Effect of Rape Seed on the Thyroid of the Chick

Kennedy and Purves (1941) reported marked enlargement of the thyroids of rats fed a diet containing 45% of the seeds of the Brassica family. The feeding of supplemental iodine failed to prevent the thyroid hyperplasia thus induced. Later work (Purves, 1943) has further confirmed the evidence that the substance present in these seeds acts upon the thyroxine-secreting mechanism of the thyroid in a manner comparable to thiourea and thiouracil (for discussion see Schultze and Turner, 1945) rather than as soybeans or cabbage leaves. Since Kempster and Turner (1945) reported that the addition of 0.2% thiouracil to the ration of New Hampshire broilers greatly improved the market grade during 16- and 36-day fattening periods, it seemed of interest to compare the goitrogenic effects of varying amounts of ground rape seed in comparison with thiouracil in the diet of chicks with the idea that rape seed might take the place of thiouracil . . .