Effect of replacement of ordinary ruminant feed with Hedychium gardnerianum or Pittosporum undulatum on in vitro rumen fermentation characteristics

The present study was undertaken to assess the effect of replacement of ruminant feed with stepwise levels (0, 25, 50, 75 and 100%) of Hedychium gardnerianum (HG) or Pittosporum undulatum (PU) on in vitro gas production characteristics, CH4 production, microbial activities and energy parameters. The assessment was carried out using in vitro gas production technique. Cumulative gas production was recorded at 3, 6, 9, 12, 24, 48, 72 and 96 h of incubation. Bacterial and protozoal counts were microscopically estimated. In vitro true dry matter digestibility and CH4 production were also determined by the end of fermentation course. The results showed that the treatment HG25% significantly surpassed (P<0.05) all other treatments in most of investigated parameters, followed by the treatment PU25%. While, treatment HG100% was the least significant one (P<0.05). Cumulative gas production was in a range 24.09 - 49.91 ml 200 mg?1DM whereas, CH4 production laid in a range 4.48 - 18.71 ml 200 mg?1 DM. Total bacterial and total protozoal counts were in ranges 1.92 - 6.23 x 108 and 2.0 - 5.17 x 105 cell ml?1, respectively. Furthermore, the recorded ranges for short chain fatty acids and metabolizable energy were 0.273 - 0.567 mmol 200 mg?1 DM and 4.36 - 6.32 MJ kg?1 DM, respectively. The current study suggested that the partial inclusion of the tested plants to the ruminant diet can be a promising strategy for improving ruminant feed efficiency and reducing ruminant feed cost as well.