Disappearance of cis-18 : 1(n-9) from ruminal in vitro cultures supplemented with either oleic acid or oleamide was measured over 48 h to determine if the amide resisted biohydrogenation. Oleamide added to the substrate maintained higher concentrations of cis-18 : 1(n-9) in the microbial cultures at 24 and 48 h of incubation compared to substrates with added oleic acid. Disappearance rates of cis-18 : 1(n-9) from the cultures, which were calculated as a measure of biohydrogenation, were 0Γ064 and 0Γ025 h~1 for the oleic acid and oleamide supplements, respectively. Four sheep were fed four diets (control, 42 g kg~1 oleic acid, 23 g kg~1 oleamide, and 45 g kg~1 oleamide) in a 4 ] 4 Latin square to determine how the amide a β ected fatty acid digestibility. Total tract digestibilities of protein and Γbre were not a β ected (P [ 0Γ05) by either oleic acid or oleamide compared to the control diet. Fatty acid and energy digestibilities were not changed (P [ 0Γ05) by oleic acid, but were increased (P \ 0Γ05) when oleamide was added to the sheep diets at 45 g kg~1. These results show that oleamide resists ruminal biohydrogenation without impairing fatty acid digestibility.
1998 SCI.