Condensed tannins in horse bean seeds: Chemical structure and apparent effects on poultry

Abstract

The seed-coats of numerous varieties of horse beans contain condensed tannins of the proanthocyanidin type. These polymers consist of molecules of flavan-3-ols (catechin, gallocatechin) and flavan-3,4-diols (leucocyanidin, leucodelphinidin). Condensed tannins of horse bean seeds appear to depress the growth of muscovy ducklings, to cause a reduction in the weight of eggs produced by laying hens and to decrease the digestibility of nitrogen compounds in growing chicks.