This trial was conducted to test the effect of supplemental dietary sodium chloride on growth of tilapia Oreochromis niloticus reared in freshwater or 10 and 20‰ brackish water (BW). High salt diets supplemented with 8% of NaCl were fed to tilapia for a period of three weeks. After this acclimatization period they were transferred to salinities and the growth rate was recorded over a 180-day-period. Dietary supplementation with NaCl improved the growth rate of fish kept in freshwater at 30 days (P<0.05), while no significant differences were observed on the growth rate in 10 and 20‰ BW. At 180 days, fish reared in 10‰ BW showed higher growth rates than those kept in freshwater or 20‰ BW (P<0.05). At 180 days fish reared in 20‰ BW showed external lesions, loss of scales, scale disorientation and swollen abdomen.
Tilapia Oreochromis niloticus; freshwater; brackish water; growth
