Immunostimulating effects of Ginkgo biloba extract against toxicity induced by organophosphate pesticide, diazinon in rainbow trout, Oncorhynchus mykiss: innate immunity components and immune-related genes

Abstract

The immunostimulating and therapeutic properties of Ginkgo biloba (GB) have always been the focus of traditional medicine over thousands of years. During last decade, special attentions were paid to use of GB in aquaculture to enhance fish health and survival. In the present study, we investigated for the first time the immunogenic effects of dietary GB against oxidative and toxicity induced by organophosphate pesticide, diazinon. In non-diazinon-exposed fish, the plasma total immunoglobulin, lysozyme activity, and peroxidase activity significantly elevated after 60-day experiment in fish supplemented with 1 and 2\xa0g GB/kg diet (p\u2009<\u20090.05). The respiratory burst activity and complement activity significantly increased only in groups supplemented with 0.5\xa0g GB/kg diet (p\u2009<\u20090.05). Furthermore, the peroxidase activity, total immunoglobulin, and lysozyme activity significantly declined in groups supplemented with 4\xa0g GB/kg diet during feeding trial (p\u2009<\u20090.05). There were no significant differences in expression of interleukin 1 beta (IL-1β) and transforming growth factor beta 1 (TGF-β1) genes in kidney between control group (non-GB-supplemented fish) and GB-supplemented fish (p\u2009>\u20090.05). In diazinon-exposed fish, all immunity components significantly decreased during exposure in control and those fed 0.5 and 4\xa0g GB/kg diet (p\u2009<\u20090.05). In fish fed 1 and 2\xa0g GB/kg diet, no alternations were found in immunity components during exposure period (p\u2009>\u20090.05). In addition, diazinon induced the expression of IL-1β and TGF-β1 genes in control and fish fed 0.5 and 4\xa0g GB/kg diet (p\u2009<\u20090.05). No significant changes were observed in expression of IL-1β and TGF-β1 genes in fish supplemented with 1 and 2\xa0g GB/kg (p\u2009>\u20090.05). In conclusion, the results of the present study suggest an immunogenic role for dietary GB at optimum dietary levels (1–2\xa0g GB/kg diet) against toxicity induced by diazinon. Nevertheless, GB at high dietary levels (4\xa0g GB/kg diet) showed immunosuppressive effects, which makes it necessary to optimize its levels in diet.