Effects Of Antibiotics Exposure To Zebrafish On The Offspring Growth And Development And Immune System

In water,the detected concentration of the major antibiotics could reach to ?g /L.Although the half-life period of most antibiotics is not long,with the continuous discharge of various kinds of antibiotics in large quantity,the fish can be interfered.Besides,the rapid development of the livestock breading and aquaculture industry lead to the increasing of the antibiotics in water in both variety and quantity,which can also bring adverse impact to the fish.The enrichment of the antibiotics in parents fishes can cause negative influence to their offspring,such as the growing development and the functional activities.However,the reports on the toxicity of antibiotics on the progeny of fish can hardly be found,especially on immunotoxicity.Since the immune system is the most important defense system for fish to against environmental pollution,the breeding activity of the fish can be better protected if the developmental of immunotoxic effects of antibiotics could be clarified.In this research,the zebrafish was selected as the research object.Fifteen kinds of common antibiotics in the environment are used under their general outside density.Then,the mixture of the antibiotics was used to expose the F0 generation zebrafish in different concentration(1 ?g/L-low,100 ?g/L-high).During the entire exposing period(28 days),every 7 days,the zebrafish under the same exposure concentration mated and spawned.Next,the related growth and development indexes of the F1 generation were recorded.Thus,the influence caused by the antibiotic exposure of the F0 generation zebrafish on the F1 generation can be analyzed.During the incubation of the F1 generation,not only its antibacterial ability was analyzed,but the impact of the F1 generation zebrafish was further analyzed by detecting the relevant indexes of the immune system and oxidative stress.Consequently,the toxic effects of antibiotics exposure on the fish offspring could be comprehensively evaluated.Results showed that under low-density antibiotics,the amount of the eggs of the zebrafish increased,but the embryonic stillbirth rate and unfertilized rate both increased with the duration and concentration of antibiotics exposing.Also,the hatchability and the length of the F1 generation zebrafish(5 days)were restrained by long-time antibiotic exposure.Therefore,It is believed that long-term exposure of antibiotics to zebrafish lead to the slow development of their offspring.Furthermore,when the progeny of the zebrafish coexisted with Vibrio parahaemolyticus,the mortality will increase if the F0 generation zebrafish had been exposed to the antibiotics for a long period of time.Therefore,it is considered thatlong-time antibiotic exposure can decrease the antibacterial capacity of the F1 generation.In addition,this result could be further proved by the in situ hybridization and activity detection experiment of lysozyme.According to the measurement of immune genes and immune proteins of F1 generation zebrafish,the results suggest that the immunity of F1 generation zebrafish has decreased after long-term antibiotic exposure,higher the concentration of the antibiotics,lower the immunity capacity.Through the measurement of the ROS,CAT and T-AOC of the F1 generation zebrafish,it showed that the active oxygen free radicals in the F1 generation zebrafish will increase after the antibiotic exposure to their parents.The overmuch active oxygen free radicals would be converted to hydrogen peroxide,and then the catalase activity would be induced.Thus,the antioxidant capacity will increase.Hence,it is believed that the antibiotic exposure to the parents generation can cause the oxidative stress response in their offspring.Furthermore,The measurement of NO level and NOS activity also confirmed the impaired immunity and the occurrence of osidative stress response in the F1 generation zerafish.The results indicate that after the antibiotic exposure to the parents generation,the growth and development and the immune system of the zebrafish progeny are significantly affected.This result will also be of great importance to ensure the breeding of fish populations and protect the stability of the ecosystem.