The garlic component, allicin, prevents disease caused by Aeromonas hydrophila in rainbow trout, Oncorhynchus mykiss (Walbaum)

Abstract

Allicin was fed at 0 (= control), 0.5 and 1.0 ml of Allimed® liquid 100 g-1 of feed for 14 days to rainbow trout (Oncorhynchus mykiss, Walbaum) fingerlings before infection with Aeromonas hydrophila with a resultant reduction in mortalities from 80% in the controls to 8% (relative percent survival [RPS] = 90%) and 0% (RPS = 100%) among the treated fish. Allicin was strongly antibacterial compared to the control, with a minimum inhibitory concentration (MIC) of >400 µL mL-1 of Allimed® liquid. Use of allicin led to a lower number of white blood cells (132.0±0.4 x 103) as compared to 175.0±0.1 x 103 in the controls, but elicited increased phagocytic activity, i.e a phagocytic value of 39.2% compared to 13.6% in the controls, and serum lysozyme activity, which showed significant (P>0.05) differences compared to the control at 15 and 30 min after the first reading at 0 min of incubation.