Lipogenesis and stearoyl-CoA desaturase gene expression and enzyme activity in adipose tissue of short- and long-fed Angus and Wagyu steers fed corn- or hay-based diets
Lipogenesis and stearoyl-CoA desaturase gene expression and enzyme activity in adipose tissue of short- and long-fed Angus and Wagyu steers fed corn- or hay-based diets
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DOI：
10.2527/jas.2006-087
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发表时间：
2007-02-01
影响因子：
3.3
通讯作者：
Smith, S. B.
中科院分区：
文献类型：
--
作者：
Chung, K. Y.;Lunt, D. K.;Smith, S. B.
食用高粗饲料的安格斯和和牛在脂肪组织脂肪酸组成上表现出很大的差异，但在硬脂酰辅酶A脱饱和酶(SCD)活性或基因表达的末端指标上没有差异。此外，饲喂玉米基础日粮的牛的脂肪组织脂比饲喂干草的牛具有更高的MUFA：SFA比率。我们假设，SCD基因表达和活性的任何变化都将先于短期和长期喂养终点之间脂肪组织脂肪生成的类似变化。此外，生产终点之间SCD活性和基因表达的变化在玉米和干草饲喂的牛之间以及和牛和安格斯牛之间会有所不同。安格斯(n=8)和和牛(n=8)饲喂玉米基础日粮8mo(短饲；16mo)或16mo(长期饲喂；24mo)，另一组安格斯(n=8)和和牛(n=8)饲喂干草日粮12mo(短饲；20mo龄)或20mo(长期饲喂；28mo龄)，以匹配玉米饲喂牛的终点体重。在体外，玉米饲喂的肉牛的脂肪中乙酸乙酯的掺入量高于干草饲喂的肉牛(P<；0.01)，和牛的醋酸盐掺入量有高于MGUS的趋势(P=0.06)。这是因为Wagyu中脂肪组织的比例是玉米饲喂、短饲料饲养的安格斯脂肪组织的两倍。在IM中，脂肪生成存在饮食和终点的交互作用。和S.C.脂肪组织(均为P<；0.01)，因为长期饲喂的牛的脂肪生成比饲喂以玉米为基础的饲料的短期饲喂的牛低60%至90%。Angus S.C.的SCD酶活性最高。在24mo龄(玉米饲料)观察到脂肪组织，但和牛脂肪组织在28mo龄时活性最高(干草饲料；品种×饲料×终点交互作用，P=0.08)。对于南卡罗来纳州安格斯的短期与长期终端。脂肪组织SCD活性较低(干草日粮)或相同(玉米日粮)。相反，在饲喂以干草或玉米为基础的日粮(品种x终点互作；P<；0.01)的长期饲养和牛中，SCD基因的表达最高。与我们的假设相反，SCD活性随着时间的推移而增加，而醋酸盐的脂肪生成减少。然而，干草饲喂的Angus和Wagyu脂肪组织中SCD基因表达和活性的发育模式明显不同，这可能解释了这些牛脂肪组织中MUFA/SFA比率的差异。
Angus and Wagyu steers consuming high-roughage diets exhibit large differences in adipose tissue fatty acid composition, but there are no differences in terminal measures of stearoyl-CoA desaturase (SCD) activity or gene expression. Also, adipose tissue lipids of cattle fed corn-based diets have greater MUFA:SFA ratios than cattle fed hay-based diets. We hypothesized that any changes in SCD gene expression and activity would precede similar changes in adipose tissue lipogenesis between short- and long-fed endpoints. Furthermore, changes in SCD activity and gene expression between production endpoints would differ between corn- and hay-fed steers and between Wagyu and Angus steers. Angus (n = 8) and Wagyu (n = 8) steers were fed a corn-based diet for 8 mo (short-fed; 16 mo of age) or 16 mo (long-fed; 24 mo of age), whereas another group of Angus (n = 8) and Wagyu (n = 8) steers was fed a hay-based diet for 12 mo (short-fed; 20 mo of age) or 20 mo (long-fed; 28 mo of age) to match the end point BW of the corn-fed steers. Acetate incorporation into lipids in vitro was greater (P < 0.01) in corn-fed steers than in hay-fed steers and tended (P = 0.06) to be greater in Wagyu than in mgus s.c. adipose tissue because the rate in Wagyu was twice that of Angus adipose tissue in the corn-fed, short-fed steers. There were diet x end point interactions for lipogenesis in i.m. and s.c. adipose tissues (both P < 0.01) because lipogenesis was 60 to 90% lower in the long-fed cattle than in short-fed cattle fed the corn-based diet. The greatest SCD enzyme activity in Angus s.c. adipose tissue was observed at 24 mo of age (corn-based diet), but activity in Wagyu adipose tissue was greatest at 28 mo of age (hay-based diet; breed x diet x end point interaction, P = 0.08). For short- vs. long-fed endpoints in Angus, s.c. adipose tissue SCD activity was less (hay diet) or the same (corn diet). Conversely, SCD gene expression was greatest in long-fed Wagyu steers fed the hay- or corn-based diets (breed x end point interaction; P < 0.01). Contrary to our hypotheses, SCD activity increased over time, whereas lipogenesis from acetate decreased. However, the developmental pattern of SCD gene expression and activity differed markedly between hay-fed Angus and Wagyu adipose tissues, which may explain the differences in the MUFA:SFA ratios observed in adipose tissues from these cattle.