Deficiency of Methionine in Raw and Autoclaved Faba Beans in Chick Diets

Productive performance was determined for chicks fed diets (21% protein) containing 87% of either raw or autoclaved faba beans (Vicia faba L. var. minor) and varying levels of added methionine. Autoclaved, compared with raw, faba bean diets improved weight gains (10%, P < 0.01) and feed:gain ratios (10%, P < 0.01), and decreased pancreas size (17%, P < 0.01). Liver size was not affected (P > 0.05). Optimal productive performance was obtained for birds consuming diets containing 0.21% or more added methionine. The total dietary methionine and sulfur amino acid levels under these conditions were 0.43 and 0.68%, respectively. The addition of methionine (0.21%) to the basal diet improved growth rate 110% (P < 0.01), feed intake 33% (P < 0.01) and feed: gain ratio 38% (P < 0.01), and decreased relative pancreas and liver size 14 and 21%, respectively (P < 0.01). The methionine level of faba beans used in this study was 0.17% of the entire bean or 0.9 g/100 g of protein. Based on chemical analysis, the balance of the other amino acids in faba beans relative to those required by chicks appears to be good.