Role of Age-Related Shifts in Rumen Bacteria and Methanogens in Methane Production in Cattle.

Chong Liu,Rui Gao,Shangquan Gan,Yongxing Chen,Mengsi Xu,Min Shen,Qinghui Meng

doi:10.3389/fmicb.2017.01563

Abstract

Rumen microbiota are essential for maintaining digestive and metabolic functions, producing methane as a byproduct. Dairy heifers produce large amounts of methane based on fermentation of digested organic matter, with adverse consequences for feed efficiency and the environment. It is therefore important to understand the influence of host age on the relationship between microbiota and methane production. This study explored the age effect on the relationship between microbial communities and enteric methane production in dairy cows and heifers using high-throughput sequencing. Methane production and volatile fatty acid concentrations were age-related. Heifers (9–10 months) had lower methane production but higher methane production per dry matter intake (DMI). The acetate:propionate ratio decreased significantly with increasing age. Age-related microbiota changes in the rumen were reflected by a significant shift in bacterial taxa, but relatively stable archaeal taxa. Prevotella, Ruminococcus, Flavonifractor, Succinivibrio, and Methanobrevibacter were affected by age. This study revealed different associations between predominant bacterial phylotypes and Methanobrevibacter with increasing age. Prevotella was strongly correlated with Methanobrevibacter in heifers; howerver, in older cows (96–120 months) this association was replaced by a correlation between Succinivibrio and Methanobrevibacter. This shift may account for the age-related difference in rumen fermentation and methane production per DMI.

Highlights

Methane is one of the most abundant greenhouse gasses in the atmosphere, with a significant impact on global warming 28-times that of carbon dioxide (IPCC, 2014)
If we assume that rumen microbiota respond or adapt to host age, this suggests that the taxa composition, and interactions among the microbes determining energy metabolism and methane production, may differ in host populations of different ages
The population of methanogens increased with age, with a significant difference between the S1 and S3 groups (p < 0.05), but there was no significant difference in the bacteria population size or methanogen:bacteria proportion (%) between the groups (p = 0.34)

Summary

Introduction

Methane is one of the most abundant greenhouse gasses in the atmosphere, with a significant impact on global warming 28-times that of carbon dioxide (IPCC, 2014). Age-Related Rumen Microbes Change Methane on methane emission (Basarab et al, 2013; Carberry et al, 2014; Henderson et al, 2015; Zhao et al, 2015; Roehe et al, 2016). These aforementioned factors have direct or indirect effects on rumen microbes that respond or adapt to environmental changes, potentially resulting in physiological changes in their host. The authors did not correlate changes in microbiota in different age groups with enteric methane production

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Discussion

Conclusion