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Ileal digestibility of amino acids for zero-tannin faba bean (Vicia faba L.) fed to broiler chicks
Research Note Ileal digestibility of amino acids for zero-tannin faba bean (Vicia faba L.) fed to broiler chicks T. A. Woyengo and C. M. Nyachoti1 Department of Animal Science, University of Manitoba, Winnipeg, Canada R3T 2N2 ibilities were determined by the difference method. On d 21, the birds were killed by cervical dislocation and contents of the lower-half of the ileum were obtained for determination of apparent AA digestibility. The CFB and ZFB were similar in CP, AA, neutral detergent fiber, and acid detergent fiber contents. The ZFB did not contain tannins, whereas the CFB contained 0.82% tannins. The ZFB had greater (P < 0.05) AID for all AA (except Met) compared with that of the CFB by an average of 12.6 percentage points. The 2 faba-bean types were similar in AID of Met. The results show that the ZFB evaluated in the current study had greater AID of AA than CFB, and hence, it may be a better source of protein for broiler chicks than CFB.
Key words: broiler, ileal digestibility, amino acid, zero-tannin faba bean 2012 Poultry Science 91:439–443 doi:10.3382/ps.2011-01678
INTRODUCTION
poultry. To our knowledge, the apparent ileal digestibility (AID) of AA for low-tannin faba beans has only been determined in one study (Nalle et al., 2010), and hence, such data are lacking in the NRC (1994) publication. Therefore, the objective of the current study was to determine the AID of AA in zero-tannin faba beans (ZFB; Vicia faba L.) for broilers.
The faba bean is rich in protein, and varieties of the same (faba beans) that are well-adapted to cool climates have been developed (Bond, 1987; Crepon et al., 2010). Therefore, it has potential to serve as an alternative to conventional sources of protein in poultry diets in temperate regions, such as Canada. However, the use of conventional faba beans (CFB) in the formulation of diets for monogastric animals, such as poultry, has been limited, partly by the high content of tannins, which reduces amino acid (AA) digestibility and utilization (Crepon et al., 2010). As a result, there has been increased interest in the development of low-tannin faba beans that could be used in large amounts for feeding monogastrics, including poultry (Crepon et al., 2010). The relentless efforts in plant breeding research have led to the development of low-tannin faba bean varieties (Crepon et al., 2010), which could replace considerable amounts of conventional sources of protein in poultry diets. However, there is limited information on the digestibility of AA in low-tannin faba beans fed to
MATERIALS AND METHODS Birds and Housing In total, 120 one-day-old male broiler chicks of the Ross 308 strain were obtained from a commercial hatchery (Carlton Hatchery, Grunthal, Manitoba, Canada) and used in this study. The chicks were individually weighed upon arrival and divided into 24 groups of 5 birds that were balanced for BW. They were then group-weighed and each group was housed in a cage within electrically heated Petersime battery brooders (Petersime Incubator Company, Gettysburg, OH). The brooder and room temperatures were set at 32 and 29°C, respectively, during the first week. Thereafter, heat supply in the brooder was switched off and room temperature was maintained at 29°C throughout the experiment. Light was provided for 24 h daily throughout the experiment. All experimental procedures were
©2012 Poultry Science Association Inc. Received June 14, 2011. Accepted November 19, 2011. 1 Corresponding author: [email protected]
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ABSTRACT An experiment was conducted to determine the apparent ileal digestibility (AID) of amino acids (AA) in zero-tannin faba beans (ZFB; Vicia faba L.) fed to broiler chicks. In total, 120 broiler chicks were divided into 24 groups of 5 birds that were balanced for BW and fed 1 of 3 diets in a completely randomized design (8 groups/diet) from d 14 to 21 of age. The diets were a soybean meal-cornstarch-based basal diet or the basal diet with soybean meal and cornstarch replaced by 50% of either conventional (tannin-containing) faba beans (CFB) or ZFB. The CFB were fed for comparison with ZFB. All of the 3 diets contained chromic oxide (0.3%) as an indigestible marker, and nutrient digest-
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reviewed and approved by the University of Manitoba Animal Care Protocol Management and Review Committee, and birds were handled in accordance with the guidelines described by the Canadian Council on Animal Care (CCAC, 2009).
Experimental Diets Three experimental diets consisting of a soybean meal-cornstarch-based basal diet, in which soybean was the sole source of protein, or the basal diet of cornstarch and soybean meal replaced by 50% of either CFB or ZFB (Table 1) were used. The varieties of the evaluated CFB and ZFB were Fatima and Snowbird, respectively, and were obtained from Dakedo Ventures Inc., Morris, Manitoba, Canada. The faba beans were ground through a 2-mm screen before diet formulation.
