Effect of nanoemulsified oils addition on rumen fermentation and fatty acid proportion in a rumen simulation technique

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 I 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 (P < 0.002) the relative proportions of both Butyrivibrio fibrisolvens and Ruminococcus albus. A significant decrease (P = 0.035) in Butyrivibrio proteoclasticus was only noticed after the nanoemulsified soyabean-fish oil blend addition. Regarding the fatty acids in the fermentation fluid, the nanoemulsified oils increased significantly (P < 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 ru men fermentation parameters.