Nutritional composition of black soldier fly (Hermetia illucens) reared on chicken waste meal, fruit & vegetable waste, and their mixture

Abstract

Fruits and vegetables are wasted in huge amounts and nearly 30% of all produced food is never consumed which leads to many economic and environmental issues. Similarly, the poultry industry generates a huge volume of waste. This refuse is reported to have high nutritional value and could be used as ingredients in the feed industry. Black soldier flies, Hermetia illucens, are potentially capable of converting different organic wastes into protein-rich biomass and considered as a viable alternative protein source to partially substitute fish meal used in aquafeeds, thereby contributing to the sustainability of aquaculture. In this study, the effect of two different organic waste substrates and their mixture, namely chicken waste meal (C), fruit & vegetable waste (FV), and a combination (1:9) of chicken waste meal and fruit & vegetable waste (M) on the nutritional content of black soldier fly prepupae (BSFP) was investigated. Significant differences were observed in energy content and proximate composition of the substrates which significantly altered the energy content and nutritional composition of the BSFP. BSFP reared on FV were low in crude protein, crude lipid and high in crude carbohydrate compared to BSFP reared on C and M. The amino acid contents of BSFP were characterised by high levels of lysine, leucine, and valine. Significant differences were detected between BSFP groups in terms of amino acid content. The fatty acid composition of the BSFP were dominated by the saturated fatty acids (SFA) ranging between 41.8±0.10% (M) and 67.11±0.08% (C). M-fed BSFP had significantly higher SFA, monosaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) compositions than C- and FV-fed BSFP. M-fed BSFP had a high C18:1n9 (17.01±0.02%), C16:0 (17.02±0.09%), C18:2n-6 (14.63±0.02%), and C12:0 (15.19%) fatty acid composition. The fatty acid profile of the C-fed BSFP was characterised by high levels of C14:0 (28.16±0.11%), C12:0 (25.79±0.09%), and C18:1n-9 (13.41±0.03%), whereas FV-fed BSFP was characterised by high levels of C16:0 (19.33±0.08%), C12:0 (16.64±0.18%), and C18:1n-9 (12.51±0.04%). Our results demonstrated that chicken waste meal, fruit & vegetables waste, and their mixture can be used to feed BSFP for sustainable production. However, M-fed BSFP could be used to partially substitute fish meal in carnivorous fish feeds for having a substantially greater nutritional value than BSFP reared on other wastes and for its similarity to fish meal in terms of amino acid content.