1722
Supplementation of lemongrass oil and a mixture of garlic and ginger oil improved in vitro feed digestion
Lemongrass has shown antibacterial, antioxidant, and antihyper-NH3-producing ruminal bacterial activities. However, the lemongrass, especially its essential oil (EO) has little been evaluated on its effect on ruminal fermentation. The objective of this study was to investigate the effect of lemongrass oil (LMO) and a mixture (1:1) of garlic and ginger oil (CEO) on gas production (GP) and feed digestion in batch culture. Four feeds: wheat distillers dried grains with solubles (DDGS), barley grain, grass hay, and a total mixed ration (TMR) were used as substrate with varying EO dosages from 0, 100, 200 to 300 mg/kg substrate DM. The TMR consisted of 35% grass hay, 15% alfalfa hay, 20% barley grain, 10% corn DDGS, 10% wheat DDGS, 5% canola meal, and 5% vitamin and mineral supplement. GP was measured at 3, 6, 12, 24, 36, and 48 h post incubation, and disappearance of DM (DMD) and neutral detergent fiber (NDFD) were determined at 24 and 48 h of incubation, respectively. There was no interaction on in vitro DMD and NDFD between the EO source and EO dose. DMD (% of input) were greater (P < 0.05) with CEO compared to LMO for wheat DDGS (48.6 vs. 47.9) and barley grain (61.5 vs. 60.3), but less (P < 0.03) for TMR (40.9 vs. 41.8) after 24 h of incubation. Increasing dosage of either CEO or LMO linearly (P < 0.01) increased DMD and NDFD of grass hay and TMR at 24 and 48 h of incubation, whereas increasing CEO or LMO dosages linearly (P < 0.01) increased only DMD of wheat DDGS and barley grain at 24 h of incubation. Cumulative GP was affected (P< 0.03) by both LMO and CEO in a quadratic manner after 24, 36 or 48 h of incubation with greatest GP at 200 mg/kg grass hay or TMR. These results suggested that the LMO and CEO appeared to be more effective to improve the DMD of fibrous feeds and modulated the digestive microorganisms in a dose-dependent manner. The EO used in the present study could be potentially developed as rumen modifier to improve feed digestion in ruminant.
Keywords:
dry matter disappearance, in vitro, lemongrass oil