Claudemir Martins Soares

Exigência de proteína digestível para larvas de tilápia do Nilo (Oreochromis niloticus), durante a reversão sexual

ABSTRACT - The aim of the work was to determine the digestible protein requirement (PD) for Nile tilapia in the sexual reversionphase, where 1250 larvae were assigned to 25 aquariums (60 L), with five treatments and five replicates in a completly randomiz ed design.The larvae were fed ad libitum , five times a day, with isoenergy, isocalcium, isophophorus rations, with 30, 34, 38, 42 and 46% of PD,and 30 mg/kg of a-metil hormone testosterone. The animals of each experimental unit were counted and weighed at each 15 and 28 daysof experiment for evaluation of the survival and average weight. For the average weight of the animals quadratic effect was obs erved,with point of maximum of 39.06 and 38.56% of PD at 15 and 28 days, respectively. The survival rate linearly decreased as the P D levelsincreased, at 15 and 28 days. Water temperature, pH, conductivity and dissolved oxygen level presented average values of 24.60 of ±2.02 o C; 7.34 ± 0.22; 218.47 ± 16.29 µS/cm; and 6.38 ± 1,18 mg/L respectively. The PD requirement of for Nile tilapia in the sexual reversionphase was of 38.6%.Key Words: protein requirement, larval phase, Nile tilapia,