Dietary yeast β-glucan supplementation improves eggshell color and fertile eggs hatchability as well as enhances immune functions in breeder laying hens

The study was conducted to evaluate the effects of dietary yeast β-glucan (YG) on performance and immune functions in breeder hens in a non-challenged setting. A total of 512 43-week-old Hy-Line Brown breeder hens were assigned into four treatments, and fed a basal diet with YG at 0, 50, 100 and 200 mg /kg for 8 weeks, respectively. Results showed that supplementation of YG did not affect production performance, but linearly increased hatchability (P < 0.05). Compared with the control, hens fed with 200 mg/kg YG had improved eggshell color and reduced mortality. Moreover, feeding 200 mg/kg YG significantly (P < 0.05) enhanced lymphocyte proliferation response to LPS, increased the percentage of peripheral blood CD3+ T cells and phytohemagglutinin (PHA) skin response; remarkably down-regulated splenic TLR4, IL-6 and TGF-β mRNA levels while upregulated TLR6 and IFN-γ mRNA levels (P < 0.05). In addition, inclusion of YG at 200 mg/kg considerably promoted the production of serum cytokines, total IgA, and specific antibody titers against BSA, AIV and NDV vaccine (P < 0.05). These results suggested that dietary inclusion of 200 mg/kg YG could improve eggshell color and fertile eggs hatchability and enhance cellular and humoral immune function of breeder hens in a nonchallenged setting without disturbing immune homeostasis.