Influence of spp. and Infection on Growth Performance and Toltrazuril Residues in Chickens.

Coccidiosis and necrotic enteritis are among the most common diseases affecting poultry, with economic impact due to reduced production and the costs of treatment and prevention. Eimeria invasion contributes to gut damage that promotes the growth of other harmful pathogens, such as . Coccidiostats, with toltrazuril as an example, are widely used to control these infections. In this study, we assessed the effects of spp. infection and coinfection with spp. and on chicken weight and toltrazuril concentrations, along with two metabolites-toltrazuril sulfoxide and toltrazuril sulfone-using liquid chromatography coupled with mass spectrometry. The analysis of liver and muscle samples showed lower levels of residues in groups challenged with spp. In the case of combined and infection, no significant differences were observed. These findings suggest that the combination of and does not significantly alter the residue levels of toltrazuril and its metabolites, providing valuable insight into the pharmacokinetics of toltrazuril in poultry under infection conditions. This research contributes to optimizing drug use and residue management in poultry production.