The effect of organic or conventional feeding on the immune response of pigs was determined using organic or conventional
housing in a pig fattening unit. The experimental design involved four pens of four animals per housing and diet combination
(organic housing and organic nutrition; organic housing and conventional nutrition; conventional housing and organic nutrition
and conventional housing and conventional nutrition). The IgM, IgA and IgG responses against intramuscularly injected bovine
thyroglobulin were determined as indicators of the antigen-specific immune responsiveness. Some general health and welfare related
parameters were evaluated by measuring haptoglobin concentrations at selected times; blood lactate concentration was measured at
slaughter.
Conventional housing led to a higher IgG response three weeks after the first immunisation. Organic housing led to lower
haptoglobin and lactate concentrations at slaughter, indicating a higher stress resistance in these pigs. No major differences between
the two feeding types were found. We conclude that the immune responses following either a conventional or an organic diet are
comparable, whereas organic housing can increase stress resistance at slaughter compared to conventional housing.
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