The efficacy of mineral oil combined with feed restriction in enhancing the elimination of heptachlor epoxide from mink (Mustela vison)

Abstract

Adult female mink previously fed diets containing 0 (control) and 6.25 mg heptachlor/kg diet for 181 days were fed either the same control diet ad libitum (AL) or the control diet containing 10% mineral oil and restricted by 45% of ad libitum intake (MO/R) for 21 days to determine the efficacy of the latter treatment in enhancing the elimination of heptachlor epoxide (HE) from mink. Kit mink (2–3 months of age) whelped by dams of the control and 6.25 mg/kg groups were also fed the MO/R or AL diets for 21 days. Daily consumption (g/kg bw/day) of the AL diet by kit mink was significantly greater than consumption of the same diet by the adult females. Body weights of the control adults and the control and 6.25 mg/kg kits were significantly reduced by feeding the MO/R diet. Two adults from the control group and one adult from the 6.25 mg/kg group fed the MO/R diet died during the 21-day period. No mortalities occurred in kit mink fed either diet. Administration of the MO/R diet caused a significant reduction in body fat of the control adults and kits, but not in the 6.25 mg/kg adults and kits. Decreases in body fat of the MO/R groups were not associated with greater elimination of HE when compared to the AL groups. Comparison of HE body burdens in adult female and kit mink from the former 6.25 mg/kg heptachlor group at day 21 indicated that consumption of the MO/R diet did not increase the elimination of HE when compared to day 21 HE body burdens in adults and kits fed the AL diet. Heptachlor epoxide body burdens were reduced by 78 (MO/R) and 80% (AL) in the 6.25 mg/kg adults, while HE elimination from the 6.25 mg/kg kits was 96 and 93%, respectively. The half-lives of HE in the adults were 9.1 (AL) and 10.9 (MO/R) days, and 4.9 (AL) and 4.6 (MO/R) days in the kits. These results indicate that HE is readily mobilized and eliminated from mink.