DIETARY EXPOSURE OF MINK TO CARP FROM SAGINAW BAY, MICHIGAN .2. HEMATOLOGY AND LIVER PATHOLOGY

The effects of consumption of environmental contaminants contained in carp (Cyprinus carpio) from Saginaw Bay, Michigan on various hematolog ical parameters and liver integrity of adult female mink (Mustela viso n) were determined. Mink were fed diets that contained 0 (control), 10 , 20, or 40% carp prior to and throughout the reproductive period (182 days). The diets contained 0.015, 0.72, 1.53, and 2.56 mg polychlorin ated biphenyls (PCBs)/kg diet and 1.0, 19, 40, and 81 pg 2,3,7,8-tetra chlorodibenzo-p-dioxin equivalents (TEQs)/g diet, respectively. Mink f ed the diets containing carp showed a general dose-dependent occurrenc e of clinical signs commonly associated with chlorinated hydrocarbon t oxicity, including listlessness, nervousness when approached, anorexia , and melena. Erythrocyte counts were less in mink exposed to Saginaw Bay carp than in controls, while the number of white blood cells was g reater than in controls. Significant differences (p < 0.05) in the con centrations of neutrophils, lymphocytes, monocytes, and eosinophils we re also found between the control and carp-fed groups, but are conside red to be of limited clinical or biological importance. Hematocrit val ues for the mink fed the 20 and 40% carp diets were significantly less than those of mink in the control and 10% carp groups. There were no significant differences in hemoglobin concentrations among the groups. Necropsies revealed enlarged yellowish livers in many of the carp-fed mink, especially those fed the 40% carp diet. Liver, spleen, and lung weights of carp-fed mink were significantly greater than those of con trol mink. Histopathologic examination of the livers revealed various degrees of congestion, hepatocellular fatty changes, and scattered por tal lymphocytic infiltration which were most prevalent in mink fed the carp diets. These clinical signs, hematological effects, and histolog ic alterations are similar to those previously described for chlorinat ed hydrocarbon toxicoses in mink.