Effect of digestible threonine on performance, egg quality, blood metabolites, and immune responses in laying hens fed a wheat-based diet in the second cycle

Abstract

The current experiment was conducted to evaluate the effects of digestible threonine (dThr) on performance, egg quality, blood metabolites, and immune responses in laying hens fed a wheat-based diet during the second cycle. Also, dThr requirements were determined based on nutrient dose-response data. A total of 384, 105-week-old post-molt Hy-line-W36 laying hens were allocated to six groups, 0.02% increments, ranging from 0.44 to 0.54% dThr, with eight replicates/treatment and eight birds each, from 105 to 116 wk. By increasing, dThr levels improved egg weight with a linear trend (p