Effect Of Chinese Medicine Additives On Meat Quality And Muscle Fibre Types Of Beef Cattle Under High Temperature In Summer

The high temperature and humidity environment in the south declined Finishing performance of beef cattle,worsed beef quality,and reduced the efficiency of beef cattle.Muscle fiber is an important part of muscle,and their quantity and type is a key factor to affect meat quality.In this trail,traditional Chinese medicine compound was added to basic feed of beef cattle,and effect of traditional Chinese medicine additives on beef quality and muscle fiber types were incestigated under high temperature of summer.The study consists of three details as follows.The first experiment:in order to study the effect of traditional Chinese medicine compound on meat quality,antioxidant and physiological indexes of beef cattle under high temperature in summer heat.Twelve healthy and uncastrated bulls with initial body weight of?437.50±9.46?kg were randomly divided into 2 groups with 6 heads per each group.Animals were fed under environment of high temperature and humidity in summer.The cattle in the control group were fed the basal diet,and the cattle in the treating groups were fed the basal diets with Chinese medicine prescriptions supplied by 1%.The test lasted for60 days.At the end of the trial,three bulls were selected randomly from each group,and the longissimus dorsi muscle was collected for the analysis of meat quality.The results showed that the average temperature humidity index?THI?was above 79,the body temperature with Chinese medicine group were decreased significantly compared with control group?P<0.05?,but there was no significant difference about respiratory frequency.Also,the ADF of Chinese medicine additive treatment were increased Compared with control group,but no difference about the ADG and FCR?P>0.05?,Moreover,pH_24h value of Chinese medicine additive group were decreased,and a significant reduction was notice on the contents of crude ash compared with control group?P<0.05?,but no significant change about the contents of CP and fate in muscle.The activity of glutathione peroxidase with Chinese medicine additive were enhanced by 19.8%compared with control group?P<0.05?,but no difference about the SOD activity and MDA contents?P>0.05?.These results indicated that traditional Chinese medicine additive improved the performance of beef cattle,and influenced pH value of beef cattle under high temperature environment in summer.The second experiment:in order to study the effect of Chinese medicine additives on muscle metabolism of and energy and glycolysis in beef cattle under high temperature,the activity of energy metabolism and glycolytic enzyme were investigated.Results show that:compared with control group,the activity of adenosine triphosphate?ATP?,adenosine monophosphate?AMP?in the longissimus dorsi muscle of Chinese medicine additives group were increased by 66.55%and 62.24%respectively?P<0.05?,AMP activated protein kinase?AMPK?was declined compared with control group?P<0.05?.Also,the cotents of lactic acid,glycogen and glycolytic potential with Chinese medicine additives treatment were decreased,and the activities of lactate dehydrogenase?LHD?,caproic acid kinase?HK?and pyruvate kinase?PK?were declined compared with control group?P<0.05?These results indicated that dietary with traditional Chinese medicine additives reduced the glycolytic potential and the activities of glycolysis related enzymes.The third experiment:in order to further investigate the influence of Chinese medicine additives on muscle fiber characteristics and its mechanism.The morphosis and typs of skeletal muscle were oberseved by frozen section and PCR technology.Results showed that:compared with control group,the density of muscle fiber with the Chinese medicine group was increased significantly,the number and ratio of type?b muscle fibers were decreased significantly?P<0.05?,but no difference about the number and ratio of type?and?a muscle fiber?P>0.05?.The mRNA expression of muscle fiber type?and?type with Chinese medicine additive group were increased,but the mRNA expression of?b type were significantly decreased?P<0.05?.The mRNA expression of AMPK?2 in Chinese medicine group was significantly lower than that in the control group,but the mRNA expression of PGC-1?in Chinese medicine additive group were enhanced by110.90%compared with control group?P<0.05?.These results indicated that dietary with traditional Chinese medicine additives affected the morphology and structure of muscle fiber,and promoted transformation from the muscle fiber type?b to type?a and?a by up-regulated the gene expression of PCG-1?.