PSXI-26 Effects of condensed tannins in purple prairie and white prairie clover on ruminal fermentation and methane production in vitro.

Q Huang,T Mcallister,Y Wang,M Schellenberg,A Iwaasa,K Peng

doi:10.1093/jas/sky404.924

Abstract

It has been reported that condensed tannins (CT) from some forages decreases methane production. Purple prairie clover (PPC; Dalea purpurea Vent.) and white prairie clove (WPC; D. candida Michx. ex Willd) are native legumes adapted to the North American prairie and contain high concentration of CT. The objective of this study was to assess the effects of CT in PPC and WPC on ruminal fermentation and methane production. Whole-crop PPC and WPC were harvested at full flower stage and divided into two equal portions. One portion was freeze-dried and the other was sun-cured. Batch culture incubations were conducted using conserved forages as a substrate with and without inclusion of polyethylene glycol (PEG), which inactivates CT. Each incubation was repeated twice with two fermentation vials for each treatment in each run of the incubation. Concentration of CT (g/kg DM) in freeze-dried and sun-cured PPC and WPC were 90.5 ± 16.91, 88.1 ± 2.53, 62.8 ± 2.41 and 58.1 ± 2.82 respectively. Inclusion of PEG increased (Pin vitro DM disappearance (IVDMD), total gas production (GP) and ammonia concentration with PPC, regardless of conservation method. Freeze-dried PPC had greater (P<0.01) IVDMD and GP, but lower (P<0.01) ammonia concentration than sun-cured PPC. However, with WPC, no difference was observed in IVDMD or GP between the freeze-dried and sun-cured samples with or without PEG. Similar to PPC, addition of PEG also increased (P<0.05) ammonia concentration when WPC was incubated. Methane production was similar between the two forages and addition of PEG did not affect methane production from either forage. The greater effects of PEG on IVDMD, GP and ammonia production for PPC than for WPC is likely due to the higher concentration of CT in PPC than WPC. The results indicated that CT in PPC and WPC had no effect on ruminal methane production despite their high concentrations in these forages. Key Words:

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