Effect of Honey Supplementation on Growth Performance, Microbial Load, and Nutritional Composition of Black Soldier Fly (Hermetia illucens) Larvae

Abstract

Black Soldier Fly larvae (BSFL) have gained global attention as a sustainable alternative protein source for animal feed because of their rapid growth, high feed conversion efficiency, and ability to valorize organic waste. Optimizing larval nutrition is essential for maximizing biomass yield, improving feed safety, and enhancing nutritional quality. This study evaluated the effects of graded supplementation with commercial, unprocessed natural honey (0%, 5%, 10%, and 15% v/w) on growth performance, microbial load, and proximate composition of BSFL over a 21-day rearing period. A completely randomized design with triplicate treatments was employed. Growth parameters assessed included survival rate, average larval weight, feed conversion ratio (FCR), and total biomass yield. Microbial analyses measured total plate count, Escherichia coli, and lactic acid bacteria populations, while proximate composition was determined using standard AOAC methods. Honey supplementation significantly improved larval survival, weight gain, and biomass production (p < 0.05), with the 10% inclusion level yielding the most favorable overall performance. Honey-treated groups exhibited reduced total microbial and E. coli loads alongside increased lactic acid bacteria counts, although the mechanisms underlying these microbial changes were not directly investigated. Nutritional analysis revealed enhanced crude protein and lipid contents in supplemented larvae, particularly at 10%, without significant effects on ash or moisture. These findings indicate that moderate inclusion of natural honey may function as a nutritional and microbial-modulating feed additive for BSFL. However, because conventional honey is relatively high-value, its commercial sustainability will depend on the availability and safety of lower-value, surplus, downgraded, or otherwise non-marketable honey streams.