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Omega-3 canola oil, a safe dietary source of DHA
A study found that n-3-rich modified canola oil is as safe as other commercial canola oils and is suitable as an alternative oil source in salmon diets.
The limited availability of fish oil, rich in health-promoting omega-3 long-chain polyunsaturated fatty acids, is one of the major constraints for further growth of the aquaculture industry. Long-chain n-3 rich oils from crops GM with algal genes are promising new sources for the industry.
Norwegian and Australian researchers studied the use of docosahexaenoic acid (DHA) omega-3 canola oil (DHA-CA), genetically modified with algal genes, to replace fish oil in diets of Atlantic salmon fingerlings, as part of two feeding trials in Australia and Norway. Two dietary levels of DHA-CA were compared with two dietary levels of fish oil at two water temperatures.
Fish increased their weight approximately 20-fold at 16°C and 12-fold at 12°C during the experimental periods, with equal growth in salmon fed the fish oil diets compared with DHA-CA diets. Salmon fed DHA-CA diets had approximately the same EPA+DHA content in whole body as salmon fed FO diets. Gene expression, lipid composition and oxidative stress-related enzyme activities showed only minor differences between the dietary groups, and the effects were mostly a result of dietary oil level, rather than the oil source.
Researchers found that the levels of phytosterols, vitamin E and minerals in the n-3 modified canola oil fall within the natural variation of commercial canola oils and levels of undesirable compounds were undetectable. Researchers conclude that the n-3-rich modified canola oil (DHA-CA) is as safe as other commercial canola oils and is suitable as an alternative oil source in salmon diets.
The work will be presented at the World Congress on Oils & Fats 2020 in Sydney, Australia.
Read open access article here.