The invention discloses a method for preparing soy isoflavone aglycones and the application of the soy isoflavone aglycones to
livestock breeding. The preparation method comprises the following steps of extracting defatted soy raw materials for many times under the assistance of ultrasonic
waves by using an
aqueous solution of
ethanol and water, and mixing and centrifuging extract; adsorbing centrifugate by using a
macroporous resin, extracting centrifuging precipitates, eluting the
macroporous resin by using extract liquor, and collecting eluent; adding acids into the eluent, and performing refluxing extraction; concentrating the eluent, adding water, standing a
mixed solution, and centrifugally collecting precipitates; dissolving the centrifugally collected precipitates, and performing
crystallization and recrystallization;
drying crystals to obtain the soy isoflavone aglycones. According to the method,
soy isoflavones in two forms are separately extracted, pass through the
macroporous resin in a centralized way, and are treated by the acids, so that the interference of components such as phospholipids and proteins is avoided, and the obtained soy isoflavone aglycones are high in extraction rate and purity and easy to industrially produce; when the products are used for
livestock breeding, the growth of animals is promoted, the
immunity can be improved, the egg yield and the
milk yield can be improved, and the quality and the
flavor of meat can be improved.