Exigências alimentares de fósforo em duas espécies nativas: peixe-rei (Odontesthes bonariensis) e jundiá (Rhamdia quelen)

Abstract

To determine the requirements for total phosphorus in the diet of the pejerrey (Odontesthes bonariensis) and silver catfish (Rhamdia quelen) were formulated two purified diets (basal diet with low levels of total phosphorus) and two practical diets (with conventional ingredients used in diets of fish). The purified diet for juvenile pejerrey showed levels of total phosphorus concentrations of 0.09, 0.27, 0.57 and 0.83% for juvenile silver catfish and 0.04, 0.30, 0.47 and 0.70%. The basal practical diet showed level of 0.76% at total phosphorus, and the others supplemented with dicalcium phosphate resulted in levels of 0.90, 1.20, 1.97%.In all the experiments were evaluated for yield performance variables such as weight gain, length, specific growth rate and survival. At the end of the experiment was conducted analysis of body composition. In fish subjected to different levels of phosphorus in purified diets were determined the mineral composition of calcium, phosphorus, magnesium and potassium in the bones and scales. To juveniles pejerrey levels of 0.43% of total phosphorus result in better performance, however to maximize mineral deposition are required 0.63% of total phosphorus. The use of with practical diets at least 0.76% of phosphorus not needs supplementation with phosphate. With respect to juvenile silver catfish phosphorus levels resulting in better performance were 0.53 based purified diet the requirement of phosphorus for juvenile silver catfish is 0.53% for a good productive performance. Practical diets with at least 0.76% of total phosphorus do not need supplementation of phosphate, it does not improve the growth of juvenile silver catfish. Purified diet based on the requirement of phosphorus for juveniles of silver catfish is 0.53% for a good productive performance. Practical diets with at least 0.76% of total phosphorus do not need supplementation of phosphate, because it does not improve the growth of juvenile silver catfish.