Effects of hydroalcoholic α-galactoside extraction and phytase supplementation on the nutritive utilization of manganese, iron, zinc and potassium from lupin (Lupinus albus var. multolupa)-based diets in growing rats

The effects of α-galactoside removal, using a hydroalcoholic extraction process and phytase supplementation, on the digestive and metabolic utilization of total ash, Mn, Fe, Zn and K from Lupinus albus var. multolupa-based diets by growing rats were evaluated, using a balance technique, and compared to the results obtained using a casein–cystine control diet. The specific amount of minerals needed to complement those provided by the lupin flours and casein in order to reach the target requirements of the growing rat were supplemented as heme or non-heme iron sources or in the form of inorganic salts in the case of Zn or K. The nutritive utilization of total ash, Mn, Fe and Zn was higher from raw and α-galactoside-free lupin flour diets than from the casein–cystine control or the phytase-supplemented diets, whereas smaller differences were found regarding the nutritive utilization of K. Differences in mineral retention were reflected in changes of the mineral contents of some tissues, which varied among the different cations studied.