From d 1 to 13 of age, the birds were fed a standard commercial broiler starter diet. The 3 experimental diets were each randomly assigned to 8 groups from d 14 to 21 of age. Fresh water and feed were available to all chicks for ad libitum intake throughout the experiment. On d 21, the birds were weighed and killed by cervical dislocation and contents of the lower-half of the ileum (from the middle of the ileum to approximately 1 cm above the ileal-cecal junction) were obtained and stored frozen at −20°C for later determination of AID of N and AA. Table 1. Ingredient and nutrient composition of experimental diets (as fed) Diet1 Item Ingredient, % Soybean meal (45.8% CP) Cornstarch Faba beans Limestone Monocalcium phosphate Vitamin and mineral premix2 Chromic oxide Calculated nutrient content,3 % CP Ca Total P Nonphytate P
C-SBM
C-SBM-FB
50.0 45.0 — 1.6 1.6 1.5 0.3 24.0 1.05 0.66 0.45
20.0 25.0 50.0 1.6 1.6 1.5 0.3 23.1 0.96 0.47 0.37
1C-SBM = corn starch-soybean meal-based basal diet formulated to meet NRC (1994) nutrient requirements; C-SBM-FB = the basal diet with corn starch and soybean meal replaced by 50% of either conventional faba bean or zero-tannin faba bean. 2Provided per kilogram of diet: vitamin A, 8,255 IU; vitamin D , 3,000 3 IU; vitamin E, 30 IU; vitamin B12, 0.013 mg; vitamin K3, 2.0 mg; niacin, 41.2 mg; choline, 1,300.5 mg; folic acid, 1.0 mg; biotin, 0.25 mg; pyridoxine, 4.0 mg; thiamine, 4.0 mg; calcium pantothenic acid, 11.0 mg; riboflavin, 6.0 mg; manganese, 70.0 mg; zinc, 80.0 mg; iron, 80.0 mg; iodine, 0.5 mg; copper, 10 mg; and selenium, 0.3 mg. 3Calculated nutrient content was based on ingredient composition data from the NRC (1994). The analyzed CP values for C-SBM, CSBM-conventional faba bean, and C-SBM-zero-tannin faba bean-based diets were 25.4, 23.1, and 21.8%, respectively.
Ileal digesta samples were freeze-dried. Samples of faba beans, soybean meal, diets, and ileal digesta were finely ground in a coffee grinder (CBG5 Smart Grind; Applica Consumer Products Inc., Shelton, CT) and thoroughly mixed for analysis. All samples were analyzed for DM, N, and AA. The samples were further analyzed as follows: soybean meal, CFB, and ZFB for neutral detergent fiber (NDF) and acid detergent fiber (ADF); CFB and ZFB for condensed tannins; and diet and ileal digesta for Cr content. Dry matter was determined according to the AOAC (1990) method 925.09, whereas N was determined using an N analyzer (model CNS-2000; Leco Corp., St. Joseph, MI). Samples for AA analysis were prepared by acid hydrolysis according to the AOAC (1990) method 982.30 and as modified by Mills et al. (1989). Samples for analysis of sulfur-containing AA (Met and Cys) were subjected to performic acid oxidation before acid hydrolysis. Tryptophan was not determined. Samples for Cr analysis were ashed and digested according to procedures described by Williams et al. (1962) and were read on an inductively coupled plasma mass spectrometer (Varian Inc., Palo Alto, CA). The NDF and ADF were determined using an Ankom 200 Fiber Analyzer (Ankom Technology, Fairport, NY). The tannin content in faba bean samples was analyzed using the acid butanol method (Porter et al., 1986) standardized with purified sorghum procyanidin (condensed tannin) (Hagerman and Butler, 1980).
Calculations and Statistical Analysis The AID of N and AA in diets were calculated as described by Nyachoti et al. (1997). The AID of N and AA for soybean meal were determined using the direct method, whereas the difference method (Fan and Sauer, 1995) was used for the determination of AID of N and AA for CFB and ZFB. Data were analyzed using the GLM procedure of SAS (SAS 9.1, SAS Institute Inc., Cary, NC) as a completely randomized design. Treatment means were compared using simple contrasts.
RESULTS AND DISCUSSION The analyzed composition of feed ingredients is presented in Table 2. The ZFB was lower in DM than the CFB, and the reason for the low DM content for the ZFB is not clear. The CFB and ZFB were similar in CP, NDF, and ADF contents. The AA composition of CFB was similar to values reported by Ravindran et al. (2005) and Palander et al. (2006). The CFB and ZFB were similar in contents of AA (Table 2). Mariscal-Landin et al. (2002) have also reported similar AA contents in the CFB and ZFB. In both CFB and ZFB, Arg, Leu, and Lys were the most abundant indispensable AA and Glu the most abundant dispensable AA; whereas Met and Cys were the least abundant
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Experimental Procedure
Sample Preparation and Analyses
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RESEARCH NOTE
values reported by Ravindran et al. (2005) for CFB fed to broilers. The AID of Met for CFB observed in the current study (83%) was higher than the value (63%) reported by Ravindran et al. (2005) for CFB fed to broilers, and the reason for this is not clear. The AID of N and of all AA (except Met) was higher (P < 0.05) for ZFB than for CFB, which was due to the presence of tannins in the latter. Tannins precipitate protein, thereby reducing the availability of protein for digestion and absorption (Asquith and Butler, 1986; Ortiz et al., 1993). Tannins have also been shown to precipitate proteolytic digestive enzymes in poultry (Ahmed et al., 1991), implying that they can further reduce protein digestibility by reducing the activity of the digestive enzymes. The presence of undigested feed or inactivation of digestive enzymes in the gastrointestinal tract results in increased secretion of the digestive enzymes through negative feedback mechanisms (Hara et al. 2000; Morisset, 2008). Binding of tannic acid to pepsin in the stomach of rats was been shown to result in increased pepsin secretion (Mitjavila et al., 1973). Therefore, the binding of tannins to digestive enzymes can result in increased secretion of the enzymes via negative feedback mechanisms, leading to endogenous AA losses. The addition of tannins in diets for poultry has indeed been shown to reduce protein digestibility (Longstaff and McNab, 1991; Ortiz et al., 1993) and to increase endogenous losses of AA (Mansoori and Acamovic, 2007). The differences between the AID values of AA for CFB and ZFB were greatest for hydrophobic AA, including Val, Ile, Tyr, Phe, and Pro. Mitaru et al. (1984) also reported a greater improvement in AID of hydrophobic AA in pigs fed sorghum because of deactivation of tannins in the sorghum. In their study, tannins in
