Abstract
The effects of fatty acids, at low concentrations (0–005-O5 g/1), on the growth of seven species of rumen bacteria were examined. Anaerovibrio lipolytica(strain 5 S), Peptostreptococcus elsdenii(type 2), Bacteroides ruminicola46/52 and Selenomonas ruminantium(strain 17) were unaffected by addition of oleic acid to the medium. Growth of ButyrivibrioB 835 was stimulated by low concentrations of oleic (< 0–01 g/1), lauric (< 0–1 g/1) or capric (< 0–1 g/1) acids while higher concentrations of these acids were inhibitory. Myristic, palmitic and stearic acids were inhibitory at all concentrations tested. Ruminococcus4263/1 was inhibited at all concentrations of the six acids. Production of methane by pure cultures of Methanobacterium ruminantiumwas also inhibited by the additions of long-chain fatty acids. Oleic acid was the most inhibitory of the series of acids. These results are consistent with the reported effects of lipids on rumen function.
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