Protozoan Parasitic Infections of the Chick Intestine and Protein Digestion and Absorption

Abstract

Parasitic infections of the duodenum (Eimeria acervulina), jejunum (Eimeria necatrix), and ileum, cecum, and colon (Eimeria brunetti) were established in chicks and the digestion and absorption of ¹⁴C generally labeled chlorella protein were observed. The infections were untreated and allowed to proceed through the infective, acute, recovery and postrecovery phases. In all trials, all infections resulted in decreased rates of weight gain in 4-week-old chicks from days 6 to 28 of the infection. Visible intestinal damage (hemorrhage, edema, and necrotic foci) occurred in all infections on day 6, but healed by day 14 in all but the E. necatrix infections which had healed by day 28. Protein digestion and absorption were decreased during the acute phase of infection in E. necatrix-infected birds when compared with noninfected birds, indicating that this area of the intestine was most critical for these functions. Protein digestion and absorption were not markedly decreased in the other infections during the acute phase, indicating that the duodenum, ileum, cecum, and colon were less critical areas for protein digestion and absorption. Increases in the amount of protein absorption were observed in the infected birds during the recovery phase above the amount of absorption occurring in uninfected birds.