Differential effects of reduced protein diets on fatty acid composition and gene expression in muscle and subcutaneous adipose tissue of Alentejana purebred and Large White x Landrace x Pietrain crossbred pigs
Differential effects of reduced protein diets on fatty acid composition and gene expression in muscle and subcutaneous adipose tissue of Alentejana purebred and Large White x Landrace x Pietrain crossbred pigs
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DOI：
10.1017/s0007114512004916
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发表时间：
2013-07-28
影响因子：
3.6
通讯作者：
Prates, Jose A. M.
中科院分区：
文献类型：
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作者：
Madeira, Marta S.;Pires, Virginia M. R.;Prates, Jose A. M.
本研究评估了猪基因型（脂肪型与瘦肉型）、饲粮蛋白质和赖氨酸水平（正常与降低）对肌内脂肪（IMF）含量、皮下脂肪组织（SAT）沉积、脂肪酸组成和控制脂质代谢基因mRNA水平的影响。试验选用60头活重60 ~ 93公斤的完整公猪（30头阿连特贾纳纯种猪和30头大白×长白×皮特兰杂交猪）。试验动物分为3组，分别饲喂赖氨酸平衡的对照饲粮（粗蛋白质17.5%，赖氨酸0.7%）、赖氨酸平衡的还原蛋白质饲粮（粗蛋白质13.2%，赖氨酸0.6%）和赖氨酸不平衡的还原蛋白质饲粮（粗蛋白质13.1%，赖氨酸0.4%）。结果表明，RPD增加了瘦肉猪腰最长肌的脂肪沉积，而在肥肉猪基因型中没有。因此，RPD对杂交猪腰最长肌的影响可能是通过限制赖氨酸介导的。在RPD处理下，IMF含量的增加伴随着硬脂酰辅酶a去饱和酶（SCD）和PPARG mRNA水平的升高。RPD对瘦肉型和肥肉型猪的背膘厚度没有影响，但增加了总脂肪酸含量。与瘦肉猪相比，肥胖猪的SAT含量越高，与ACACA、CEBPA、FASN和SCD基因的表达水平越高有关。综上所述，这些数据表明，调节猪脂肪沉积的机制具有基因型和组织特异性，并且与关键脂肪生成基因的表达调控有关。
The present study assessed the effect of pig genotype (fatty v. lean) and dietary protein and lysine (Lys) levels (normal v. reduced) on intramuscular fat (IMF) content, subcutaneous adipose tissue (SAT) deposition, fatty acid composition and mRNA levels of genes controlling lipid metabolism. The experiment was conducted on sixty intact male pigs (thirty Alentejana purebred and thirty Large White x Landrace x Pietrain crossbred), from 60 to 93 kg of live weight. Animals were divided into three groups fed with the following diets: control diet equilibrated for Lys (17.5% crude protein (CP) and 0.7% Lys), reduced protein diet (RPD) equilibrated for Lys (13.2% CP and 0.6% Lys) and RPD not equilibrated for Lys (13.1% CP and 0.4% Lys). It was shown that the RPD increased fat deposition in the longissimus lumborum muscle in the lean but not in the fatty pig genotype. It is strongly suggested that the effect of RPD on the longissimus lumborum muscle of crossbred pigs is mediated via Lys restriction. The increase in IMF content under the RPD was accompanied by increased stearoyl-CoA desaturase (SCD) and PPARG mRNA levels. RPD did not alter backfat thickness, but increased the total fatty acid content in both lean and fatty pig genotype. The higher amount of SAT in fatty pigs, when compared with the lean ones, was associated with the higher expression levels of ACACA, CEBPA, FASN and SCD genes. Taken together, the data indicate that the mechanisms regulating fat deposition in pigs are genotype and tissue specific, and are associated with the expression regulation of the key lipogenic genes.