Formulating a Cost-Effective Substrate for Growth of the Black Soldier Fly Larvae

Abstract

The black soldier fly (BSF; Hermetia illucens L.) is a very promising insect species due to its ability to convert low‐value substrates into a highly nutritious animal feed. This work aimed at formulating a substrate growth media using a mixture of wastes (wheat bran, brewer’s spent grain and market fruit waste) to achieve a good growth performance of BSF larvae using least costs. The wastes were mixed in varying proportions to supply 3 nutrient concentrations; low (LNC), intermediate (MNC) and high nutrient concentrations (HNC), which were the substrate mixtures (treatments) used for rearing the seven-day old larvae (7 DOL) for a period of 14 days. Each of the three treatments was replicated six times, with each replicate containing equal amounts of the growth mixture (500gm) to rear 3.8gms of the 7 DOL. Growth performance of the larvae was determined by assessing three growth parameters; weight, length and girth at the 7th and 14th days of the experiment. Data collected was subjected to ANOVA using R studio software followed by Post hoc Tukey tests to separate means significantly affected at 5%. The study revealed that maximum performance of BSF larvae in the treatments was registered at the eighth day of the experiment with HNC performing best in both average larval weight and girth while MNC performed best only in average larval length. Treatment LNC resulted into nutrient limitation, resulting in significantly lower average larval weights, length and girth. Furthermore, treatment HNC used the least costs since it had the highest benefit cost ratio (BCR) of 1.96 followed by MNC with a BCR of 1.50 and lastly LNC with 1.22. This study indicated that the growth performance of BSF larvae is highly affected by both protein and energy concentrations of the substrate.