Chemical composition, chitin and cell wall nitrogen content of Black Soldier Fly (Hermetia illucens) larvae after physical and biological treatment

The use of insects as feed may provide a potential solution to overcome the increasingly limited supply of feed, especially protein sources. Black soldier fly (BSF, Hermetia illucens) larvae is characterized by its easy production system, rapid growth, able to efficiently convert organic waste and contains high protein, i.e., around 40%. However, the BSF exoskeleton contains chitin which is a component of cell wall and may inhibit the process of nutrient utilization in the digestive tract of ruminants. This experiment aimed to reduce chitin in BSF through physical (separation of the exoskeleton part) and biological (fermentation with chitinolytic bacteria) treatments. There are four treatments tested in this study: BSF larvae control (T1), BSF larvae without exoskeleton (T2), fish meal (T3), fermented BSF larvae using Bacillus subtilis ATCC 19659 (T4).Physical and biological treatments were able to reduce crude fiber content from 20.27% (T1) to 4.29% (T2), 13.18% (T4), and there was a decrease in ADF content up to 21.78% (T2) and 19.69% (T4). Bacillus subtilis also had lipase enzyme activity, so it can reduce ether extract in BSF larvae by 25.83%. The value of deacetylation degree from chitin isolated without treatment (T1) had a higher value of 66.11. This shows that the fermentation process using chitinolytic bacteria is able to reduce the quality of chitin and change the characteristics of chitin. It can be concluded that physical and biological treatment of BSF prepupa larvae can reduce chitin content, which is indicated by a decrease in crude fiber and fiber fraction (NDF and ADF). Fermentation using chitinolytic bacteria can change chitin characteristics and affect chitin quality.