Effects of copper sulfate on ion balance and growth in tilapia larvae (Oreochromis mossambicus).
Newly hatched tilapia larvae were exposed to sublethal concentrations of Cu2+ (0, 30, 50, and 100 microg/L) and lethal concentrations of Cu2+ (200 and 400 microg/L) for 24-96 h. The interaction of the exposure dose and time was related to the Cu2+ accumulation rate, which showed a higher accumulation rate with sublethal concentrations of Cu2+ within 24 h compared to the other treatments. Furthermore, Cu2+ contents in the whole body of larvae significantly increased following Cu2+ exposure times up to 96 h. Cu2+ in the medium produced a dose-response effect on Na+ and K+ contents in larvae after 96 h of exposure time. Changes in Ca2+ contents statistically significantly decreased and were shown to be dose-responsive for larval exposure times exceeding 72 h. Changes of Ca2+ contents were more sensitive than those of Na+ and K+ with Cu2+ treatment of early larvae. Notably Na+ and K+ contents showed significant increases of 17-23% in larvae exposed to low concentrations of Cu2+ (30-50 microg/L) for 24-72 h as compared to control larvae. Cu2+ caused no significant effect on body Cl- content or osmolality except at 100 microg/L Cu2+ for 24 h in tilapia larvae as compared to the control. However, there was a restoration phenomenon in larvae exposed to 100 microg/L Cu2+ for longer than 72 h. The water content of larvae exposed to Cu2+ for 96 h significantly decreased. The yolk absorption rate of tilapia larvae was significantly suppressed when they were exposed to Cu2+ medium containing 30, 50, 100, 200, or 400 Cu2+ microg/L from 72 h post transfer. These results obviously show that larvae are sensitive to Cu2+ during early development.
Wu
S M
SM
Department of Aquatic Biosciences, National Chiayi University, 300 University Road, Chiayi 600, Taiwan, ROC. sumei@mail.ncyu.edu.tw
Jong
K J
KJ
Kuo
S Y
SY
D000818:Animals; D019327:Copper Sulfate / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004639:Emetics / Q000633:toxicity*; D007474:Ion Exchange; D007814:Larva / Q000254:growth & development; D011188:Potassium / Q000493:pharmacokinetics*; D012964:Sodium / Q000493:pharmacokinetics*; D017210:Tilapia / Q000235:genetics* / Q000502:physiology*; D014873:Water Pollutants / Q000633:toxicity*
D004639:Emetics; D014873:Water Pollutants; D012964:Sodium; D019327:Copper Sulfate; D011188:Potassium