Herbal extracts and organic acids as natural feed additives in pig diets

This article summarizes experimental knowledge of the efficacy, modes of action and applications of herbal extracts and organic acids as feed additives for pigs. Herbal extracts comprise a wide variety of herbs, spices and, most importantly, essential oils. Organic acids, characterized as short-chain weak acids, are widely distributed in nature as normal constituents of herbal or animal tissues. Herbal extracts and organic acids can stimulate feed intake and the production of endogenous secretions and nutrient absorption, protect against the colonization of pathogenic microorganisms in the animal gut, reduce the fermentation process and production of toxic metabolites, and present a beneficial effect on the intestinal microbiota. Therefore, these compounds could replace antibiotics as growth promoters for pig production. However, a systematic approach to the efficacy and safety of herbal extracts and organic acids as feed additives for swine is still non-existent.