Effects of immunopotentiators on laying performance and Newcastle disease vaccine immune efficacy in laying hens

Yu Shupei; Bian Hongchun; Han Kunpeng; Chen Jinghua; Xiao Xia; Xia Wenlong

doi:10.20154/j.cnki.issn1672-9692.2025.04.009

Abstract：This study aimed to investigate the effects of Zengyisu,an immunopotentiator,on laying performance and Newcastle disease(ND)vaccine immune efficacy in laying hens.A total of 180 fifty-one-week-old Hy-Line Brown commercial laying hens were randomly divided into two groups,with 6 replicates per group and 15 hens per replicate.The control group was fed a basal diet,while the experimental group received the basal diet supplemented with 0.02%Zengyisu(main components:α-mannan,alkaline polypeptides,T-factor,α-mannanoligosaccharides)per ton.The trial lasted 35 days,including a 7-day pre-trial period and a 28-day formal trial period.Seven days after the pre-trial period,both groups were immunized with inactivated Newcastle disease vaccine.Results showed that compared to the control group,the experimental group exhibited increased egg production rate and average egg weight,along with reduced average daily feed intake and soft/broken egg rate,though these differences were not statistically significant(P>0.05).The feed-to-egg ratio in the experimental group was significantly lower than that of the control group(P<0.05).At 21 days post-immunization,the experimental group demonstrated higher average antibody titers and lower dispersion compared to the control group.Serum immunoglobulin A(IgA)levels and interleukin-2(IL-2)content in the experimental group were higher than those in the control group,but not significantly(P>0.05).However,serum immunoglobulin M(IgM)and immunoglobulin G(IgG)levels were significantly elevated in the experimental group(P<0.05).The study indicates that Zengyisu can serve as an effective immunopotentiator for Newcastle disease vaccines,improving laying performance,reducing feed-to-egg ratio,and enhancing immune function in laying hens.