The article presents the results of the development of technology for obtaining and evaluating the biological activity of a feed additive containing humic acids. The technology of obtaining humic derivatives of high quality and with high stability of components from organic livestock wastes has been optimized. A humic feed additive has been developed and an estimation of its biological activity in vitro using a cell level test system (Paramecium caudatum) has been made. The presence of membrane-protective properties in humic derivatives has been revealed, which discovers the prospects of their use in animal husbandry and veterinary medicine as the means, possessing a hepatoprotective orientation and increasing the resistance of the organism to various unfavorable factors.