The Effect Of Myostatin Knockout On Glucose Metabolism In Cattle

As a negative regulator of myogenesis,Myostatin(MSTN)is related to skeletal muscle development and energy metabolism in mammals.Glucose,the most important energetic contents,has relation with MSTN gene.Previous research about the effect of MSTN malfunction on glucose metabolism mainly focused on the the insulin resistance signal pathway and glucose transporter.In current study,two types of MSTN knockout(KO)F1 calves,which carried 6bp or 115bp deletion,were used to study the effect of MSTN KO on the growth,physiology and biochemistry and glucose metabolism of calves.Firstly,the effect of MSTN KO on calf growth were determined by measuring the growth traits monthly,from one month to twelve month.Secondly,the physiological metabolite difference of MSTN KO cattle and control calves were compared by MSTN protein content and biochemical analysis of blood.Finally,the effect of MSTN KO on glucose metabolism was evaluated through the analyzing of the expression of glucose transport?glucose oxidation?glycogen synthesis and the substrate and rate-limiting enzyme of pentose phosphate pathway.The results were as follows:1.The content of MSTN protein in the blood was significantly reduced(P<0.01)in MSTN KO calves.2.MSTN gene KO could significantly increase the growth rate of calves.The growth index of MSTN short deletion bull calves were significantly higher than long deletion bull calves and control bull calves.However,the growth traits of cow calves were less affected by MSTN KO.3.The blood biochemical analysis revealed that MSTN KO significantly increased the alkaline phosphatase content and reduced the glucose level in blood.But the transglutaminase,aspartate aminotransferase,alanine aminotransferase,blood amylase,urea nitrogen,blood phosphorus,blood calcium,albumin,cholesterol,uric acid creatine kinase,creatinine,total bilirubin,total protein,globulin and other indicators were not affected.4.MSTN KO increased the substrate content related to glucose uptake/translocation and glucose oxidation,and the expression level of rate-limiting enzyme,while at the same time suppressed the glycogen synthesis.In conclusion,MSTN KO improved the growth and development of calves,affected the substrate content of glucose metabolism and the expression of the rate limiting enzyme genes,increased the glucose metabolism,which resulted in the decrease of blood glucose level.