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Keywords:

  • Conjugated linoleic acid;
  • growth performance;
  • hepatic fatty acid profile;
  • lipid deposition;
  • lipid metabolism;
  • Synechogobius hasta

Abstract

This study was conducted to determine the effect of dietary CLA (Conjugated linoleic acid) levels on growth performance, fatty acid profiles and lipid metabolism of liver in Synechogobius hasta. Fish were fed six diets with fish oil replaced by 0 (control), 5, 10, 15, 20 and 25 g kg−1 CLA for 8 weeks. Weight gain, WG, and SGR (specific growth rate) tended to increase when dietary CLA levels increased from 0 to 10 g kg−1 and then decline with further increasing dietary CLA levels to 25 g kg−1. FCR (feed conversion ratio) showed contrary trend with WG and SGR. The reduced VSI (vicero somatic index) and increased HSI (hepatosomatic index) were observed in fish fed increasing dietary CLA levels. Whole-body lipid content declined, but hepatic lipid content increased with increasing dietary CLA levels. Dietary CLA modified total percentages of the main groups of fatty acids in liver. Hepatic 6PGD, ME and ICDH activities increased with increasing dietary CLA levels. FAS and G6PD were very variable and not related to dietary treatments. CPT I activities showed no significant differences among the treatments. Based on second-order polynomial regression analysis of WG and FCR against dietary CLA level, 8.7–10.1 g kg−1 was indicated to be the optimal dietary CLA range for maximum growth and feed utilization for S. hasta.