Impact of salinity and flaxseed oil -enriched diet on growth and some enzyme activity of Nile tilapia Oreochromis niloticus

This study was conducted to evaluate the effect of flaxseed oil as a source of omega 3 and salinity factor on growth and some enzyme activity Nile tilapia (Oreochromis niloticus) (mean initial weight 1.18 ± 0.1 g ) in indoor recycle aquarium tanks for 45 days. Results showed that adding flaxseed oil and salinity factors did not alter negatively the growth rate of Nile tilapia. Also, our data showed that fish in salinity group exhibited higher aspartate transaminase and alanine transaminase activities in liver while decreased in the flaxseed oil groups in comparison with the control. In conclusion, rearing Nile tilapia in brackish water can be a viable substitute to fresh water in Nile tilapia aquaculture without affecting the growth of tilapia. Moreover, flaxseed oil could be a viable substitute to the fish oil in Nile tilapia aquaculture without affecting the growth of tilapia. Most importantly, salinity factor can improve some enzyme activities such as ALT and AST in liver of Nile tilapia. .