Nutrient influx, Water quality and growth performance of Nile tilapia fry fed Recycled Food Waste Based Diet in a Closed Recirculating Fish Culture System

Abstract

The nutrient influx, water quality and growth performance of Nile tilapia Oreochromis niloticus fed recycled food wastebased diets was studied in a closed recirculation system for 11 weeks, during which no water renewal was carried out in the system. Fish (mean weight 1.2 + 0.11 g) were fed with different levels of recycled waste materials supplemented with lysine (lys) and methionine (met), and were designated as D1 (0% FIW+SSW), D2 (57.90 % FIW+SSW + lys and met) and D3 (54.84% FIW+SSW only). The results showed that fish fed D2 diet had a higher (P<0.05) growth performance and feed efficiency than those fed the other diets. The biofilter used in the recirculation system effectively converted ammonia to
nitrate, as such toxic ammonia and nitrite were negligible. However inorganic phosphorus was similar among the treatments. The water coloration and turbidity were higher in the tanks of fish fed D3 diet. The results of this study revealed that inclusion of recycled food waste materials had less negative impact on the water quality in a closed  recirculating fish culture system.

Key words: Food industry waste; Growth performance; Recycled food waste; Soy sauce waste; Tilapia fry.