Effects of low-dose yeast-zinc on production performance,egg quality,calcium metabolism-related indexes,and zinc content in laying hens

CHEN Mengyuan; GAO Jie; ZHOU Xingyu; DONG Yi; HUANG Xin; ZHANG Xin; LI Lanlan; DING Binying

doi:10.13557/j.cnki.issn1002-2813.2025.05.009

Abstract：The experiment aimed to investigate the effects of low-dose yeast-zinc supplementation in diets on the production performance,egg quality,calcium metabolism-related indexes,and zinc content in laying hens.A total of 384 Jingfen No.1 laying hens aged 18 weeks were randomly divided into four groups,with eight replicates per group and 12 laying hens per replicate.The control group was supplemented with 60 mg/kg zinc sulfate(in terms of zinc)in the basal diet,while experimental groups Ⅰ,Ⅱ,and Ⅲ were supplemented with 5,10,and 15 mg/kg yeast zinc(in terms of zinc)in the basal diet,respectively.The pre-trial period lasted two weeks,and the formal trial period lasted seven weeks.The results showed that compared with the control group,the rate of unqualified eggs in the experimental groups at 21～24 weeks of age was significantly reduced(P<0.05).The average egg weight at 25～27 weeks of age,as well as egg weight,eggshell weight,and yolk color at 27 weeks of age,were significantly increased in experimental groups Ⅱ and Ⅲ(P<0.05).The egg shape index at 24 weeks of age and yolk ratio at 27 weeks of age were significantly decreased(P<0.05).The eggshell weight at 24 weeks of age,as well as eggshell strength and thickness at 27 weeks of age in experimental group Ⅲ were significantly increased(P<0.05).Low-dose yeast-zinc had no significant effect on serum calcium ion(Ca2+)levels,alkaline phosphatase(AKP)activity,and carbonic anhydrase(CA)activity in laying hens at 24 and 27 weeks of age(P>0.05),it had no significant effect on serum zinc ion(Zn2+),calcitonin(CT),parathyroid hormone(PTH),and 1,25-dihydroxyvitamin D3[1,25-(OH)2-D3]levels,and eggshell zinc content at 27 weeks of age(P>0.05).The study indicates that supplementing diets with 10 mg/kg and 15 mg/kg yeast zinc(in terms of zinc)can improve the production performance and egg quality of laying hens,and has no negative effects on calcium metabolism and zinc content.