PFOS对中华倒刺鲃幼鱼爆发游泳及运动后代谢恢复的影响

为探究水体全氟辛烷磺酸(PFOS)污染对鱼类爆发游泳及其代谢恢复能力的影响, 将中华倒刺鲃幼鱼(Spinibarbus sinensis)暴露在不同浓度(0、0.32、0.8、2和5 mg/L)PFOS后, 测定PFOS暴露对其静止代谢率(RMR)、爆发游泳速度(U_burst)以及运动力竭后代谢恢复特征的影响。结果发现, 暴露浓度对实验鱼的U_burst和相对爆发游泳速度(rU_burst)均影响显著(P<0.05), 5 mg/L PFOS暴露导致U_burst和rU_burst分别下降了17.4%和10.8%, PFOS对rU_burst的影响表现出“非单调剂量效应”; 暴露浓度对实验鱼的RMR影响显著(P<0.05), 5 mg/L PFOS暴露导致RMR显著升高, 但PFOS对运动后代谢峰值(MMR)、代谢率增量(MS)、代谢变化倍率(F-MS)、力竭运动后过量氧耗(EPOC)无显著影响(P>0.05)。研究结果提示: PFOS污染改变实验鱼能量代谢水平的下限, 而对其代谢水平的上限无明显的限制性作用; PFOS污染将可能对鱼类捕食——逃避捕食者、穿越激流寻找适宜生境等生存关联的生命活动起到负面影响, 但对无氧代谢关联的代谢恢复能力无显著的生态毒理效应。

EFFECTS OF PFOS ON BURST SWIMMING PERFORMANCE AND METABOLIC RECOVERY IN JUVENILE SPINIBARBUS SINENSIS

To assess the effects of PFOS pollution on burst swimming performance and metabolic recovery of fish, juvenile Spinibarbus sinensis were exposed to different PFOS concentrations (0, 0.32, 0.8, 2 and 5 mg/L) for 28d. There after, the burst swimming speed (U_burst), relative U_burst (rU_burst), resting metabolic rate (RMR) and metabolic recovery after exhaustive swimming of the fish were measured. The results showed that PFOS had a profound effect on the U_burst and rU_burst of fish (P<0.05). TheU_burst and rU_burst were reduced by 17.4% and 10.8%, respectively, upon exposure to 5 mg/L PFOS. A possible non-monotonic dose response was found in rU_burst to PFOS. Moreover, PFOS significantly increased RMR (P<0.05), but did not have a marked effect on maximum metabolic rate (MMR), metabolic scope (MS), factorial metabolic scope (F-MS) and excess post-exercise oxygen consumption (EPOC) (P>0.05). The results indicated that PFOS had more dramatical effect on RMR than MMR of the experimental fish. Presumably, PFOS negatively impact survival-related activities such as capturing prey, avoiding predators, hunting for suitable habitats without significant ecotoxicological effects on metabolic recovery associated with anaerobic metabolism.