Evaluating the growth of genetically improved tilapia Oreochromis niloticus reared at different temperatures

This study aimed to evaluate the growth and performance of genetically improved tilapia reared at different temperatures. Four hundred and eighty fingerlings of Genomar Supreme Tilapia, GST (8.39 ± 0.60 g) were equally separated into three indoor water recirculation systems maintained at 22, 26 and 30 ºC. Each of four tanks contained 500 liters with 40 fish per tank in natural photoperiod. The fish were fed ad libitum with the same feed for each growth phase, weighing the total feed supplied. After 30 min of feeding, leftover feed was collected, dried in an oven and weighed. Ten fish from each tank were weighed at days 1, 30, 60, 90, 120, 150, 180 and 210. Survival, weight gain, feed conversion and feed intake in each period were determined. Fish reared at 30 ºC and 26 ºC showed a higher specific growth rate than that of fish reared at 22ºC (P≤0.05). Feed intake increased along temperature and feed conversion and was poorest in fish reared at 26ºC (P≤0.05). Final fish weight estimates at day 210 by the Gompertz model were 597.84, 819.26 and 1079.39 g for 22, 26 and 30 ºC, respectively. At 30 ºC, fish had a higher absolute growth rate (7.76 g day⁻¹) and lower weight (459.30 g) and age (95.85 days) at the inflection point. Tilapia at 22 ºC had a higher weight (539.57 g) and age (197 days) and lower absolute growth rate (4.52 g day⁻¹). It was concluded that GST tilapia can potentially improve aquaculture in all Brazilian regions based on different rearing temperatures.