Empirical Evaluation of Fishmeal Substitution with Black Soldier Fly Larva Meal on Growth and Health of Tilapia in Cross River State

Black soldier fly larva meal has emerged as one of the most promising alternative protein sources for aquafeeds, combining high protein content, favourable amino acid profiles, and sustainable production from organic wastes. This study empirically evaluates the effect of replacing fishmeal with black soldier fly larva meal at inclusion levels of 0%, 25%, 50%, 75%, and 100% on growth performance, feed utilisation, haematological parameters, gut histology, and selected immune indices of Nile tilapia in Cross River State, South South Nigeria. Larval meal was produced from Hermetia illucens larvae reared on mixed food waste and characterised for proximate and amino acid composition. Two hundred and fifty tilapia with an initial mean weight of 12.4 g were distributed across 25 tanks and fed experimental diets for 12 weeks. Results showed that tilapia fed diets with up to 50% fishmeal replacement by larva meal achieved growth performance not significantly different from the control group. Haematological parameters, including packed cell volume, haemoglobin, and lymphocyte percentages, were within normal reference ranges at 50% replacement. Gut histology revealed no pathological lesions at 50% replacement, while villus atrophy was observed at 100% replacement. Lysozyme activity, a proxy for innate immunity, was comparable between the 50% larva meal and control groups. The study confirms that black soldier fly larva meal can replace up to 50% of fishmeal in Nile tilapia diets without adverse health or production effects, supporting sustainable feed development for aquaculture in Cross River State.

Keywords: black soldier fly, Hermetia illucens, fishmeal replacement, Oreochromis niloticus, Cross River State