Effects of melatonin on laying performance and egg quality of laying hens at the end of laying

ZHANG Zhen; ZHANG Miaorui; YANG Pengkun; SUN Yujiao; GUO Hongwei; ZHAO Xuyong; ZHENG Ming; WANG Yongfen

doi:10.13557/j.cnki.issn1002-2813.2025.12.009

Abstract：The experiment aimed to investigate the effects of melatonin on the laying performance and egg quality in late-phase laying hens.A total of 1 800 520-day-old Lohmann Brown layers were randomly divided into five groups,with six replicates per group and 60 hens per replicate.The control group was fed a basal diet,while the experimental groups were fed a basal diet supplement with 0.5,1.0,1.5,and 2.0 mg/kg of melatonin,respectively.The pre-test period was one week and the formal test period was four weeks.The results showed that compared with the control group,the laying rate of hens added with melatonin was significantly increased(P＜0.05).The average egg weight of 1.0 mg/kg,1.5 mg/kg and 2.0 mg/kg groups was significantly increased(P＜0.05),while the feed-to-egg ratio and broken egg rate were significantly decreased(P＜0.05).The eggshell strength of 1.0 mg/kg and 1.5 mg/kg groups was significantly increased(P＜0.05).After adding 0.1 to 1.5 mg/kg melatonin,the concentrations of luteinizing hormone(LH),follicle-stimulating hormone(FSH),and calcium ion(Ca2+)of laying hens were significantly increased(P＜0.05).When the dosage of melatonin was 1.0 mg/kg,LH content increased by 46.90％,FSH content increased by 59.13％,Ca2+content increased by 47.55％,and the relative expression of LH and FSH were the highest(P＜0.05),exceeding which was more than twice that of the control group.The results indicate that melatonin supplementation has a positive effect on maintaining the laying rate and improving egg quality of laying hens at ate-phase laying,and the optimal supplemental level of melatonin is 1.0 mg/kg.