Immunoglobulin concentrations in serum and tissues of vitamin A-deficient broiler chicks after Newcastle disease virus vaccination.

The effect of all-trans retinol and retinoic acid (RA) on the local and systemic immune system of broiler chicks was examined. Chicks fed diets supplemented with .2 micrograms retinol/g of diet had significantly greater serum immunoglobulin IgG, IgM, and IgA concentrations 5 wk after primary vaccination with live B1 strain of Newcastle disease virus (NDV) than did chicks fed 2 micrograms retinol/g of diet. Eight days after a second vaccination with an inactivated La Sota strain of NDV, serum, intestinal, and tracheal IgG and IgM concentrations were higher in chicks fed a diet without retinol or retinoic acid (RA) than in chicks fed either 2 micrograms of retinol or RA/g of diet, respectively. Despite an increase in serum immunoglobulin concentration, serum antibody titer in response to the second NDV vaccination was significantly lower in chicks fed a vitamin A-deficient diet than in chicks fed adequate retinol and RA-supplemented diets. Eight days after revaccination, IgA concentrations in bile were also significantly lower in vitamin A-deficient chicks than in controls. Serum IgG, IgM, IgA, biliary IgA, and antibody responses were greater in chicks fed diets supplemented with 2 micrograms of RA/g of diet than in chicks fed an equivalent amount of vitamin A in the form of retinol.