Effects of folic acid on growth performance and blood parameters of flathead grey mullet, Mugil cephalus

Folic acid is one of the most important vitamins for aquatic organisms' growth and health in aquaculture. This study investigates the effect of folic acid administration on the growth and physiological performance and blood parameters of flathead grey mullet. The blood parameters include RBCs, Leucocytic count, PCV, Hb, MCV, MCH and MCHC were chosen as an important tool for fish physiological and health status indicators. A total number of 240 flathead grey mullets were caught and kept in indoor fiberglass tanks with 300 L capacity filled with brackish water. They were divided into 4 treatments: control was fed on a diet without folic acid, T-1 was fed on a diet with 10 mg folic acid/kg, T-2 was fed on a diet with 30 mg folic acid/kg, and T-3 was fed on a diet with 50 mg folic acid/kg for 2 months. The best results of final weight and weight gain were observed on T-3 followed by T-2. The peak values of the K factor were recorded in control and the GSI values showed a significant increase in T-2 followed by T-1. The best result of RBCs was recorded in T-1 and the peak of the leucocytic count was recorded in T-2 followed by T-3. The Hb and PCV values showed a significant decrease in the groups treated with folic acid. The best result of MCV was calculated on T-1 but the peak value of MCHC was calculated on T-3. AST and ALT have recorded the peak values in T-3. It could be concluded that folic acid on doses of 30 and 50 mg/kg could improve flathead grey mullet growth and physiological performance, health, and haematological parameters.