Bacillus amyloliquefaciens BLCC1-0238 Can Effectively Improve Laying Performance and Egg Quality Via Enhancing Immunity and Regulating Reproductive Hormones of Laying Hens

In this study, we sought to evaluate the effects of dietary Bacillus amyloliquefaciens ( B. amyloliquefaciens ) BLCC1-0238 supplementation on laying performance, egg quality, antioxidant enzyme activities, reproductive hormone, and immunity of laying hens. A total of 240 Hy-Line Brown laying hens (28 weeks old) were randomly divided into four groups, and three replicates per group ( n = 20 per replicate). The control group was fed a standard basal diet, and the three treatment groups were provided the basal diet supplemented with either 0.01%, 0.03%, or 0.06% B. amyloliquefaciens BLCC1-0238 (2 × 10 10 CFU/g), respectively. Hens were allowed 2 weeks to acclimate prior to initiation of the 8-week experiment. It was observed that dietary supplementation with 0.01% or 0.03% B. amyloliquefaciens BLCC1-0238 significantly increased egg production and egg mass. However, no significant differences in feed intake, egg weight, and feed conversion ratio among the four groups were observed. Different levels of B. amyloliquefaciens BLCC1-0238 supplementation also significantly increased egg shell strength and thickness. With respect to the levels of reproductive hormones in the hens, B. amyloliquefaciens BLCC1-0238 supplementation significantly reduced serum adrenal cortical hormone (ACTH) levels, while increasing estradiol (E2) and follicle-stimulating hormone (FSH) secretion in the treatment groups compared to the control group. Relative to the control group, supplementation with 0.03% and 0.06% B. amyloliquefaciens BLCC1-0238 was observed to significantly increase serum glutathione S-transferase (GST) concentration, and supplementation significantly reduced serum IL-1 and IL-6 levels, whereas IL-4 levels increased for all concentrations tested. In conclusion, supplementation of a basal chicken diet with B. amyloliquefaciens BLCC1-0238 can improve laying performance and egg quality through the reduction of stress responses, up-regulation of growth hormones, and supporting immunity in laying hens.