Effects Of Dietary Arginine Supplementation On Muscle Fiber Characteristics And Meat Quality Of Sheep

A total of 12 sheep aged 3 months old were randomly divided into control group and arginine group in this paper.The control group was given basic diet,and the arginine group was supplemented with 1%arginine according to the basic diet quality.After 90 days of feeding,the effects of dietary arginine on muscle fiber characteristics and meat quality were analyzed by ATPase histochemical staining,real-time fluorescence quantitative PCR and enzyme-linked immunosorbent assay to make clear the correlation between muscle fiber and meat quality and explore the internal mechanism of muscle fiber type transformation.It provides a theoretical basis for improving meat quality by changing nutritional levels to regulate muscle fiber characteristics.Slaughter performance,carcass and meat quality of sheep supplemented with arginine were studied according to the results that there was no significant effect of arginine supplementation on slaughter performance and carcass quality（P>0.05）,but improved meat quality.The addition of arginine significantly reduced the L*and p H₂₄value of two parts（longissimus dorsi and biceps femoris）and b*value of longissimus dorsi（P<0.05）,high significantly reduced the shear force value（P<0.01）,and significantly increased the a*value of in LD and BF（P<0.05）.The effects of dietary arginine supplementation on muscle fiber properties were studied.In the control group,the number ratio,area ratio of type IIB muscle fibers and My HC IIb gene expression in LD and BF of the arginine group were significantly decreased（P<0.01）,the diameter of type I muscle fibers and the diameter and cross-sectional area of type IIB muscle fibers were significantly decreased（P<0.05）,and the LDH activity in the muscle was significantly decreased（P<0.05）,the density of muscle fibers in both parts was increased,and it was significantly indigenous in LD（P<0.05）.In addition,the number ratio,area ratio of type IIA muscle fibers and My HC IIa gene expression in LD were significantly increased（P<0.01）,and the SDH and MDH activities were significantly increased（P<0.05）.The number ratio,area ratio of type I muscle fibers and My HC I gene expression in BF were significantly increased（P<0.05）.The results showed that dietary arginine increased the proportion of oxidative muscle fibers in sheep muscle,decreased the proportion of glycolytic muscle fibers,and improved the oxidative metabolism ability of muscle.Through the internal mechanism of arginine supplementation on muscle fiber type transformation,it was found that the n NOS content in the LD of the sheep obviously grew in arginine group（P<0.05）,and the expression levels of n NOS,AMPKα1 and Sirt1 genes were significantly increased（P<0.05）,and the expression levels of AMPKα2 and PGC-1αgenes were obviously increased（P<0.01）.The expression levels of PGC-1αand Sirt1genes in BF were significantly increased（P<0.05）.Combined with the results of muscle fiber characteristics analysis and gene expression measurement,dietary arginine supplementation may activate Sirt1/AMPK pathway by increasing NO levels in the body,and send inversion of muscle fiber types from glycolytic to oxidative.