Effects of florfenicol on skin mucus immune parameters and immune related genes expression in zebrafish (Danio rerio)

Florfenicol (FF) is a common, inexpensive antibiotic with relatively low toxicity. The present study investigates the possible effects of Florfenicol on cutaneous mucus immune parameters and immune related genes expression in Danio rerio . After two weeks adaptation, fish were stocked in experimental units at density of 20 fish per aquaria and fed with experimental diets containing 0, 10, 30 and 50 mg/kg FF per for 11 days. Evaluation of immune parameters at the end of trial showed that the control group had a significantly lower level of lysozyme activity when compared with those treated with antibiotic. However, the skin mucus total immunoglobulins level of fish fed diets containing antibiotics did not show any significant difference compared to the control group. The highest expression level of TNF-α, IL1β and lysozyme was observed in fish treated with 10 mg/kg FF while the lowest expression was noticed in those fish treated with 30 and 50 mg/kg FF. The present results indicate the relatively positive effects of this antibiotic on the immune system of zebrafish, and it seems that the appropriate dosage of the drug can serve as an immunostimulant for zebrafish.