Dialyzable leukocyte extract as inductor of interferon gamma concentration in serum of weaned pigs

Abstract

In most intensive pig production systems piglets are weaned at 3 weeks of age, which creates stress because of feeding changes and hierarchy. This increases the incidence of respiratory symptoms, diarrhea, poor weight gain and cause economic losses. Dialyzable leukocyte extract (DLE) can enhance the immune response by increasing the levels of interferon gamma (IFN-γ). In this study we evaluated the effect of porcine DLE (DLEp), when applied 7 times intradermally in piglets during the first four weeks at two different doses. Forty eight piglets were divided into 3 groups of 16 animals each. Group A: high dose (77 mg/kg), group B: low dose (17 mg/kg), group C: control (sodium chloride). Blood and serum samples were obtained at days 0, 14 and 30 for leukocyte accounts by haemogram and IFN-γ quantification by ELISA. In addition, we determined the daily incidence of diarrhea and respiratory symptoms and measured the weight of the animals studied. The high dose (77 μg/kg), produced a significant increase in serum IFN-γ concentration in the third sampling (d = 2,288, α = 0.05, P = 0.003). The rest of the variables analyzed showed no significant difference between the treated and the control groups (P > 0.05). Conclusion: applying seven DLEP doses intradermally in weaned pigs significantly increased IFN-γ concentration in the serum at 30 days post treatment.