Preparation, nutrient composition and digestibility of fermented shrimp head silage

Raw heads of the river prawn, Macrobrachium vollenhovenii, were fermented with Lactobacillus plantarum at 30 °C using molasses or cassava starch as the carbohydrate source. After incubation for 7 days, a desirable and stable pH < 4.5 was attained, and the carbohydrate source did not affect non-protein nitrogen (NPN) content or the proximate composition of the liquid silage after 30 days incubation. Hydrolysed feather meal, poultry by-product meal or soybean meal, used as alternative filler, was blended with the liquid silage (85:15, w/w) and solar-dried. The dried shrimp head silage meals were incorporated as protein supplements into pelleted semi-purified diets for catfish, Clarias gariepinus. Apparent digestibility coefficients of dry matter, crude protein, gross energy and essential amino acids in the silage by catfish fingerlings was high (> 70%). It was concluded that dried fermented fish silage is suitable and has a potential as a protein feedstuff in fish diets.