Organic Acids as Rumen Modifiers

Organic acids have been used as rumen modifiers in ruminants for more than three decades to reduce bacterial and fungal growth in feedstuffs and maintain their storage life. Organic acids in the rumen help to prevent the fall in ruminal pH and reducing methanogenesis. Thus, in the rumen, these acids can stimulate ruminal growth of prominent bacteria and consequently change favorably ruminal fermentation, improving ruminant performance. Acids used as feed additives are predominantly compounds that naturally occur in cell metabolism, thus they are natural products with minimum level of toxicity. Performance and health promoting effects have been demonstrated for a number of organic acids, including citric, fumaric, formic, and lactic acid and their salts. The acids showed significant effects on feed digestion and absorption and on stabilization of rumen microflora which have been demonstrated in a number of studies. The object of this paper is to review the different studies with organic acids and discuss their impact on ruminants.