Effects of dietary supplement of ε-polylysine hydrochloride on laying performance, egg quality, serum parameters, organ index, intestinal morphology, gut microbiota, and volatile fatty acids in laying hens

ε-polylysine hydrochloride (ε-PLH) is a naturally occurring antimicrobial peptide extensively utilized in the food and medical industries. However, its impact on animal husbandry remains to be further explored. Therefore, this experiment aimed to determine the effect of ε-PLH on laying hens' health and laying performance. Dietary supplementation with ε-PLH to the diet significantly increased average egg weight (AEW) of the week 1-8. Meanwhile, compared with the control group, supplementation with ε-PLH decreased feed egg ratio (FER) during 9-12 week and egg breakage rate (EBR) during 9-16 week，while increased eggshell strength during 1-4 and 13-16 week. The ε-PLH 0.05% group increased yolk percentage of the 5-8 week and yolk color during 1-4 week. Furthermore, ε-PLH supplementation significantly increased the concentrations of total protein (TP), albumin (ALB), globulin (GLO) and reproductive hormones estradiol (E2), decreased interleukin-1 beta (IL-1β) and malondialdehyde (MDA) in the serum. Compared with the control group, supplementation with 0.05% ε-PLH significantly increased the relative abundance of Cyanobacteria and Gastranaerophilales and decreased the abundance of Desulfovibrio and Streptococcus in the cecum microbiota. In addition, ε-PLH 0.1% supplementation also increased acetic acid content in the cecum. Dietary supplementation with ε-PLH has a positive impact on both productive performance and egg quality in laying hens. Furthermore, ε-PLH can also relieve inflammation by promoting the immunity and reducing oxidative damage during egg production. ε-PLH has been shown to improve intestinal morphology, gut microbial diversity, and intestinal health. This article is protected by copyright. All rights reserved.