1. Experiments were conducted to study the effects of dietary vicine (2,6-diamino-4, 5 dihydroxy pyrimidine-5 (P-D-ghcopyranoside)) and supplemental vitamin E on the performance of laying hens and growing chicks.2. Chicks fed on diets that contained vicine had similar growth rates but slightly higher levels of spontaneous haemolysis of erythrocytes than birds fed on a control diet.3. Vicine when fed to laying hens had a very dramatic effect. It depressed food consumption, egg weight, fertility and hatchability of eggs, packed cell volume and erythrocyte haemoglobin levels and led to increased liver weights, liver glutathione levels, liver and plasma lipid levels, plasma lipid peroxide levels and erythrocyte haemolysis in vitro. Liver protein and plasma vitamin E:lipid levels were not altered. Vitamin E supplementation slightly increased egg weights, markedly improved fertility and hatchability of eggs and lowered liver weights and lipid levels but did not affect the other factors examined.4. It is concluded that vicine which was isolated from faba beans (Viciafaba L.) has a marked influence on the metabolism of the laying hen and only a slight effect on the growing chick. Vicine or its metabolites or both cause peroxidation of cellular components which result in abnormal lipid transport or synthesis or both, increased fragility of erythrocytes, and reduced fertility. These effects are overcome to varying extents by supplemental vitamin E.Faba beans contain thermolabile and thermostable antinutritional factors. The thermolabile factors consist of several types of tannins (exclusively located in the testa), trypsin, chymotrypsin or general protease or both, and amylase inhibitors (equally distributed between the hull and cotyledon), and the lectins which are only found in the cotyledon (Marquardt et al. 1975(Marquardt et al. , 1977 Dietary vicine and convicine have been shown to lower egg and yolk weights and, to a minor extent, the egg production rate (Olaboro, Campbell et af. 1981 ;Muduuli, 1980;Muduuli et al. 1981. In addition, laying birds fed vicine had fewer developing ova, an altered yolk shape and very fragile yolk membrane with increased incidence of blood spots (Muduuli et al. 1981). These birds had heavier livers and elevated levels of plasma lipid and lipid peroxides, liver lipid peroxides and glutathione (GSH), and erythrocyte haemolysis in vitro and depressed plasma vitamin E : lipid levels; however, liver and plasma protein levels were not affected by dietary vicine. Vicine and convicine are also suspected in the aetiology of favism (Mager et al. 1969).
