Effects of dietary bovine lactoferrin on growth, haemato- biochemical parameters, immune functions and tolerance to air exposure stress in the African cichlid Sciaenochromis fryeri

The effects of dietary bovine lactoferrin (LF) on the growth, haemato-biochemical pa- rameters, non-specific serum immunity and stress responses were investigated in the African cichlid, Sciaenochromis fryeri. Four isocaloric diets containing 0 (control), 200, 400 and 800 mg LF kg−1 diet were formulated and fed to juvenile fish for 8 weeks. The treatments had no effects on the survival rate, growth performance or haematological parameters. Nor were the serum levels of total protein, albumin and globulin signifi- cantly influenced. Serum iron levels and total iron binding capacity (TIBC), however, changed vigorously as the result of dietary LF. Dietary LF led to significant reductions in serum levels of alanine transaminase and alkaline phosphatase. The highestlysozyme and bactericidal activities were observed in the fish fed the diets with 200 and 800 mg/ kg of LF, respectively, while no changes were observed in their ACH50 levels. Recovery rates were measured after 10 min of air exposure stress. The rate was about twice higher (36% vs 20%) in fish fed on 400 mg LF than in those fed the control diet. Results revealed that adding 400 mg/kg LF could be beneficial as an iron discriminator, for liver function as well as an immune and stress resistance promoter.