The vast majority of the Southern Bluefin Tuna (SBT) farmed in South Australia is sold fresh for sashimi production in Japan. Premium prices are obtained for sashimi grade tuna with a high fat content. Unfortunately, fatty fish tissues with their high polyunsaturated fatty acid (PUFA) content are prone to oxidation. This results in poor flesh quality, reduced shelf life and significant trimming of the tuna carcass at the market.

FRDC Project No. 2004/209 investigated the impact of dietary supplements on the flesh quality of farmed SBT. Specifically, it investigated the impact of the dietary antioxidants vitamins C and E and the mineral selenium. Project No. 2004/209 showed that these supplements can extend the shelf life of muscle samples taken from farmed SBT fed diets containing higher than normal concentrations of the antioxidants.

Although Project No. 2004/209 has been very successful, performing diet trials with live SBT is expensive and logistically difficult. It is also time-consuming and the statistical power of the experiments is limited by the fact that it is economically unfeasible to have multiple replicate sea-cages for each dietary treatment. As a result of these constraints, experiments must be repeated over several years to obtain statistically valid results.

Recently, we produced the world’s first SBT cell line and to our knowledge the first cell line for any tuna species. The cell line has the potential to reduce the number of experiments with live SBT and to greatly increase the number of dietary supplements that can be screened in a given period of time. With the cell line, it takes only one week to screen 24 different supplements with 3-4 replicates of each. This compares with years for similar experiments with live SBT.

This project will evaluate the cell line as a platform for testing dietary antioxidant supplements for SBT.