Eimeria tenella infection in broiler chickens is associated with haemorrhagic typhlitis and anemia. The study aimed to evaluate the haematological parameters and oxidative stress profile of caecal coccidiosis in broiler chickens infected with E. tenella following the administration of the methanolic leaf extract of Vernonia amygdalina and its fractions. To evaluate the parameters, 210 broiler chickens were divided into seven groups with two replicates (n=15). The experimental groups were negative control (NC), positive control (PC), standard amprolium control (SC), crude methanol extract (ME), hexane fraction (HF), butanol fraction (BF), and aqueous residue fraction (AF). All birds were infected with 105 sporulated oocysts of E. tenella except those in the NC group and treated accordingly. The haematological parameters and oxidative stress markers were assessed at 7 and 14 days post-infection as evaluation criteria for the evaluation of the anticoccidial efficacy of treatments. The packed cell volume (PCV) of the NC group showed a significant decrease at 7 days post-infection but markedly improved at 14 days post-infection. There was a non-significant difference in the antioxidant values of the birds in all groups (p > 0.05), as no definite trend in the value measured parameters were recorded. It was concluded that treating infected birds with V. amygdalina effectively decreased blood loss and improved oxidative defence during caecal coccidiosis.

Phytochemical screening of the crude methanolic leaf extract of Vernonia amygdalina was carried out. The extract and its fractions were tested for in vitro anticoccidial efficacy against the unsporulated oocysts of Eimeria tenella by the oocyst sporulation inhibition model in a 96-well microtitre plate. Phytochemical analysis of the extract revealed the presence of alkaloids, tannins, saponins, glycosides, and triterpenoids. Different concentrations of the extracts, including 250 mg/ml, 125 mg/ml, 62.5 mg/ml, 31.25 mg/ml, 15.625 mg/ml, and 7.8 mg/ml, were tested against freshly prepared unsporulated oocysts of E. tenella. Triplicate assays were conducted for each concentration of the extract to screen for anticoccidial activity. The methanol extract and fractions showed activity against the oocysts of E. tenella in a dose-dependent manner. The sporulation inhibition rate was determined as effective when the result showed more than 50% inhibition at each concentration level of treatment. Only the methanol extract and its butanol fraction at the lowest treatment concentration of 7.8 mg/ml showed an inhibition rate of 55% and 68%, respectively. All treatments: methanol extract (100%), hexane fraction (100%), butanol fraction (100%), and aqueous residue fraction (58%) were active at the highest concentration of 250 mg/ ml. It is concluded that the methanol leaf extract of Vernonia amygdalina and its butanol fraction had better oocyst sporulation inhibition activity against Eimeria tenella and may further be explored for their anticoccidial properties.