Water stability, nutrient leaching and nutritional properties of moist fermented fish silage diets

Abstract

Fermented fish silage was prepared from whole mixed-sex tilapia ( Oreochromis niloticus), 15% molasses and 5% Lactobacillus plantarum starter culture and used as protein source in tilapia diets. Four alternative binders (carboxymethyl cellulose, corn starch, guar gum or wheat gluten) were incorporated in diets at 3% and their effects on water stability and nutrient leaching were determined. Water stability of the pellets showed that high physical stability of the pellets was maintained regardless of the binder used, and losses of total nitrogen were low (< 3%) on a per gram diet recovered basis. All-male O. niloticus fingerlings (mean weight, 48·9 g) were fed the appropriate diets at a rate of 5% of body weight per day, twice daily, for 30 days in a recirculated water system with water temperature maintained at 27°C. Apparent digestibility coefficients for dry matter, nitrogen or lipid in the diets were high and similar when carboxymethyl cellulose, corn starch or wheat gluten was used as the binder; but were reduced ( P < 0·05) with guar gum.