Exigência de fósforo para tilápia do Nilo (Oreochromis niloticus) na terminação

Abstract

This work was carried out to determine the available phosphorus requirement of finishing Nile tilapia, thai strain (140-580g). A hundred and twenty fish reverted sexually for male were assigned to a entirely randomized design with four treatments and three replicates. Diets with 29% of digestible protein and 3300 kcal of digestible energy/kg were used, containing 0.31; 0.44; 0.52 and 0.83% of available phosphorus. The dicalcium phosphate was used as inorganic phosphorus source. Fish were fed three times a day to apparent satiation for 84 days. No effects of dietary phosphorus on feed intake, protein efficiency ratio, hepatosomatic index, fillet yield, humidity and protein on carcass were observed. Dietary phosphorus resulted in linear reduction of carcass body fat and zinc concentration in the vertebra bones and linear increase in carcass ash and calcium and available phosphorus. It was observed a quadratic effect on weight gain, feed conversion ratio, apparent digestibility coefficients of energy, phosphorus carcass, vertebral bone calcium, phosphorus, iron and magnesium, Seedor Index and bone density and villus height being their best values estimated with 0.61, 0.66, 0.54, 0.72, 0.64, 0.63, 0,69, 0.67, 0.67; 0.72 and 0.52%, respectively. It was concluded that dietary requirement of finishing Nile tilapia is 0.66% of available phosphorus.