Characterization of different types of spent mushroom substrate (SMS) for African catfish (Clarias Gariepinus) diet suitability

Spent Mushroom substrate (SMS) is one of agricultural wastes produced by thever expending mushroom industries in Malaysia. Chemically, it is rich in organic matter which potentially can be utilized for aquaculture. Utilization of SMS as fish feed has never been conducted before as very limited information on SMS biochemical composition is available. Regarding to this matter, new formulation of fish feed was developed by incorporating SMS and other ingredients namely soybean waste, fish meal, topioca flour and rice bran. Commanly, different types of SMS that being cultivated at six to seven cycles were collected which identified as white oyster (Pleuratos ostreatus), grey oyster (Pleuratos sajor-caju), abalone (Pleuratos cystidiosus), ganoderma (Ganoderma lucidium) and black jelly (Auricularia polytricha). Those SMS were tested on their biochemical composition which involving the analysis of crude protein, carbohydrate, fat, lignin and ash. Overall trend showed an increment in crude protein and fat content, whereas carbohydrate and lignin showed a reduction in the content. Ganoderma attained the highest protein value, 36.6 g, followed by black jelly, white oyster, grey oyster and abalone. Contradictory, lowest carbohydrate reduction was observed in ganoderma at 70.42 g and the most was in black jelly. Increment in fat and reduction in lignin showed almost similar value for each SMS. The highest (ganoderma), medium (white oyster) and lowest (abalone) protein content were the basis of SMS types selection to be incorporated in pellet formulation using Pearson square method which emphasized on the protein and energy. The ingredients were mixed and a pelletalization was carried out after 40 minutes of steaming process at 80° C. A series of physical properties test of SMS pellets were conducted to confirm the applicability of the formulated pellet for fish consumption by comparing with commercial fish feed.