E. Perkins, B. Griffin, M. S. Hobbs
Apr 1, 1997
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0
Influential Citations
46
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Journal
Aquatic Toxicology
Abstract
Abstract Copper sulfate is regularly used in the aquaculture industry as an algicide and for the treatment of various ectoparasitic infections. In this study, male and female channel catfish ( Ictalurus punctatus ) (100 fish per group) were treated for 10 weeks with three levels of copper sulfate, giving water concentrations of 220, 354, and 465 μg Cu 1 −1 . Six fish were sampled at 2-week intervals and copper levels in muscle and hepatic tissue were measured. No copper accumulation was detected in muscle tissue during the exposure period, but hepatic accumulation began to occur within the first 2 weeks of treatment, with a peak at 4–6 weeks and subsequent decrease before the end of exposure. No mortality was seen in controls or at 220 mg Cu 1 −1 . However, lethality was seen within the first week in the 354 and 465 μg Cu 1 −1 exposures, with males being more susceptible than females. Metallothionein (MT) levels showed an increasing trend through the 6-week time point, followed by a general decrease toward control levels for the remainder of the exposure. The pattern of hepatic MT content was similar to that of hepatic copper accumulation, with a correlation coefficient ( r ) of 0.767 ( P ≤ 0.001). Measures of whole-body weight, body length, liver weight, liver somatic index, and condition factor were recorded as indicators of sublethal stress. No substantial change was seen in any of these measures in females; however, a decreasing tendency was seen in males for body weight, body length, and condition factor. However, correlation analysis of hepatic copper with somatic measures showed a significant relationships in both sexes. When hepatic MT was compared to somatic indices, significant correlations were observed in males, but not females. The results of this study indicate an association between MT expression and sublethal stress in males as well as a potential protective mechanism other than MT in prespawn female channel catfish exposed to copper.