Dietary linoleic acid divergently affects immune responsiveness of growinglayer hens

The effects of linoleic (LA)- and linolenic acid (LNA)-enriched diets on hu moral and in vivo cellular immune responses to keyhole limpet hemocyanin (K LH)-dinitrophenyl (DNP) and Mycobacterium butyricum were studied in growing layer hens. Pullets were fed one of three diets: a control, LA enriched, o r LNA enriched. Pullets were assigned to one of three immunization treatmen ts: KLH-DNP, M. butyricum, or PBS. The LA-enriched diet enhanced the antibo dy response to KLH in pullets immunized with KLH-DNP. On the other hand, th e antibody response to M. butyricum in M. butyricum-immunized birds was dec reased by feeding an LA-enriched diet. In vitro lymphocyte proliferation in the presence of Concanavalin A was affected by the interaction between die t and immunization. Neither cutaneous hypersensitivity to KLH nor to M. but yricum was affected by the diet. The BW gain before immunization was not af fected by the diet, but after immunization, the LA-enriched diet enhanced g rowth in birds immunized with M, butyricum. Diets had various effects on or gan weights. We concluded that dietary linoleic acid enrichment of the diet has an antigen-dependent divergent effect on the antibody response. The di etary LNA effect on the antibody response is less pronounced and is opposit e to that of the LA effect.