Aquaculture plays a vital role in global food security, with African catfish (Clarias gariepinus) being a key species in Africa. Despite industry growth, challenges in sustainable fish nutrition persist, as traditional feeds like fishmeal and soybean meal are costly and environmentally taxing. Black Soldier Fly (BSF) larvae offer a promising alternative, providing high protein content and eco-friendly benefits. However, their impact on haematological parameters, gut morphology, and histopathology in African catfish remains underexplored. Investigating these effects will enhance understanding of BSF larvae’s role in optimising fish health and aquaculture sustainability.
The study was conducted at the UI-FAO greenhouse, University of Ibadan, using 105 juvenile African catfish (Clarias gariepinus). Fish were randomly assigned to five dietary treatments: (1) 100% commercial feed, (2) 40% live Black Soldier Fly (BSF) larvae + 60% commercial feed, (3) 80% live BSF larvae + 20% commercial feed, (4) 100% live BSF larvae, and (5) 100% formulated diet. The 10-week trial assessed haematological parameters, gut morphology, and histopathology. Blood and tissue samples were analysed to evaluate BSF larvae’s impact on fish health, providing insights into sustainable aquaculture nutrition.
African catfish fed Black Soldier Fly larvae showed stable haematological health. Oxygen transport, immune response, and red blood cell indices remained consistent across treatments, with slight platelet and eosinophil variations suggesting immune modulation. No adverse effects observed. The fish fed Black Soldier Fly larvae exhibited varying gut morphology. The T1 and T5 had the highest villi height and width, enhancing absorption, while T2, T3, and T4 had lower values. Crypt depth varied, while muscle thickness differed, affecting intestinal integrity and digestion. Dietary treatments influenced African catfish organ health. Control diet showed no lesions, while Black Soldier Fly larvae diets caused kidney necrosis and liver swelling. Histopathological changes varied, highlighting diet-dependent effects on intestinal, hepatic, and renal tissues
This study established that black Soldier Fly larvae diets influenced haematological stability, gut morphology, and organ health in African catfish, demonstrating potential for sustainable aquaculture nutrition while highlighting the need for optimised formulations to minimise histopathological alterations and enhance overall fish growth and physiological resilience