作 者：
徐超;李向飞;田红艳;周嫚;蔡万存;刘文斌
单 位：
南京农业大学动物科技学院江苏省水产动物营养重点实验室
关键词：
团头鲂;投饵率;血脂水平;脂质代谢;基因表达
摘 要：
为了探究不同投饵率对团头鲂幼鱼脂肪代谢机能的影响,选取840尾平均体质量为(23.74±0.09)g的团头鲂幼鱼,随机分为6组,每组4重复,每重复35尾鱼,分别对应6种投饵率:2%、3%、4%、5%、6%和7%(日投喂量占鱼体质量的比例),饲养60 d后,测定其血脂水平及脂肪代谢相关基因表达的指标。结果发现,随着投饵率的升高,血浆甘油三酯和总胆固醇含量先升高后降低,且各组间差异显著;6%投饵率组的血浆高密度脂蛋白和5%投饵率组的低密度脂蛋白含量显著高于2%组,但与其他组无显著差异;而血浆极低密度脂蛋白含量在投饵率为4%时最高。此外,不同投饵率对脂肪代谢相关基因的表达量也有显著影响。当投饵率由2%升高至4%时,肝脏酰基肉碱转移酶I和II、脂酰辅酶A氧化酶、载脂蛋白B、脂肪酸结合蛋白、过氧化物酶体增殖物激活受体等的m RNA表达量显著升高;当投饵率进一步升高时,载脂蛋白B、脂酰辅酶A氧化酶、脂肪酸结合蛋白和过氧化物酶体增殖物激活受体β呈现下降趋势,但差异不显著;投饵率3%和6%组的脂蛋白酯酶的mRNA表达量显著高于其他组,而肝X受体和脂肪酸转运蛋白的表达量则随着投饵率的升高呈先上升后下降的趋势,并分别在投饵率为3%和5%时达到最高值。研究表明,不同投饵率显著影响了团头鲂幼鱼的血脂含量和肝脏脂质代谢相关基因的表达水平;投饵率为2%~3%时,脂肪酸转运和氧化的程度较低;投饵率为5%~7%时,将导致血脂含量和脂肪沉积相关基因的表达量降低;投饵率为4%~5%时能够维持团头鲂幼鱼脂肪代谢的平衡。
译 名：
Effects of feeding rates on plasma lipid profiles and the m RNA expressions of genes related to lipid metabolism in juvenile blunt snout bream(Megalobrama amblycephala)
作 者：
XU Chao;LI Xiangfei;TIAN Hongyan;ZHOU Man;CAI Wancun;LIU Wenbin;College of Animal Science and Technology, Nanjing Agricultural University;
关键词：
Megalobrama amblycephala;;feeding rate;;plasma lipid profiles;;lipid metabolism;;gene expressions
摘 要：
This study aimed to investigate the effects of feeding rates on plasma lipid profiles and the m RNA expressions of genes related to lipid metabolism in juvenile blunt snout bream, Megalobrama amblycephala(average initial weight: 23.74±0.09 g). A total of 840 fish were randomly distributed into 24 cages and fed with a commercial feed at six feeding rates ranging from 2% to 7% body weight(BW)/day for 60 days. The results indicated that plasma triglyceride and total cholesterol levels increased first, then decreased as feeding rates increased with significant differences observed between treatments(P<0.05). The highest high density lipoprotein and low density lipoprotein concentrations were observed in fish group fed 6% and 5% BW/day respectively. They were significantly higher than those of fish fed 2% BW/day(P<0.05), but showed no statistical difference with those of the other treatments(P>0.05).Very-low-density lipoprotein was the highest in fish offered a feeding rate of 4% BW/day. In addition, feeding rates had a significant effect on the expressions of genes related to lipid metabolism(P<0.05). The m RNA expressions of carnitine palmitoyl transferase-I and II, Acyl-Co A oxidase,apolipoprotein B, fatty acid binding protein and peroxisome proliferators activated receptors all increased significantly(P<0.05) as feeding rates increased from 2% to 4% BW/day, but Acyl-Co A oxidase, fatty acid binding protein and peroxisome proliferator-activated receptor β m RNA expressions are decreased with further increasing ration levels(P>0.05). Lipoprotein lipase expressions of fish fed 3% and 6% BW/day were significantly(P<0.05) higher than that of the other treatments. Liver X receptor and fatty acid transporter protein expressions increased first, then decreased as feeding rates increased with the highest value observed in fish fed 3% and 5%BW/day, respectively. In summary, our results suggest that different feeding rates significantly affect plasma lipid profiles and the m RNA expressions of genes related to lipid metabolism in juvenile blunt snout bream. Low feeding rate(2–3% BW/day) leads to the lower fatty acid transport and oxidation. Higher feeding rate(5–7%BW/day) will result in decreased plasma lipid profiles and the m RNA expressions of genes related to fat deposition. The optimal feeding rate(4–5% BW/day) can maintain fat metabolism balance of juvenile blunt snout bream.
