Parasitological and immunological response to Haemonchus contortus infection: Comparison between resistant Garole and susceptible Sahabadi sheep

Abstract Parasitological and immunological responses to the experimentally induced Haemonchus contortus infection were compared between Garole and Sahabadi breeds of sheep. The experiment was conducted in a 2 (breed) × 2 (infection status) factorial arrangement with a completely randomised design. Two breeds of sheep were divided into infected (n = 10) and control (n = 6) groups, and the infected groups were orally infected with H. contortus (500 stage 3 larvae per kilogram of body weight). Faecal egg counts (FEC) were determined from 18 days post infection (DPI) at 3-day intervals until 42 DPI. Average daily body weight gain, packed cell volume (PCV), concentrations of serum immunoglobulin (Ig) G1, IgG2, IgE and peripheral eosinophil count were measured at 14-day intervals from 0 to 42 DPI. Lymphocyte proliferation in response to somatic antigen of H. contortus was determined by in vitro lymphoproliferation assay, and concentrations of interferon gama (IFN-γ) and interleukin 4 (IL-4) in lymphocyte culture supernatant were measured at 14-day intervals until 42 DPI. Variables were analysed using the repeated measures mixed model procedure over DPI. Faecal egg count was significantly (p