Potential of mealworm (Tenebrio molitor ) as an alternative protein source in practical diets for African catfish, Clarias gariepinus

Abstract

Two separate 7-week feeding trials were conducted to evaluate the use of mealworm, Tenebrio molitor, as an alternative protein source for African catfish, Clarias gariepinus. In Experiment 1, six isonitrogenous (40% crude protein) and isoenergetic (14.64 kJ g−1) practical diets were formulated. The fish meal component of the diets was progressively substituted at 0, 20, 40, 60, 80 and 100% with mealworm meal. The experimental diets were fed to triplicate groups of catfish fingerlings (mean initial weight of 5.1 ± 0.2 g) at 4% body weight day−1. Growth performance and feed utilization efficiency of catfish fed diets with up to 40% replacement of fish meal with worm meal were not significantly different (P > 0.05) compared to fish fed the control diet without any worm meal. Catfish fed diets with up to 80% replacement of fish meal with the worm meal still displayed good growth and feed utilization efficiency. In Experiment 2, the nutritive value of mealworms was compared with a commercial catfish pellet. Three dietary treatments consisting of fish fed catfish pellets only, catfish pellets and mealworms, and mealworms only were tested. Catfish fed solely on mealworms displayed a slight depression in growth performance but when fed in combination with the catfish pellets grew as well or better than fish fed the commercial catfish pellet only. In both experiments, mealworms, whether used as such or transformed into a dry meal, were found to be highly palatable to the African catfish. Catfish fed mealworm-based diets also tend to have significantly higher lipids in their carcass. Results indicate that mealworm was an acceptable alternative protein source for the African catfish.