Antifungal Potential of Pleurotus ostreatus and Its Application in Fish Feed for Clarias gariepinus

Abstract

The effect of Pleurotus ostreatus culture broth on the growth of toxigenic fungi, Aspergillus parasiticus and A. flavus, was studied. Its effect on the nutritional composition of compounded fish feed was also investigated. The mycelium of P. ostreatus was cultivated on potato dextrose agar for 17 days, and its antifungal activity against Aspergillus spp. was studied over 8 days. Bioactive compounds produced by P. ostreatus inhibited the growth of A. flavus and A. parasiticus. Three different fish feed formulations were prepared: the compounded fish feed only (C), the compounded fish feed plus P. ostreatus (CM), and a commercially obtained fish feed (COMM). The addition of P. ostreatus broth to the compounded fish feed for 4 days improved the protein and fibre contents of the compounded feed. The growth of catfish (Clarias gariepinus) fed the three feed formulations increased over the 31-day experimental period, with no significant difference at p > .05. However, the catfish fed with compounded feed plus P. ostreatus exhibited better growth performance (1.358 g mean weight gain) than the fish fed with the commercial feed (1.079 g mean weight gain). Overall, P. ostreatus demonstrates significant potential as a cost-effective antifungal agent because its cultivation requires minimal investment and risk, and it is a rich source of protein for application in the fish feed industry.