Bioaccumulated provitamin A in black soldier fly larvae is bioavailable and capable of improving vitamin A status of gerbils.

The aim was to study whether provitamin A (proVA), which can bioaccumulate in black soldier fly larvae (BSFL), is bioavailable and can restore VA status in mammals. A model for studying the metabolism of this vitamin, the gerbil, was either fed a standard diet (C+ group), a diet without VA (C-), a diet in which VA was provided by ß-carotene (ß-C) from sweet potatoes (SP), or a diet in which VA was provided by ß-C from BSFL that had been fed sweet potatoes (BSFL). The animals were killed at the end of the supplementation period and ß-C, retinol and retinyl esters were measured in plasma and liver. As expected ß-C was not detected in plasma and liver of the C+ and C- groups. ß-C concentrations were lower (p < 0.05) in plasma and liver of the BSFL group as compared to the SP group. Liver retinol and retinyl ester concentrations were lower in the C- group than in all the other groups (p < 0.05). These concentrations were not significantly different in the C+ and SP groups while they were lower in the BSFL group (p < 0.05 for retinyl oleate and retinyl linoleate). In total, the liver stock of retinol equivalent was almost twice lower in the BSFL group than in the SP group. Thus, ß-C present in the BSFL matrix is bioavailable and capable of improving VA status, but this matrix decreases its effectiveness by a factor of around two compared to the sweet potato matrix.

Using black soldier fly larvae reared on fruits and vegetables waste as a sustainable dietary source of provitamin a carotenoids.

We showed that black soldier fly larvae reared on fruits and vegetables rich in provitamin A carotenoids can accumulate significant amounts of these vitamin A precursors. Using a simulated gastro-intestinal digestion model, we demonstrated that α- and ß-carotene from the larvae are as bioaccessible as from the fruits and vegetables they were reared on. We calculated that provitamin A carotenoid-rich larvae have the capacity to provide more vitamin A than fruits and vegetables rich in these molecules. Remarkably, the incorporation of usual quantities of these larvae in feed could cover the needs of several production animals for this vitamin. Thus, our findings suggest that rearing black soldier fly larvae on by-products or waste rich in provitamin A carotenoids could be a sustainable strategy to recycle a fraction of vitamin A back into the food chain and could represent a new approach to fight against vitamin A deficiency.