Chemical and nutritional quality of raw, cooked and salted fish silages

Abstract

Fermented fish silages were prepared from whole tilapia ( Oreochromis niloticus), molasses and Lactobacillus plantarum starter culture. The effects of cooking and addition of 5% salt on the proximate composition, various protein and lipid quality parameters were measured over a 30-day period of incubation at 30°C. The silages were stable during fermentation and storage, and no appreciable loss of nutrient contents was noted. The changes observed were increased degree of autolysis and ammonia production. Addition of salt or cooking of substrate before fermentation prevented continued protein hydrolysis by inhibiting the activity of endogenous autolyzing enzymes and decreased the formation of total volatile bases. The apparent digestibility of dry matter, of nitrogen and of the energy content of silage-based diets for tilapia was higher in both the cooked and salted fish silages than in the raw fish silage.