CRESCIMENTO DE TRÊS LINHAGENS DE TILÁPIA SOB CULTIVO SEMI-INTENSIVO EM VIVEIROS

Abstract

This work had as objective to evaluate the growth of three strains of tilapia (Nilotica, Red koina and Chitralada) in semi-intensive culture ponds, in order to define the most adequate strain to commercial scale. Twelve 50 m2 ponds were used in a randomized entirely experimental design with three treatments and four replicates. The culture run 112 days and the ponds were submitted to a preparation that consisted of liming (100 g/m2 of hydrated lime) and chemical fertilization (3 g/m2 of simple superphosphate and 5g/m2 of ammonium sulfate). After verifying good conditions for culture, the ponds were stocked with 75 fingerlings (56.7 + 7.0 g) corresponding to a density of 1.5 fishes/m2. Fishes were fed with 32% crude protein extruded formulated diet in the first 60 days and another with 28% was used for the last 52 culture days, twice a day, at 8:00 a.m. and 4:00 p.m. Feeding rate varied from 4% to 2% of live weight from the beginning to the end of culture. Data analysis demonstrated that there were significant differences among treatments (P<0.05) with Chitralada strain showing the best performance as survival (94.33%), specific growth rate (2.42%/day) and feed conversion ratio (1.14). Thus it was observed that is possible to obtain productivities over 6 ton/ha/cycle using Chitralada strain, being recommended for semi-intensive culture in ponds.