Table 2. Chemical composition of soybean meal, conventional faba bean (CFB), and zero-tannin faba bean (ZFB) diets (% DM basis) Item DM, % CP, % Indispensable amino acids, % Arg His Ile Leu Lys Met Phe Thr Val Dispensable amino acids, % Ala Asp Cys Glu Gly Pro Ser Tyr Neutral detergent fiber, % Acid detergent fiber, % Tannins, %
Soybean meal
CFB
ZFB
91.46 50.09 3.31 1.24 2.02 3.78 3.30 0.66 2.39 1.92 2.13 2.13 5.49 0.64 9.01 1.97 2.46 2.57 1.59 7.26 5.71 —
90.10 28.97 2.30 0.68 0.98 2.03 1.76 0.21 1.09 0.94 1.09 1.12 2.94 0.32 4.54 1.13 1.14 1.40 0.77 12.28 11.34 0.82
85.40 28.45 2.04 0.68 0.98 2.04 1.85 0.22 1.11 0.97 1.11 1.12 2.89 0.30 4.58 1.14 1.15 1.43 0.81 16.04 11.42 0.00
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indispensable and dispensable AA, respectively. Other studies (Mariscal-Landin et al., 2002; Ravindran et al., 2005; Nalle et al., 2010) have also reported similar AA profiles in CFB and ZFB, implying that the AA acid composition of faba beans does not change, regardless of tannin content. Therefore, the faba bean is a good source of Lys (one of the most limiting AA in practical poultry diets) but a poor source of Met (which is also one of the most limiting AA in practical poultry diets). The soybean meal used in the current study was also rich in Lys but not in Met. Similarly, other studies have shown that leguminous feedstuffs, including pulses like field peas, chick peas, and lupins, and soybean meal are good sources of Lys but not of Met (NRC, 1994; Ravindran et al., 2005; Nalle et al., 2010). The ZFB did not contain tannins, whereas the CFB contained 0.82% tannins. The tannin content in CFB was similar to the values reported by van der Poel et al. (1992) and Jansman et al. (1993) but lower than values reported by Oomah et al. (2011) for CFB. It should, however, be noted that in the current study and those of van der Poel et al. (1992) and Jansman et al. (1993) tannin phenols were used as analytical standards, whereas in the study of Oomah et al. (2011), a nontannin phenol was used as the analytical standard. Tannin analysis results have been reported to vary with the analytical method (Maxson and Rooney, 1972). Therefore, the differences in tannin content of faba beans among the studies could have been due to differences in methods of tannin analysis. The growth performance of birds was not affected by the type of faba bean (data not shown). Table 3 shows the AID of N and AA. The AID values of all AA (except Met) for CFB were similar to
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Table 3. Apparent ileal digestibility (%) of nitrogen and amino acids in soybean meal (SBM), conventional faba bean (CFB), and zero-tannin faba bean (ZFB) diets fed to broiler chicks1 P-value2 Item
1Data 2CFB
meal.
CFB
ZFB
SEM
CFB vs. ZFB
ZFB vs. SBM
87.9 94.0 91.7 90.0 90.4 92.0 87.6 90.9 86.6 89.1 90.1 88.7 73.4 93.0 87.7 89.8 89.3 91.1
77.5 83.0 74.0 62.5 71.4 80.9 83.1 70.6 69.5 63.4 74.0 74.8 58.1 81.2 68.6 66.7 75.0 69.1
84.4 90.7 86.5 80.8 84.7 89.9 81.7 84.9 82.2 81.7 86.2 85.6 70.1 90.6 80.6 80.9 85.3 84.4
1.96 1.72 1.94 2.64 2.28 1.86 2.05 2.49 2.41 2.70 2.06 2.11 3.64 1.82 1.94 2.56 2.00 2.35
0.021 0.005 <0.001 <0.001 <0.001 0.003 0.633 <0.001 0.001 <0.001 <0.001 0.002 0.029 0.002 <0.001 <0.001 0.002 <0.001
0.219 0.189 0.076 0.022 0.090 0.434 0.051 0.104 0.211 0.065 0.199 0.312 0.525 0.374 0.017 0.023 0.169 0.057
are means of 8 pens of broilers with 5 broilers per pen. vs. ZFB = contrast of conventional faba beans vs. zero-tannin faba bean; and ZFB vs. SBM = contrast of zero-tannin faba bean vs. soybean
the ileal digesta were more associated with hydrophobic AA (Ile, Val, Pro, and Tyr) than hydrophilic AA, implying that tannins have higher affinity for the former than for latter. Therefore, in the current study, the large differences between CFB and ZFB, with regard to the AID values of hydrophobic AA, could be attributed to the fact that tannins have high affinity for hydrophobic AA. The AID of AA values for the ZFB were similar to those for soybean meal, which is commonly used in the formulation of poultry diets. The AID of AA for the ZFB were also similar to those reported by Adedokun et al. (2008) for soybean meal fed to broilers. Therefore, it appears that the AA digestibilities in the ZFB are comparable to that of soybean meal, and hence, ZFB could replace large amounts of soybean meal in poultry diets. In conclusion, the ZFB used in the current study had greater AID of AA than CFB, and hence, it is a better source of AA for poultry than the CFB. The digestibility of AA in the ZFB was similar to that of soybean meal. Therefore, the ZFB could replace a considerable portion of soybean meal in broiler chicken diets.
ACKNOWLEDGMENTS The authors thank Harry Muc (University of Manitoba, Winnipeg, Canada) for his technical assistance and N. Matanga (University of Manitoba) for assistance with taking care of the birds. The authors also thank Ann E. Hagerman (Miami University, Oxford, OH) for the assistance in tannin analysis and interpretation of tannin analysis data.
