Studies with Chicks on the Growth Depressing Factor(s) in Faba Beans (Vicia faba L. var. minor)

Abstract

The growth response of broiler chicks was improved when they were fed diets containing high levels (>85%) of heat treated as compared to raw faba beans. Pelleting and microwave treatment of faba beans containing 10% moisture resulted in maximal improvements in chick growth rates and feed efficiency of only 6% and 8%, respectively. Steam autoclaving (121° for 20 minutes), extrusion (130° or 152°), or microwave treatment of faba beans containing 18% added water resulted in maximal improvements of 16% in growth rates and 19% in feed:gain ratios. The above study, a time course study of the relationship between faba bean autoclaving time and chick growth response, and studies with individual faba bean fractions (starch isolate and protein isolate) suggests that processing improves the utilization of faba bean mainly through its effect on components associated with the protein and possibly the hull portions of faba beans. The utilization of faba bean starch is not improved with processing. Although the nature of the growth depressing factor(s) has not been established, the results from this study indicated that the major component does not appear to be a trypsin inhibitor, hemagglutinin, some other heat labile protein, or vicine.