Intestinal absorption following challenge of immune chicks with Eimeria acervulina

The absorption of glucose or L-methionine was measured in vitro in the intestine of broilers challenged with 1 x 10(6) sporulated oocysts of Eimeria acervulina. These broilers had various degrees of immunity resulting from previous inoculation with several dosages of oocysts given one to six times. Unimmunised broilers were also given the challenge inoculation of oocysts. The level of immunity had a marked effect on nutrient absorption post challenge (p.c.). Partially immune birds showed an enhanced absorption at 3 hours p.c. compared with absorption in unchallenged birds. With high levels of immunity, the enhanced absorption at 3 hours p.c. was not seen. A significant malabsorption was seen 6 hours p.c., but absorption returned to normal by 24 hours p.c. The absorption pattern during the first 24 hours in unimmunised control broilers was similar to that in partially immune birds. The degree of immunity was directly related to the protection against malabsorption at 6 days p.c. In solidly immune birds, absorption at 6 days p.c. was significantly greater than in immunised, unchallenged birds and equal to that in the unimmunised, unchallenged controls. The diffusion and mediated components of methionine absorption were, in general, both affected during malabsorption or stimulation of absorption. There was no evidence histologic-ally of epithelial loss in the 24 hours p.c. The pH in the duodenum was significantly decreased at 8 and 24 hours p.c. in immunised birds but was not affected by a primary inoculation given to unimmunised birds.