REFERENCES Adedokun, S. A., O. Adeola, C. M. Parsons, M. S. Lilburn, and T. J. Applegate. 2008. Standardized ileal amino acid digestibility of plant feedstuffs in broiler chickens and turkey poults using a nitrogen-free or casein diet. Poult. Sci. 87:2535–2548. Ahmed, A. E., R. Smithard, and M. Ellis. 1991. Activities of enzymes of the pancreas, and the lumen and mucosa of small intestine in growing broiler cockerels fed on tannin-containing diets. Br. J. Nutr. 65:189–197. AOAC. 1990. Official Methods of Analysis. 15th ed. Assoc. Off. Anal. Chem., Washington, DC. Asquith, T. N., and L. G. Butler. 1986. Interaction of condensed tannins with selected proteins. Phytochemistry 25:1591–1593. Bond, D. A. 1987. Recent developments in breeding field beans (Vicia faba L.). Plant Breed. 99:1–26. Canadian Council on Animal Care. 2009. Guidelines on: The care and use of farm animals in research, teaching, and testing. Canadian Council on Animal Care, Ottawa, ON, Canada. Crepon, K., P. Marget, C. Peyronnet, B. Carrouee, P. Arese, and G. Duc. 2010. Nutritional value of faba bean (Vicia faba L.) seeds for feed and food. Field Crops Res. 115:329–339. Fan, M. Z., and W. C. Sauer. 1995. Determination of apparent ileal amino acid digestibility in barley and canola meal for pigs with the direct, difference, and regression methods. J. Anim. Sci. 73:2364–2374. Hagerman, A. E., and L. G. Butler. 1980. Condensed tannin purification and characterization of tannin-associated proteins. J. Agric. Food Chem. 28:947–952. Hara, H., S. Ohyama, and T. Hira. 2000. Luminal dietary protein, not amino acids, induces pancreatic protease via CCK in pancreaticobiliary-diverted rats. Am. J. Physiol. Gastrointest. Liver Physiol. 278:G937–G945. Jansman, A. J. M., J. Huisman, and A. F. B. van der Poel. 1993. Ileal and faecal digestibility in piglets of field beans (Vicia faba L.) varying in tannin content. Anim. Feed Sci. Technol. 42:83–96. Longstaff, M., and J. M. McNab. 1991. The inhibitory effects of hull polysaccharides and tannins of field beans (Vicia faba L.) on the digestion of amino acids, starch, and lipid and on digestive enzyme activities in young chicks. Br. J. Nutr. 65:199–216. Mansoori, B., and T. Acamovic. 2007. The effect of tannic acid on the excretion of endogenous methionine, histidine, and lysine with broilers. Anim. Feed Sci. Technol. 134:198–210.
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N Indispensable amino acid Arg His Ile Leu Lys Met Phe Thr Val Dispensable amino acid Ala Asp Cys Glu Gly Pro Ser Tyr
SBM
RESEARCH NOTE
Oomah, B. D., G. Luc, C. Leprelle, J. C. G. Drover, J. E. Harrison, and M. Olson. 2011. Phenolics, phytic acid, and phytase in canadian-grown low-tannin faba bean (Vicia faba L.) genotypes. J. Agric. Food Chem. 59:3763–3771. Ortiz, L. T., C. Centeno, and J. Trevino. 1993. Tannins in faba bean seeds: Effects on the digestion of protein and amino acids in growing chicks. Anim. Feed Sci. Technol. 41:271–278. Palander, S., P. Laurinen, S. Perttila, J. Valaja, and K. Partanen. 2006. Protein and amino acid digestibility and metabolizable energy value of pea (Pisum sativum), faba bean (Vicia faba), and lupin (Lupinus angustifolius) seeds for turkeys of different age. Anim. Feed Sci. Technol. 127:89–100. Porter, L. J., L. N. Hrstich, and B. G. Chan. 1986. The conversion of procyanidins and prodelphinidins to cyaniding and delphinidin. Phytochemistry 25:223–230. Ravindran, V., L. I. Hew, G. Ravindran, and W. L. Bryden. 2005. Apparent ileal digestibility of amino acids in dietary ingredients for broiler chickens. Anim. Sci. 81:85–97. van der Poel, F. B., S. Gravendeel, D. J. van Kleef, A. J. M. Jansman, and B. Kemp. 1992. Tannin-containing faba beans (Vicia fabu L.): Effects of methods of processing on ileal digestibility of protein and starch for growing pigs. Anim. Feed Sci. Technol. 36:205–214. Williams, C. H., D. J. David, and O. Iismaa. 1962. The determination of chromic oxide in fecal samples by atomic absorption spectrophotometry. J. Agric. Sci. 59:381–385.
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Mariscal-Landin, G., Y. Lebreton, and B. Seve. 2002. Apparent and standardized true ileal digestibility of protein and amino acids from faba bean, lupin, and pea, provided as whole seeds, dehulled, or extruded in pig diets. Anim. Feed Sci. Technol. 97:183–198. Maxson, E. D., and L. W. Rooney. 1972. Evaluation of methods for tannin analysis in sorghum grain. Cereal. Chem. 49:719–728. Mills, P. A., R. G. Rotter, and R. R. Marquardt. 1989. Modification of the glucosamine method for the quantification of fungal contamination. Can. J. Anim. Sci. 56:1105–1107. Mitaru, B. N., R. D. Reichert, and R. Blair. 1984. The binding of dietary protein by sorghum tannins in the digestive tract of pigs. J. Nutr. 114:1787–1796. Mitjavila, S., G. de Saint Blanquat, and R. Derache. 1973. Effet de l’acide tannique sur la sécrétion gastrique chez le rat. Ann. Nutr. Metab. 15:163–170. Morisset, J. 2008. Negative control of human pancreatic secretion: Physiological mechanisms and factors. Pancreas 37:1–12. Nalle, C. L., V. Ravindran, and G. Ravindran. 2010. Nutritional value of faba beans (Vicia faba L.) for broilers: Apparent metabolisable energy, ileal amino acid digestibility, and production performance. Anim. Feed Sci. Technol. 156:104–111. NRC. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC. Nyachoti, C. M., C. F. M. de Lange, and H. Schulze. 1997. Estimating endogenous amino acid flows at the terminal ileum and true ileal amino acid digestibilities in feedstuffs for growing pigs using the homoarginine method. J. Anim. Sci. 75:3206–3213.
