Bioconversion of the forest wastes into oyster mushrooms as a circular bio-economy with promise for health aspects of blue tilapia

Abstract

Forestry residues and spent mushroom substrate (SMS) represent two major lignocellulosic waste streams require for sustainable management. The current study explores a circular bioresource approach by utilizing these wastes for mushroom cultivation and subsequently applying the derived products in aquaculture. Pleurotus flabellatus was used for the bioconversion of forestry residues and SMS. The nutritional efficacy of the resulting mushroom extract was evaluated as a partial replacement for fish meal in the experimental diets of Oreochromis aureus (blue tilapia). A ten-week feeding trial was conducted using seven experimental diets containing graded levels of mushroom extract: M0 (0 g kg⁻¹), M1 (0.005 g kg⁻¹), M2 (0.01 g kg⁻¹), M3 (0.02 g kg⁻¹), M4 (0.03 g kg⁻¹), M5 (0.04 g kg⁻¹), and M6 (0.05 g kg⁻¹). Growth performance, metabolic biomarkers, antioxidant activity, and histomorphological characteristics of intestinal and hepatic tissues were assessed. Fish fed mushroom-supplemented diets exhibited improved antioxidant responses, along with increased plasma protein and glucose levels compared to the control. Moderate inclusion levels (particularly M3–M5) showed better overall performance, although growth parameters did not differ significantly among the treated groups. These findings demonstrate that forestry residues and SMS can be effectively valorized into a functional aquafeed ingredient, contributing to the circular economy, waste reduction and sustainable aquaculture practices.