LAB as probiotics and silage inoculants for enteric methane inhibition in ruminants

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Date
2022-10-19
Authors
Mbandlwa, Philiswa
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University College Cork
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Abstract
There is a constant need for antimicrobial agents and producers that can be used in animal feed and other applications in the agricultural industry. This need justifies the research on novel antimicrobial alternatives such as bacteriocins. Data showed the agricultural environment as a source of LAB, dominated by Lactobacillus species with bacteriocin-producing abilities. Subsequently, an investigation on using CFS and bacteriocins from LAB to reduce methane production in Methanobrevibacter found that L. plantarum (LP58) was most effective in reducing methane from M. gottschalkii while individual strains of L. lactis affected methane production in Methanobrevibacter differently. Purified bacteriocins nukacin and lacticin 3147 did not influence in vitro methane production. The nutritive and fermentative properties of L. plantarum and L. lactis were detailed as silage co-inoculants and these inoculants enhanced the beneficial microbes in the silage and resulted in silage with significantly higher lactic acid concentration. Finally, an animal feeding trial showed significant methane reduction in the dairy cattle fed LAB-treated silage. Gaining insight into the different ruminotypes can enable more targeted approaches for methane mitigation. An investigation of the role of LAB in modifying the rumen microbiome and metabolome showed that LAB positively impacts the rumen by significantly increasing acetate and butyrate production while significantly decreasing Proteobacteria. Livestock farming is a significant sector in the Irish economy as it creates jobs, enables export, and is an intricate part of Irish culture. Although it will be challenging for Irish agriculture to meet its climate targets, concerted efforts, such as using LAB as enteric methane mitigators, can enable Ireland to reach its target of reducing atleast 10% of its GHG emissions by 2030. If overall methane emissions are lowered, the national dairy herd can be maintained or increased, and jobs can be created while continuing to supply meat and milk to the growing world population. Future research will focus on finding even more potent methane reducing LAB and characterisation and elucidating the mechanism of methane inhibition in vitro using LAB CFS.
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Lactic acid bacteri , Methane , Probiotics , Gastrointestinal tract , Bacteriocins
Citation
Mbandlwa, P. 2022. LAB as probiotics and silage inoculants for enteric methane inhibition in ruminants. PhD Thesis, University College Cork.