RESEARCH - Research Summary

Animal Production Theme

Research Summary

To diversify Canada’s marine aquaculture sector, several cold-water fish including haddock (Melanogrammus aeglefinus), Atlantic halibut (Hippoglossus hippoglossus) and sablefish (Anoplopoma fimbria) are currently under development. This is one of several AquaNet funded projects to help improve aquaculture husbandry practices and fish health. Feed represents the single largest operational expense of fish farming, with the lipid (fat) component of fish feed accounting for as much as 25% of the diet cost. This project is directed to establish the optimum dietary levels of lipids for sablefish, haddock, cod and Atlantic halibut (market-size fish only). It will also facilitate least cost diet formulation, reduce the discharge of organic matter and nitrogen into the aquatic environment and improve the lipid utilization of these commercially important finfish species. In addition, public interest in the supply and safety of marine fish oils and fish meals in feed formula have led to increased research efforts in these areas of aquaculture husbandry practices and techniques.

The findings of this study will make recommendations concerning the most cost-effective alternative sources of lipid from animal and/or plant sources for use in formulated diets for sablefish, haddock, cod and Atlantic halibut. This project investigates alternate lipid sources for fish diets and their effects on fish growth, health and flesh quality. Special emphasis is directed to fish flesh quality to ensure that the health benefits of highly unsaturated fatty acids naturally contained in these fish products are maintained.

There is a significant potential to increase the use of Canadian vegetable oils and poultry fat in aqua-feeds and to reduce the importation of marine fish oils into Canada. Studies on the adverse consequences of dietary lipid oxidation on the growth, health and physiology of Atlantic salmon, sablefish and haddock will provide important information for maintenance of proper diet quality assurance programs for these species. Improvement of the health management of alternate species through an understanding of their basic immune system and how this is influenced through lipid nutrition is an essential component of this study. New information on pathogen susceptibility and immune response to vaccination will be obtained for sablefish and Atlantic halibut in relation to life history stage and water temperature. All the findings from this study will have a direct application to the Canadian aquaculture industry.

This research project has made significant progress in developing appropriate nutritional strategies to improve dietary lipid utilization for Atlantic salmon, halibut and haddock. It yielded useful findings for the Canadian feed industry regarding the potential for using vegetable oils to replace marine fish oils. Experiments are underway to examine the effects of dietary lipid utilization and oxidative quality on immune responses of fish. Ongoing studies on the efficiency of lipid utilization, changes in tissue lipid composition and sensory attributes of fish will provide additional information regarding the effects of these changes on the nutritional value and the quality attributes of farmed fish for human consumption.

Network Investigators

Santosh P. Lall, Institute for Marine Biosciences, National Research Council, Halifax, NS
David A. Higgs, West Vancouver Laboratory, Fisheries and Oceans Canada, Vancouver, BC
Brent Skura, Faculty of Agricultural Sciences, University of British Columbia, Vancouver, BC
Fereidoon Shahidi, Department of Biochemistry, Memorial University of Newfoundland, St. John’s, NL
Shannon Balfry, The University of British Columbia, West Vancouver, BC

Publications

Wagner, G.N., Balfry, S.K., Higgs, D.A. and Farrell, A. P.Farrell. 2004. Dietary fatty acid composition affects the repeat swimming performance of Atlantic salmon in seawater. Comparative Biochemistry and Physiology. (Accepted)