Propolis is a honeybee product showing several biological properties that enhance the immune response, depending on the concentration and intake period. Because propolis possesses an immunomodulatory action on mammals, the objective of our study was to investigate the effects of propolis on the humoral immune response of laying hens by evaluating antibody production. Laying hens (ISA Brown) were divided into 5 groups with 7 birds each. Group 1 was a nonimmunized control, whereas birds in group 2 were immunized intravenously with SRBC, and those in groups 3, 4, and 5 were treated intraperitoneally with propolis (2, 10, and 50 mg/kg, respectively) on 3 consecutive days and then inoculated intravenously with SRBC. Hematological and serological analyses were carried out on d 0, 3, and 38. Natural and specific antibody levels were determined by hemagglutination with rabbit red blood cells and SRBC, respectively. Propolis-treated birds (50 mg/kg) showed a significant decline in heterophils and in the heterophil:lymphocyte ratio. After SRBC immunization, significant increases in levels of IgG were observed in groups 4 and 5. Furthermore, higher levels of natural antibodies were observed in propolis-treated laying hens. The administration of propolis to laying hens increased the production of IgG specific to SRBC and natural antibodies, and could be used to increase antigen-specific antibody responses to vaccines.

Estudos anteriores têm demonstrado os efeitos sobre o sistema imune e sobre os níveis de colesterol da dieta com fibra solúvel e proteína de soja em ratos. Nesse estudo, nós avaliamos os efeitos do farelo de aveia e da farinha de soja na resposta imune humoral de ratos Wistar tratados com dietas hipercolesterolêmicas. Os animais (6 grupos) foram alimentados com diferentes dietas por 6 semanas e inoculados duas vezes com antígeno (IgY). As amostras de plasma foram coletadas após cada inoculação e os níveis de anticorpos anti-IgY (IgM, IgG1 e IgG2a) foram avaliados por ELISA. Os animais que receberam 1% de colesterol apresentaram um aumento de IgG1 anti-IgY e uma redução de IgM e IgG2a anti-IgY em relação aos animais controle. Estes efeitos foram anulados em animais alimentados com ARTIGOS / ARTICLES CIÊNCIAS BIOLÓGICAS E DA SAÚDEPrevious studies have demonstrated the immunological and hypercholesterolaemic effects of soluble dietary fibre and soy protein in rats. In this study, we evaluated the effects of oat bran and soy flour on humoral immune response in Wistar rats fed hypercholesterolaemic diets. Animals (6 groups) fed with different diets for 6 wks were inoculated twice with antigen (IgY). Plasma samples were collected after each inoculation and anti-IgY antibody (IgM, IgG1 and IgG2a) levels were evaluated by ELISA. Animals receiving 1% cholesterol presented an increase in anti-IgY IgG1 and a reduction in anti-IgY IgM and IgG2a relative to control animals. These effects were abrogated in animals fed 1% cholesterol and oat bran or oat bran+soy protein, but not in animals fed 1% cholesterol and soy protein. Diets containing 1% cholesterol resulted in hepatic lesions and higher liver and spleen relative weights, but did not affect lipid profile, weight gain, food intake, or food conversion efficiency. In conclusion, a high-cholesterol diet influences classes of antibodies produced in response to an antigen in a way that can be reversed by oat bran. Resumo