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Unformatted text preview: 2004 Poultry Science Association, Inc. Effects of Excess Methionine from Meeting Needs for Total Sulfur Amino Acids on Utilization of Diets Low in Crude Protein by Broiler Chicks 1 J. Si,* C. A. Fritts,* P. W. Waldroup,* ,2 and D. J. Burnham† Poultry Science Department, University of Arkansas, Fayetteville, Arkansas 72701; and ‡Ajinomoto Heartland LLC, Chicago, Illinois 60631 Primary Audience: Nutritionists, Researchers, Feed Manufacturers SUMMARY Failure to obtain optimum performance by broilers fed low CP diets supplemented with amino acids may be due to a number of factors, including potential toxic effects of amino acids in excess of requirements. The objective of the present study was to evaluate the effect of excess levels of Met on performance of broilers fed low CP diets. Corn and soybean meal of known composition were used to formulate diets with 22, 20, 18, and 16% CP with 100 and 110% of NRC recommendations. DL-Methionine was used to meet Met and TSAA requirements; the dietary levels of Met exceeded minimum needs. Within each CP level, 2 additional series were prepared. For one series, only the amount of DL-methionine needed to reach the Met requirement was added, leaving a calculated deficit of TSAA. For a second series, excess Met was replaced with sufficient Cys to meet Met and TSAA exactly. Each of the test diets and a 23% CP positive control were fed to 6 replicate pens of 5 male broiler chicks from 1 to 21 d of age. Performance of the birds fed 22% CP diets did not differ significantly from that of chicks fed the positive control. Chicks fed diets with less than 22% CP had significantly lower BW and increased FCR regardless of level of amino acid supplementation. There was no significant effect of Met status on performance, indicating that corn-soybean meal diets do not appear to be deficit in Cys and do not respond to levels of Met greater than minimum NRC recommendations for Met. Excess levels of Met in this study did not appear to contribute to the reduced performance at low CP levels. Key words: broiler, amino acid balance, methionine, nitrogen pollution 2004 J. Appl. Poult. Res. 13:579–587 DESCRIPTION OF PROBLEM Attempts to reduce overall CP content of broiler diets have been successful to a point, 1 Published with approval of the Director, Arkansas Agricultural Experiment Station, Fayetteville, AR 72701. Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the University of Arkansas and does not imply its approval to the exclusion of other products that may be suitable. 2 To whom correspondence should be addressed: Waldroup@uark.edu. but most researchers agree that at some reduced level of CP overall performance of birds suffers even though, theoretically, one has met all re- quirements for those amino acids considered es- JAPR: Research Report 580 TABLE 1. Composition (g/kg) of diets with different levels of CP and essential amino acids 22% CP 20% CP 18% 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 South Pacific.
- Spring '11
- The Land