Herbal extracts modulate growth, immune responses and resistance to Aeromonas hydrophila infection in GIFT tilapia ( Oreochromis niloticus )

Abstract

An 8-week feeding trial was performed in GIFT tilapia to evaluate the effects of three herbal extracts (jamun leaf, Syzygium cumini (JLE); avaram senna, Cassia auriculata (ASE); and myrobalan seed, Terminalia chebula (ME) on the growth, haematobiochemical, immunological parameters, antioxidant indicators and disease resistance against A. hydrophila. Fish were fed with herbal extract 0% (control diet); JLE 10 g/ kg diet; ASE 10 g/kg diet; and ME 10 g/kg diet. The herbal extracts supplemented diets exhibited significantly higher growth performances and feed utilization than the control. The blood and serum indices, haemoglobin, MCV, MCH and cholesterol were significantly (p < 0.05) higher in the herbal extracts supplemented diets than in the control. The respiratory burst activity (RBT), myeloperoxidase, superoxide dismutase (SOD) and catalase in GIFT tilapia were significantly higher in herbal extracts supplemented diets than in control during the post-challenge condition. Furthermore, increase in all immunological and antioxidant parameters was observed in herbal extracts supplemented diets after the challenge. In addition, the percentage of survival was recorded maximum in herbal extracts supplemented diets and less in control after the bacteria challenge test. The results suggest that herbal extracts modulate growth and immune responses, particularly the diet supplemented with jamun leaf extract at 10 g/kg has the potential in enhancing growth, immunity and reduce mortality against bacterial challenge in GIFT tilapia.