Digestible Methionine and Lysine Requirements, Ratio and Interactions in Lohmann Egg-Type Cockerels

Authors : Chengzhang WANG, Yinghua SHI, Yuxin YANG, Zhentian LI, Yuxia GUO, Yibao JIANG

Pages : 417-424

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Metabolism and growth trials were conducted to study true digestible methionine insert ignore into journalissuearticles values(tMet); and lysine insert ignore into journalissuearticles values(tLys); requirements for growing Lohmann egg-type cockerels and to evaluate the effects of 2 dietary tMet levels and 4 tLys levels in a factorial arrangement on growth, nitrogen balance and serum biochemical indices. In the metabolism trial, 20 caecectomised and anus-stitch-surgery healthy adult male birds were used to determine the true digestibility of Met and Lys. In the growth trial, 30 Lohmann egg-type cockerels were allocated to each of 32 floor pens insert ignore into journalissuearticles values(total 960 birds);. During the 0-6 week starting period, 2 levels of tMet insert ignore into journalissuearticles values(0.37, 0.42%); and 4 levels of tLys insert ignore into journalissuearticles values(0.84, 0.92, 1.00, 1.08%); were fed to birds, while during the 7-10 week finishing period tMet levels were 0.29% and 0.33% and tLys levels 0.73%, 0.80%, 0.87% and 0.94%, respectively. The results showed that the survival rate in all treatments was 100% during the whole period, indicating that levels of tMet and tLys in the experiment had no influence on the rate. Considering the average daily gain insert ignore into journalissuearticles values(ADG);, average daily feed intake insert ignore into journalissuearticles values(ADFI);, feed conversion ratio insert ignore into journalissuearticles values(FCR);, nitrogen retention ratio insert ignore into journalissuearticles values(N-retention);, and serum uric acid insert ignore into journalissuearticles values(UA); content of all treatments together with Met and Lys digestibility, optimal tMet and tLys levels were 0.42%/1.00% insert ignore into journalissuearticles values(T7); for the starter diet and 0.33%/0.94% insert ignore into journalissuearticles values(T8); for the finisher diet. Although serum growth hormone insert ignore into journalissuearticles values(GH);, thyroxine insert ignore into journalissuearticles values(T4); and triiodothyronine insert ignore into journalissuearticles values(T3); contents of chicks indicated significant differences among the treatments during the whole period, the relationship between dietary tMet and tLys levels and serum GH, T4 and T3 contents seemed irregular. The results also showed that there were interactions between tMet and tLys, and that this interaction had influenced ADG, ADFI, FCR, N-retention, serum UA and hormone contents significantly during the whole period.
Keywords : Digestible methionine, digestible lysine, nitrogen balance, hormone, egg type cockerels