Interactions of Toxaphene and Vitamin C in Channel Catfish

The involvement of vitamin C as a cofactor in detoxication mechanisms of fish was investigated by feeding selected amounts of the vitamin in diets of fingerling channel catfish (Ictalurus punctatus) that were concurrently exposed to toxaphene, a widely used organochlorine insecticide in the Southeastern United States. Three groups of fish were exposed continuously to each of five toxaphene concentrations—37, 68, 106, 218, and 475 ng/liter—and fed a diet containing 63, 670, or 5,000 mg/kg of vitamin C. After 150 days of toxaphene exposure, backbone collagen was significantly decreased in most fish fed the diet containing 63 mg/kg of vitamin C. However, the toxaphene concentrations of 37 and 68 ng/liter did not cause this effect in fish fed the 670 mg/kg vitamin C diet, and only the 475 ng/liter concentration significantly depressed backbone collagen in fish fed the 5,000 mg/kg diet. Spinal deformities were common among fish fed low vitamin C diets, but the incidence decreased as dietary vitamin C ...