ENCAPSULATED FEED SUPPLEMENTS IN BROILERS

In conclusion, inclusion of a powdered phytogenic additive characterized by menthol and anethole at 150 mg/kg had no effect but only a tendency towards improved performance and AIA of phosphorus, whereas essential oils addition in encapsulated form characterized by caravacol, thymol, and limonene at 100 mg/kg improved performance as well as apparent ileal digestibility of nutrients in broilers, possibly due to improved secretion of digestive enzymes. In this study, the benefits of supplementation of broiler diet with a mixture of encapsulated essential oils were superior to the tested PFA in powdered form.

ACKNOWLEDGMENTS

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The study was financed by BIOMIN Holding GmbH, Erber Campus 1, 3131 Getzersdorf, Austria. The authors have no conflict of interest to disclose. For their technical support during the both broiler trials and for laboratory analysis, the authors express deep appreciation to L. Ebersbach, and K. Topp from the Institute of Animal Nutrition, Freie Universit¨ at Berlin, Germany.

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