Effects of Limosilactobacillus reuteri on ruminal microbiota, muscle protein metabolism, and flavor of Sunit lamb

Abstract

To investigate the effects of dietary Limosilactobacillus reuteri (L. reuteri) supplementation on rumen microbiota, protein metabolism, and flavor, 12 three-month-old Sunit lambs were randomly divided into CG group (basal diet) and LG group (basal diet + L. reuteri) for 90 days. Each group of sheep had six replicates. Metagenomics, gas chromatography-mass spectrometry (GC-MS), real-time PCR, and electronic nose were used to measure the samples. The results showed that L. reuteri significantly increased muscle aromatic compounds (P < 0.05). In the rumen of the LG group, Prevotella, Bacteroides, Paraprevotella, Fibrobacter, and propionate abundance significantly increased (P < 0.05), with their function enriched in carbohydrate degradation (glycoside hydrolases and glycosyl transferases) based on CAZy analysis. Additionally, L. reuteri enhanced the expression of ZO-1, Occludins, and GPCR43 in the rumen epithelium. The mTOR and eIF4B genes were downregulated, while the TSC1 gene was upregulated in muscle (P < 0.05). Propionate was negatively correlated with g_Selenomonas, g_Schwartzia, mTOR, and eIF4B genes, while positively correlated with aromatic component receptor and TSC1 gene. In conclusion, dietary supplementation with L. reuteri can enhance rumen fermentation, regulate protein degradation, and optimize muscle aromatic compounds. These findings provide new perspectives for improving the quality of captive lambs.