Effects of dietary phospholipids on growth performance, fatty acid composition, and expression of lipid metabolism related genes of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lancolatus ♂)

Abstract

The present study was conducted to investigate the effects of dietary phospholipids on growth performance, fatty acid composition, and lipid metabolism in juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lancolatus ♂). Five isonitrogenous and isolipidic diets with graded levels of phospholipids (14.10, 32.10, 52.50, 70.20, and 91.30 g/kg) were fed to triplicate groups of juvenile grouper (initial body weight 13.00 ± 0.02 g) for 61 days. Results showed that dietary phospholipids produced no statistical influence on growth performance of grouper. The fatty acids profiles of experimental fish are correlated well with dietary fatty acids composition. The increase of dietary phospholipids significantly elevated the crude lipid content in whole fish body, liver and muscle. Meanwhile, the increased dietary phospholipids significantly promoted hepatic triglyceride (TG) accumulation. The results of gene expression analysis revealed that dietary phospholipids did not significantly affect the expression of lipogenesis related genes, FAS, ACC and DGAT2. In addition, high dietary phospholipids inclusion significantly decreased the expression of fatty acids oxidation related genes, PPARɑ and CPT1. In summary, juvenile grouper don’t have a specific requirement for dietary phospholipids which inclusion aggravated lipid deposition through the regulation of fatty acids oxidation at the transcriptional level.