PSXII-27 Effect of Feed Additives in the Production of Greenhouse Gases

Abstract

Abstract The mitigation of greenhouse gases is a strong trend in promoting the intensification of ruminant production through greater efficiency in the use of dietary energy. The objective of this study was to evaluate the effects of the inclusion of the NC Conf Engorda Greentech mineral mixture containing feed additives to replace the regular mineral mixture in corn-based substrates on the production of gases and methane. The experiment was carried out under anaerobic conditions using ANKOM Gas Pressure Monitor bottles at 39 ºC containing artificial saliva, ruminal fluid, and two grams of substrates from each treatment: (MI) Control, 1.62 g of corn and 0.38 g of mixture mineral; and (MM) 1.28 g of corn and 0.72 g of NC Conf Engorda Greentech (Suplemento Nutrição Animal) containing 0.326% of glucomannans, 0.253% of mannans, 0.200% monensin and 1x106· kg-1 UFC of Saccharomyces cerevisiae. Duplicate substrates and duplicate blanks were fermented for each treatment in two runs, with a total of four repetitions per treatment. The accumulated pressure resulting from the fermentation was measured automatically over 48 h using the Gas Monitor software connected to the ANKOM modules of each bottle. The conversion of pressure to gas volume was calculated as follows: Volume (mL) = 2.3932 + 3.4053 × pressure (R2 = 0.9146; n = 1.151). At the end of each run, a gas sample was collected from each bottle to measure methane concentration using gas chromatography. To obtain the methane production for every 100 mL of gas produced, the total volume of methane produced was multiplied by 100 and divided by the total gas production. Data were analyzed in a completely randomized design using analysis of variance (ANOVA) at α = 0.05. There was a 24.53% decrease in the total gas production in the MM treatment (64.79 mL) compared with the MI substrate (48.90 mL; P = 0.0084; Table 1). Methane production decreased from 46.5 to 14.91 mL in the presence of MM (P < 0.001). A reduction from 71.96 to 30.59 mL of methane was observed for every 100 mL of gas produced when feed additives were included (P < 0.001). The Saccharomyces cerevisiae strain is a precursor of mannans, which, like glucomannans, acts as a prebiotic, and together with monensin, influences the selection of the ruminal microbiota and modifies the volatile fatty acid profile, increasing the molar proportion of propionate, and consequently reducing methane production. The addition of the NC Conf Engorda Greentech mineral mixture with glucomannans, mannans, monensin, and Saccharomyces cerevisiae decreased the production of gases and methane in a corn-based substrate.