Hydroalcoholic extract of pitaya (Hylocereus guatemalensis) supplied in the diet for blue Betta splendens and its effects on fish pigmentation

The experiment was conducted to evaluate the composition of the hydroalcoholic extract of pitaya bark (Hylocereus guatemalensis) and its effects on the diet of male blue Betta splendens in terms of skin color, concerning the content of digestive enzymes, liver metabolism, and antioxidant activity. The fish were supplemented with hydroalcoholic extract of pitaya bark (HEPB) at the doses of 0.24, 0.45, and 0.90 mg kg-1 of feed for 21 days. The inclusion of 0.24 and 0.45 mg kg-1 of the HEPB promoted the best weight gain. and did not change the coloration of blue beta fish (P>0.05). The digestive activity showed an increase in alkaline phosphatase activity only in fish fed 0.45 mg kg-1 HEPB. The inclusion of 0.45 and 0.90 mg kg-1 from the HEPB promoted a decrease in hepatic ALT activity. An increase in CAT activity was observed in the skin of fish fed diets with added HEPB. In conclusion, the addition of hydroalcoholic extract of pitaya bark in the diet of Betta splendens is beneficial for the weight gain parameter and has a hepatoprotective effect but does not affect skin coloration.