Effect of Lactobacillus salivarius SNK-6 on egg quality, intestinal morphology, and cecal microbial community of laying hens
Wei Liu, Jie Liu, Dapeng Li, Haixia Han, Huaxiang Yan, Yan Sun, Qiuxia Lei, Jie Wang, Yan Zhou, Dingguo Cao, Huimin Li, Fuwei Li
Abstract
The objective of this study was to investigate the effect of Lactobacillus salivarius (L. salivarius) SNK-6 supple-mentation on the laying performance, egg quality, blood parameters, intestinal morphology, and cecal microbial community of laying hens. A total of 432 healthy 30-wk-age laying hens were randomly divided into 3 groups with 6 replicates under the same husbandry and dietary regimes: control (CON); 2.0 × 108 CFU/kg L. salivarius supplementation (T1); 2.0 × 109 CFU/kg L. salivarius supplementation (T2). The experiment lasted for 10 weeks. The results indicated that the supplementation resulted in a significant reduction in the broken egg and unqualified egg ratios, and a significant increase in the eggshell strength, eggshell relative weight, albumen height, and Haugh units (P < 0.05). The L. salivarius-treated hens exhibited significantly reduced serum malondialdehyde levels (P < 0.05); significantly increased total protein, phosphorus, calcitonin, and immunoglobulin M (P < 0.05); significantly increased cecal secretory immunoglobulin A concentration (P < 0.05); significantly improved villus height (VH) in the duodenum and VH to crypt depth ratio in the jejunum (P < 0.05). The serum globulin and interleukin-1β, immunoglobulin G concentrations, and catalase activity significantly increased in T2 (P < 0.05). Furthermore, the serum interferon-α level in T1 was significantly higher than that of the CON (P < 0.05). The intestinal barrier-related mRNA gene ZO-1, CLDN1, and MUC2 expression in the jejunum was significantly upregulated in the T1 and T2 groups (P < 0.05). The Firmicutes/Bacteroidetes ratio was higher and the relative abundances of Flavonifractor and Clostridiales_noname were significantly higher in the T1 group (P < 0.05). In conclusion, dietary supplementation with L. salivarius SNK-6 may improve hen egg quality, serum antioxidant capacity, immune function, and intestinal health.