Effects of Varying Concentrations of Eimeria Challenge on the Intestinal Integrity of Broiler Chickens

The objective of the current investigation was to evaluate several Eimeria challenges and the resulting alterations in intestinal permeability, intestinal morphology, and intestinal lesion scores in broiler chickens. This study included four groups with ten replicate cages per treatment, in which each group received a different treatment dosage of Eimeria, characterizing high, medium-high, and medium-low challenges. Five days after the challenge, intestinal lesions and permeability were assessed. The results showed that the increase in Eimeria challenge led to a considerable decrease in the height of intestinal villosities, in the ratio between villosity size and crypt depth, and in goblet cells. Moreover, after the challenge, there was a considerable increase in intestinal permeability. In conclusion, the medium-low, medium-high, and high-challenge models can be utilized for experimental infection. In the context of clinical studies, it has been observed that the administration of medium-high and high-challenge doses has proven to be adequate. However, it is advisable to utilize a medium-low challenge level to develop a subclinical challenge model for forthcoming investigations that aim to evaluate nutritional recommendations.