Biological properties of a lipid preparation based on the liver of a schoolmaster gonate squid Berryteuthis magister was studied on a group of Wistar male rats with experimental cardioangiopathy model. The preparation containing 10% polyunsaturated fatty acids and 50% alkyl-diacylglycerides ("Magister-Oil" nutritional additive) exhibits (i) a lipid-correction effect (manifested by a decrease in the levels of triglycerides and cholesterol of the atherogenic lipoprotein fraction and by an increase in the level of cholesterol of a high-density lipoprotein fraction); (ii) immunomodulant effect (manifested by activation of the phagocyte neutrophil link); and (iii) stimulation of the erythro- and lymphopoiesis. The obtained results allow the "Magister-Oil" nutritional additive to be recommended as a means of prophylaxis and treatment of disorders accompanied by disturbances in lipid metabolism, immunity system, and peripheral blood parameters.