Legume Proteins of the Vicilin Family are More Immunogenic Than Those of the Legumin Family in Weaned Piglets

Two experiments were conducted to study the systemic and local immune responses to legume proteins in piglets weaned at 28 d of age. The pigs were fed a control diet (C) based on casein or diets in which 50% of crude protein (CP) was supplied by soya bean meal (SBM), pea (P), faba bean (FB), or lupin (L) seeds in experiment 1, and white chickpea (WCP) or black chickpea (BCP) seeds in experiment 2. Blood samples and intestinal secretions were collected at slaughter four weeks later and analysed for specific antibodies using ELISA and western blotting. Piglets fed the legume-containing diets had higher (P < 0.10) plasma immunoglobulin (Ig) G ELISA titres to legume proteins than did piglets fed a casein-based diet. Many protein bands in the molecular weight range of 94.0-14.4 kDa were recognized by plasma IgG and IgA antibodies. The most immunogenic bands belonged to proteins of the vicilin family and to other unidentified minor proteins. No specific IgA antibodies were detected in intestinal secretions by ELISA and western blotting.