|Dozier iii, William|
Submitted to: Southern Poultry Science Society Meeting Abstracts
Publication Type: Proceedings
Publication Acceptance Date: 10/30/2004
Publication Date: 1/15/2005
Citation: Thornton, S.A., Corzo, A., Dozier III, W.A., Miles, D.M., Kidd, M.T. 2005. Is valine limiting in broiler growth diets based on corn and soybean meal. Southern Poultry Science Society Meeting. Abstract 191. p. 45. Interpretive Summary:
Technical Abstract: Broiler diets formulated to contain crystalline L-Thr when priced below the shadow value, in addition to synthetic Met and crystalline Lys, allow for more efficient amino acid utilization. However, minimums for the less limiting amino acids become more critical. Valine has not been researched to the extent of Ile, but initial dose response data indicated that the 21 to 42 d old broiler needs 0.65% digestible Val. Because this level is lower than that recommended (NRC, 1994), we conducted an experiment to determine Val responses in growing male broilers. Ross x Ross 508 chicks (360) were randomized across 30 floor pens and fed common diets to d 22. Five dietary treatments (6 replications/treatment) were implemented from 22 to 42 d: 1) Control with 0.74% digestible Val; 2) Val reduced to 0.65% digestible; 3) as 2 plus L-Val to equal treatment 1; 4) as 2 plus a non-essential amino acid mixture to equal the N content that L-Val contributed in treatment 3; and 5) as 3 with L-Arg and L-Trp to equal treatment 1. Growth performance was measured for the 22 to 42 d period, and processing characteristics, and litter ammonia were measured at d 42. Feed conversion (P = 0.66) and BW gain (P = 0.11) did not differ among treatments. However, broilers fed treatment 4 had reduced (P < 0.05) feed intake vs treatments 1, 2, and 5. Differences (P < 0.05) in carcass yields did not occur. However, carcass and tender weight in broilers receiving treatment 4 were lower than treatments 1 and 5, and 1, 3, and 5, respectively. No differences (P < 0.05) in litter ammonia were found among treatments. These results indicate that Val needs may be below 0.74% digestible for the growing male broiler. In addition, these results point to the ability to marginally reduce less limiting amino acids without compromising bird performance.