Effects of salinity level on growth performance, feed utilization, and chromatic deformity of the hybrid Red tilapia, Oreochromis niloticus x O. mossambicus

Abstract

Four different salinities (0, 13, 26, and 39 ppt) were tested to evaluate their effects on growth performance, feed utilization, carcass composition, and chromatic deformity of the hybrid red tilapia (Oreochromis niloticus and O. mossambicus). 204 samples of 97 days post-hatch fingerlings red tilapia were stocked in a glass aquarium filled with 80 liters of water at a stocking rate of 17 fingerlings/ aquarium (0.21fingerlings/L), with an average initial weight of 12.48±0.04 g/fish and three replicates for each treatment. Fingerlings were fed on the experimental diet containing 30.3% protein at a 5% feeding rate, and re-adjusted periodically every10 days. The experimental period was 42 days. The results revealed that the final weight, weight gain, ADG, and SGR values increased significantly (P≤0.05) at the salinity level of 26 ppt, followed by 13 ppt salinity level. The survival % showed that all salinity levels had a high percentage without recording significant differences (P>0.05) between treatments. The best FCR was recorded in a salinity level of 26 ppt with significant differences (P≤0.05) between the treatments. The highest values of PER, PPV, and energy gain were recorded at 26 ppt. Salinity levels significantly influenced dry matter, protein, ether extract, ash, and carcass energy under the investigated salinities. The lowest percent of the chromatic deformity was achieved at salinity 26 ppt. It could be concluded that cultivating hybrid red tilapia in salinity levels between 13 and 26 ppt would significantly improve growth performance and feed utilization and reduce the percentage of fish with chromatic deformity as well.