Study On The Difference Of Fat Catabolism Between Natural Grazing Sheep In Hay Period And Green Grass Period

[Objective] The nutritional value of the forage in the hay stage is not high,and the sheep in this period are in a state of poor nutrition for a long time.This experiment explores the difference in fat catabolism between different tissues of sheep in the hay and green grass period,and provides a theoretical basis for further research on the fat metabolism of sheep in the hay period,and provides a practical reference for further improving the quality of mutton and breeding benefits.[Methods] In this study,Sunit sheep in the pastoral area of Damao Banner,Mongolia were used as the research object.The adipose tissue(subcutaneous fat,tail fat,and perirenal fat)and muscle tissue(triceps brachii,biceps brachii,longissimus dorsi)and liver were collected.Real-time fluorescent quantitative PCR method was used to detect gene expression levels in triglyceride synthesis(DGAT2,LPL),triglyceride hydrolysis(ATGL,ABHD5,PLIN2),fatty acid oxidation(ACADL,CPT-1B),and c AMP-PKA signaling pathways(GNAS,PRKACA,CREB).Western blotting was used to detect the expression of ATGL protein in different tissues,and ELISA was used to detect the content of corresponding proteins(c AMP,PKA,ACAC,BHBA,OA)during lipolysis.[Results] 1.Triglyceride synthesis-related genes expression results showed that,except for the DGAT2 gene of tail fat,the hay stage was significantly higher than the green grass stage,and the hay stage of the rest of the tissues was significantly lower than the green grass stage.The expression level of the LPL gene in adipose tissue was significantly lower than that in the hay stage but was not significant in muscle tissue and liver.2.The test results related to triglyceride hydrolysis showed that the expression of ATGL genes in subcutaneous fat,triceps,and biceps was significantly higher in the hay stage than in the grass stage.While the gene expression in tail fat and liver in dry grass period is significantly lower than the green grass period.The expression of the ABHD5 gene was not significant in the tested tissues.Except for the PLIN2 gene of perirenal fat and liver,which was not significant,the other tissues showed that the expression level in the hay stage was significantly higher than that in the grass stage.Subsequently,the ATGL protein was detected by Western blotting,and it was found that the expression of ATGL only in the triceps brachii and biceps brachii of sheep was significantly higher than that in the grass stage.3.Detect the GNAS,PRKACA,and CREB genes in the c AMP-PKA signaling pathway.The results showed that the GNAS gene expression level of sheep in the hay stage was significantly higher in adipose tissue than in the grass stage,but was significantly lower in the liver than in the grass stage,and was not significant in muscle tissue.The results of PRKACA gene expression in adipose tissue and biceps brachii during the dead grass stage were significantly higher than those in the grass stage.The expression of the CREB gene in adipose tissue and biceps brachii during the dead weed stage was significantly lower than that in the grass stage,while in the triceps brachii muscle,the expression level of the dead weed stage was significantly higher than that in the green grass stage.Subsequently,the adenylate cyclase(c AMP)and protein kinase A(PKA)in the c AMP-PKA signal pathway were determined by ELISA.In all tissues,the content of c AMP in the hay stage was significantly higher than that in the grass stage.The expression of PKA was significantly higher in the hay stage than in the grass stage,except that the expression of PKA was not significant in the perirenal tissues.4.The test results of the fatty acid oxidation process showed that the expression of the ACADL gene in the subcutaneous fat and longissimus dorsi of sheep in the hay stage was significantly higher than that in the grass stage.The expression of the CPT-1B gene in subcutaneous fat and longissimus dorsi muscle during the dead weed stage was significantly higher than that in the grass stage.Subsequently,the intermediate products in the fatty acid oxidation process were detected by the ELISA method.The expression levels of oxaloacetic acid(ACAC),β-hydroxybutyric acid(BHBA),and oxalic acid(OA)only showed significant levels of subcutaneous fat in the subcutaneous fat stage.The result is higher than the grass stage,and it is not significant in the longissimus dorsi muscle and liver tissue.[Conclusion] 1.The key genes and proteins of fat synthesis and catabolism in different tissues of sheep in the withered and grass period are different to different degrees.Compared with the grass period,the triglyceride hydrolysis and fatty acid oxidation of sheep in the hay stage increased significantly.2.The cAMP-PKA signaling pathway mediates the hydrolysis of triglycerides in sheep at the subtilis stage by regulating the ATGL gene,and GNAS and PRKACA may play a major regulatory role.The expression of genes related to triglyceride synthesis in sheep decreased in the hay period,indicating that the fat storage content of sheep in the hay period was lower than that in the grass period.