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4th Edition of
World Aquaculture and Fisheries Conference

June 24-26, 2024 | Paris, France
WAC 2021

Christopher C Parrish

Christopher C Parrish, Speaker at Aquaculture Conferences
Memorial University of Newfoundland, Canada
Title : Replacement of fish oil by a high-dha microbial oil in salmon diets: Effect on growth performance, lipid composition and gene expression


The omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential nutrients for farmed fish and for their human consumers. Fish oil is one of the main sources of these long-chain polyunsaturated fatty acids; however, due to an increasing demand for EPA and DHA and with a limited supply from wild fisheries, there is a need for alternative sources that are sustainable and cost effective for aquaculture. Here we investigated replacement of fish oil with a high-DHA, low-EPA oil extracted from single-celled thraustochytrids. This provided a unique opportunity to determine how these dietary fatty acids independently influence lipid metabolism and physiological pathways in salmonids.

A 16-week feeding trial was conducted with Atlantic salmon fed diets with a complete or partial replacement of fish oil with microbial oil. There was no significant difference in growth performance among the dietary treatments but we observed differences in lipid composition and gene expression. We investigated total lipid class and fatty acid composition in liver and muscle tissues using thin-layer chromatography and gas chromatography with flame ionization detection and mass spectrometric detection. Our results showed no significant differences in total lipids and lipid class concentrations among the dietary treatments for both tissues; however, significant difference were observed in proportions of omega-3 and omega-6 total lipid fatty acids and phospholipid fatty acids. In addition, there were differences in the phytosterol composition and in triacylglycerol and phospholipid molecular species. These results correlated with hepatic lipid metabolism biomarkers, although some levels were the same with high dietary DHA (high microbial oil) and high EPA (fish oil) indicating successful replacement of fish oil with microbial oil.


Dr. Christopher C. Parrish has a B.Sc.(Hons) in Chemistry and Oceanography from Wales, and a Ph.D. in Oceanography from Dalhousie University, Canada. He is a University Research Professor and Interim Head of Department. He works at the interface of chemistry and biology in the area of marine lipid research studying food web connections, aquaculture nutrition, and environmental impacts on trophic ecology. He recently expanded into lipidomics and gene expression work focusing on alternative lipid sources for aquaculture that are sustainable and cost effective, and ways to maximize the healthfulness of the food product. He has published >190 refereed journal articles.