Vol. 1, Issue 11 (2016)
Effects of varying stocking densities and temperature on growth performance of Nile tilapia (Oreochromis niloticus) fingerlings cultured in semi closed system
Author(s): Mohamed AA Salih, Tamador E Elinor, Asaad H Mohamed
Abstract: An experiment was conducted to determine the impact of stocking densities (SDs) on growth rates, specific growth rates (SGR), daily weight gain (DWG), feed conversion ratio (FCR), feed conversion efficiency (FCE) and survival rate (SR) for Nile tilapia (Oreochromis niloticus) fingerlings in the fish hatchery of Sudan University of Science and Technology. Fingerlings (1.32±0.28g) were stocked in triplicate at stocking densities; 10 (T1), 15 (T2) and 20 (T3) fish/tank, in indoor plastic tanks 40×46×64cm for seventy days. Fish which were fed a commercial floating diet containing 35% crude protein has been added two times per day five days a week in 9% of the stock biomass. Growth measurement of fingerlings and water physiochemical parameters were recorded every 10 days. Result show that Daily weight gain (DWG) is higher (p>0.05) in SD (T2) (0.28±0.06g day-1) compared with (T3) (0.21±0.03g day-1) and and) (T1) (0.19±0.03g day-1). Concerning feed conversion ratio (FCR) which is in general very low, specific growth rate (SGR) and feed conversion efficiency (FCE) there is no significant different due to stocking densities (p> 0.05), but it is in all show more bust in SD (T2) compare to SD (T1) and SD (T3). The results showed that, there is no effect on survival rate according to different stockings densities (p> 0.05). Fish meat analysis indicated that, there is no significant differences according to stocking densities (p> 0.05) except for crude protein concentrate which record higher value in (T1) (31.15±0.21) and (T3) (31.05±0.21). Except some temperature fluctuations observed, all water quality parameters tested throughout the experimental period revealed that all parameters were within the permissible levels for optimum growth of O. niloticus. The pH gives no significant differences between the three stocking densities, but with more effects by temperature. In summary, the results showed that the medium stocking density (T2) (15 fingerlings/tank) give favored growth comparing with 10 (T1) and 20 (T3) fingerlings/tank.