Supplementing farm animal feed, involves adding an enzymatic complex comprising a mixture of proteases obtained by culturing a Streptomyces fradiae strain to farm animal feed, where among this mixture of proteases one of them has an isoelectric point of 7 and another has an isoelectric point of 8. Independent claims are included for 1) feed composition for farm animals comprising: the enzymatic complex comprising a mixture of proteases obtained by culturing a Streptomyces fradiae strain, and optionally including excipients or vehicles for nutriments； and 2) manufacturing the enzymatic complex involving: culturing the Streptomyces fradiae strain, filtering the fermentation broth, then extracting the enzymatic complex by ultrafiltration and ion exchange chromatography followed by an isoelectric focusing, and finally, lyophilizing the complex thus obtained.
