Technical basis for the small-scale production of black soldier fly, Hermetia illucens (L. 1758), meal as fish feed in Benin

Abstract

Promoting black soldier fly (BSF) rearing in Benin to replace fishmeal in fish diet could reduce fish production costs. This study aims to set up a breeding technique of BSF as a protein source. BSF reproduction has been carried out in sunlight. Two densities (8500 individuals/m 3 and 10,500 individuals/m 3 ) associated with 2 attractants (soybean and pineapple waste) were tested on imago egg-laying. A larvarium with a prepupae self-harvesting system was designed and its efficiency was evaluated by testing 3 densities of larval rearing (1 larva/g, 2 larva/g, 3 larva/g). Two diets, VGD (soybean meal ​+ ​euphorbia leaves and seeds ​+ ​colza oil) and FOD (soybean meal ​+ ​fish offal) were formulated to optimize polyunsaturated fatty acid profile of prepupae to meet nutritional requirements of tilapia. Best oviposition was obtained with 8500 individuals/m 3 with pineapple waste and optimal larval load density was 2 larva/g. Prepupae fed with VGD accumulated C18:2n-6 (10.1%) which is essential for tilapia. Prepupae fed with FOD contained C20:5n-3 (2.20%), a fatty acid beneficial to humans. The lowest production cost of BSF meal was estimated at $1.84/Kg and was obtained with the FOD diet. BSF can easily be reared under local conditions throughout the year. Its nutritional qualities are very interesting to meet Nile tilapia requirements. • Reproduction and larval breeding of BSF are easily carried out in natural conditions in Benin. • Larval rearing containers are easy to design and have prepupae self-harvesting system. • From agricultural by-products, BSF meal can be enriched with essential fatty acids to feed tilapia. • Black soldier fly breeding guidelines in Benin are available.