Dietary Saccharomyces cerevisiae fermentation product improved egg quality by modulating intestinal health, ovarian function, and cecal microbiota in post-peak laying hens

Saccharomyces cerevisiae fermentation product (SCFP), a postbiotic feed additive, has potential to improve animal growth and productivity. However, its effects on post-peak laying hens have not been thoroughly investigated. Therefore, this study aimed to explore the effects of SCFP on production, egg quality, intestinal health, ovarian function, and cecal microbiota in post-peak laying hens. A total of 600 45-week-old Lohmann pink laying hens were randomly assigned into three treatments, with ten replicates and twenty hens per replicate. The hens were fed either a basal diet (CON) or basal diet supplemented with SCFP at 750 mg/kg (SCFP1) and 1250 mg/kg (SCFP2) for 16 weeks. The results showed no significant effects on the laying performance (P > 0.05). SCFP supplementation increased Haugh unit, yolk color, albumen height, and eggshell ratio compared to the CON diet(P < 0.05). Hens received SCFP diets exhibited a higher intestinal villus height-to-crypt depth ratio (P < 0.05) and up-regulated the expression of jejunal occludin, zonula occluden-1 (ZO-1), and mucin 2 (MUC-2) (P < 0.05). Additionally, SCFP supplementation increased the concentration of jejunal secretory immunoglobulin A (SIgA) (P < 0.05), elevated serum levels of immunoglobulin A (IgA), IgG, interleukin-10 (IL-10), and interferon-γ (IFN-γ) (P < 0.05). Furthermore, dietary SCFP tended to decrease ovarian cell apoptosis and enhanced antioxidant capacity in laying hens (P < 0.05). Compared to CON group, the SCFP1 and SCFP2 groups had lower total bacteria and Escherichia coli, higher Lactobacillus (P < 0.05), and a greater abundance of Streptococcus, Pedosphaerales, Christensenellales, and Prevotellaceae in cecum. Significant correlations were observed between egg quality, intestinal health, ovarian function, and cecal microbiota. In addition, cecal microbial functional prediction indicated that SCFP altered various nutritional metabolism pathways. Dietary SCFP supplementation effectively improved egg quality in post-peak laying hens by modulating intestinal health, ovarian function, and cecal microbiota. Collectively, SCFP could be used as a valuable feed additive for post-peak laying hens, with 1250 mg/kg SCFP showing the better effects.