SYSTEMIC AND LOCAL GUT-SPECIFIC ANTIBODY-RESPONSES IN PRERUMINANT CALVES SENSITIVE TO SOYA

The systemic and local (gut) patterns of antibodies against various pr oteins from soyabean were analysed in preruminant calves fed milk subs titutes based on skim milk powder (SMP) or heated soyabean flour (HSF) as the main protein sources. The titres of IgM, IgA, IgG(1) and IgG(2 ) antibodies were determined against feed extracts and purified soyabe an proteins by dot-blotting in plasma after three months and jejunal m ucous secretions after six months of feeding the experimental diets. T he calves fed HSF had higher levels of circulating IgA, IgG(1) and IgG (2) antibodies against raw or heated soya extracts and purified protei ns including alpha-conglycinin, beta-conglycinin, Bowman-Birk protease inhibitors and lectins than the calves fed SMP. In contrast, the diff erences between the IgM titres of the groups were most often not signi ficant. The patterns of specific antibodies present in the jejunum wer e broadly similar to those observed in the blood, although the differe nces between the groups of calves more often reached significance for IgG(2) and IgM than for IgA and IgG(1), when the purified soyabean pro teins were considered.