Lysine supplementation of low-protein diets for broiler breeder males
1992
Revington, W.H. | Moran, E.T. Jr | Bilgili, S.F. | Bushong, R.D.
Two experiments were conducted to assess the impact of supplemental L-lysine HCl on N balance in broiler breeder males fed 8% CP corn-based diets (3,220 kcal ME(n)/kg; .15% supplemental DL-methionine; .24% basal lysine). In Experiment 1, 78-wk-old males were fed the basal diet with either O, .05, .10, or.25% supplemental L-lysine HCl. Birds were allowed to eat for 1 h each day to a maximum intake of 325 kcal ME(n) per bird per day. Total excreta were collected for 8 consecutive days. Nitrogen retention and balance were not different among treatments (P > .05) and responded neither linearly nor quadratically to dietary lysine level. Removing the variation due to differences in N intake with analysis of covariance did not change the response. In Experiment 2, 30-wk-old males were fed the same basal diet with supplemental lysine levels of 0, .15, .30, .45, .60, and .75% L-lysine HCl for 5 consecutive days. Nitrogen balance and retention were different among diets, and both variates responded linearly to increases in dietary lysine. Removing the variation due to differences in N intake removed treatment effects, however, suggesting that at least part of the difference was the result of variable levels of intake. Regression analysis indicated a significant linear increase in both N balance and retention with increasing dietary lysine level (R(2) = .82). These results suggest that young broiler breeder males can make better use of the protein of corn if supplemental lysine is provided. However, older birds do not demonstrate improved N balance as a result of supplemental dietary lysine.
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