The nutritional values of faba bean flours varying in their mean particle size in young chickens

Abstract

Seeds from a tannin-containing cultivar (Alfred) and a tannin-free cultivar (Blandinc) of faba beans were separated into their cotyledon and hull fractions, and then ground either to 0.5 or 0.16 mm mean particle size. Cotyledon fractions, with or without their corresponding hull fractions, formed 41% of diets given as mash to 3-week-old chickens for balance experiments. Grinding to a small particle size (0.16 mm) did not affect the apparent digestibility of faba bean proteins. In contrast, the digestibility of faba bean starch and the apparent metabolisable energy value (AMEn) of faba beans were markedly increased when the mean panicle size of faba bean flours was decreased from 0.5 to 0.16 mm. The addition of hulls did not affect the digestibility of starch. The negative effect of hulls from tannin-containing seeds on the apparent protein digestibility was confirmed. The lower starch digestibility of the tannin-free cultivar Blandine than the tannin-containing cultivar Alfred was also confirmed.