Chen Xingjie, Li Defa, Yin Jingdong, Ding Yuhua, Zhang Heliang, Zhang Huawei, Yi Ganfeng
National Key Laboratory of Animal Nutrition, China Agricultural University, No. 2. Yuanmingyuan West Road, Beijing 100094, PR China.
Domest Anim Endocrinol. 2006 Oct;31(3):269-83. doi: 10.1016/j.domaniend.2005.11.003. Epub 2005 Dec 1.
Two experiments were conducted to evaluate the effects of dietary energy level and source of oil on leptin mRNA and long form leptin receptor (Ob-Rl) mRNA expression in dorsal, abdominal and visceral adipose tissues in young growing pigs. In experiment one, 15 barrows (initial body weight 15.0 kg) were used to examine the effects of dietary energy levels on leptin mRNA and Ob-Rl mRNA expression. The pigs were randomly allotted to one of three dietary treatments (n=5 per treatment) containing 13.4, 15.1 or 16.7 MJ DE/kg diet for 28 days. Based on the results of experiment one, experiment two was designed to examine the effects of oil sources including soybean oil (rich in n-6 polyunsaturated fatty acids) or fish oil (rich in n-3 polyunsaturated fatty acids) on leptin mRNA and Ob-Rl mRNA expression in the same adipose tissues examined in experiment one. The energy content of these diets was 15.1 MJ/kg. Fourteen barrows (initial weight 20.5 kg) were allocated to either of the two dietary treatments (n=7 per treatment), which was supplemented with either soybean or fish oil (both 5.73% of the diet) and fed to the pigs for 21 days. At the end of both experiments, blood samples were collected to determine plasma leptin and insulin concentrations. Adipose tissues were sampled to determine leptin and Ob-Rl mRNA expression using real-time fluorescence quantification PCR. In experiment one, plasma leptin concentrations were enhanced (P=0.02), and insulin concentrations were decreased (P<0.01) in pigs fed the high-energy diet (16.7 MJ DE/kg). Dorsal adipose tissue leptin mRNA expression was increased by feeding the diet containing 15.1 MJ/kg DE compared with the diets containing 13.4 and 16.7 MJ/kg DE. There was no difference in leptin mRNA expression in abdominal and visceral adipose tissue. In experiment two, there were no differences in plasma leptin and insulin concentrations between pigs fed with either fish oil or soybean oil diets. Nevertheless, fish oil decreased both leptin mRNA and Ob-Rl mRNA expression in dorsal adipose tissues compared with soybean oil (P<0.01). These experiments indicate that the source of oil plays a more potent role in regulation of leptin mRNA expression relative to dietary energy levels by an insulin-independent mechanism. Plasma leptin concentrations may also be regulated by a post-transcriptional mechanism.
进行了两项试验，以评估日粮能量水平和油脂来源对生长育肥仔猪背部、腹部和内脏脂肪组织中瘦素mRNA和瘦素长型受体（Ob-Rl）mRNA表达的影响。在试验一中，选用15头公猪（初始体重15.0 kg），研究日粮能量水平对瘦素mRNA和Ob-Rl mRNA表达的影响。将猪随机分为3组（每组5头），分别饲喂含13.4、15.1或16.7 MJ DE/kg日粮的饲料，为期28天。基于试验一的结果，试验二旨在研究油脂来源（包括富含n-6多不饱和脂肪酸的大豆油或富含n-3多不饱和脂肪酸的鱼油）对试验一中相同脂肪组织中瘦素mRNA和Ob-Rl mRNA表达的影响。这些日粮的能量含量为15.1 MJ/kg。选用14头公猪（初始体重20.5 kg），随机分为2组（每组7头），分别饲喂添加大豆油或鱼油（均占日粮的5.73%）的日粮，为期21天。在两项试验结束时，采集血样以测定血浆瘦素和胰岛素浓度。采集脂肪组织样本，采用实时荧光定量PCR法测定瘦素和Ob-Rl mRNA表达。在试验一中，饲喂高能日粮（16.7 MJ DE/kg）的猪血浆瘦素浓度升高（P=0.02），胰岛素浓度降低（P<0.01）。与含13.4和16.7 MJ/kg DE的日粮相比，饲喂含15.1 MJ/kg DE日粮的猪背部脂肪组织瘦素mRNA表达增加。腹部和内脏脂肪组织中瘦素mRNA表达无差异。在试验二中，饲喂鱼油或大豆油日粮的猪血浆瘦素和胰岛素浓度无差异。然而，与大豆油相比，鱼油降低了背部脂肪组织中瘦素mRNA和Ob-Rl mRNA的表达（P<0.01）。这些试验表明，相对于日粮能量水平，油脂来源通过非胰岛素依赖机制在调节瘦素mRNA表达方面发挥更重要的作用。血浆瘦素浓度也可能受转录后机制调控。
