Influence of betaine and salinomycin on intestinal absorption of methionine and glucose and, on the ultrastructure of intestinal cells and parasite developmental stages in chicks infected with Eimeria acervulina

The effect of betaine and salinomycin on absorption of methionine and gluco se in tissue from the duodenal loops of Eimeria acervulina-infected chicks was determined. Differences in the ultrastructure of the intestinal cells a nd parasite developmental stages were also examined. With a drug-resistant isolate off. acervulina, methionine absorption was significantly higher in chicks fed a basal diet supplemented with 0.15% betaine as compared with ab sorption in chicks fed the unsupplemented basal diet. Addition of 66 ppm sa linomycin to the diet containing betaine did not further enhance absorption . Conversely, with a drug-sensitive isolate, methionine absorption was sign ificantly higher in chicks fed a diet supplemented with both betaine and sa linomycin than in chicks fed the unsupplemented basal diet. Tissue from chi cks fed any of the supplemented diets was usually significantly heavier tha n that from chicks fed the unsupplemented diet, even when weight gains of t he birds were similar. Glucose absorption was similar in all diet groups. E pithelial cells in coccidia-infected and uninfected chicks fed diets supple mented with betaine or betaine plus salinomycin were less electron dense th an cells from chicks fed diets that were not supplemented with betaine. Mer ozoites of E. acervulina in chicks fed diets supplemented with salinomycin had extensive membrane disruption and vacuolization, bur the damage was pre vented when betaine was added to the diet. Numerous merozoites and intact s chizonts were seen in the intestinal lumen of chicks fed the diet containin g betaine plus salinomycin.