Effect of different levels of methionine, protein and tallow on the productive performance and egg quality of laying hens in the late-phase production

摘要

An experiment was conducted to determine the effects of different levels of methionine, protein and tallow on productive performance and egg quality of laying hens in the late phase of production. A completely randomized design with a 3×2×2 factorial arrangement, with three levels (0.34, 0.31, and 0.27%) of methionine (MET), two levels (12.8 and 14.7%) of protein (PRO) and two levels (1 and 3%) of tallow (TAL) with constant level of linoleic acid (1.55 ± 0.02%), was used. A number of 144 Hi-Line W-36 layers from 70 to 76 wk of age was randomly distributed into 12 treatment groups with 4 replicates of 3 hens each. Egg production and egg weight were daily recorded and feed intake and egg quality traits were recorded every 2 wk. There was a significant interaction between PRO levels and TAL for egg weight. Low levels of TAL and PRO decreased egg weight throughout the experiment. High levels of MET and TAL with concomitant reduced PRO, increased eggshell thickness, and a significant interaction between levels of MET, PRO and TAL was observed during the experiment (70 to 76 wk). Low level of protein (12.8%) significantly decreased albumen weight in the third 2-wk period. Yolk color increased when hens were fed low levels of PRO and TAL. Results of this experiment indicated that the simultaneous reduction of dietary PRO and MET in diets of Hi-Line W-36 laying hens in the late phase of production, reduced egg weight (P<0.05). Productive performance and egg quality were not affected by 12 and 20% reduction of PRO and MET, respectively. It seems that decreasing the levels of MET and PRO to lower than the recommended values can decrease egg weight without negative effects on productive performance and egg quality of laying hens in the late phase of production.