Effectiveness of antimicrobial agents to reduce epibiont community in estuarine crab embryos

The influence of antimicrobial agents on aquatic fauna has been described in many studies, but few have tested the effects on invertebrate embryos and the associated epibiotic community. The role of epibiotic microorganisms in embryonic development needs to be better understood due to their ecological role and use for aquaculture purposes. Therefore, enabling the removal of the microbiota without affecting embryonic development is the first step to understanding the effects of microbiota on organism development. We tested the impact of two antimicrobial agents, Terramycine (oxytetracycline compound) and Biofor (iodine compound), during the embryonic development of the crab Leptuca thayeri to verify their effectiveness in reducing the microbial load and the impact on embryonic development. The mortality rate, time and rate of embryo hatching, and microbial growth in Petri dishes were evaluated over 30 days of embryonic development under laboratory conditions. Biofor reduced the hatching rate and increased mortality, whereas Terramycin did not differ from the control for both variables. The time in days to hatching was not influenced by contact with Terramycin. Both antimicrobial agents efficiently reduced the microbial load, with greater effectiveness over time for Biofor. The concentrations and exposure time tested for Terramycin were promising in reducing the microbial load without harming the embryos, facilitating future studies. In addition to ecological importance, our results apply to sterilizing live embryos.