“…Coccidial vaccines can mitigate negative effects of coccidiosis by enhancing immunity of the birds with low dose exposure of Eimeria oocysts ( Chapman et al, 2002 ; Chapman, 2014 ). However, they may lead to sub-clinical infection and potential growth reduction in early period (2 wk following vaccination), which is often associated with mild intestinal inflammation and oxidative stress as a result of damage to bird intestinal epithelium ( Li et al, 2005 ; Cervantes, 2015 ), resulting in nutrient malabsorption, enhanced immune response and decrease in the expression of brush-border membrane nutrient transporters ( Paris and Wong, 2013 ; Su et al, 2014 ; Lee et al, 2022 ). Moreover, the coccidial vaccination is reported to induce the incidence of bacterial enteritis ( Williams, 2002 ).…”