This study evaluated effects of the addition of garlic powder allicin (GPA) mixture on rumen fermentation with methane in Hanwoo steer. On in vitro trial, two experimental groups were used: control (without GPA) and treatment group (addition of 0.1% GPA mixed with the basal concentrate). Similar to in vitro trial, two experimental groups were used in vivo trial. Five Hanwoo steers (3 steers in one group and 2 in another group; average body weight = 500 ± 43 kg) were assigned by crossover design for 20 d consists of 15 d diet adaptation and 5 d data collection in each experimental period. Daily feed intake and enteric methane production were recorded by an automated head chamber system. The results of in vitro study showed that the GPA treatment group had higher acetic acid (24.30 vs 23.45 mmol/L) and butyric acid (16.55 vs 15.47 mmol/L) concentrations, but lower CH4 production (1.40 vs 2.71 mmol/ml) after 24 h of incubation compared to the control (p<0.05). Total gas, propionic acid, total volatile fatty acid (VFA), and acetic acid: propionic acid ratio were not affected by treatment after 24 h incubation. In the in vivo experiment, rumen pH and VFA were not significantly different between treatments (p>0.05), except acetic acid, which was significantly higher in GPA mixture group (60.97 vs 53.94 mM) than in the control group (p<0.05). Furthermore, no significant differences were recorded in CH4 production (g/d) and CH4 yield (g/kg DMI) between the two groups (p>0.05). In conclusion, the addition of 0.1% GPA mixture reduced CH4 proudcition on in vitro trial, but no effect on in vivo trial.

Abstract
Introduction
Materials and Methods
    1. In vitro experiment
    2. In vitro sample analyses
    3. In vivo experiment
    4. In vivo data collection and sample analyses
    5. Statistical analysis
Results and Discussion
    1. In vitro experiment
    2. In vivo experiment
References

• Seon-Ho Kim(Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, Sunchon National University)
• Ashraf Ali Biswas(Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, Sunchon National University)
• Mahfuzul Islam(Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, Sunchon National University)
• Sang-Suk Lee(Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, Sunchon National University) Corresponding author