Effect of Orally Administered Taurine on Myofibrillar Proteolysis and Expression of Proteolytic-Related Genes of Skeletal Muscle in Chicks

We examined the effect of orally administration of taurine on myofibrillar proteolysis in food-deprived chicks. Chicks were food-deprived of 24 hours (h) and then chicks were orally administered 57, 133, or 225 mg taurine/100 g body weight. Two hours after the administration, the animals were killed and gastrocnemius muscle was taken. Myofibrillar proteolysis was determined based on plasma Nr-methylhistidine concentrations. Expression of proteolytic-related genes in the muscle was determined by real-time PCR analysis. The administration of taurine decreased myofibrillar proteolysis, as well as the levels of mRNA expression of m-calpain, the C1 and C2 proteasomal subunits, and caspase-3, whereas had no effect on the levels of mRNA expression of ubiquitin, atrogin-1/MAFbx and cathepsin B. These results indicate that oral administration of taurine suppresses myofibrillar proteolysis and the expression of proteolytic-related genes in skeletal muscle of chicks.