The effect of Sunphenon 30S-O on methane emission, nutrient intake, digestibility and rumen fermentation

• Sunphenon 30S-O reduced methane emission and dietary energy loss.
• Total-tract digestibility was not influenced by addition of Sunphenon 30S-O.
• Intake was affected relatively at higher concentration of Sunphenon 30S-O.
• The presence of catechin is the key factor influencing methane emission.
• Sunphenon 30S-O did not affect protein and energy balance

Sunphenon 30S-O is obtained from the leaves of traceable green tea (Camellia sinensis) and standardized for its catechin content (205 g/kg DM). This experiment was conducted to evaluate the effect of supplementation with different concentrations of Sunphenon 30S-O on methane emissions, nutrient intake, digestibility, protozoa abundance and the concentrations of volatile fatty acids (VFA) and ammonia-N (NH3-N) in sheep. Four Corriedale wethers with an average body weight of 64.25 ± 3.86 kg were arranged in a 4 × 4 Latin square and fed a basal diet of Guinea grass (Panicum maximum) hay at the maintenance level with four different concentrations of Sunphenon 30S-O (0, 10, 25 and 40 g/Kg DM intake). The experiment was conducted over 84 days in four 21-day periods that consisted of 14 days of acclimatization, five days of measurement and two 24-h runs in open-circuit respiration chambers to measure gas exchange. A second study was also conducted using an in vitro continuous gas quantification system and in vitro digestion techniques. All of the data were subjected to polynomial regression analysis. Dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fibre (ADF) and gross energy (GE) intake all declined linearly (P < 0.01) and quadratically (P < 0.05) with increasing concentrations of Sunphenon 30S-O. Conversely, the apparent nutrient digestibility remained similar among treatments regardless of the concentration of Sunphenon 30S-O in the ration. In vivo methane emission (l/kg digestible OM intake) declined linearly (P < 0.05) by 7.4–13.5% with increasing concentrations of Sunphenon 30S-O, and a similar trend was observed in in vitro methane emissions. Urinary and methane energy decreased linearly (P < 0.01) from 17.4% to 11.2% and from 7.3% to 6.2% of the gross energy intake, respectively, with increasing supplement concentrations, and the in vitro VFA (mmol/L) and NH3-N concentrations (mg/ml) were also reduced (linear P < 0.01; quadratic P < 0.01). The total abundance of the protozoa population also declined linearly and quadratically (P < 0.01), and the in vitro DM degradability (IVDMD) was reduced (linear P < 0.01; quadratic P < 0.01) with increasing concentrations of Sunphenon 30S-O. The findings of this study indicated that the addition of Sunphenon 30S-O reduced in vivo methane emissions without affecting total tract nutrient digestibility, and energy and protein retention were not affected despite the reduction in total nutrient intake. Thus, to achieve optimum reduction of methane emissions and the concomitant saving of dietary energy without any negative impacts on total-tract digestibility and nutrient balance, Sunphenon 30S-O supplementation up to 40 g/kg DM could be an option.