PSXIII-23 Effect of Methionine Inclusion in Mineral Mixture on Greenhouse Gas Production

Abstract

Abstract The reduction in enteric methane production in cattle can have a rapid impact on global warming. Therefore, changes in the population of microorganisms in the rumen can significantly reduce the production of this greenhouse gas. This in vitro study aimed to evaluate the production of gases and methane with the inclusion of Suplemax mineral mixture containing methionine. The experiment was carried out under anaerobic conditions using ANKOM Gas Pressure Monitor bottles kept at 39 ºC containing artificial saliva, ruminal fluid, and two grams of a substrate from each treatment: (FE) Control, 1.75 g of Tifton hay 85 and 0.25 g of a mineral mix; and (FM) 1.75 g of hay and 0.25 g of Suplemax mineral mixture (Suplemento Nutrição Animal) containing 0.3% of methionine. 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 no significant effect on gas production with the inclusion of 0,3% of methionine (FE 37.77 mL vs FM 42.54 mL, P = 0.3175; Table 1). Methane production decreased from 22.74 to 18.15 mL (P = 0.0121) in the FM treatment compared with the FE treatment, representing a 20.18% decrease. Methane production for every 100 mL of gas decreased by 31.08% with the inclusion of methionine (FE 61.62 vs FM 42.47 mL, P = 0.0248). The inclusion of methionine in the mineral supplement contributes to a change in the molar proportion of short-chain fatty acids, increasing propiogenesis, that is considered a sink of hydrogen ions in the ruminal environment, which in turn inhibits methane production. Thus, the inclusion of Suplemax with hay reduced gas and methane production in vitro.