Skip to main content

ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Microbial Physiology and Metabolism
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1498109
This article is part of the Research Topic Biosynthesis of secondary metabolites in bacteria: genes, pathways, and evolution View all 6 articles

Ligilactobacillus agilis W70: A probiotic with capacity to enhance ammonia assimilation in the rumen

Provisionally accepted
Xiaowei Duan Xiaowei Duan 1,2Stafford Vigors Stafford Vigors 2Rui Ma Rui Ma 3Lu Ma Lu Ma 1,4Jingang Gu Jingang Gu 3Dengpan Bu Dengpan Bu 1*
  • 1 State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
  • 2 School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
  • 3 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, Beijing Municipality, China
  • 4 National Center of Technology Innovation for Dairy, Inner Mongolia, China

The final, formatted version of the article will be published soon.

    Ruminants excrete both undigested and excess consumed nitrogen (N) through feces and urine, which results in the waste of feed protein and environmental pollution. This study aims to screen bacteria to identify strains with potential to improve nitrogen utilization in the rumen. In a tube screening test, when 30 mmol/L ammonium sulfate was added as the only nitrogen source in liquid medium, among 115 bacterial strains belonging to Bacillus and lactic-acid bacteria, 10 strains with the highest growth (OD600nm level) in comparison to the other evaluated strains were identified, and of these, Ligilactobacillus agilis W70 and Limosilactobacillus fermentum M50, had the highest ammonia nitrogen utilizing capabilities of ammonium sulfate (32.09% and 40.64%, respectively). A subsequent in vitro fermentation experiment was conducted with the diet consisting of 0.5g TMR, 50 mL buffer solution, and 25 mL fresh rumen fluid per serum bottle which was incubated at 39 ℃ for 24h. The experiment consisted of 3 treatments, CTL, L. agilis W70 (1 × 10 9 cfu/mL), and L. fermentum M50 (1 × 10 9 cfu/mL), each treatment had 6 replicates, repeated across 3 batches. The addition of L. agilis W70 decreased NH3N (P < 0.01), the ratio of acetate to propionate (A:P) (P < 0.01), and increased the yields of microbial protein (MCP) (P < 0.01) and enzymatic activities of glutamate dehydrogenase (GDH) (P < 0.05) and glutamine synthetase (GS) (P < 0.05). Further genome analysis revealed that the L. agilis W70 harbors the glutamate dehydrogenase and glutamine synthetase-encoding genes gdhA and glnA that play key roles in ammonia utilization. This study identified L. agilis W70 as a strain which exhibits high NH3N utilization capability and enhances ammonia assimilation in vitro. The strain was further characterized to elucidate this ammonia assimilation potential. Further studies will be conducted to develop strain L. agilis W70 as a new feed additive to improve the nitrogen utilization efficiency in ruminant animals.

    Keywords: Ligilactobacillus agilis, NH3N, Rumen fermentation, screening, functional and physicochemical characterization

    Received: 18 Sep 2024; Accepted: 12 Dec 2024.

    Copyright: © 2024 Duan, Vigors, Ma, Ma, Gu and Bu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Dengpan Bu, State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.