Journal of Integrative Agriculture ›› 2020, Vol. 19 ›› Issue (6): 1644-1655.DOI: 10.1016/S2095-3119(20)63174-4

所属专题: 动物营养合辑Animal Nutrition

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  • 收稿日期:2019-02-27 出版日期:2020-06-01 发布日期:2020-04-26

Effects of different molecular weights of chitosan on methane production and bacterial community structure in vitro

TONG Jin-jin1, 2*, ZHANG Hua1*, WANG Jia1, LIU Yun3, MAO Sheng-yong4, XIONG Ben-hai5, JIANG Lin-shu1 
  

  1. 1 Beijing Key Laboratory for Dairy Cow Nutrition, Beijing University of Agriculture, Beijing 102206, P.R.China
    2 Beijing Bei Nong Enterprise Management Co., Ltd., Beijing 102206, P.R.China
    3 College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, P.R.China
    4 College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P.R.China
    5 State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, P.R.China
  • Received:2019-02-27 Online:2020-06-01 Published:2020-04-26
  • Contact: Correspondence JIANG Lin-shu, Mobile: +86-13801059171, Fax: +86-10-80796368, E-mail: jls@bac.edu.cn; XIONG Ben-hai, Mobile: +86-13801090939, Fax: +86-10-62815988, E-mail: xiongbenhai@caas.cn
  • About author:* These authors contributed equally to this study.
  • Supported by:
    This study was financially supported by the projects of the National Natural Science Foundation of China (31802091, 31702302 and 31772629) and the National Key Research and Development Plan of China (2016YFD0700205, 2016YFD0700201 and 2017YFD0701604). 

Abstract:

As a new feed additive, chitosan has been shown in recent years to have a certain role in reducing methane emissions from the gastrointestinal tracts of ruminants.  However, the effects of chitosan with different molecular weights on rumen fermentation, methane production and bacterial community structure are not yet clear.  A basal diet without chitosan served as the control (CTL), and the treatment diets were supplemented with chitosan with different molecular weights: 1 000 (1K), 3 000 (3K), 5 000 (5K), 50 000 (5W) and 200 000 (20W) dry matter (DM).  Six fermentation units per treatment were established.  Gas chromatography was used to measure the concentrations of methane, H2 and volatile fatty acids (VFAs).  The bacterial 16S rRNA genes were sequenced with an Illumina MiSeq platform and analysed to reveal the relative abundances of bacterial community taxa.  The results showed that the propionate proportion was significantly increased by the addition of chitosan with different molecular weights (P<0.05), while methane production and the acetate proportion were significantly decreased (P<0.05).  The relative abundances of Rikenellaceae_RC9_gut_group and Prevotellaceae_UCG_003 were significantly increased in the 3K chitosan group compared with the CTL group, whereas the relative abundance of Ruminococcaceae_NK4A214_group was significantly decreased (P<0.05).  Correlation analyses of the relative abundances of the bacterial genera showed that Prevotella was positively related to propionate production (P<0.05).  In conclusion, 3K chitosan could reduce methane production by replacing fibrolytic bacteria (Firmicutes and Fibrobacteres) with amylolytic bacteria (Bacteroidetes and Proteobacteria) in the bacterial community structure.
 

Key words: chitosan ,  high-throughput DNA sequencing ,  methane