氟苯尼考对太平洋牡蛎(Crassostrea gigas)早期发育的影响

氟苯尼考作为氯霉素的替代物,理化性质稳定,在水产养殖业中被广泛使用,致使其在多种水体环境中大量残留。本研究分析了氟苯尼考(0.1、1.0和10 mg/L)对牡蛎幼虫的生长发育、运动能力、免疫抗性的影响。结果表明,氟苯尼考暴露24 h后,随着暴露浓度的增加,牡蛎幼虫的存活量呈升高趋势,而幼虫壳高和壳宽显著降低;氟苯尼考暴露不会引起牡蛎幼虫移动速度的变化,1 mg/L氟苯尼考暴露后,牡蛎幼虫移动距离呈显著性增加(P<0.05)。氟苯尼考暴露浓度、牡蛎幼虫存活量及水体细菌总数之间呈显著性相关,但水体细菌总数的变化并不是造成牡蛎幼虫发育、生长状态不同的主要原因。牡蛎幼虫在不同浓度氟苯尼考的暴露下,ILPR、Cg-Tyr和Ferritin等生长发育相关基因的表达受到影响,进而影响其生长发育、运动能力。另一方面,高浓度氟苯尼考的暴露,引起牡蛎幼虫HSP70和Cg-Tal基因相对表达量上调,积极地参与抵抗氟苯尼考暴露引起的应激反应。养殖水环境中抗生素残留可能会影响水生动物早期发育阶段的生长发育及免疫抗性,需提高对养殖水体中抗生素残留危害的认识及监测,进一步加强养殖水体水质的净化。

Effects of florfenicol on the development of Crassostrea gigas during the early developmental stage

Florfenicol, the alternative of chloramphenicol, is the most commonly used antibiotic in aquaculture. Its residues are widely distributed in the aquatic environment because of its low degradability. In the present research, the effects of florfenicol (0.1, 1.0, and 10mg/L) on the growth and development, motor behavior, and immunity of Crassostrea gigas larvae during the early developmental stage were investigated. The results showed that the survival of larvae increased with increasing florfenicol concentration, whereas the shell height and shell width of the larvae considerably decreased after exposure for 24h. Further, there was little effect on moving velocity, and the moving distance considerably increased when exposed to florfenicol at the concentration of 1mg/L. The correlations among the concentration of florfenicol, survival of the larvae, and total number of bacteria were observed, In contrast, the total numbers of bacteria may not be the main reason for the differences in growth and development. Florfenicol affected the mRNA expression of ILPR, Cg-Tyr, and ferritin, which further influenced the growth and development as well as the motor ability of the larvae. On the other hand, the high concentration of florfenicol induced oxidative stress in the larvae, the levels of HSP70 and Cg-Tal were upregulated, and they participated in the immune stress response. The antibiotic residues in aquaculture may affect the growth and immunity of animals during the early developmental stage. Thus, it is necessary to improve the understanding and monitoring of antibiotic residues in the aquatic environment and to strengthen the water purification efforts.