Effect Of Undernutrition And Compensation On The Tenderness Related Gene MRNA Expression In Sheep

This experiment was conducted to research the effects of different dietary energy and protein ratio restriction and feed compensation on the meat quality and tenderness relevant gene expression in lamb, Eighty WuZhuMuQin lambs (average body weight14.72kg)were selected and divided into4groups.The feeding trial lasted150days includes60days of feed restriction and90days of feed compensation.The nutrition level of the diet in feed restriction period (0-60d) were ME:10.88MJ/kg,CP:10%for restricted group I (RG I); ME:9.41MJ/kg,CP:10%for restricted group Ⅱ (RG Ⅱ);and ME:8.62MJ/kg,CP:5.7%for restricted groupIII (RGIII) and ME:10.88MJ/kg,CP:15%for control group (CG). Experimental diets were ad libitum and water were available during the entire experimental period.During nutrition compensatory period (60-150days), all lambs were offered the same diet.The experimental results showed:Nutrient limitation promoted calpain family Calpainl, Calpain2and CAST gene expression, through the compensatory growth, all genes expression return to normal level, except Calpain2gene. Low protein nutrition restriction inhibited Cathepsin B, Cathepsin D expression, but promote Cathepsin L expression. Low energy levels of nutrition restriction on Cathepsin B, Cathepsin D, Cathepsin L expression level have little effects. Protein energy double limits level on Cathepsin B, Cathepsin D expression without negative effects, but on Cathepsin L expression have negative effect. The later period Cathepsin B and Cathepsin nutrition compensations on Cathepsin L expression have negative effects, while promoting the Cathepsin D expression.Nutrition restriction on post-mortem45mins in group RG3pH have a variation influence.At the end of the limit period, and on post-mortem45mins and24h lambs in longissimus dorsi of pH manifestations of RG3was the highest.At the end of the compensation period, and post-mortem45mins in group RG2after pH was significantly higher than the other three groups. In the post-mortem24h all groups pH changes have no difference.Nutrition restriction and compensation on muscle water holding capacity have no effect.At the end of the limit period, group RG3shear force values significantly lower than the other three groups. At the end of compensation period, RG1group and RG2group were significantly higher than the control group and RG3group.