Effects of Cysteamine on Ruminal Fermentation Parameters and Methane Production of Water Buffalo by in vitro Gas Production Method

Abstract Text: In our previous studies, supplement Cysteamine (Cs) could increase the Conjugated Linoleic Acids content in water buffalo milk, but we do not know whether Cs could reduce the methane production. Thus, the aim of this present study was to evaluate the effect of Cs on ruminal fermentation parameters and methane production of water buffalo by in vitro gas production Method. In vitro fermentations were conducted in 180-mL serum bottles with a reading pressure in vitro gas production system. The oven-dried subtrate (187.50 mg maize grain, 56.25 mg soybean meal, 196.88 mg elephant grass, 140.63 mg brewer`s grains and 168.75 mg cassava pulps, DM basis) was weighted with three replicates into 90 ml buffer medium. The ratio of concentrate to forage of substrate was 32.5:67.5. Cs was supplemented in concentrate at levels of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0% (dry matter basis), respectively. The water buffalo rumen contents obtained were mixed and strained through four layers of cheesecloth into a flask under CO₂ in the water bath at 39 °C. The pressure and methane production were measured at 6 h, 12 h, 24 h. At the end of the incubation (24 h), the incubation fluids were sampled and samples were stored at – 20 °C for an analysis of NH₃-N concentration and VFA composition. There were no significant differences for NH₃-N concentration (6.40, 6.53, 6.43, 7.07, 7.24 and 6.30 mg/dL for the levels of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0% Cs supplement, P =0.652) and acetate (20.91, 20.95, 20.86, 20.44, 21.22 and 19.42 mmol/L, P =0.702), propionate (7.06, 7.08, 6.71, 6.44, 6.71, 6.20 mmol/L, P =0.436), total VFA (32.77, 32.81, 31.56, 30.98, 31.85 and 29.20 mmol/L, P =0.499) and acetate/propionate (2.97, 2.97, 3.11, 3.17, 3.16 and 3.13, P =0.086) among each treatments. Methane production at 6 h (0.14, 0.13, 0.10, 0.10, 0.08, 0.09 mmol/L, P =0.03), 12 h (0.37, 0.36, 0.25, 0.28, 0.26 and 0.28 mmol/L, P <0.0001), 24 h (0.61, 0.61, 0.49, 0.54, 0.51, 0.58 mmol/L, P =0.004) were decreased with an increasing level of Cs. Butyrate content (4.80, 4.79, 3.99, 4.09, 3.92 and 3.59 mmol/L, P =0.037) at 24 h were decreased with an increasing level of Cs. The results of in vitro gas production method indicate that Cs can promote rument microbe fermentation, but decrease methane production of water buffalo when supplemental level of Cs is 0.8%.

Key Words: cysteamine, methane emission, water buffalo