Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Mol Biol Rep. 2011 Nov;38(8):5307-12. doi: 10.1007/s11033-011-0680-y. Epub 2011 Jan 21.
The effect of castration on carcass quality was investigated by ten Chinese Simmental calves. Five calves were castrated randomly at 2 months old and the others were retained as normal intact bulls. All animals were slaughtered at 22 months old. The results showed that bulls carcass had higher weight (P < 0.05), dressing percentages and bigger longissimus muscle areas (P < 0.05) than steers. But steer meat had lower shear force values and was fatter (P < 0.05) than bull. Furthermore, in order to discover genes that were involved in determining steer meat quality, we compared related candidate gene expression in longissimus muscle between steer (tester) and bull (driver) using suppressive subtractive hybridization. Ten genes were identified as preferentially expressed in longissimus muscle of steer. The expression of four selected differentially expressed genes was confirmed by quantitative real-time PCR. Overall, a 1.96, 2.41, 2.89, 2.41-fold increase in expression level was observed in steer compared with bull for actin, gamma 2, smooth muscle, tropomyosin-2, insulin like growth factor 1 and hormone-sensitive lipase, respectively. These results implied that these differentially expressed genes could play an important role in the regulation of steer meat quality.
本研究选用 10 头中国西门塔尔公牛，随机选择其中的 5 头在 2 月龄去势，其余 5 头公牛作为正常公牛，在 22 月龄时进行屠宰，研究去势对其肉质的影响。结果表明：公牛的胴体重、屠宰率和背最长肌面积均显著高于阉牛（P < 0.05），但公牛的肌肉剪切力显著低于阉牛（P < 0.05），肌肉嫩度较好；为了寻找与决定肉质相关的候选基因，利用抑制消减杂交技术比较了阉牛和公牛背最长肌组织中相关候选基因的表达差异。结果共筛选到 10 个在阉牛肉中特异性表达的基因，利用实时荧光定量 PCR 对其中 4 个基因的表达进行了验证，结果显示，与公牛相比，actin、gamma 2、smooth muscle、tropomyosin-2、IGF-1 和激素敏感脂肪酶基因在阉牛背最长肌中的表达水平分别上调了 1.96、2.41、2.89、2.41、2.89 和 2.41 倍。这些结果提示这些差异表达基因可能在调控阉牛肉质方面发挥着重要作用。
