The Effect of a Purified Guar Degrading Enzyme on Chick Growth

Guar gum, a galactomannan, is growth depressing when fed to chicks. As part of the continuing studies on the mode of action of this and other gums in the intestine, a mannanase has been isolated which degrades guar gum. A commercial hemicellulase was separated into several protein fractions by chromatography on DEAE-cellulose. Only one of these proteins effectively reduced the viscosity of a guar gum solution. Activity towards pectin, rye water extract, and barley water extract was not present in the fraction which degraded guar gum but was found in other fractions at lower concentrations. Graded levels of this purified guar-degrading enzyme were incorporated into chick diets having 2% guar gum. This purified enzyme was effective at levels as low as .6 mg protein/kg diet in preventing growth depression caused by the guar gum and thus permitting growth equivalent to controls. Purity of this mannanase was confirmed by chromatography on QAE-Sephadex at pH 6.0 and by slab-gel electrophoresis at pH 8.4.