Two consecutive rumen batch cultures were used to study the effect of nanoemulsified oils as a new type of supplement, on the in vitro fatty acid proportion and vaccenic acid formation. Three levels (3, 5, and 7%) of 2 different oil blends [soybean:fish oil (SF) or rapeseed-fish oil (RF)] were used. Both oil blends were used either in the raw form (SF or RF, respectively) or in the nanoemulsified form (NSF or NRF, respectively). The diets were the control (0%), which consisted of a dry total mixed ration without any supplements, the control plus 3, 5, or 7% of the SF or RF oil blend in appropriate form (raw or nanoemulsified). For each treatment, 6 incubation vessels were used. Each batch culture was incubated for 24h and conducted twice in 2 consecutive days. All supplements were calculated as a percentage of the substrate dry matter (400mg). Nanoemulsified supplements were recalculated to make sure the oil amount was equal to the raw oil supplementation levels. The results from both experiments indicated that the proportions of vaccenic acid and cis-9,trans-11 C18:2 increased when a raw oil blend was supplemented; on the other hand, no influence of nanoemulsified form of oil blend was observed on the proportion cis-9,trans-11 C18:2. Generally, supplementation with the nanoemulsified oil blends had less effect on biohydrogenation intermediates than the raw form of oil blends. However, the nanoemulsified form had a greater effect on the increase of n-3 and n-6 fatty acids. Nanoemulsified oil blends had a positive effect on decreasing the transformation rate of polyunsaturated fatty acids to saturated fatty acids in the biohydrogenation environment. Supplements of nanoemulsified oil blends tended to be more effective than supplements of raw oils in preserving a greater proportion of polyunsaturated fatty acids in the fermentation culture.
Keywords: batch culture; nanoemulsion; oil blend; rumen; unsaturated fatty acid.
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