Lymphocyte depression induced in chickens on diets deficient in vitamin A and other components

Chickens maintained from time of hatching to age of 30 days on a diet lacking vitamin A, and on 2 diets lacking vitamin A and other nutritional components showed depletion of lymphocyte and plasma cell populations in nasal, paranasal and bursal lymphoepithelial tissues. Effects were significant with all diets but most severe with the most deprived diet. Infection of these birds with Newcastle disease virus showed further depletion of plasma cells, subnormal inflammatory response, keratinization of bursal epithelia and postsloughing metaplasia of nasal mucociliated epithelia. The bursae of infected chickens on the diet lacking only vitamin A were completely devoid of lymphocytes 6 days after Virus inoculation. Infected chickens on the most deprived diet showed atrophy of areas of intranasal epithelia which indicated failure of basal cells to synthesize replacement cells.