Spent oyster mushroom substrate as a potential bioactive and nutritional food ingredient for tilapia culture: a review

Nile tilapia (Oreochromis niloticus) is one of the most economically important fish cultivated in intensive aquaculture; however, these conditions cause stress and reduce its immune system responses, making it susceptible to infections and reducing production yields. Spent oyster mushroom substrate (SOMS) is the residue left after Pleurotus spp. mushroom cultivation, and it is expected that for every kilogram of harvested mushrooms, 5 kg of residue is generated. However, during solid fermentation of the used substrate, mycelium can change substrate composition by degrading lignocellulosic material, making it more digestible and enhancing its chemical composition. Thus, it becomes a novel raw material for aquaculture; mycelium is rich in bioactive compounds such as antioxidants and polysaccharides, which can reduce stress and even act as immunostimulants. SOMS and its effect on Nile tilapia have recently become a focus due to its benefits in health promotion and growth performance. In this review, we will explore its composition and uses in aquaculture.