Effects Of Clostridium Butyricum On Fat Metabolism And Meat Quality Of Lambs

To investigate the effect of Clostridium butyricum supplementation on fat metabolism and meat quality of Lambs.Three-month-old Dorper×Small-Tailed Han sheep（24 sheep）were randomly divided into two groups:the control group was fed a basal diet（a typical corn-soybean diet）,and the Clostridium butyricum group was supplemented with Clostridium butyricum at 5 g/head using the diet of the control group（a typical corn-soybean diet,the number of viable bacteria was 5×10⁸cfu/g Clostridium butyricum）,half male and half female.The effects of Clostridium butyricum on meat quality and fat metabolism of Lambs and its mechanism of action were analyzed by real-time fluorescence quantitative PCR and macrogenomics,and the results were as follows:Analysis of the differences in slaughter performance,carcass quality,and meat quality between the two groups revealed that net meat weight and loin eye area were significantly higher（P<0.05）,intramuscular fat content in the longissimus dorsi muscle（LD）and biceps femoris muscle（BF）was significantly higher（P<0.05）and shear force values were significantly lower（P<0.05）in the Clostridium butyricum group.The H_24hvalue of the LD was significantly lower（P<0.05）,the redness value and ash content were significantly higher（P<0.05）,and the cooking loss rate of the BF was significantly lower（P<0.05）.A comparison of fat metabolism in Lambs revealed that TG,TC,and NEFA levels were significantly lower（P<0.05）,and HDL levels were significantly higher（P<0.05）among the serum lipid metabolism indicators of Lambs in the Clostridium butyricum group.Among muscle fatty acids,palmitic acid and total saturated fatty acids were significantly reduced（P<0.05）and oleic acid andα-linolenic acid were significantly increased（P<0.05）in the LD of the Clostridium butyricum group,and eicosapentaenoic acid,docosahexaenoic acid and total monounsaturated fatty acids were significantly increased（P<0.05）in the BF.Among the gene pathways related to lipid metabolism,the relative expressions of ACC,SREBP-1c,and SCD m RNA were significantly increased（P<0.05）,and the relative expressions of AMPKα2 and CPT1 m RNA were significantly decreased（P<0.05）in the LD,and the relative expressions of HSL and CPT1 m RNA were significantly decreased（P<0.05）in the BF in the Clostridium butyricum group.Measurement of muscle enzyme activities revealed that FASN and ACC activities were significantly increased（P<0.05）in the LD,and HSL activity was significantly decreased（P<0.05）in the BF in the Clostridium butyricum group.In conclusion,the addition of Clostridium butyricum to the diet can promote muscle fat deposition and inhibit muscle lipolysis in Lambs.A comparison of the intestinal flora of Lambs revealed that the Shannon index and Observed species index in the intestine of Lambs were significantly higher（P<0.05）with the addition of Clostridium butyricum to the diet.At the phylum level,compared with the control group,the abundance values of Firmicutes,Fibrobacters,and Spirochaetes were significantly increased（P<0.05）and the abundance values of Proteobacteria were significantly decreased（P<0.05）in the Clostridium butyricum group.At the genus level,the abundance values of Clostridium,Prevotella,and Fibrobacter in the Clostridium butyricum group were significantly increased（P<0.05）and the abundance values of Parabacteroides were significantly decreased（P<0.05）.KEGG database comparison showed that the lipid metabolic pathway was found to be significantly enriched in the Clostridium butyricum group,where the gene abundance values for primary bile acid biosynthesis,secondary bile acid biosynthesis,and fatty acid biosynthesis were significantly increased（P<0.05）.To further investigate the way in which intestinal flora affects lipid metabolism,bile acid content,and its receptor gene expression were determined.Among them,total bile acid content in the duodenum,cecum,feces,and blood were significantly increased in the Clostridium butyricum group（P<0.05）,and the expression of the receptor gene FXR m RNA in the LD and the receptor gene TGR5 m RNA in the BF were significantly increased（P<0.05）.On the whole,the addition of Clostridium butyricum to the diet can affect the process of muscle fat metabolism by mediating intestinal flora and its metabolites（bile acids）,and ultimately improve the carcass quality and meat quality of Lambs.