新疆褐牛和安格斯牛公犊脂代谢相关肉品质性状的比较

动物体脂沉积具有明显的时空变化特征,且与其肉品质性状密切相关。新疆褐牛是我国著名的肉乳兼用培育品种,但与国外优良肉牛品种相比,其脂代谢相关肉品质性状的生长发育变化以及其相关调控基因的表达变化缺乏系统研究。本研究以相同饲养条件下安格斯肉牛和新疆褐牛3月龄公犊为对象,对其屠宰性状、不同脂肪组织形态测量指标、背最长肌和脂肪组织中脂肪酸合成酶(FASN)、脂肪酸结合蛋白4(FABP4)、激素敏感脂酶(HSL)、脂蛋白脂酶(LPL)和瘦素(LEP)基因的m RNA及其蛋白表达以及血清中其激素水平进行了测定。以期为后续的品种比较研究提供早期生长发育变化基础。结果为:(1)安格斯公犊肉骨比极显著高于新疆褐牛(p<0.01),而肋脂厚和眼肌面积显著小于新疆褐牛(p<0.05)。(2)安格斯肉牛心周脂肪和网膜脂肪组织中的脂肪细胞面积/单位面积脂肪细胞数量之比显著高于新疆褐牛(p<0.05)。(3)在背最长肌和肾周脂肪中安格斯牛的FASN基因mRNA表达量均呈现出显著(p<0.05)和极显著(p<0.01)低于新疆褐牛的一致性变化;而在心周脂肪中则呈现安格斯公犊极显著高于新疆褐牛的相反变化(p<0.01)。此外,在心周脂肪中安格斯牛的LEP和LPL基因的m RNA表达量极显著(p<0.01)和显著(p<0.05)高于新疆褐牛,而在肾周脂肪中安格斯牛的LPL、HSL和FABP4基因的mRNA表达量均极显著低于新疆褐牛(p<0.01)。在心周脂肪组织和肾周脂肪中安格斯牛的LPL蛋白表达量极显著(p<0.01)和显著(p<0.05)高于新疆褐牛;(4)安格斯公犊血清5种激素浓度均显著(p<0.05)或极显著(p<0.01)低于新疆褐牛。除LEP外,该结果与肾周脂肪中其余4种激素编码基因的mRNA相对表达量变化一致。本研究结果表明,三月龄新疆褐牛体脂沉积能力大于安格斯牛,而产肉率有低于安格斯牛的趋势。体脂代谢相关基因及其蛋白表达的品种间差异主要体现在背最长肌、肾周、心周脂肪等组织。

Comparison on the Fat Metabolism Related Meat Quality Traits between Calves of Xinjiang Brown Cattle and Angus

Fat deposition in animals has significant spatial-temporal features and is closely associated with the meat quality traits.Xinjiang brown cattle was one of famous cattle breeds with dual-purpose of meat and milk bred in China,whereas the development of the fat metabolism related meat quality traits and the expression of their regulating genes in Xinjiang brown cattle are not well elucidated in the comparison with those famous foreign beef cattle breeds.In this paper the slaughtering traits and the expression of some fat metabolism related meat quality control genes,i.e.,fatty acid syntheses(FASN),fatty acid-binding protein 4(FABP4),hormone-sensitive lipase(HSL),lipoprotein lipase(LPL)and leptin(LEP)mRNA,and their products were compared between 3 month old Angus and Xinjiang brown cattle calves to lay a foundation for the early growth and development of the subsequent comparison between breeds.The resultswere as follows:(1)The ratio of meat/bone in Anguswas extremely high than that of Xinjiang brown cattle(p<0.01),whereas the thickness of rib fat and the eye muscle area in Angus were sig-nificantly smaller than those of Xinjiang brown cattle(p<0.05);(2)The ratio of adipocyte area/number of adipoc-yte per unit in the pericardial and omental adipose tissue of Angus was significantly higher than that of Xinjiang brown cattle(p<0.05);(3)The expression of FASN gene's mRNA in longissimus muscle and perirenal adipose tissue of Angus was significantly and extremely lower than those of Xinjiang brown cattle,while in the pericardial adipose tissue of Angus it was extremely higher than that of Xinjiang brown cattle(p<0.01).In addition the express-ion of LEP and LPL genes mRNA in the pericardial adipose tissue of Angus was extremely and significantly higher than those of Xinjiang brown cattle,but the expression of LPL,HSL and FABP4 genes'mRNA in the perirenal adipose tissue was extremely lower than those ofXinjiang brown cattle(p<0.01).The expression of LPL protein in the pericardial and perirenal adipose tissues ofAngus was extremely(p<0.01)and significantly(p<0.05)higher than those of Xinjiang brown cattle;(4)Five blood hormones of Angus were significantly lower than those of Xinjiang brown cattle,which was consistent with the expression of their encoding genes'mRNA except for LEP.It is indicated that the meat productivity in Angus is higher than that of Xinjiang brown cattle,whereas the fat deposition is lower than that of Xinjiang brown cattle.The breed differences in terms of fat metabolism related mea quality control genes expression is mainly reflected in the longissimus muscle,perirenal and pericardial adipose tissues.