Can dietary ginger (Zingiber officinale) alter biochemical and immunological parameters and gene expression related to growth, immunity and antioxidant system in zebrafish (Danio rerio)?

Effects of the dietary ginger (Zingiber officinale) on growth, some immunological and biochemical parameters and gene expression related to growth, immunity and antioxidant systems in zebrafish were studied. Immune parameters such as immunoglobulin level, alternative complement activity, and lysozyme activity were significantly higher in treatment groups fed with 2% and 3% ginger than the control fish. Amylase activity also increased significantly in the same pattern as the immunological parameters. Catalase and lysozyme mRNA expression levels representatives of antioxidant and immune genes respectively, were up-regulated in the fish fed with 3% ginger. Conversely, expression of gene encoding ghrelin was down-regulated in all treatment groups compared with the control group. Present study suggests that powdered ginger especially at 3% might augment some immunological and biochemical responses as well as expression of genes relevant to antioxidant and immune systems in zebrafish.