Investigating the Effects of Higher Concentrations of Azolla and Vermicompost on Growth, Yield and Nutrition of White Oyster Mushrooms (Pleurotus ostreatus)

Abstract

Oyster mushrooms are a healthy staple in many cuisines and with a growing need to satisfy global food demands for healthy plant based diets, it has become essential to increase its yield and nutrition quality. The purpose of the present study is to evaluate the growth, yield and nutrition of white oyster mushrooms, Pleurotus ostreatus, grown on a media supplemented by vermicompost and Azolla. 5 treatments including Control were followed, namely: Control (No additives), T1 (10% vermicompost, 5% Azolla), T2 (10% vermicompost, 10% Azolla), T3 (20% vermicompost, 5% Azolla), T4 (20% vermicompost, 10% Azolla). Their growth rate and yields were tabulated and T1 showed comparable growth rate to control, with an increased yield while treatments with increased concentrations of vermicompost and Azolla (T3 and T4) showed much slower growth rates and lower yields. Nutrition testing for proteins was done by Lowry’s assay on aqueous and ethanolic extracts of the mushrooms, which showed comparable levels of proteins across all treatments, with slight decrease as concentrations of vermicompost and Azolla increased (T1=Control> T3> T4>T2). The Folin-Ciocalteu method was used to estimate total phenolics in aqueous extracts and all treatments showed higher phenolic content than Control, with T3 being the highest (T3>T2>T4>T1>Control). Phenol - sulphuric acid method was carried out for aqueous extracts for total carbohydrate estimation and T1 and T2 showed the lowest carbohydrate content, with control and T4 being the highest (T4=control> T3> T2>T1). Higher concentrations of Azolla and vermicompost showed inhibitory activities on the growth, yield and nutrition of white oyster mushrooms and Treatment T1 (10% vermicompost and 5% Azolla) was overall the best with higher yield and phenolic content and lower levels of carbohydrates. Lower levels of carbohydrates make them favourable choices for keto-diets.