Effects of Enrofloxacin on the Expression Analysis of CYP2 and Activity of APND in Litopenaeus vannamei

Abstract:

The cytochrome P450 is an important group of multi-functional oxidases engaged in the metabolism of exogenous substances. In this study we investigated the effects of enrofloxacin on the expression of CYP2 and activity of APND enzyme in hepatopancreas of Litopenaeus vannamei. Real-time PCR analysis revealed that CYP2 in L. vannamei was expressed in all tested tissues, including hepatopancreas, gills, hemolymph, muscle, carapace, intestine, stomach, heart and eyestalk. The expression level was the highest in hepatopancreas, and the lowest in hemolymph. After oral administration of enrofloxacin at different concentrations including 15 mg/kg (low-dose group), 30 mg/kg (middle-dose group), and 60 mg/kg (high-dose group), the level of CYP2 transcript in hepatopancreas decreased significantly (P<0.05) especially at 9 h (P<0.01), however exceptions occurred at 1 h, 24 h, and 96 h. The activity of APND that indicated the activity of CYP2 was measured with ELIASA. The result showed that the activity of APND was lower in the experimental groups than in the control group. APND activity in the high-dose group was lower than that in the low-dose group. All three experimental groups, especially the high-dose group (P<0.01), showed a significant decrease in APND activity (P<0.05) after 9 h, but an exception occurred at 3 h. The enzyme activity in all experimental groups was reduced (P<0.01) and reached the minimum level at 12 h. Changes in both the enzyme activity and the expression level displayed the same pattern. These results indicated that the expression of CYP2 could be impacted by enrofloxacin. Therefore, when administrating drugs in combination, the cumulative effects should be carefully evaluated.