Theoretical Methane Emission Estimation from Volatile Fatty Acids in Bovine Rumen Fluid

Sang-Ryong Lee,Yunseo Cho,Eunjeong Kim,Hyuck K Ju

doi:10.3390/app11167730

Abstract

Methane production from livestock farming is recognized as an important contributor to global GHGs. Volatile fatty acids (VFAs) found in bovine rumen may be utilized as a substrate for methanogens to form CH4, and thus improvement of quantitative VFA measurements can help facilitate greater understanding and mitigation of CH4 production. This study aims to contribute to the development of more accurate methods for the quantification and specification of VFAs in bovine rumen. The VFAs were analyzed using the conventional method and an alternative catalytic esterification reaction (CER) method. Substantial differences in the detected concentrations of the C3+ VFAs (chain length ≥ 3) were observed between both methods, especially for butyric acid. Evaluation of the sensitivity of both methods to detecting the VFA concentrations in standard solutions confirmed that the values resulting from the CER method were closer to the known concentrations of the standard solution than those from the conventional method. The results of this study provide the first quantitative proof to show the improved accuracy of the measurements of C3+ VFAs when using the CER method compared with the conventional method. Therefore, the CER method can be recommended to analyze the VFAs found in rumen, especially butyric acid and other C3+ VFAs.

Highlights

Food and Agriculture Organization (FAO) statistics show that the worldwide supply of animal protein has risen from 34 to 43 kg per capita per year between 1993 and2013 [1]
Rumen fluids were obtained from the National Institute of Animal Science (NIAS) in
The determination of acetic acid, propionic acid, and butyric acid is important because they account for about 95% of the total Volatile fatty acids (VFAs) in rumen fluid [24]

Summary

Introduction

Food and Agriculture Organization (FAO) statistics show that the worldwide supply of animal protein has risen from 34 to 43 kg per capita per year between 1993 and2013 [1]. To sate our massive demand for meat and dairy products, concentrated animal feeding operations (CAFOs) have inevitably served the long-term viability of the livestock industry over the last three decades [2,3,4]. Despite their economic benefits and production efficiencies, CAFOs have triggered unwanted environmental problems due to the large production of manure waste, far exceeding the capacity of land to assimilate the loadings of organic carbon and nutrients [5,6]. Animal agriculture contributes 9% of anthropogenic CO2 emissions, 37% of CH4 emissions, and 65% of N2 O emissions, and the combined emissions expressed as a CO2 equivalent amounts to about 18% of anthropogenic greenhouse gas (GHG) emissions [7]

Objectives

Methods

Results

Conclusion