Study On The Regulation And Mechanism Of α-ketoglutarate And Fat On Fat Deposition In Rats

In swine production,long-term one-way selection reduces the subcutaneous fat content and increases lean meat rate,but at the same time,the intramuscular fat is decreased.The low content of intramuscular fat seriously affects the flavour and mouthfeel of the meat and is closely related to the incidence of PSE meat.Improving fat deposition and increasing intramuscular fat content have important scientific significance and practical value for pork quality improvement.Our previous study has shown that dietary supplementation of alpha-ketoglutarate(AKG)can increase the intramuscular fat content in pigs,but the mechanism is not clear.This study was ues 2×2 experimental design rat model AKG and fat were added in diet to explore their effect on intramuscular fat deposition in a rat model,and the difference between AKG and high fat on the fat deposition was analyzed through the expression of genes related to fat metabolism,amino acid metabolism and energy balance,aiming to reveal the potential mechanism of AKG in promoting intramuscular fat deposition from the aspect of intestinal-liver-fat tissue metabolism,and to provide a theoretical basis for AKG in regulating fat deposition and improving meat quality.The results showed that:(1)Dietary supplementation of AKG in basal diet can increase the intramuscular fat content in rat,which may relate to the increased expression of fat synthesis-related genes FAS and ACC in the muscle tissue by AKG(P<0.05).Compared with the basal diet group,the high-fat diet increased the expression of FAS and ACC genes(P<0.05).However,AKG reduced the expression of FAS and ACC of muscle tissue in the high-fat diet group(P<0.05).(2)Dietary supplementation of AKG in the basal or high-fat diet significantly decreaseed the expression of cholesterol synthesis-related genes LDL-R and HMG-Co A in the liver but increaseed LDL-R expression in back fat and prerenal fat(P<0.05).Dietary supplementation of AKG in basal or high-fat diet significantly increase the expression of the bile acid-related gene GPBAR1 in the hypothalamus(P<0.05).Compared with the basal diet group,the high-fat diet significantly reduced the expression of the lipolysis-related gene LPL in the liver but increased the expression of the LPL gene in the parental fat(P<0.05).Dietary supplementation of AKG in basal or high-fat diet significantly reduced the expression of the lipolysis-related gene LPL in the liver but increased the expression of the LPL gene in the parental fat(P<0.05).Dietary supplementation of AKG in basal or high-fat diet increased the expression of ATGL,a gene related to the fatty acid breakdown in back fat(P<0.05)(3)Supplementation of AKG in the basal diet increased the level of glutamate in the blood,while supplementation of AKG in basal diet or high-fat diet increased the levels of isoleucine,leucine,threonine,valine,serine,tyrosine,aspartic acid and alanine in the kidney tissue(P<0.05),which may relate to the increased expression of EAAC1,LAT1,ASCT2 amino acid transporter-related genes in the jejunum by AKG.(4)Compared with the basal diet group,the high-fat diet reduced the depth of the duodenal crypts of rats(P<0.05),and supplementation of AKG in basal diet or high-fat diet increased the height of ileal villi(P<0.05),which may relate to the reduced inflammatory cytokine levels in ileum by AKG.In addition,supplementation of AKG in basal or high-fat diet promoted the expression of tight junction proteins Occludin and Claudin-1 in the jejunum(P<0.05).(5)Supplementation of AKG in basal or high-fat diet decreased the expression of energy metabolism-related genes m TOR and FTO in the liver,muscle,and abdominal fat but increased the expression of m TOR and FTO in back fat and perineal fat(P<0.05).In addition,supplementation of AKG in basal or high-fat diet decreased the expression of NPY and NPY receptors in the hypothalamus(P<0.05).In summary,dietary supplementation of AKG can increase the fat content in the muscle tissue of rats,which may be related to the improvement of hypothalamusintestine-liver-fat tissue axis metabolism and the increased expression of fat synthesis-related genes in the muscle tissue by AKG.In addition,AKG exhibits different regulatory effects on fat deposition and metabolism in basal diet or high-fat diet models,which provides a new idea for AKG to regulate fat deposition.