ANSWER

The addition of suitable antioxidants is the most feasible method to prevent oxidation. Natural antioxidants such as tocopherols, vitamin C, and flavonoids may be effective for a short period in food preserving, but in many cases such protection is not sufficient (Błaszczyk et al., 2013).

Thus, synthetic antioxidants such as ethoxyquin, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are the most commonly used antioxidants due to their efficiency in inhibiting the oxidation of fish oil and feed ingredients (FAO, n.d.; Błaszczyk et al., 2013; Maqsood et al., 2014).

Besides, the addition of a combination of two antioxidants, BHT and BHA, was observed to have a slightly larger effect in enhancing the oxidative stability of fish-oil than the addition of a single antioxidant, BHT, with the addition of same amount (0.2 wt.%) of antioxidant (Lin & Lee, 2010).

References

Błaszczyk, A., Augustyniak, A., & Skolimowski, J. (2013). Ethoxyquin: An Antioxidant Used in Animal Feed. International Journal Of Food Science, 1-12. http://doi.org/10.1155/2013/585931

Food and Agriculture Organization (FAO). (n.d.). Chapter 10: Antioxidants in Compounded  Feeds.

Lin, C. Y. & Lee, J. C. (2010). Oxidative stability of biodiesel produced from the crude fish oil from the waste parts of marine fish. Journal of Food Agriculture and Environment, 8(2).

Maqsood, S., Benjakul, S., Abushelaibi, A., & Alam, A. (2014). Phenolic Compounds and Plant Phenolic Extracts as Natural Antioxidants in Prevention of Lipid Oxidation in Seafood: A Detailed Review. Comprehensive Reviews In Food Science And Food Safety, 13(6), 1125-1140. http://doi.org/10.1111/1541-4337.12106