Modulation of nutrient composition of black soldier fly (<i>Hermetia illucens</i>) larvae by feeding seaweed-enriched media

<div><p>Black soldier fly (<i>Hermetia illucens</i>) larvae are a promising source of protein and lipid for animal feeds. The nutritional composition of the BSF larvae depend partly on the composition of the feeding medium. The BSF lipid profile in part mimics the feeding media lipid profile, and micronutrients, like minerals and vitamins, can readily accumulate in black soldier fly larvae. However, investigative studies on bioconversion and accumulation of nutrients from media to black soldier fly larvae are scarce. Here we show that inclusion of the brown algae <i>Ascophyllum nodosum</i> in the substrate for black soldier fly larvae can introduce valuable nutrients, commonly associated with the marine environment, into the larvae. The omega-3 fatty acid eicosapentaenoic acid (20:5n-3), iodine and vitamin E concentrations increased in the larvae when more seaweed was included in the diet. When the feeding media consisted of more than 50% seaweed, the larvae experienced poorer growth, lower nutrient retention and lower lipid levels, compared to a pure plant based feeding medium. Our results confirm the plasticity of the nutritional make-up of black soldier fly larvae, allowing it to accumulate both lipid- and water-soluble compounds. A broader understanding of the effect of the composition of the feeding media on the larvae composition can help to tailor black soldier fly larvae into a nutrient profile more suited for specific feed or food purposes.</p></div

The use of seaweed as sustainable feed ingredient for the house cricket (<i>Acheta domesticus</i>): investigating cricket performance and nutritional composition

The house cricket (Acheta domesticus) is considered one of the most promising farmed insect to be used as novel food, thanks to its attractive nutritional profile and its great taste. To the best of our knowledge, crickets in Europe are reared on soybean meal-rich feed which won’t be sustainable in the long run. Insect producers have shown interest in using more environmentally friendly substrates for cricket’s rearing. Among these, seaweed has been investigated as feed ingredients for insect rearing. However, no studies on crickets are available. We aimed to evaluate the potential use of the alga Palmaria palmata in the diet of house crickets (5%, 10% and 20% of the diet), in terms of insect performances and nutritional composition (protein, lipid, amino acids and fatty acids). Crickets fed seaweed-enriched diets showed good performance parameters (individual weight, cricket yield and survival) compared to crickets fed the control diet without presenting statistically significant differences (P > 0.05), while their nutritional composition changed significantly for some components. Protein content of the crickets increased when more seaweed was added to their diets (P = 0.0115), while the fat content decreased (P = 0.0451). Also, the amino acid composition of the crickets remained stable between dietary groups, except for histidine, methionine and lysine which increased in crickets fed more seaweed in the diet (P = 0.0430, P = 0.0342, P = 0.0302, respectively). Finally, the presence of seaweed in the diet led to a transfer of the omega-3 eicosapentaenoic acid from the seaweed to the crickets (P < 0.0001), which are naturally lacking this fatty acid. Based on this study, we conclude that the red alga Palmaria Palmata is a suitable substrate for cricket mass rearing up to 20 g/100 g of the diet. However, higher seaweed inclusion and longer dietary administration time could affect the nutritional composition of the house cricket differently, therefore they should be investigated.</p

Mineral retention (% added minerals recuperated in larvae) of black soldier larvae grown on increasing inclusions of brown algae in feeding media.

<p>Mineral retention (% added minerals recuperated in larvae) of black soldier larvae grown on increasing inclusions of brown algae in feeding media.</p

Proximate composition (%, dry weight) and dry matter of black soldier fly larvae (% wet weight) grown on increasing inclusions of brown algae in feeding media.

<p>Proximate composition (%, dry weight) and dry matter of black soldier fly larvae (% wet weight) grown on increasing inclusions of brown algae in feeding media.</p