1. A feed additive containing: a homotrimer, heterotrimer, homotetramer and / or heterotetramer of a carbohydrate component, its derivative or extract, or mixtures thereof, wherein said carbohydrate component is selected from the group consisting of pentose saccharide and hexose saccharide, glucuronic and galacturonic acids and where the carbohydrate components are linked by α- or β-bonds, and-medium chain fatty acid (MCFA), or a salt thereof, or a derivative and / or a mixture thereof, wherein said MCFA is selected from the group consisting of caproic acid (C6), caprylic acid s (C8), capric acid (C10) and lauric acid (C12) .2. The feed additive according to claim 1, wherein the pentose saccharides are selected from the group consisting of ribose, arabinose, xylose and lyxose. The feed additive according to claim 1 or 2, wherein the hexose saccharides are selected from the group consisting of allose, altrose, gulose, idose, talose and mannose. A feed additive according to claim 1 with an MCFA provided as free MCFA, as a mono-, di- and / or triglyceride of said MCFA and / or NH4-, Na-, K- and / or Ca-salt of said MCFA. The feed additive according to claim 1, additionally containing raw materials and / or growth-promoting substances. The feed additive according to claim 5, wherein the raw materials are selected from the group consisting of aromas and plant extracts, and where the growth promoting ingredients are selected from the group consisting of antibiotics, probiotics, prebiotics, essential oils, enzymes, fatty acids and organic acids. . The feed additive according to claim 1, wherein said homotrimer, heterotrimer, homotetramer and / or heterotetramer of said carbohydrate components is in a liquid or solid phase, wherein said MCFAs are in a liquid or solid phase, and where1. Кормовая добавка, содержащая:- гомотример, гетеротример, гомотетрамер и/или гетеротетрамер углеводного компонента, его производную или экстракт, или их смеси, при этом указанный углеводный ко
