Effects of Dietary Vitamin D3 Supplementation on Laying Performance,Egg Quality,Lipid Metabolism and Cecal Microflora of Laying Ducks in Late Laying Period
This experiment was conducted to investigate the effects of dietary vitamin D3(VD3)supplementa-tion on laying performance,egg quality,lipid metabolism and cecal microflora of laying ducks in late laying period.A total of 432 healthy Longyanshan Ma ducks at 58 weeks of age with similar laying rate were random-ly divided into 6 groups with 6 replicates per group and 12 ducks per replicate.Ducks in the control group were fed a basal diet(without adding VD3),and those in experimental groups were fed the basal diets supplemented with 800,1 600,2 400,3 200 and 4 000 IU/kg VD3,respectively.The pre-trial period was 2 weeks,and the experimental period was 16 weeks.The results showed as follows:1)dietary VD3 supplementation significant-ly increased the laying rate and daily egg weight of laying ducks in late laying period(P＜0.05),and signifi-cantly decreased the feed to egg ratio(P＜0.05).Among them,from weeks 1 to 16,compared with the con-trol group,the laying rate and daily egg weight(except for 1 600 IU/kg VD3 supplemental group)of experi-mental groups were significantly increased(P＜0.05),and the feed to egg ratio was significantly decreased(P＜0.05).2)Compared with the control group,dietary supplementation of 1 600 IU/kg VD3 significantly decreased the yolk weight at week 12 and the average yolk weight during the whole experiment period(P＜0.05),and the average yolk ratio and average albumen ratio during the whole experiment period had linear and quadratic changes with the increase of dietary VD3 supplemental level(P＜0.05).3)Dietary VD3 supplementa-tion had a trend of decreasing the contents of triglyceride and total cholesterol in liver of laying ducks in late laying period(P＞0.05),and the contents of total cholesterol and low-density lipoprotein in liver were firstly decreased and then increased with dietary VD3 supplemental level increasing(P＜0.05).4)Compared with the control group,dietary supplementation of 2 400 IU/kg VD3 significantly decreased the crypt depth in duode-num of laying ducks in late laying period(P＜0.05),significantly increased the villus height to crypt depth ra-tio in duodenum(P＜0.05),and the villus height to crypt depth ratio in duodenum was firstly increased and then decreased with the increase of dietary VD3 supplemental level(P＜0.05).5)Dietary VD3 supplementation had no significant effects on the richness and diversity of cecal microflora of laying ducks in late laying period.At the genus level,dietary VD3 supplementation significantly increased the relative abundances of short-chain fatty acid(SCFA)synthetic bacteria such as Blautia,Alistipes and Lachnoclostridium(P＜0.05).In conclu-sion,dietary VD3 supplementation can improve the laying performance,lipid metabolism and intestinal mor-phology of laying ducks in late laying period,and promote the enrichment of SCFA synthetic bacteria in ce-cum.It is suggested that dietary VD3 supplementation level is 2 400 to 3 200 IU/kg for laying ducks in late lay-ing period.[Chinese Journal of Animal Nutrition,2024,36(7):4350-4364]
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