Apparent phosphorus availability in food for the Nile tilapia (<em>Oreochromis niloticus</em>)

Abstract

Apparent availability of phosphorus from various foodstuffs for sexually reversed Nile tilapia (Oreochromis niloticus) was provided. Fish with an average weight of 16.0  0.5g were randomly stocked in 21 aquariums equipped with feces collector (Guelf system), at the rate of five fish per aquarium. Each set of three aquariums was provided with a biological filter, aeration and flowing water (0.75 L/min discharge). An egg albumin-gelatin purified diet containing 0.1% chromic oxide was used as reference and basal diet. Dicalcium phosphate, bone and fish meals, soybean and wheat bran and middlings were added to the basal diet at 3.5, 6.0, 21.67, 40.0, 12.0 and 10.62% respectively, at the expense of albumin, gelatin and dextrose. Dicalcium phosphate was the best phosphorus source (apparent availability of 74.23%) for tilapia fingerlings. In decreasing order it was followed by bone and soybean meals (54.59 and 35.13%), wheat middlings (30.49%), fish meal (27.15%) and corn meal (7.33%). Whereas fish meal had the lowest apparent phosphorus availability among animal foodstuff, soybean meal was the best among plant foodstuffs.