Effects of supplementation levels of L. extract on in vitro ruminal fermentation characteristics and methane emission.

BACKGROUND

Ruminants release the majority of agricultural methane, an important greenhouse gas. Different feeds and additives are used to reduce emissions, but each has its drawbacks. This experiment was conducted to determine the effects of L. () extract on in vitro ruminal fermentation characteristics, and on methane emission.

METHODS

Rumen fluid was taken from two cannulated rumen Hanwoo cow (with mean initial body weight 450 ± 30 kg, standard deviation = 30). Rumen fluid and McDougall's buffer (1:2; 15 mL) were dispensed anaerobically into 50 mL serum bottles containing 300 mg (DM basis) of timothy substrate and extracts (based on timothy substrate; 0%, 1%, 3%, 5%, 7%, or 9%). This experiment followed a completely randomized design performed in triplicate, using 126 individual serum bottles (six treatments × seven incubation times × three replicates).

RESULTS

Dry matter degradability was not significantly affected (-value > 0.05) by any treatment other than 1% extract at 24 h incubation. Methane emission linearly decreased extract concentration increased at 12 and 24 h incubation (value < 0.0001; -value = 0.0003, respectively). Acetate concentration linearly decreased (-value = 0.003) as extract concentration increased at 12 h incubation. Methanogenic archaea abundance tendency decreased (value = 0.055) in the 1%, 7%, and 9% extract groups compared to that in the 0% group, and quadratically decreased (value < 0.0001) as extract concentration increased at 24 h incubation.

CONCLUSION

extract had no apparent effect on ruminal fermentation characteristics or dry matter degradability. However, it reduced methane emission and methanogenic archaea abundance.