EN
The present study was carried out to investigate the potential of different oils nanoemulsions on the modulation of fatty acid proportions and their effect on selected ruminal bacteria using four-fermenter RUSITEC units of 1 l capacity each. Four treatments were investigated: 1. control group (11 g of dried total mixed ration), 2. the control plus soyabean oil (5% on dry matter basis), 3. the control plus fish oil (5% on dry matter basis), and 4. the control plus soyabean-fish oils blend (1:1 v/v; 5% on dry matter basis). All oils were in nanoemulsified form and were added directly to the RUSITEC fermenters during the 10-day-feeding process. The obtained results indicated that the use of the nanoemulsified oils didn’t affect total bacterial count; however, the nanoemulsified fish and soyabean-fish oil blend treatments decreased ( < 0.002) the relative proportions of both and . A significant decrease ( = 0.035) in was only noticed after the nanoemulsified soyabean-fish oil blend addition. Regarding the fatty acids in the fermentation fluid, the nanoemulsified oils increased significantly ( < 0.001) the proportions of oleic, linoleic and linolenic acids. In conclusion, nanoemulsified soyabean oil modulates the polyunsaturated fatty acids in ruminal cultures without the negative effect on rumen fermentation parameters.