Abstract: The aim of this study was to investigate the effect of probiotics on rumen and intestinal microbial abundance and metabolites, plasma lipid parameters and meat quality in Sunit lambs. Totally 12 Sunit lambs at 3 months of age were randomly divided into two groups of 6 animals each: control group (fed on a basal diet) and probiotics group (fed on the same diet supplemented with a probiotic combination at 1.50 × 109 CFU/g), and the feeding period lasted for 90 days. The results showed that the structure of rumen and intestinal microflora in the probiotics group differed from that in the control group. The abundance of rumen Bacteroidetes, Bacteroides and f-Bacteroidales-BS11-gut-group as well as intestinal f-Lachnospiraceae and Ruminococceae-UCG-002 in the probiotics group was significantly higher than that in the control group (P < 0.05) and the opposite was true for the levels of butyric acid as gastrointestinal metabolites (P < 0.05). The probiotics group exhibited a significant increase in plasma high-density lipoprotein cholesterol (HDL-C) concentration and significant decrease in plasma low-density lipoprotein cholesterol (LDL-C) concentration (P < 0.05). The pH24 and shear force of lamb meat in the probiotics group were significantly lower than those in the control group (P < 0.05), while a* value was significantly higher than that in the control group (P < 0.05). Correlation analysis showed that the abundance of rumen Bacteroidetes was positively correlated with acetic acid and propionic acid levels (P < 0.05); the abundance of intestinal Ruminococcaceae-UCG-002 was positively correlated with isobutyric acid and isovaleric acid levels (P < 0.05); the abundance of rumen Prevotella-1 was negatively correlated with plasma HDL-C (P < 0.01); the abundance of rumen of Firmicutes was negatively correlated with cooked meat percentage (P < 0.01); and the abundance of intestinal Firmicutes was positively correlated with meat a* value (P < 0.05). Overall, this study concluded that dietary supplementation of probiotics can change the gastrointestinal microfloral structure and metabolites as well as plasma lipid parameters and consequently improve meat quality.

Key words: Sunit lamb, gastrointestinal microflora, metabolites, plasma lipid parameters, meat quality