Influence of diets supplemented with tryptophan on self-balancing, feed intake and productive performance in white cachama (Piaractus brachypomus)

Abstract

This study evaluated the ability of juvenile white Pirapitinga to select food with different tryptophan content in order to self-balance the amino acid intake using information originated from the food source. Therefore, how Tryptophan (Trp) intake affected self-balance of food and productive performance is assessed. The experiment consisted in providing diets supplemented with Trp and a control diet to juveniles with initial weight from 46.99 to 47.59 g as follows: Rc (0.32% Trp - control ration), R2 - 0.64% Trp, R4 - 1.28% Trp and R6 - 1.92% Trp. The number of the diet corresponds to the number Trp was multiplied by in the control diet. Two hand-made feeders were used at the bottom of the aquarium in which 2% of the fish live weight was placed in each diet per day for 14 days. The results showed that the white Pirapitinga was able to self-balance the daily consumption of Trp, benefiting food consumption, weight gain and standard length, as well as food conversion. In conclusion, juvenile Pirapitinga can regulate the tryptophan consumption at a 0.80% level in the diet, equivalent to 20.69 mg/day.