PDF(Pubmed)
Abstract：
In this study, we conducted an 8-week feeding trial to investigate the effects of replacing fish oil (FO) with coconut oil (CO) on the growth performance, blood components, tissue fatty acid (FA) profile, and mRNA levels of genes related to lipid metabolism in the liver of the orange-spotted grouper (Epinephelus coioides). Five isolipidic and isoproteic diets were formulated through increasing the CO levels (0, 25%, 50%, 75%, and 100%, respectively). Triplicate groups of twenty-five fish (initial wet weight of about 22.4 g/fish) were fed one of the diets twice daily to apparent satiety. The 25% CO diet had the highest growth rate and feed utilization, and the 100% CO diet exhibited a comparable growth and feed utilization with that of the control diet, indicating a suitable FO substitute. Moreover, the hepatosomatic index, intraperitoneal fat rate, liver lipid content, as well as the serum HDL-C content and ALT activity had positive linear and/or quadratic responses, but the serum TC and LDL-C contents exhibited the opposite trend, with an increasing CO inclusion level. The FA profile in the liver and muscle generally mirrored the FA profile in the feed. Furthermore, the mRNA levels of the fas, acc, g6pd, srebp-1c, and δ6fad genes in the liver had positive linear and/or quadratic responses, but the mRNA levels of elovl 4 and elovl 5 had the opposite trend, with increasing dietary CO inclusion levels. When compared with the control diet, 25% and 50% CO diets up-regulated the mRNA levels of cpt 1, while the 75% and 100% CO diets down-regulated its mRNA levels. The hsl and atgl were down-regulated through the addition of dietary CO. The mRNA level of lpl was not affected by dietary treatments. Results showed that CO could completely replace FO without affecting growth performance, but high CO will lead to the significant liver lipid deposition and lower LC-PUFAs contents of fish flesh.
摘要：
在这项研究中,我们进行了为期8周的饲喂试验，以研究用椰子油（CO）代替鱼油（FO）对生长性能的影响，血液成分,组织脂肪酸（FA）谱，橙色斑点石斑鱼（Epinepheluscoioides）肝脏中脂质代谢相关基因的mRNA水平。通过增加CO水平（0，25％，50%,75%,100%,分别)。一式三份的25条鱼(初始湿重约22.4g/鱼)每天两次饲喂其中一种饮食以达到明显的饱腹感。25%CO日粮生长速率和饲料利用率最高,100%CO饮食表现出与对照饮食相当的生长和饲料利用率，表示合适的FO替代品。此外，肝细胞指数，腹膜内脂肪率，肝脏脂质含量，以及血清HDL-C含量和ALT活性具有正的线性和/或二次响应，但血清TC和LDL-C含量表现出相反的趋势，随着CO包含水平的提高。肝脏和肌肉中的FA谱通常反映了饲料中的FA谱。此外，Fas的mRNA水平，acc,g6pd,srepp-1c,肝脏中的δ6fad基因具有正线性和/或二次响应，但是elovl4和elovl5的mRNA水平具有相反的趋势，随着饮食中CO含量的增加。与对照饮食相比，25%和50%CO饮食上调cpt1的mRNA水平,而75%和100%CO饮食下调其mRNA水平。通过添加膳食CO下调hsl和atgl。Ipl的mRNA水平不受饮食处理的影响。结果表明，CO可以完全替代FO，而不影响生长性能，但是高CO会导致明显的肝脏脂质沉积和鱼肉中LC-PUFAs含量降低。
