The influence of feeding media enriched with different oils on the fatty acid composition of the Black soldier fly (Hermetia illucens)

The black soldier fly (Hermetia illucens) has emerged as an interesting alternative protein source in animal feed due to its ability to grow on various substrates. Although it has many rearing benefits and possible applications, it has an unfavourable fatty acid profile if used for htunan consumption due to its high content of lauric acid and low content of polyunsaturated fatty acids. In order to investigate whether the lipid composition of black soldier fly larvae can be altered, the feeding media were supplemented with varying concentrations of fish, linseed or coconut oil (1, 2.5 and 5%). Two-week-old larvae were collected, measured and their tissue fatty acid composition was determined. The fatty acid profile of the larvae showed significant plasticity, depending on the life stage and the fatty acid composition of the feeding media. The addition of 2.5 and 5% of different oils significantly changed the fatty acid composition of larvae, depending on the type and percentage of oil. The n6/n3 ratio was considerably improved by supplementing fish and linseed oil. The addition of linseed oil increased the content of linolenic acid, but bioconversion to eicosapentaenoic and docosahexaenoic acids was low. In contrast, the addition of fish oil significantly increased the content of eicosapentaenoic and docosahexaenoic acids in the larvae. The content of lauric acid significantly increased after coconut addition. The trial showed that by using different oils, the lipid composition of black soldier fly larvae could be specifically changed to increase the beneficial long chain n3 polyunsaturated fatty acids, and the amount of lauric or linolenic acid.