Feeding supplemental iodine to mink: Reproductive and histopathologic effects

Abstract

Adult mink were fed various concentrations of supplemental iodine, ranging from 10 to 320 ppm, for 1 or 7 mo before breeding. Long‐term, low‐level (10–20 ppm) iodine supplementation was beneficial for both reproduction and lactation. Supplemental iodine in excess of 80 ppm, however, resulted in a reduction in the number of females that whelped, a decrease in litter size, and an increase in kit mortality. Thyroid glands of kits whelped and nursed by dams fed more than 20 ppm supplemental iodine, both short‐term and long‐term, showed hypertrophy marked by follicular cell hyperplasia and a decreased amount of colloid. Similar histopathologic lesions were observed in the thyroids of adults that received 80 ppm or more supplemental iodine; also observed were numerous lesions in the gallbladder.