Abstract
Fowls maintained on a zinc‐deficient diet from hatching and immunised either by intraperitoneal injections of bovine serum albumin (BSA) or by a combination of ocular drops and intraperitoneal injections showed no antibody response as judged by immunoelectrophoresis and immuno‐fluorescence, whereas birds on a zinc‐sufficient diet had serum antibody and anti‐BSA cells in the Harderian gland, Peyer's patches, spleen and thymus. The localisation of immunoglobulins did npt differ between control and deficient birds except in the bursa of Fabricius where follicle‐associated epithelium of deficient fowls stained for immunoglobulins, especially IgA, whereas in sections from control birds these cells remained unstained.