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Key words: broiler, ileal digestibility, amino acid, zero-tannin faba bean 2012 Poultry Science 91:439–443 doi:10.3382/ps.2011-01678
INTRODUCTION
poultry. To our knowledge, the apparent ileal digestibility (AID) of AA for low-tannin faba beans has only been determined in one study (Nalle et al., 2010), and hence, such data are lacking in the NRC (1994) publication. Therefore, the objective of the current study was to determine the AID of AA in zero-tannin faba beans (ZFB; Vicia faba L.) for broilers.
The faba bean is rich in protein, and varieties of the same (faba beans) that are well-adapted to cool climates have been developed (Bond, 1987; Crepon et al., 2010). Therefore, it has potential to serve as an alternative to conventional sources of protein in poultry diets in temperate regions, such as Canada. However, the use of conventional faba beans (CFB) in the formulation of diets for monogastric animals, such as poultry, has been limited, partly by the high content of tannins, which reduces amino acid (AA) digestibility and utilization (Crepon et al., 2010). As a result, there has been increased interest in the development of low-tannin faba beans that could be used in large amounts for feeding monogastrics, including poultry (Crepon et al., 2010). The relentless efforts in plant breeding research have led to the development of low-tannin faba bean varieties (Crepon et al., 2010), which could replace considerable amounts of conventional sources of protein in poultry diets. However, there is limited information on the digestibility of AA in low-tannin faba beans fed to
MATERIALS AND METHODS Birds and Housing In total, 120 one-day-old male broiler chicks of the Ross 308 strain were obtained from a commercial hatchery (Carlton Hatchery, Grunthal, Manitoba, Canada) and used in this study. The chicks were individually weighed upon arrival and divided into 24 groups of 5 birds that were balanced for BW. They were then group-weighed and each group was housed in a cage within electrically heated Petersime battery brooders (Petersime Incubator Company, Gettysburg, OH). The brooder and room temperatures were set at 32 and 29°C, respectively, during the first week. Thereafter, heat supply in the brooder was switched off and room temperature was maintained at 29°C throughout the experiment. Light was provided for 24 h daily throughout the experiment. All experimental procedures were
©2012 Poultry Science Association Inc. Received June 14, 2011. Accepted November 19, 2011. 1 Corresponding author: [email protected]
439
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 6, 2015
ABSTRACT An experiment was conducted to determine the apparent ileal digestibility (AID) of amino acids (AA) in zero-tannin faba beans (ZFB; Vicia faba L.) fed to broiler chicks. In total, 120 broiler chicks were divided into 24 groups of 5 birds that were balanced for BW and fed 1 of 3 diets in a completely randomized design (8 groups/diet) from d 14 to 21 of age. The diets were a soybean meal-cornstarch-based basal diet or the basal diet with soybean meal and cornstarch replaced by 50% of either conventional (tannin-containing) faba beans (CFB) or ZFB. The CFB were fed for comparison with ZFB. All of the 3 diets contained chromic oxide (0.3%) as an indigestible marker, and nutrient digest-
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reviewed and approved by the University of Manitoba Animal Care Protocol Management and Review Committee, and birds were handled in accordance with the guidelines described by the Canadian Council on Animal Care (CCAC, 2009).
Experimental Diets Three experimental diets consisting of a soybean meal-cornstarch-based basal diet, in which soybean was the sole source of protein, or the basal diet of cornstarch and soybean meal replaced by 50% of either CFB or ZFB (Table 1) were used. The varieties of the evaluated CFB and ZFB were Fatima and Snowbird, respectively, and were obtained from Dakedo Ventures Inc., Morris, Manitoba, Canada. The faba beans were ground through a 2-mm screen before diet formulation.
From d 1 to 13 of age, the birds were fed a standard commercial broiler starter diet. The 3 experimental diets were each randomly assigned to 8 groups from d 14 to 21 of age. Fresh water and feed were available to all chicks for ad libitum intake throughout the experiment. On d 21, the birds were weighed and killed by cervical dislocation and contents of the lower-half of the ileum (from the middle of the ileum to approximately 1 cm above the ileal-cecal junction) were obtained and stored frozen at −20°C for later determination of AID of N and AA. Table 1. Ingredient and nutrient composition of experimental diets (as fed) Diet1 Item Ingredient, % Soybean meal (45.8% CP) Cornstarch Faba beans Limestone Monocalcium phosphate Vitamin and mineral premix2 Chromic oxide Calculated nutrient content,3 % CP Ca Total P Nonphytate P
C-SBM
C-SBM-FB
50.0 45.0 — 1.6 1.6 1.5 0.3 24.0 1.05 0.66 0.45
20.0 25.0 50.0 1.6 1.6 1.5 0.3 23.1 0.96 0.47 0.37
1C-SBM = corn starch-soybean meal-based basal diet formulated to meet NRC (1994) nutrient requirements; C-SBM-FB = the basal diet with corn starch and soybean meal replaced by 50% of either conventional faba bean or zero-tannin faba bean. 2Provided per kilogram of diet: vitamin A, 8,255 IU; vitamin D , 3,000 3 IU; vitamin E, 30 IU; vitamin B12, 0.013 mg; vitamin K3, 2.0 mg; niacin, 41.2 mg; choline, 1,300.5 mg; folic acid, 1.0 mg; biotin, 0.25 mg; pyridoxine, 4.0 mg; thiamine, 4.0 mg; calcium pantothenic acid, 11.0 mg; riboflavin, 6.0 mg; manganese, 70.0 mg; zinc, 80.0 mg; iron, 80.0 mg; iodine, 0.5 mg; copper, 10 mg; and selenium, 0.3 mg. 3Calculated nutrient content was based on ingredient composition data from the NRC (1994). The analyzed CP values for C-SBM, CSBM-conventional faba bean, and C-SBM-zero-tannin faba bean-based diets were 25.4, 23.1, and 21.8%, respectively.
