Effect of High Iodine Intake on Selected Parameters of Immunity in Sheep

The study aimed at defining the immunity risks connected with high iodine supplementation in ewes and their lambs. The feed ration for control group (C) of ewes (n=6) contained 3.1 mg of iodine per kilogram of dietary dry matter and for experimental group (E) of ewes (n=6) 5.1 mg of iodine per kilogram of dietary dry matter. The animals were fed the diets for 8 months. Parallelly with different iodine supplementation, some immunological parameters (percentage of γ-globulins, concentration of immunoglobulin G, and white blood cell count) were examined in ewes and their lambs. The difference in the average concentration of immunoglobulin G between the ewes of group C and E was not significant during the experiment. A significant decrease (P<0.01) in the concentration of immunoglobulin G from 19.6 mg/mL before the experiment to 9.8 mg/mL on day 60 of the experiment was demonstrated in the ewes of group E. The average percentage of γ-globulins in the whole period after parturition was lower in the ewes of group E than in group C. The concentration of immunoglobulin G and the percentage of γ-globulins in lambs from dams in group E was continually lower (P<0.01) for the entire period of 1-30 d and demonstrated immunological risks of the excessive intake of iodine. The obtained results document a dangerous influence of high iodine intake on immunity in the prenatal period in ewes and mainly in the postnatal period in their lambs.