Exposure to enrofloxacin affects the early development and metabolic system of juvenile American shad, as indicated by host metabolism and the environmental microbiome.

Abstract

Enrofloxacin as a special fish medicine is widely used in aquaculture fishes in China. But the effect of enrofloxacin exposure to the gut of aquatic animals is still unclear. In our investigation, enrofloxacin (300 mg/kg feed) was experimentally exposed to the juvenile American shad for 7 days and monitored for alterations in metabolomic and transcriptomic responses. The results showed the similar subset of affected pathways (P-value<0.05), but there were still many differences in the number of identified biomarkers (520 differentially expressed genes genes and 230 metabolites). Most gut metabolic profiles were related to oxidative stress, inflammation, and lipid metabolism. These multiomic results reveal the specific metabolic disruption by enrofloxacin altering many signaling pathways (P-value<0.05), such as arginine and proline metabolism pathways, pyrimidine metabolism, the FoxO signaling pathway, and purine metabolism. In addition, the predicted functions of proteins analysis showed that enrofloxacin exposure in an aquaculture environment could prevent the occurrence of organic diseases, including Vibrio cholerae infection and bacterial toxins, in aquatic systems. This is the first research indicating that enrofloxacin affects the relationship between environmental microorganisms and intestinal metabolism, and a study of the ecotoxicity of enrofloxacin occurrences in the aquatic system is warranted.