Ileal digesta samples were freeze-dried. Samples of faba beans, soybean meal, diets, and ileal digesta were finely ground in a coffee grinder (CBG5 Smart Grind; Applica Consumer Products Inc., Shelton, CT) and thoroughly mixed for analysis. All samples were analyzed for DM, N, and AA. The samples were further analyzed as follows: soybean meal, CFB, and ZFB for neutral detergent fiber (NDF) and acid detergent fiber (ADF); CFB and ZFB for condensed tannins; and diet and ileal digesta for Cr content. Dry matter was determined according to the AOAC (1990) method 925.09, whereas N was determined using an N analyzer (model CNS-2000; Leco Corp., St. Joseph, MI). Samples for AA analysis were prepared by acid hydrolysis according to the AOAC (1990) method 982.30 and as modified by Mills et al. (1989). Samples for analysis of sulfur-containing AA (Met and Cys) were subjected to performic acid oxidation before acid hydrolysis. Tryptophan was not determined. Samples for Cr analysis were ashed and digested according to procedures described by Williams et al. (1962) and were read on an inductively coupled plasma mass spectrometer (Varian Inc., Palo Alto, CA). The NDF and ADF were determined using an Ankom 200 Fiber Analyzer (Ankom Technology, Fairport, NY). The tannin content in faba bean samples was analyzed using the acid butanol method (Porter et al., 1986) standardized with purified sorghum procyanidin (condensed tannin) (Hagerman and Butler, 1980).
Calculations and Statistical Analysis The AID of N and AA in diets were calculated as described by Nyachoti et al. (1997). The AID of N and AA for soybean meal were determined using the direct method, whereas the difference method (Fan and Sauer, 1995) was used for the determination of AID of N and AA for CFB and ZFB. Data were analyzed using the GLM procedure of SAS (SAS 9.1, SAS Institute Inc., Cary, NC) as a completely randomized design. Treatment means were compared using simple contrasts.
RESULTS AND DISCUSSION The analyzed composition of feed ingredients is presented in Table 2. The ZFB was lower in DM than the CFB, and the reason for the low DM content for the ZFB is not clear. The CFB and ZFB were similar in CP, NDF, and ADF contents. The AA composition of CFB was similar to values reported by Ravindran et al. (2005) and Palander et al. (2006). The CFB and ZFB were similar in contents of AA (Table 2). Mariscal-Landin et al. (2002) have also reported similar AA contents in the CFB and ZFB. In both CFB and ZFB, Arg, Leu, and Lys were the most abundant indispensable AA and Glu the most abundant dispensable AA; whereas Met and Cys were the least abundant
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Experimental Procedure
Sample Preparation and Analyses
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values reported by Ravindran et al. (2005) for CFB fed to broilers. The AID of Met for CFB observed in the current study (83%) was higher than the value (63%) reported by Ravindran et al. (2005) for CFB fed to broilers, and the reason for this is not clear. The AID of N and of all AA (except Met) was higher (P < 0.05) for ZFB than for CFB, which was due to the presence of tannins in the latter. Tannins precipitate protein, thereby reducing the availability of protein for digestion and absorption (Asquith and Butler, 1986; Ortiz et al., 1993). Tannins have also been shown to precipitate proteolytic digestive enzymes in poultry (Ahmed et al., 1991), implying that they can further reduce protein digestibility by reducing the activity of the digestive enzymes. The presence of undigested feed or inactivation of digestive enzymes in the gastrointestinal tract results in increased secretion of the digestive enzymes through negative feedback mechanisms (Hara et al. 2000; Morisset, 2008). Binding of tannic acid to pepsin in the stomach of rats was been shown to result in increased pepsin secretion (Mitjavila et al., 1973). Therefore, the binding of tannins to digestive enzymes can result in increased secretion of the enzymes via negative feedback mechanisms, leading to endogenous AA losses. The addition of tannins in diets for poultry has indeed been shown to reduce protein digestibility (Longstaff and McNab, 1991; Ortiz et al., 1993) and to increase endogenous losses of AA (Mansoori and Acamovic, 2007). The differences between the AID values of AA for CFB and ZFB were greatest for hydrophobic AA, including Val, Ile, Tyr, Phe, and Pro. Mitaru et al. (1984) also reported a greater improvement in AID of hydrophobic AA in pigs fed sorghum because of deactivation of tannins in the sorghum. In their study, tannins in
Table 2. Chemical composition of soybean meal, conventional faba bean (CFB), and zero-tannin faba bean (ZFB) diets (% DM basis) Item DM, % CP, % Indispensable amino acids, % Arg His Ile Leu Lys Met Phe Thr Val Dispensable amino acids, % Ala Asp Cys Glu Gly Pro Ser Tyr Neutral detergent fiber, % Acid detergent fiber, % Tannins, %
