Reproductive effects in mink (Mustela vison) exposed to the pesticides Lindane, Carbofuran and Pentachlorophenol in a multigeneration study

Abstract

The mammalian reproductive system is sensitive to exposure to endocrine disrupting chemicals, particularly during sexual maturation. The purpose of this study was to examine reproductive function in second and third generation male and female mink exposed to pesticides from conception to maturity. The mink were fed untreated feed or feed treated with Lindane (1 mg kg-1 day-1), Carbofuran (0.05 mg kg-1 day-1 ) or Pentachlorophenol (1 mg kg-1 day-1) from the time they were weaned. The second generation mink had also been exposed to the pesticides in utero and from their mother's milk as their mothers were similarly fed pesticides, from 3 weeks before breeding. The third generation mink were the offspring of mink (second generation females) who had themselves undergone long-term exposure to pesticides from conception onwards. Blood samples and endocrine tissues were obtained at necropsy from both generations of mink. No overt signs of toxicity were seen. The pesticides did not affect the percentage of mink mated. Lindane treatment reduced the proportion of mated mink that subsequently whelped (P < 0.1) and the litter size of mink that whelped (P < 0.05). Testis size was reduced in the Lindane-treated, third generation males (P < 0.05). Serum concentrations of cortisol, testosterone and oestradiol were not affected by any pesticide treatment; however, thyroxine concentration was reduced by Pentachlorophenol (P < 0.05). In conclusion, exposure of mink to Lindane from conception resulted in a decrease in reproductive efficiency when they were subsequently mated, leading to a 60% reduction in the number of kits born.