Resposta imune de cordeiros infectados experimentalmente com Haemonchus contortus e tratados com associação de zinco e cobre injetáveis

Abstract

In the sheep industry, one of the biggest problems faced is the worms; among gastrointestinal helminths affecting sheep in Brazil, Haemonchus contortus species is most prevalent and pathogenic. Studies have been conducted to develop alternative to reduce the use of anthelmintics media and among them we highlight the use of minerals. The present study aimed to evaluate the immune response of lambs experimentally infected with Haemonchus contortus (H. contortus) and treated with an injectable compound of zinc (Zn) and copper (Cu). Twenty four Corriedale and Texel lambs, male, eight months old, weighing 17 kg, were used as our experimental model. The animals were divided into three groups, as follows: GC: (control group), composed by healthy animals; GI: (group infected withH.contortus); GIT: (group infected with H. contortus and treated). Animals of GIT were treated subcutaneously with 1.5mg/kg of Zn and 0.45 mg/kg of Cu on days 10 (D10) and 45 (D45) post-infection (PI). Animals of GI and GIT were orally infected with 15,000 larvae of H. contortus. Blood was drawn, from all the animals, on days 10, 24, 38, 52, 66 and 80 p.i. in order to evaluate the serum concentrations of interleukins (IL1, IL4 and IL6), interferon-gamma (INFγ), tumor necrosis factor (TNFα) and immunoglobulins (IgA, IgE, IgG and IgM). The parasitic infection was monitored through counting of eggs per gram of feces (EPG), at the same intervals of blood drawing. At the end of the experiment 5 animals from each group were euthanized for quantification of parasite load and to determine the concentrations of Zn and Cu liver. A significant increase in OPG only on day 14 for GI and GIT was observed. Between D14 to D42 significant increase of cytokines and immunoglobulins in GI and GIT compared to animals of the GC. After D52, GI showed levels of interleukins and immunoglobulins smaller than GIT. Regarding the concentrations of Zn and Cu liver was found that the infection caused a depletion in the liver of these minerals, however, supplementation did not prevent this effect. Based on these findings we can conclude that the administration of a dose of Zn and Cu increased the immune response in infected sheep with H. contortus response, and presents a potential beneficial effect as adjunct therapy to combat this parasite.