AUTHOR=Wu Yunya , Li Rui , Wu Xingxing , Guo Wei , Li Yongming , Song Yanlong , Tao Binbin , Chen Ji , Han Dong , Xie Shouqi , Wang Yaping , Zhu Zuoyan , Hu Wei 

TITLE=Improved liver lipid catabolism and utilization in growth hormone transgenic common carp (Cyprinus carpio L.) through enhanced lipolytic and fatty acid β-oxidation pathways

JOURNAL=Frontiers in Endocrinology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.982488

DOI=10.3389/fendo.2022.982488

ISSN=1664-2392

ABSTRACT=<p><italic>Growth hormone</italic> (<italic>GH</italic>) transgenic common carp (<italic>Cyprinus carpio</italic> L.) show desirable aquaculture traits. Their specific growth rate (SGR) and feed efficiency (FE) are approximately 12% and 17% higher than the wild-type (WT) common carp, respectively. However, the mechanisms of lipid catabolism (lipolysis and fatty acid β-oxidation) and utilization in <italic>GH</italic> transgenic common carp are still unclear. In this study, we firstly compared the lipid metabolism of <italic>GH</italic> transgenic (initial weight 3.72 ± 0.32 g) and WT (initial weight 3.30 ± 0.28 g) common carp fed with a normal fat level diet (6% lipid, 33% protein) for two months, then compared the growth performance of <italic>GH</italic> transgenic (initial weight 3.65 ± 0.33 g) and WT (initial weight 3.27 ± 0.26 g) common carp fed with different fat levels diets (6% lipid and 12% lipid, 33% protein) for two months. We found that the lipid content in serum, liver and whole body was significantly reduced in <italic>GH</italic> transgenic common carp, the hepatic activities of the lipolytic enzymes hormone-sensitive lipase and adipose triglyceride lipase were enhanced, and the hepatic expression level of <italic>hormone-sensitive lipase</italic> was upregulated. In addition, the mitochondrion numbers were increased, and the expression level of <italic>carnitine palmitoyltransferase-1a</italic> and <italic>carnitine palmitoyltransferase-1b</italic> was upregulated in the liver of <italic>GH</italic> transgenic common carp. <italic>GH</italic> transgenic common carp showed higher weight gain and SGR than that in WT carp when fed with a normal-fat diet as they did when fed with a high-fat diet, and <italic>GH</italic> transgenic common carp showed higher FE than that in WT carp when fed with a high-fat diet. These results suggested that the lipid catabolism and utilization was improved in the <italic>GH</italic> transgenic common carp liver through enhanced lipolytic and fatty acid β-oxidation pathways. Our study provides new insights into improving lipid utilization in some aquaculture fish species.</p>