Dietary DHA/EPA ratio affected tissue fatty acid profiles, antioxidant capacity, hematological characteristics and expression of lipid-related genes but not growth in juvenile black seabream (Acanthopagrus schlegelii)

PLoS One. 2017 Apr 21;12(4):e0176216. doi: 10.1371/journal.pone.0176216. eCollection 2017.

Abstract

An 8-week feeding trial was conducted to investigate the effects of dietary docosahexaenoic to eicosapentaenoic acid ratio (DHA/EPA) on growth performance, fatty acid profiles, antioxidant capacity, hematological characteristics and expression of some lipid metabolism related genes of juvenile black seabream (Acanthopagrus schlegelii) of initial weight 9.47 ± 0.03 g. Five isonitrogenous and isolipidic diets (45% crude protein and 14% crude lipid) were formulated to contain graded DHA/EPA ratios of 0.65, 1.16, 1.60, 2.03 and 2.67. There were no differences in growth performance and feed utilization among treatments. Fish fed higher DHA/EPA ratios had higher malondialdehyde (MDA) contents in serum than lower ratios. Serum triacylglycerol (TAG) content was significantly higher in fish fed the lowest DHA/EPA ratio. Tissue fatty acid profiles reflected the diets despite down-regulation of LC-PUFA biosynthesis genes, fatty acyl desaturase 2 (fads2) and elongase of very long-chain fatty acids 5 (elovl5), by high DHA/EPA ratios. Expression of acetyl-CoA carboxylase alpha (accα) and carnitine palmitoyl transferase 1A (cpt1a) were up-regulated by high DHA/EPA ratio, whereas sterol regulatory element-binding protein-1 (srebp-1) and hormone-sensitive lipase (hsl) were down-regulated. Fatty acid synthase (fas), 6-phosphogluconate dehydrogenase (6pgd) and peroxisome proliferator-activated receptor alpha (pparα) showed highest expression in fish fed intermediate (1.16) DHA/EPA ratio. Overall, this study indicated that dietary DHA/EPA ratio affected fatty acid profiles and significantly influenced lipid metabolism including LC-PUFA biosynthesis and other anabolic and catabolic pathways, and also had impacts on antioxidant capacity and hematological characteristics.

MeSH terms

  • Animals
  • Antioxidants / metabolism*
  • Docosahexaenoic Acids / administration & dosage*
  • Eicosapentaenoic Acid / administration & dosage*
  • Sea Bream / genetics*
  • Sea Bream / growth & development

Substances

  • Antioxidants
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid

Grants and funding

This research was supported by the National Natural Science Foundation of China (Grant Nos. 31272670 and 41476125), Major Spark Plan Project of the National Ministry of Science and Technology (2014GA701001), the Open Fund of Zhejiang Provincial Top Key Discipline of Aquaculture in Ningbo University, K. C. Wong Magna Fund and K. C. Wong Education Foundation at Ningbo University.