The present invention relates to the production of feed additives for productive animals. More specifically, the present invention relates to the production of concentrated feed additives with high contents of glucose and other easily digestible carbohydrates, namely, feed starch syrup, from the starch-containing grain and grain legumes by the enzymatic method. The invention makes it possible to increase the environmental safety and stability of the process, ensures complete starch processing, and affords a product with a high content of simple carbohydrates suitable for long-term storage without additional treatment. The method for the production of feed starch syrup from starch-containing plant raw materials comprises the cavitation treatment of water in a disperser, introduction of ground starch-containing plant raw material at a weight ratio of water to starch-containing raw material of 1 : 0.4-0.6 and liquefying amylolytic enzymes, gelation and liquefaction of plant starch； introduction of the second part of the starch-containing raw material pretreated with IR radiation in an amount sufficient for reaching the total weight ratio of water to starch-containing raw material of 1 : 0.9-1.1 and liquefying amylolytic enzymes, gelation and liquefaction of plant starch, introduction of saccharifying amylolytic enzymes, and saccharification of starch.
