Effects of zinc methionine on eggshell ultrastructure,carbonic anhydrase activity,intestinal morphology,immune function,and zinc content in laying hens

GAO Jie; WANG Xin; LAI Yujiao; ZHANG Zhengfan; DING Binying; LI Lanlan

doi:10.13557/j.cnki.issn1002-2813.2025.16.007

Abstract：The experiment aimed to investigate the effects of zinc methionine(Zn-Met)on the eggshell ultrastructure,carbonic anhydrase(CA)activity,intestinal morphology,immune function,and zinc(Zn)content in laying hens.A total of 720 Jinghong No.1 laying hens with similar egg production performance were randomly divided into six groups,with six replicates per group and 20 hens per replicate.The control group was fed a basal diet(Zn-free)supplemented with 80 mg/kg zinc sulfate(as Zn),while the experimental groups received the basal diet supplemented with 20,40,60,80,or 100 mg/kg Zn-Met(as Zn),respectively.The pre-test period was one week and the formal test period was 10 weeks.The results showed that compared with the control group,the cross-sectional mastoid width in the 80 and 100 mg/kg Zn-Met groups was significantly decreased(P＜0.05),and the cross-sectional fence layer thickness was significantly increased(P＜0.05).The CA activity in eggshell gland(ESG)of laying hens in the 80 and 100 mg/kg Zn-Met groups was significantly higher than that in the control group(P＜0.05).Compared with the control group,the intestinal villus height and villus area in the 60 and 80 mg/kg Zn-Met groups were significantly increased(P＜0.05).The content of immunoglobulin M(IgM)of ileal in the 80 and 100 mg/kg Zn-Met groups was significantly increased(P＜0.05).The Zn content in the feces of laying hens in the 20,40 and 60 mg/kg Zn-Met groups was significantly decreased(P＜0.05),and the Zn content in the liver,kidneys and pancreas of laying hens in the 80 and 100 mg/kg ZN-Met groups was significantly increased(P＜0.05).The study indicates that supplementation with 60～80 mg/kg Zn-Met can improve Zn metabolism and deposition,enhance eggshell ultrastructure,and positively regulate intestinal morphology and immune performance of laying hens.