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Unformatted text preview: METABOLISM AND NUTRITION Responses of Broiler Chickens to Cottonseed- and Soybean Meal-Based Diets at Several Protein Levels 1 K. G. Sterling,* E. F. Costa,† M. H. Henry,* ,2 G. M. Pesti,* ,3 and R. I. Bakalli* *Department of Poultry Science, University of Georgia, Athens, Georgia 30602-2772; and †Department of Agricultural and Applied Economics, University of Georgia, Athens, Georgia 30602 ABSTRACT Three experiments were conducted to evaluate the performance of broiler chicks fed diets with cottonseed meal (CSM) as the major protein source. Ex- periment 1 was a 3 × 2 factorial with three crude protein levels (17, 20, and 23%) by two protein sources, CSM or soybean meal (SBM). Diets were fed to male broilers (n = 840) in floor pens from 21 to 49 d of age. L-Lysine-HCl was added to keep lysine at 5.22% of protein. Protein source and level had significant ( P < 0.001) effects on BW gain (BWG) and feed conversion ratio (FCR), respectively (no source by level interactions). The average BWG were 1.80, 2.00, and 2.00 kg for birds fed CSM-based diets, compared with 1.93, 2.09, and 2.21 for SBM-based diets (17, 20, and 23% protein, respectively). The average FCR were 2.56, 2.31, and 2.25 for CSM-fed broilers and 2.39, 2.16, and 2.08 for SBM-fed broilers. Significant effects of protein source or level were found for percentage of chilled carcass, fillets, tenders, saddles, and fat pads. In Experiment 2, male broiler chicks (n = 336) were used to determine the lysine requirement of chicks fed a corn and CSM-based diet with 20% CSM and 6% SBM. The basal diet contained by calculation 3,200 kcal/kg of ME, 20% CP, and 0.81% lysine. Graded levels of lysine (0.81 to 1.30% in increments of 0.07%) were fed to chicks from 10 ( Key words : broiler, cottonseed meal, lysine, soybean meal, crude protein) 2002 Poultry Science 81:217–226 INTRODUCTION Soybean meal (SBM) is the most widely used protein source in the formulation of poultry diets. However, when the price of soybean meal increases, poultry nutri- tionists seek sources of protein that are more economical to use in the formulation of poultry rations. Cottonseed meal (CSM) has long been considered a potential source 2002 Poultry Science Association, Inc. Received for publication June 8, 2001. Accepted for publication September 27, 2001. 1 Funded by: Georgia Food Processing Council, Atlanta, GA 30332. 2 Present address: U.S. Food & Drug Administration, Center of Veteri- nary Medicine, Rockville, MD 20855. 3 To whom correspondence should be addressed: gpesti@ arches.uga.edu. 217 to 20 d, and BW and residual feed were measured at 20 d. The requirement, as determined by breakpoint analy- sis, was 1.023 ± 0.01% lysine (R 2 = 0.84) for BWG and 1.028 ± 0.02% lysine (R 2 = 0.56) for FCR. In Experiment 3, a 2 × 2 × 4 factorial arrangement of treatments involved feeding CSM or SBM to male and female broiler chicks (n = 768) from 21 to 42 d at four dietary protein levels (17, 20, 23, and 26% CP). Lysine was kept at 5.5% of the(17, 20, 23, and 26% CP)....
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This note was uploaded on 07/28/2011 for the course VET 4335 taught by Professor Sakomura during the Spring '11 term at University of the South Pacific, Fiji.
- Spring '11