Soybean meal
CFB
ZFB
91.46 50.09 3.31 1.24 2.02 3.78 3.30 0.66 2.39 1.92 2.13 2.13 5.49 0.64 9.01 1.97 2.46 2.57 1.59 7.26 5.71 —
90.10 28.97 2.30 0.68 0.98 2.03 1.76 0.21 1.09 0.94 1.09 1.12 2.94 0.32 4.54 1.13 1.14 1.40 0.77 12.28 11.34 0.82
85.40 28.45 2.04 0.68 0.98 2.04 1.85 0.22 1.11 0.97 1.11 1.12 2.89 0.30 4.58 1.14 1.15 1.43 0.81 16.04 11.42 0.00
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indispensable and dispensable AA, respectively. Other studies (Mariscal-Landin et al., 2002; Ravindran et al., 2005; Nalle et al., 2010) have also reported similar AA profiles in CFB and ZFB, implying that the AA acid composition of faba beans does not change, regardless of tannin content. Therefore, the faba bean is a good source of Lys (one of the most limiting AA in practical poultry diets) but a poor source of Met (which is also one of the most limiting AA in practical poultry diets). The soybean meal used in the current study was also rich in Lys but not in Met. Similarly, other studies have shown that leguminous feedstuffs, including pulses like field peas, chick peas, and lupins, and soybean meal are good sources of Lys but not of Met (NRC, 1994; Ravindran et al., 2005; Nalle et al., 2010). The ZFB did not contain tannins, whereas the CFB contained 0.82% tannins. The tannin content in CFB was similar to the values reported by van der Poel et al. (1992) and Jansman et al. (1993) but lower than values reported by Oomah et al. (2011) for CFB. It should, however, be noted that in the current study and those of van der Poel et al. (1992) and Jansman et al. (1993) tannin phenols were used as analytical standards, whereas in the study of Oomah et al. (2011), a nontannin phenol was used as the analytical standard. Tannin analysis results have been reported to vary with the analytical method (Maxson and Rooney, 1972). Therefore, the differences in tannin content of faba beans among the studies could have been due to differences in methods of tannin analysis. The growth performance of birds was not affected by the type of faba bean (data not shown). Table 3 shows the AID of N and AA. The AID values of all AA (except Met) for CFB were similar to
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Table 3. Apparent ileal digestibility (%) of nitrogen and amino acids in soybean meal (SBM), conventional faba bean (CFB), and zero-tannin faba bean (ZFB) diets fed to broiler chicks1 P-value2 Item
1Data 2CFB
meal.
CFB
ZFB
SEM
CFB vs. ZFB
ZFB vs. SBM
87.9 94.0 91.7 90.0 90.4 92.0 87.6 90.9 86.6 89.1 90.1 88.7 73.4 93.0 87.7 89.8 89.3 91.1
77.5 83.0 74.0 62.5 71.4 80.9 83.1 70.6 69.5 63.4 74.0 74.8 58.1 81.2 68.6 66.7 75.0 69.1
84.4 90.7 86.5 80.8 84.7 89.9 81.7 84.9 82.2 81.7 86.2 85.6 70.1 90.6 80.6 80.9 85.3 84.4
1.96 1.72 1.94 2.64 2.28 1.86 2.05 2.49 2.41 2.70 2.06 2.11 3.64 1.82 1.94 2.56 2.00 2.35
0.021 0.005 <0.001 <0.001 <0.001 0.003 0.633 <0.001 0.001 <0.001 <0.001 0.002 0.029 0.002 <0.001 <0.001 0.002 <0.001
0.219 0.189 0.076 0.022 0.090 0.434 0.051 0.104 0.211 0.065 0.199 0.312 0.525 0.374 0.017 0.023 0.169 0.057
are means of 8 pens of broilers with 5 broilers per pen. vs. ZFB = contrast of conventional faba beans vs. zero-tannin faba bean; and ZFB vs. SBM = contrast of zero-tannin faba bean vs. soybean
the ileal digesta were more associated with hydrophobic AA (Ile, Val, Pro, and Tyr) than hydrophilic AA, implying that tannins have higher affinity for the former than for latter. Therefore, in the current study, the large differences between CFB and ZFB, with regard to the AID values of hydrophobic AA, could be attributed to the fact that tannins have high affinity for hydrophobic AA. The AID of AA values for the ZFB were similar to those for soybean meal, which is commonly used in the formulation of poultry diets. The AID of AA for the ZFB were also similar to those reported by Adedokun et al. (2008) for soybean meal fed to broilers. Therefore, it appears that the AA digestibilities in the ZFB are comparable to that of soybean meal, and hence, ZFB could replace large amounts of soybean meal in poultry diets. In conclusion, the ZFB used in the current study had greater AID of AA than CFB, and hence, it is a better source of AA for poultry than the CFB. The digestibility of AA in the ZFB was similar to that of soybean meal. Therefore, the ZFB could replace a considerable portion of soybean meal in broiler chicken diets.
ACKNOWLEDGMENTS The authors thank Harry Muc (University of Manitoba, Winnipeg, Canada) for his technical assistance and N. Matanga (University of Manitoba) for assistance with taking care of the birds. The authors also thank Ann E. Hagerman (Miami University, Oxford, OH) for the assistance in tannin analysis and interpretation of tannin analysis data.
