Abstract:

The aim of this study is to investigate the effects of basal diet supplemented with lysozyme on the production performance，viscus weight，serum biochemical indicators，and lipid metabolism indicators of laying hens in the late stage of egg production. Healthy Hyline brown laying hens were randomly divided into four groups at 50 weeks of age，with three replicates in each group and 12 hens in each replicate. Control group was fed with the basal diet，and the experimental groups were fed with the basal diet supplemented with 300，500 and 700 mg·kg^-1 lysozyme，respectively. The pre-trial period lasted for 14 days，and the experimental period lasted for 30 days. The results showed that compared with the control group，the supplementation of 300 and 500 mg·kg^-1 lysozyme significantly（p<0.05）increased the egg production rate of laying hens at 54 and 55 weeks of age，and the average egg weight of 300 mg·kg^-1 lysozyme treatment at 55 weeks of age was also significantly higher than that of the control group. Basal diet supplemented with lysozyme had no significant effect on viscus weight，serum biochemical indicators，and lipid metabolism indicators of laying hens. In conclusion，basal diet supplemented with lysozyme can improve the production performance of laying hens，and the effect is significant after 28 days of supplementation. The optimal dosage for this experiment is 300 mg·kg^-1 lysozyme.

Key words: lysozyme, laying hen, production performance, viscus weight, serum biochemical indicator