Dietary supplementation with Lactobacillus crispatus LSC1 improves laying performance, immune and antioxidant and intestinal barrier function as well as gut microbial composition in aged laying hens.

Abstract

This study investigated the effects of dietary supplementation with Lactobacillus crispatus LSC1 (L. crispatus) on laying performance, egg quality, antioxidant status, lipid metabolism, intestinal and oviductal health, follicular function, and gut microbiota in aged laying hens. A total of 192 67-week-old Hy-Line Brown laying hens were randomly assigned to four treatments with six replicates, each group receiving the same basal diet supplemented with 0, 1 × 108 CFU/kg, 1 × 109 CFU/kg, and 1 × 1010 CFU/kg of L. crispatus, respectively (designated as C, J1, J2, and J3). The experiment lasted for 8 weeks. The results showed that compared with the control group, the addition of L. crispatus to basal diet significantly increased the rate of qualified eggs and the average daily feed intake during weeks 0-4 and elevated serum estradiol concentrations (P < 0.05). Gene expression results indicated that the J2 and J3 groups significantly up-regulated SCD-1 mRNA expression in the liver (P < 0.05), whereas ileal Occludin, Mucin-2, and IL-17 mRNA expression was increased in the J3 group (P < 0.05). Moreover, the J3 group significantly increased CAT and CA mRNA levels in the oviduct as well as serum T-AOC and GSH-Px content (P < 0.05), while the J1 and J2 groups exhibited a significant increase in CLU mRNA expression (P < 0.05). In the follicular wall, L. crispatus supplementation increased TGF-β2 mRNA expression and reduced BAX mRNA expression (P < 0.05). Ileal microbiota analysis revealed that the J3 group significantly enriched Lactobacillus delbrueckii and Lactobacillus vaginalis (P < 0.05). The cecal microbial community of the J3 group differed from that of the control group and exhibited higher relative abundances of Bacteroides, Romboutsia, and Lactobacillus. In summary, our results indicated that dietary supplementation with 1 × 1010 CFU/kg L. crispatus displayed pronounced beneficial effects on laying performance, lipid metabolism, and the health status of the gut and reproductive system of the aged laying hens.