| In this study,20 Mongolia lambs(4 months)were selected and divided into 2 groups: control group(CG) and restricted group(RG). The feeding trial was lasted 120 days, include 60days of feed restriction and 60days of feed compensation. The effects of nutrition restriction and compensation on the mRNA expression of myofiber gene and meat quality were investigated by end of the trial. The results were as follows:1. In longissimus dorsi (LD), nutrition restriction promoted the expression of MyHC Ⅱx gene, the expression of MyHC Ⅰ and MyHC Ⅱx gene were higher than that of CG after nutrition compensation; In triceps brachii (TB), nutrition restriction had negative effect on MyHC Ⅰ and MyHC Ⅱa gene expression while nutrition compensation had active effect on MyHC Ⅰ、MyHC Ⅱa and MyHC Ⅱx genes expression; In biceps femoris (BF), MyHC Ha and MyHC IIx gene expression decreased with nutrition restriction, and MyHC I gene expression increased by end of nutrition compensation.2. Nutrition restriction and compensation had impact on pH value. By the end of restriction period, pH45min and pH24h value of RG in BF and TB were both higher than that of CG(P<0.05); After nutrition compensation, pH45min value of RG in LD became lower compared to that of CG (P<0.05), whie the pH45min value of RG was higher than that of CG(P<0.05) in TB. Nutrition restriction had no influence on the LD colour, but improved L* value in TB and BF, reduced a* value in BF. After compensate period, L* value increased while a* value decreased in LD and TB. In BF, a* and b* value increased differently. Under the experimental conditions, nutrient restriction reduced intramuscular fat and water loss rate of RG and CG. After compensation, there were no differences between RG and CG except for the intramuscular fat of RG in LD.On conclusion, the mRNA expression of myofiber gene, pH, meat color, and the intramuscular fat in different parts of muscle have been influenced by nutrition restriction and compensation. |
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