Coccidial infections and iron absorption

Four-week-old chicks were infected with single oral doses of 1,000,000 sporulated oocysts of Eimeria acervulina, or 40,000 sporulated oocysts of E. necatrix, or 50,000 sporulated oocysts of E. brunetti, or 50,000 sporulated oocysts of E. tenella, or left uninfected. At intervals of 1, 3, 6, 10, 14, 21, 28, and 35 days after infection, absorption of 5 muCi Fe-59 was measured in five birds selected at random from each of the five experimental groups. Iron absorption was markedly decreased during the acute phase (day 6) of E. acervulina infections, less marked decreases were observed in E. necatrix infections, while no decreases in iron absorption were seen in the acute phase (day 6) of E. brunetti and E. tenella infections. Thus, the most critical area of the intestine for iron absorption, as shown by the largest decrease in amount of iron absorbed during the acute phase of coccidial infections, was located in the duodenum. During the recovery phase of all infections, periods of increased iron absorption were seen. This effect was marked in E. acervulina and E. tenella infections.