Immunostimulant Effects of Geophyte Plant Extract on Non-specific Defence Mechanisms of Rainbow Trout (Oncorhynchus mykiss)

Abstract

The aim of this study was to determine the immunostimulant effects of geophyte plant extract on non-specific defence mechanisms of rainbow trout (Oncorhynchus mykiss). For this purpose, Muscari comosum was collected in Muğla region and extracted in ethanol. Then, The plant extract applied into fish by intraperitonal injection in two different concentrations (0.5mg/ fish and 2.0 mg/fish). The average fish weight was 140 g. Following the injection on the 1st, 7th, 14th, 21st, 28th days the blood and serum samples were collected from fish in each group and examined for various parameters including percentage of hematocrit, the counts of nitroblue tetrazolium (NBT) positive neutrophils, total leukocyte counts, percentage of white blood cells and serum lysozyme activity. The results indicated that the counts of NBT (+) neutrophils, percentage of monocyte and neutophil and total leukocyte counts increased in the group with injected 0.5mg plant extract /fish compared to control group (P<0.05). It has been revealed that this dose of M. comosum can be suggested to use to enhance non-specific immune system for rainbow trout aquaculture. However, immunostimulant effects of oral administration of this plant extract in rainbow trout are needed to be determine in future studies.