1Unit Muscle Biology and Growth, FBN Research Institute for the Biology of Farm Animals, 18196 Dummerstorf, Germany.
Animal. 2010 May;4(5):755-62. doi: 10.1017/S1751731110000431.
This study investigated the effects of dietary linolenic acid (C18:3n-3) v. linoleic acid (C18:2n-6) on fatty acid composition and protein expression of key lipogenic enzymes, acetyl-CoA carboxylase (ACC), stearoyl-CoA desaturase (SCD) and delta 6 desaturase (Δ6d) in longissimus muscle and subcutaneous adipose tissue of bulls. Supplementation of the diet with C18:3n-3 was accompanied by an increased level of n-3 fatty acids in muscle which resulted in decrease of n-6/n-3 ratio. The diet enriched with n-3 polyunsaturated fatty acids (PUFAs) significantly inhibited SCD protein expression in muscle and subcutaneous adipose tissue, and reduced the Δ6d expression in muscle. There was no significant effect of the diet on ACC protein expression. Inhibition of the Δ6d expression was associated with a decrease in n-6 PUFA level in muscles, whereas repression of SCD protein was related to a lower oleic acid (C18:1 cis-9) content in the adipose tissue. Expression of ACC, SCD and Δ6d proteins was found to be relatively higher in subcutaneous adipose tissue when compared with longissimus muscle. It is suggested that dietary manipulation of fatty acid composition in ruminants is mediated, at least partially, through the regulation of lipogenic enzymes expression and that regulation of the bovine lipogenic enzymes expression is tissue specific.
本研究探讨了饲粮中 n-3 亚麻酸（C18:3n-3）与 n-6 亚油酸（C18:2n-6）对公牛背最长肌和皮下脂肪组织中关键脂肪生成酶乙酰辅酶 A 羧化酶（ACC）、硬脂酰辅酶 A 去饱和酶（SCD）和 Δ6 去饱和酶（Δ6d）的脂肪酸组成和蛋白表达的影响。饲粮中添加 C18:3n-3 会使肌肉中 n-3 脂肪酸水平升高，导致 n-6/n-3 比值降低。富含 n-3 多不饱和脂肪酸（PUFA）的饲粮显著抑制了肌肉和皮下脂肪组织中 SCD 的蛋白表达，并降低了肌肉中的 Δ6d 表达。饲粮对 ACC 蛋白表达没有显著影响。Δ6d 表达的抑制与肌肉中 n-6PUFA 水平的降低有关，而 SCD 蛋白的抑制与脂肪组织中油酸（C18:1 cis-9）含量的降低有关。与背最长肌相比，ACC、SCD 和 Δ6d 蛋白在皮下脂肪组织中的表达相对较高。这表明，通过调节脂肪生成酶的表达来介导反刍动物脂肪酸组成的饲粮调控，并且对牛脂肪生成酶表达的调控是组织特异性的。
