Sheep immune‐stimulated with Saccharomyces boulardii show reduced prolificacy of Haemonchus contortus

Haemonchus contortus is the most pathogenic parasite for sheep. The objective was to evaluate immunomodulation of the probiotic Saccharomyces boulardii in sheep experimentally infected with H. contortus. Twenty‐four sheep were divided into three groups: one infected with 500 H. contortus larvae/day for 26 days and supplemented with S. boulardii (40 ml with 1 × 108 CFU/ml/day); a control group only infected with H. contortus but not supplemented; and a naïve group that never came into contact with either parasites or S. boulardii. To assess the humoral immune response, production of specific serum IgG anti‐somatic H. contortus antigen was evaluated through indirect ELISA. To assess the cellular immune response, cell populations and cytokine (IL‐4, IL‐5 and IL‐10) production were evaluated through flow cytometry. For parasitological analyses, the counts of eggs per gram of faeces (EPG) and larvae per faecal culture were assessed. At all the study points, the concentration of IgG anti‐H. contortus was higher (p