Factors Affecting Growth Performance of Nile Tilapia (O. niloticus) Fingerlings Cultured in Tanks

Abstract

This study conducted in the farm and the fish hatchery at Sudan University of Science and Technology, in order to study some biological factors affect the successful of cultivation Nile tilapia (Oreochromisniloticus) fingerlings in tanks culture. Plastic tanks used for easy observation and periodic measurements.A trial was conduct to study the growth performance of O. niloticus fingerlings under three stocking densities; 10 fish tank‾¹ (SD1), 15 fish tank‾¹ (SD2) and 20 fish tank‾¹ (SD3). The results of the trial with respect to growth performance showed a significant preference (P< 0.05) for the medium stocking density 15) fish/tank(, while the effect of the stocking densities on survival rate show non-significant difference (P> 0.05). A trial was conduct to study the effect of different feed frequencies (FF) on the growth rates of O. niloticus fingerlings. The results indicated that, there is no significant difference (P> 0.05) due to repeated feeding frequency twice/day (FF1), three times/day (FF2), and four times/day (FF3), with no effect on survival rate by changes daily feeding frequencies. A trial was conduct to study the growth efficiency of O. niloticus fingerlings under influence of three feeding ratio; 5% (FR1), 9% (FR2), and 13% (FR3) from body weight. The results of the trial showed that, there is no significant benefit for daily weight gain due to different daily feeding ratios, with a significantly higher (P< 0.05) in feeding conversion rate at the daily feeding ratio 5% (FR1) than the rest, while with the survival rates there is no significance influence due to different daily feeding rates. As a result of this experiment done during a period of significant reduction in temperature (November 2015 to January 2016), the three temperature levels which were recorded had a clear relation to the fish daily weight gain during the study period, where for the three trials; different stocking densities, daily feed frequencies and daily feed ratio, the best daily weight gain was recorded with water temperature level “1” (18-20 °C), followed by water temperature level “3” (17-22 °C), and lastly water temperature level “2” (17-16°C), confirming the negative effect of temperature degree outside the optimum range of O. niloticus fishes.Concerning water physiochemical parameters study, the result indicate non-significance difference (P> 0.05) in DO, temperature, pH, P, No2, No3 and ammonia concentrationsdue to cultivation O. niloticus fingerlings in tanks within different stocking densities trial, different feed frequencies trial and different daily feed rates trial. The study of the proximate chemical analysis of O. niloticus fingerlings body showed a significance difference (P< 0.05) in crude protein due to different stocking densities and in NFE within different daily feed rates, while for moisture, dry meat, ash and crude fat contents, the study indicate none significance difference (P> 0.05) within different stocking densities, different feed frequencies and different feed rates trials.