2012/750 Visit to the laboratory of Professor Douglas Tocher (Institute of Aquaculture, University of Stirling, Scotland) to undertake collaborative research into the lipid and polyunsaturated fatty acid (PUFA) metabolism of Southern Bluefin Tuna

By Andrew Scholefield

The purpose of this grant was to undertake collaborative research into the lipid and polyunsaturated fatty acid (PUFA) metabolism of Southern Bluefin Tuna (SBT) using a SBT cell line that was recently produced. This project followed an international trend towards increasing fish oil replacement in feeds for farmed fish to improve the sustainability of the target industry. Very little is known about dietary fish oil replacement in Bluefin tuna species so the purpose of this research was to obtain data which may be used to predict the impacts of fish oil replacement in future manufactured feeds for farmed SBT. Since it was logistically difficult and expensive to obtain such data from traditional feeding trials with SBT, the approach using the SBT cell lines offered a more rapid and cost-effective alternative.

All fatty acids fed to SBT cells are incorporated into cellular lipids. Therefore the precise fatty acid composition of SBT feeds will be reflected in the composition of the flesh. This has influence on the texture, flavor and consistency of the flesh. They found that SBT cells are heavily influenced by the fatty acids in their feeds. High levels of EPA can result in modest increases in growth of SBT cells in culture which may translate to increases in growth in farmed fish.