Liver and muscle proteolytic activity in field bean (Vicia faba L.) fed birds. Effect of vitamin E

Liver and muscle proteolytic activities (cathepsin A and D) were measured in growing male chickens fed ad libitum over periods of 30 and 60 days on 20% protein diets containing either heated soybean (HSB, control) or raw field bean (RFB, Vicia faba L.) as the main sources of protein. Vitamin E (250 mg/100 g diet) was added or not to the RFB diet. It has been found that in comparison to control HSB-fed animals, RFB-fed birds showed a significant reduction in the rate of growth, together with a significant increase in the activities of both cathepsins A and D in liver and muscle. The addition of vitamin E to the RFB diet had no significant effect on either weight gain or liver and muscle proteolytic activities. The possible nature of these effects is discussed.