Nutritional aspects modulate the parasitological and immune response in infected sheep. The aim of the present study was to evaluate the parasitological and humoral immune response of Pelibuey sheep experimentally infected with Haemonchus contortus that were fed diets with two different energy (n = 12) and protein (n = 12) levels. Twenty-four Pelibuey lambs infected with H. contortus were evaluated over 12 weeks. An additional six animals were considered as a control group. Fecal egg count (FEC) was determined, in addition to packed cell volume (PCV), total plasma protein (TPP), and immunoglobulin levels (IgA, IgG, and IgM) by indirect enzyme-linked immunosorbent assay (iELISA). Data were analyzed by repeated measures over time. The lambs that received a high-energy (HighE) diet had the lowest FEC (P < 0.01) regardless of whether they received a high (HighP) or low (LowP) level of protein. The effect of energy level was also observed over time: FEC values decreased and PCV and TPP values increased. Higher immunoglobulin levels were obtained for females (P < 0.05) than males yet, overall, the energy and protein levels of the diets did not affect the response of the immunoglobulins. Over time, however, an increase in IgG and IgM was observed, whereas the IgA level remained basal.
Keywords: Dietary energy; Dietary protein; Immuglobulins; Integral diet; Nematode parasites.