Effect of Protein Sources and Sodium Sulphate Supplementation on Methane Emission from Berseem Based Rations

Variation in methane production due to protein sources or levels of sodium sulphate (Na₂SO₄) supplementation in berseem based rations was determined in vitro using buffalo rumen fluid. Three rations based on berseem fodder differing in protein sources i.e. mustard cake (1), cotton seed cake (2) and mustard cake along with cotton seed cake (3) were evaluated for in vitro rumen fermentation parameters. IVDMD and IVOMD were lower in ration 2. CH₄ (g/kg digestible DM) decreased significantly (P<0.05) in ration 2 and 3. Similar trend was observed for TVFA production. Methane oxidation (% of CH₄) was significantly (P<0.05) higher in ration 2. TCA precipitable N was comparable in all the three rations. Reductive acetogenesis (% acetate) also increased in ration 2 and 3. Three levels of sodium sulphate (1, 2 and 3g/kg DM) were added to mustard cake containing ration in second experiment Methane production (g/kg digestible DM) decreased by 7.5 and 23% when Na₂SO₄ was added @ 1or 2 g/kg ration. Reductive acetogenesis was also higher in sodium sulphate supplemented diets at 1 and 2 g/kg of ration. The increased values of CH₄ oxidation and reductive acetogenesis could possibly be assigned to decreased CH₄ production due to supplementation of Na₂SO₄. It was concluded that ration 2 and 3 consisting of cotton seed cake and mustard in combination with cotton seed cake mixture can be preferably selected over ration 1 for CH₄ mitigation purpose. Also, supplementation of Na₂SO₄ @1 or 2g/kg ration DM increased reductive acetogenesis and decreased methane production under in vitro conditions.