初生和成年黑藏羊肉品质与肌纤维特性差异分析

旨在比较放牧条件下不同年龄间黑藏羊肉品质与肌纤维组织学特性的差异.本研究选择青海自然放牧条件下体况良好的初生黑藏羊(平均体重(2.31±0.49)kg)和12月龄黑藏羊(平均体重(36.58±1.26)kg)各5只,依据年龄分为2组,即羔羊组(lamb)和成年羊组(adult).通过三磷酸腺苷酶(ATPase)染色、酶...

Difference Analysis of Meat Quality and Muscle Fiber Characteristics between Newborn and Adult Black Tibetan Sheep

This experiment was conducted to study the differences of meat quality and muscle fiber characteristics of black Tibetan lambs at different ages under grazing conditions. Five newborn black Tibetan lambs (average weight (2.31±0.49) kg) and five 12-month-old black Tibetan sheep (average weight (36.58±1.26) kg) were selected under natural grazing conditions in Qinghai. They were divided into two groups according to age, namely lamb group and adult sheep group. Via ATPase staining, ELISA and real-time qPCR, the variation of the nutrient composition, antioxidant capacity, muscle fiber type and myosin heavy chain (MyHCs) genes expression in longissimus dorsi were analyzed between lamb and adult sheep groups. The results showed as follows:1) There were no significant differences in nutrient indexes of longissimus dorsi such as moisture, crude protein, ether extract and ash between the two groups (P>0.05). Similarly there were no significant differences in catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) activities, total antioxidant capacity (T-AOC) and malondialdehyde (MDA) levels (P>0.05). 2) The diameter and cross-sectional area of type Ⅰ, ⅡA and ⅡB muscle fiber in lambs were significantly lower than those of adults (P<0.05), but the muscle fiber density was the opposites (P<0.05). The proportion of type Ⅰ muscle fiber quantity and the proportion of type Ⅰ and type ⅡA muscle fiber area of lambs were significantly higher than those of adult sheep (P<0.05). 3) The mRNA expression levels of MyHC Ⅰ and MyHC ⅡA in lambs were significantly lower than those in adults (P<0.05), but the mRNA expression level of MyHC ⅡB was the opposite (P<0.05). These results indicated that, with the increase of age, the nutrient composition and antioxidant capacity of longissimus dorsi of black Tibetan sheep had no significant changes, but the muscle fiber dramatic changed from oxidized type to glycolysis type, which influenced the body growth and development to a certain extent.