LAUSR

The profile of trans-fatty acids and the protozoan population were evaluated in four ruminally fistu - lated sheep fed a diet with meadow hay: barley grain ratio (80:20%) plus sunflower oil (SO), rapeseed oil (RO) or linseed oil (LO) (5% wt/wt). The concentrate was daily mixed with individual oils and offered at 07.00 h. A 4 × 4 Latin square with 4-week periods was used. The concentration of trans-vaccenic acid (TVA) was the highest 4 h after feeding (36.1 g/100 g FA with SO; 34.5 g/100 g FA with RO) and then decreased with the time after feeding (P < 0.05). The concentration of cis9, trans11 conjugated linoleic acid (c9,t11-CLA) with RO increased from 3.23 g/100 g FA (2 h after feeding) to 4.67 g/100 g FA (4 h after feeding). The concentration of c9,t11-CLA with SO increased from 2.09 g/100 g FA (2 h after feeding) to 2.31 g/100 g FA (4 h after feeding). The concentration of c9,t11-CLA with LO was the highest 4 h after feeding (2.07 g/100 g FA). Overall effects of the oil supplements and time after feeding on short-chain fatty acids (SCFA), medium-chain fatty acids (MCFA) and long-chain fatty acids (LCFA) in the rumen fluid were evident. A strong interaction of oil supplements and time after feeding was detected in the concentration of UFA and SFA ( P < 0.001). A significant effect of LO on the rumen ciliate population was observed; the total protozoan concentration and the number of Entodinium spp. were decreased as well as Dasytricha ruminantium, Isotricha spp., Polyplastron multivesiculatum, Ophryoscolex c. tricoronatus and Eremoplastron dilobum.