Effect of dietary supplementation of Emblica officinalis fruit pomace on methane emission, ruminal fermentation, nutrient utilization, and milk production performance in buffaloes

Effects of dietary supplementation of Emblica officinalis fruit (Indian gooseberry) pomace (EFP), a waste from fruit processing plants and rich in polyphenolic compounds, were investigated for ruminal fermentation, nutrient utilization, methane production, and milk production performance in buffaloes. An in vitro experiment was conducted using 0 to 50 g/kg of EFP (six treatments) to select an optimum dose for feeding of buffaloes. Organic matter (OM) degradability, total volatile fatty acid concentration, and acetate proportion decreased, but propionate proportion increased at the higher doses (> 30 g/kg). Methane production also decreased at the higher doses (≥ 20 g/kg). In the in vivo study, ten lactating buffaloes were randomly allotted into control and EFP groups (n = 5/group). The control group was fed a total mixed ration, whereas the EFP group was fed the control ration along with EFP at 20 g/kg of dry matter (DM) intake for 120 days. Feeding of EFP to buffaloes improved milk yield (P < 0.01) and milk production efficiency (P < 0.01). Concentration of milk protein tended (P = 0.071) to increase and that of solid not fat increased (P = 0.032) due to the EFP feeding. Yields (kg/day) of milk fat (P = 0.026), solid not fat (P = 0.011), and protein (P = 0.002) were greater in the EFP group than the control group. Somatic cell count in milk decreased (P = 0.032) due to EFP feeding. Digestibility of ether extract (P < 0.001) increased and OM (P = 0.051) tended to increase by EFP feeding. Methane production (g/d), yield (g/kg DM intake or g/kg digestible organic matter intake), and intensity (g/kg milk, g/kg milk fat, or g/kg milk protein), and methane conversion rate (percentage of gross energy intake) were lower (P < 0.01) in the EFP group than the control group. For milk fatty acid (FA) profiles, total saturated FA proportion tended to be greater (P = 0.057) in the EFP group than the control group, which was due to increased (P = 0.045) proportion of total short- and medium-chain FA (C4 to C14). Feed intake, digestibility of crude protein and fiber, and total n-6, n-3, mono-unsaturated FA, poly-unsaturated FA, and long-chain FA (C18 to C24) proportions were similar between the groups. This study suggests that feeding of EFP at 20 g/kg DM intake increases milk production and decreases methane production and intensity without impacting health of buffaloes and FA profiles of milk. This is a win–win situation for sustainable and cleaner buffalo production by improving milk production and decreasing environmental burdens of greenhouse gas emission and EFP residue disposal problems.