Dietary biochar affected prokaryotic and eukaryotic caecal microbes in broiler chickens challenged with Eimeria tenella.

Coccidiosis is a disease of major importance in poultry husbandry, and the current control measures such as chemoprophylaxis and live vaccines are not sustainable. Therefore, there is a need for sustainable alternative approaches. It has been suggested that biochar can bind to the Eimeria parasites that cause coccidiosis and inhibit their replication in the gut. The aim of this study was to evaluate the impact of dietary biochar on growth rate, infection outcome, caecal microbiota, and specific immune response of broilers experimentally infected with E. tenella. A total of 64 day-old chicks were randomly assigned to one of two dietary treatments; control or biochar. Chickens were fed the biochar diet (2% inclusion rate) from arrival and until the end of trial when they were 30 days old. Eimeria. tenella inoculation was performed when chickens were 20 days old. We found that dietary biochar did not inhibit the E. tenella infection of the caecum demonstrated by similar oocyst shedding, lesion scores and growth rates in the control and biochar groups. Furthermore, biochar did not significantly affect the different blood leukocyte populations monitored or induction of E. tenella specific immune responses. However, biochar caused decreases in the abundance of potentially beneficial bacterial families such as Lactobacillaceae and Bifidobacteriaceae, and an increase of the fungal family Aspergillaceae in the caecum. Therefore, supplementing feed with biochar may be an unsuitable or even a contraindicated approach to prevent E. tenella infection in chickens.