Chronic toxicity of dietary 2,3,7,8-tetrachlorodibenzo-p-dioxin to mink.

Mature female natural dark mink (Mustela vison) were fed 0.0006 (control), 0.016, 0.053, 0.180, or 1.40 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 131-132 d to ascertain the chronic toxic effects of TCDD in mink, including reproduction. Consumption of the 1.4 ppb TCDD diet resulted in lethargy, bloody stools, and 16.7% mortality. Final mink body weights were inversely proportional to the dietary TCDD concentrations. Due to subnormal mink breeding, definitive effects of TCDD on mink reproductive performance were not ascertained; however, there were significant dose-dependent decreases in kit (young mink) birth weight and survival from birth to 3 w of age in the groups that had reproduction. There were also significant differences in adult minkwhite blood cell counts, plasma total solids, serum iron, phosphorus, albumin, total protein, total CO2, cholesterol, osmolality, and anion gap concentrations, and alanine aminotransaminase activity between the various dietary groups. During the latter stages alopecia and thickened, deformed, and elongated toenails were observed in the adult mink fed 1.4 ppb TCDD. At termination the mink fed 1.4 ppb TCDD had ascites, gastric ulcers, intestinal hemorrhages, depletion of adipose tissue, and mottled and/or discolored livers, spleens, and kidneys. Focal lymphocytic meningitis in region of the olfactory bulb was present in 42% of the mink fed 1.4 ppb TCDD. These results confirmed the high sensitivity of mink to TCDD and revealed a toenail abnormality not previously reported for mink fed TCDD.