Characterization of fungal community of black soldier fly (Hermetia illucens) larvae reared for large-scale feed production

Population, urbanization and rising incomes are expected to double the demands for livestock products in the developing countries. FAO indicates insect-derived flour such innovative protein source and the black soldier fly (Hermetia illucens) as one of the most promising species of insect for a production of large-scale feed. H. illucens is a fly (Diptera) member of the Stratiomyidae family, which is native from America, but it is now widespread in tropical and warmer temperate regions. The aim of the present research was to study the intestinal fungal community of black soldier fly larvae fed on vegetable substrates and to characterize any toxin-producing fungi. The safety of using insects as feed ingredient is one of the priorities for both animals and humans as final consumers in the food chain; in fact the use of insects or insect-derived flour incorporated in the feed may be a risk of potential zoonoses, pathogens, toxins and contamination with heavy metals. The research has been focused on the isolation of yeasts and moulds from the intestinal content of larvae, fed on heat treated vegetable waste, and on the typing of isolates by ITS-RFLP and sequencing of the 26S rRNA D1/D2 domain. The isolated yeasts which, according to literature sources, were producers of toxins, were then used for inhibition assays on sensitive yeast strains to test their killer phenotype. Finally, the variability of the fungal community of each sample was also evaluated by metabarcoding using Next Generation Sequencing 454 technology of fungal ribosomal ITS region.