Tannins are phenolic compounds able to interfere with the biohydrogenation of polyunsaturated fatty acids. The aim of this trial was to study in vitro the effects of quebracho tannin extract (QT) on the rumen biohydrogenation (BH) of polyunsaturated fatty acids (PUFA) contained in soybean and linseed oils. Two control diets were prepared using grass hay (770 g/kg on dry matter, DM), soybean meal (55 g/kg DM), barley meal (135 g/kg DM), supplemented with 35 g/kg DM of soybean (SOC diet) or linseed oil (LOC diet). Other two diets (SOCT and LOCT) were obtained by the integration of SOC and LOC with QT (49 g/ kg DM). Feeds (2 g DM) were incubated in triplicate with 200 ml of rumen liquor in a thermostatic chamber (39 °C) equipped with thirty-six 300 ml glass fermentation vessels. Incubation times were 6, 12 and 18 h. At each fermentation time, rumen liquor was fractionated in order to obtain liquid and solid associated bacteria (SAB). Only SAB were considered for the fatty acid analysis. QT induced a decrease of the BH of PUFA, favouring the accumulation of linoleic and alpha-linolenic acid. After 18 h of fermentation the content of linoleic acid was reduced by 76% and 42% in SOC and SOCT feed, respectively, whereas the content of linolenic acid was reduced by 85% and 73% in LOC and LOCT feed, respectively. Conversely, the accumulation in rumen liquor of vaccenic acid, total CLA and the other intermediates of BH process was lower when QT was added to both SOC and LOC feeds. The content of 18:0 was significantly lower in both SOCT (-33%) and LOCT (-17%) feeds, if compared with the same feeds without QT. In conclusion, QT was effective in the reduction of the BH of PUFA in rumen liquor, especially in the case of linoleic acid.
|Titolo:||Effect of quebracho tannins on the biohydrogenation of linoleic and linolenic acid: in vitro study|
|Anno del prodotto:||2013|
|Appare nelle tipologie:||4.3 Poster|