Immunostimulating influence of herbal biomedicines on nonspecific immunity in Grouper Epinephelus tauvina juvenile against Vibrio harveyi infection

Herbals such as Cynodon dactylon , Piper longum , Phyllanthus niruri , Tridax procumbens , and Zingiber officinalis were extracted with acetone, benzene, butanol, and petroleum ether and screened against the pathogen Vibrio harveyi isolated from the infected Grouper Epinephalus tauvina . Among the different solvent extractions screening to V. harveyi , petroleum ether extracts were suppressed significantly ( P < 0.05). Equal proportions of the all-plant extracts were mixed with the artificial feeds at concentrations of 100, 200, 400, and 800 mg kg −1 of diet and fed to grouper juveniles of 20 ± 2 g average weight for a period of 60 days. Every 20 days, fish juveniles were challenged with V. harveyi and the immune response was studied. The herbal diets significantly ( P < 0.05) increased the survival, growth, and immune responses compared to the control group. The herbal diets were significantly improved ( P < 0.01) in immune parameters such as phagocytic activity and albumin–globulin (A–G) ratio. Among the different concentrations of the herbals in the diet, the 400 mg kg −1 diet was the most effective in the experiment.