Biotemas (Mar 2012)
Comparative growth in cages of three strains of Nile tilapia (Oreochromis niloticus): common, chitralada and mixed race
Abstract
The purpose of this experiment was to compare the performance of three strains of Nile tilapia, chitralada (T1), a common lineage (T2) and a mixed race (T3), in cages over a period of 98 days. The fish were stocked in nine cages with a volume of 1m3 each, where there were 200 fish/m3, in a pond that was 2,500m2 and 1.6m deep. The study had three replications, and the tilapia were fed a diet containing 32% crude protein with pellets that were 4-6mm. Measurements were made by sampling 20 fish/tank. Variables in water temperature, pH, dissolved oxygen and electrical conductivity were monitored weekly at 5am. We compared weight gain, feed conversion, biomass, specific growth rate and survival. The mixed race was not significantly different when compared to chitralada lineage, but when these two strains were compared to the common lineage, there was a significant difference for weight gain, specific growth and biomass. The feed conversion did not differ significantly between treatments (1.66; 1.68; 1.47). The survival of the mixed race did not differ when compared to the other strains; however, the chitralada lineage differed significantly from the common strain (97.67%; 94.00%). The results indicate that the mixed race adapted to the culture system evaluated.
