STEADY-STATE RATES OF LINOLEIC-ACID BIOHYDROGENATION BY RUMINAL BACTERIA IN CONTINUOUS-CULTURE

Ruminal biohydrogenation of linoleic acid was determined in fermenters with a continuous culture of microorganisms. Rates of biohydrogenatio n and changes of fatty acids in culture were measured during steady-st ate concentration of linoleic acid that was achieved by continuous inf usion of linoleic acid into the fermenters. A number of trans and cis isomers were identified using a GLC equipped with an infrared detector . The infusion of linoleic acid resulted in a substantial increase in the content of trans-C-18:1 and a lesser increase in cis-C-18:1 The ma jor trans peak consisted of a mixture of n-9 and n-7 isomers. Biohydro genation of infused linoleic acid averaged 77%. There was evidence of fatty acid loss, as determined by a decrease in the recovery of linole ic acid after 8 h of infusion. Addition of C-18:2n-6 had no major effe ct on the VFA production by ruminal microorganisms. The results were s imilar to those measured in vivo, indicating that artificial fermenter s were reliable predictors of fatty acid metabolism in vivo.