铅暴露致中华鲟（Acipenser sinensis）幼鱼弯曲畸形与畸形恢复(Exposure of Lead to Juvenile Acipenser sinensis: Effects on Body Deformation and Recovery)

铅是一种常见的污染物,在水环境中广泛分布并在水生食物链中富集,具有持久的生态效应.中华鲟(Acipenser sinensis)是我国特有的珍稀濒危大型洄游性鱼类,极具学术价值和生态价值.为了探索中华鲟在生命早期接触铅后的损伤和自我修复机制,采用水溶液静态置换法,从中华鲟受精卵发育至96h开始,进行了16周的Pb2+暴露试验,随后继续6周的排放试验.结果显示:经0.8mg·L-1和1.6mg·L-1的Pb2+暴露16周,中华鲟幼鱼会发生弯曲畸形,而0.2mg·L-1Pb2+暴露组未出现畸形个体.畸形弯曲位置主要发生在近胸鳍起点处以及背鳍起点至尾鳍末端之间,多伴有尾鳍末端下垂.Pb2+暴露浓度越高,畸形弯曲越严重,但未见椎骨变形.畸形个体的自主活动能力和摄食能力明显降低.Pb2+排放后,畸形个体的弯曲程度由重度向轻度转变而恢复正常,弯曲程度越轻恢复越快,畸形恢复个体的自主活动能力和摄食能力均明显得到恢复并逐渐复原.表明中华鲟幼鱼具有较强的排铅能力和铅损伤后的自我修复能力.

Exposure of Lead to Juvenile Acipenser sinensis: Effects on Body Deformation and Recovery

Lead is a ubiquitous pollutant, which is widespread and be larger in the tissues of animals at the top of a food chain in water environment, and with permanent ecological effects. Chinese sturgeon (Acipenser sinensis)is a rare and endangered species in most primitive teleost fishes with extremely high academic interest and eco-value. A 16-w semistatic test of Pb2+ exposure began with 96 hours developed embryos and then a 6-w depuration test were carried out in laboratory, in order to examine the injury of Pb2 + and restoration on the early life stage of Chinese sturgeon. Results showed that juveniles become curvature deformation in 0.8mg·L-1 or 1.6mg·L-1 but not in 0.2mg·L-1 Pb2 + . The deformation always appears near the points of the origin of pectoral fin or the origin of dorsal fin to the posterior margin of caudal fin, and is mostly accompanied by flaccidity of caudal fin end. The higher the Pb2+ concentration is, the higher the degree of curvature will be. But there is no obvious deformation at vertebra in curved individuals. Body deform reduced the free activity and food intake activity of curved juveniles. While with depuration in clean water for 6 weeks, the curvature degree of deformed individuals reduced gradually. The lower the curvature degree is, the faster the recovery will be. The free activity and food intake activity of curved juveniles recovered obviously and will comeback ultimately by depuration in clean water. The obtained results indicated that Chinese sturgeon possesses higher activity of Pb depuration and self-repairing capability after injured by Pb2+.