EFFECTS OF PLANT EXTRACTS RICH IN TANNINS, SAPONINS AND ESSENTIAL OILS ON RUMEN FERMENTATION AND CONJUGATED LINOLEIC ACID CONCENTRATIONS IN VITRO

摘要

The objective of this study was to investigate different plan extracts rich plant bioactives on rumen fermentation and concentrations of conjugated linoleic acid (CLA) and vaccenic acid (VA) in rumen fluid. Three tannin-rich leaves olArtocarpus heterophyllus, Ficus benghalensis, Ficus glomerata; three saponin-rich fruits of Spindus mukorossis, Acacia concinna, Acacia auriculiformis; and three essential oils-rich plant parts, i.e., buds of Syzygium aromaticum, bulbs of Allium sativum, seeds of Coriandum sativum extracted in two solvents (water and 75% ethanol) were tested at two dose levels (0.5 and 1.0 mL) for each category of plant extracts (tannins, saponins and essential oils (EO)) separately in a 4 (treatments) x 2 (dose levels) x 2 (solvents) factorial arrangement The in vitro fermentation was performed in 100-mL conical flasks containing 50 mL of culture media and 0.5 g of substrates containing 4% sunflower oil. Inclusion of all three tannin-rich plant extracts decreased in vitro dry matter degradability (IVDMD). Total volatile fatty acid (TVFA) concentration was significantly (P<0.05) decreased by the extract of A. heterophyllus at 1.0 mL. All the three tannin-rich plant extracts decreased (P<0.05) NH3-N concentration at 1.0 mL level. A. heterophyllus at 0.5 and 1.0 mL levels and F. benghalensis and F. glomerata at 1.0 mL level significantly (P<0.05) reduced protozoal count. The concentrations of VA in rumen fluid were increased (P<0.05) by the extracts of A. heterophyllus. None of the tannin-rich plant extracts changed the CLA concentration in culture media compared with control. Among the saponin rich extracts, inclusion of A. concinna at 1.0 mL level significantly (P^O.05) reduced IVDMD. TVFA concentrations were not affected by the saponin-rich plant extracts. A. concinna and S. mukorossis at 0.5 and 1.0 mL levels and A. auriculiformis at 1.0 mL level reduced (P<0.05) NH3-N concentration. The protozoal count was decreased by the extract of A. concinna and S. mukorossis at 1.0 mL level. Saponin extracts did not influence the VA concentration, but the CLA concentration significantly (P<0.05) increased owing to addition of water extract of A. concinna only. The EO extracts did not influence (P>0.05) rumen fermentation, VA and CLA concentration. Protozoa counts linearly decreased with increasing doses of ethanol extract of S. aromaticum. In conclusion, the tannin-rich water extract of A. heterophyllus and saponin-rich water extract of A. concinna have potential to increase CLA and VA concentrations in rumen fluid, which consequently may enrich the CLA content in milk and meat.