Immune enhancer and crustacean, fish and livestock feed containing the same

摘要

PURPOSE: To inexpensively obtain an immunopotentiator having high macrophage activating action and bacterial infection defensive action, thus useful in feed for livestock, fish, etc., containing, as active ingredient, a protein component obtained by heating and deactivating yeast cells followed by enzymatic treatment of the deactivated cells. CONSTITUTION: This immunopotentiator contains, as active ingredient, a protein component which is obtained by heating and deactivating yeast cells (pref. Torulaspora or Saccharomyces) followed by making a cell wall digesting enzyme and a protease act on the deactivated cells. The yeast is pref. obtained by culturing the original cells in a sulfite pulp waste liquor medium because of saving cost and high activity. It is preferable that the heating and deactivating operation be made at 90-100 deg.C for 10min. The enzymatic treatment is preferably performed by the addition of both the above enzymes at 0.2-3wt.%, respectively, for 1-30h. It is preferable thgat =15wt.% of the whole protein in the yeast cells be extracted.