Changes in Pancreatic Hormones Associated with Coccidiosis

Abstract

Compared to controls, 2- to 3-week-old broiler chicks inoculated with Eimeria acervulina (2 × 106 sporulated oocysts/bird) had significantly lower mean plasma levels of pancreatic insulin (PI) and pancreatic glucagon (PG) between 4 and 6 days after inoculation (DAI). In further trials with E. acervulina infections, significant depressions in mean PG were seen at 7 DAI and appeared to be associated with a high inoculating dose. Mean plasma levels of glucagon-like immunoreactants (GLI) were significantly increased from 3 to 8 DAI. This increase was repeatedly demonstrable at 7 DAI and was dose dependent between doses of 2 × 103 and 2 × 105 sporulated oocysts/bird. Compared to controls, chicks inoculated with E. tenella (2 × 105 sporulated oocysts/bird) had significantly higher mean plasma levels of PI at 4, 7, and 8 DAI and a significantly lower value at 6 DAI. Mean plasma PG values were significantly lower at 5 and 6 DAI. Mean plasma levels of GLI did not differ significantly from controls throughout the experiment. Changes in the hormones measured in both infections showed no direct significant statistical relationship with changes in pancreas weight, body weight, blood glucose or liver glycogen. However, an inverse correlation was found between plasma GLI and plasma pigment levels with time after infection in E. acervulina infections. The coincidence of plasma GLI increase with increased oocyst dose and diminished plasma pigment in E. acervulina infections, and the fact that E. tenella infection did not elicit a significant increase in plasma GLI, suggests that elevated GLI is closely associated with mucosal damage in the upper small intestine caused by E. acervulina.