REFERENCES Adedokun, S. A., O. Adeola, C. M. Parsons, M. S. Lilburn, and T. J. Applegate. 2008. Standardized ileal amino acid digestibility of plant feedstuffs in broiler chickens and turkey poults using a nitrogen-free or casein diet. Poult. Sci. 87:2535–2548. Ahmed, A. E., R. Smithard, and M. Ellis. 1991. Activities of enzymes of the pancreas, and the lumen and mucosa of small intestine in growing broiler cockerels fed on tannin-containing diets. Br. J. Nutr. 65:189–197. AOAC. 1990. Official Methods of Analysis. 15th ed. Assoc. Off. Anal. Chem., Washington, DC. Asquith, T. N., and L. G. Butler. 1986. Interaction of condensed tannins with selected proteins. Phytochemistry 25:1591–1593. Bond, D. A. 1987. Recent developments in breeding field beans (Vicia faba L.). Plant Breed. 99:1–26. Canadian Council on Animal Care. 2009. Guidelines on: The care and use of farm animals in research, teaching, and testing. Canadian Council on Animal Care, Ottawa, ON, Canada. Crepon, K., P. Marget, C. Peyronnet, B. Carrouee, P. Arese, and G. Duc. 2010. Nutritional value of faba bean (Vicia faba L.) seeds for feed and food. Field Crops Res. 115:329–339. Fan, M. Z., and W. C. Sauer. 1995. Determination of apparent ileal amino acid digestibility in barley and canola meal for pigs with the direct, difference, and regression methods. J. Anim. Sci. 73:2364–2374. Hagerman, A. E., and L. G. Butler. 1980. Condensed tannin purification and characterization of tannin-associated proteins. J. Agric. Food Chem. 28:947–952. Hara, H., S. Ohyama, and T. Hira. 2000. Luminal dietary protein, not amino acids, induces pancreatic protease via CCK in pancreaticobiliary-diverted rats. Am. J. Physiol. Gastrointest. Liver Physiol. 278:G937–G945. Jansman, A. J. M., J. Huisman, and A. F. B. van der Poel. 1993. Ileal and faecal digestibility in piglets of field beans (Vicia faba L.) varying in tannin content. Anim. Feed Sci. Technol. 42:83–96. Longstaff, M., and J. M. McNab. 1991. The inhibitory effects of hull polysaccharides and tannins of field beans (Vicia faba L.) on the digestion of amino acids, starch, and lipid and on digestive enzyme activities in young chicks. Br. J. Nutr. 65:199–216. Mansoori, B., and T. Acamovic. 2007. The effect of tannic acid on the excretion of endogenous methionine, histidine, and lysine with broilers. Anim. Feed Sci. Technol. 134:198–210.
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N Indispensable amino acid Arg His Ile Leu Lys Met Phe Thr Val Dispensable amino acid Ala Asp Cys Glu Gly Pro Ser Tyr
SBM
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Oomah, B. D., G. Luc, C. Leprelle, J. C. G. Drover, J. E. Harrison, and M. Olson. 2011. Phenolics, phytic acid, and phytase in canadian-grown low-tannin faba bean (Vicia faba L.) genotypes. J. Agric. Food Chem. 59:3763–3771. Ortiz, L. T., C. Centeno, and J. Trevino. 1993. Tannins in faba bean seeds: Effects on the digestion of protein and amino acids in growing chicks. Anim. Feed Sci. Technol. 41:271–278. Palander, S., P. Laurinen, S. Perttila, J. Valaja, and K. Partanen. 2006. Protein and amino acid digestibility and metabolizable energy value of pea (Pisum sativum), faba bean (Vicia faba), and lupin (Lupinus angustifolius) seeds for turkeys of different age. Anim. Feed Sci. Technol. 127:89–100. Porter, L. J., L. N. Hrstich, and B. G. Chan. 1986. The conversion of procyanidins and prodelphinidins to cyaniding and delphinidin. Phytochemistry 25:223–230. Ravindran, V., L. I. Hew, G. Ravindran, and W. L. Bryden. 2005. Apparent ileal digestibility of amino acids in dietary ingredients for broiler chickens. Anim. Sci. 81:85–97. van der Poel, F. B., S. Gravendeel, D. J. van Kleef, A. J. M. Jansman, and B. Kemp. 1992. Tannin-containing faba beans (Vicia fabu L.): Effects of methods of processing on ileal digestibility of protein and starch for growing pigs. Anim. Feed Sci. Technol. 36:205–214. Williams, C. H., D. J. David, and O. Iismaa. 1962. The determination of chromic oxide in fecal samples by atomic absorption spectrophotometry. J. Agric. Sci. 59:381–385.
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 6, 2015
Mariscal-Landin, G., Y. Lebreton, and B. Seve. 2002. Apparent and standardized true ileal digestibility of protein and amino acids from faba bean, lupin, and pea, provided as whole seeds, dehulled, or extruded in pig diets. Anim. Feed Sci. Technol. 97:183–198. Maxson, E. D., and L. W. Rooney. 1972. Evaluation of methods for tannin analysis in sorghum grain. Cereal. Chem. 49:719–728. Mills, P. A., R. G. Rotter, and R. R. Marquardt. 1989. Modification of the glucosamine method for the quantification of fungal contamination. Can. J. Anim. Sci. 56:1105–1107. Mitaru, B. N., R. D. Reichert, and R. Blair. 1984. The binding of dietary protein by sorghum tannins in the digestive tract of pigs. J. Nutr. 114:1787–1796. Mitjavila, S., G. de Saint Blanquat, and R. Derache. 1973. Effet de l’acide tannique sur la sécrétion gastrique chez le rat. Ann. Nutr. Metab. 15:163–170. Morisset, J. 2008. Negative control of human pancreatic secretion: Physiological mechanisms and factors. Pancreas 37:1–12. Nalle, C. L., V. Ravindran, and G. Ravindran. 2010. Nutritional value of faba beans (Vicia faba L.) for broilers: Apparent metabolisable energy, ileal amino acid digestibility, and production performance. Anim. Feed Sci. Technol. 156:104–111. NRC. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC. Nyachoti, C. M., C. F. M. de Lange, and H. Schulze. 1997. Estimating endogenous amino acid flows at the terminal ileum and true ileal amino acid digestibilities in feedstuffs for growing pigs using the homoarginine method. J. Anim. Sci. 75:3206–3213.
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