Abstract
ObjectiveThis study investigated the association of enzyme-producing microbes and their enzymes with starch and hemicellulose degradation during fermentation of total mixed ration (TMR) silage.MethodsThe TMRs were prepared with soybean curd residue, alfalfa hay (ATMR) or Leymus chinensis hay (LTMR), corn meal, soybean meal, vitamin-mineral supplements, and salt at a ratio of 25:40:30:4:0.5:0.5 on a dry matter basis. Laboratory-scale bag silos were randomly opened after 1, 3, 7, 14, 28, and 56 days of ensiling and subjected to analyses of fermentation quality, carbohydrates loss, microbial amylase and hemicellulase activities, succession of dominant amylolytic or hemicellulolytic microbes, and their microbial and enzymatic properties.ResultsBoth ATMR and LTMR silages were well preserved, with low pH and high lactic acid concentrations. In addition to the substantial loss of water soluble carbohydrates, loss of starch and hemicellulose was also observed in both TMR silages with prolonged ensiling. The microbial amylase activity remained detectable throughout the ensiling in both TMR silages, whereas the microbial hemicellulase activity progressively decreased until it was inactive at day 14 post-ensiling in both TMR silages. During the early stage of fermentation, the main amylase-producing microbes were Bacillus amyloliquefaciens (B. amyloliquefaciens), B. cereus, B. licheniformis, and B. subtilis in ATMR silage and B. flexus, B. licheniformis, and Paenibacillus xylanexedens (P. xylanexedens) in LTMR silage, whereas Enterococcus faecium was closely associated with starch hydrolysis at the later stage of fermentation in both TMR silages. B. amyloliquefaciens, B. licheniformis, and B. subtilis and B. licheniformis, B. pumilus, and P. xylanexedens were the main source of microbial hemicellulase during the early stage of fermentation in ATMR and LTMR silages, respectively.ConclusionThe microbial amylase contributes to starch hydrolysis during the ensiling process in both TMR silages, whereas the microbial hemicellulase participates in the hemicellulose degradation only at the early stage of ensiling.
Highlights
Ensiling is complex process that involves the interaction among plant enzymes and the action of numerous microbial species, changing the biochemistry of silage [1]
Ning et al (2017) Asian-Australas J Anim Sci 30:171-180 could be a combined action of plant and microbial enzymes under the acidic conditions [3,7]; the mechanisms associated with starch and hemicellulose degradation during ensiling have not been fully elucidated
Microbial amylase plays a role in starch hydrolysis during ensiling in both total mixed ration (TMR) silages
Summary
Ensiling is complex process that involves the interaction among plant enzymes and the action of numerous microbial species, changing the biochemistry of silage [1]. Particular emphasis has been made in studies on the reactions involved in production of acids from water soluble carbohydrates (WSC) during ensiling [2], whereas the degradation of starch and structural carbohydrates did not receive the same interest. Ning et al (2017) Asian-Australas J Anim Sci 30:171-180 could be a combined action of plant and microbial enzymes under the acidic conditions [3,7]; the mechanisms associated with starch and hemicellulose degradation during ensiling have not been fully elucidated. The loss of carbohydrates, microbial enzyme activities, succession of dominant amylolytic or hemicellulolytic microbes during ensiling as well as the microbial and enzymatic properties were investigated to clarify the main enzyme producing microbes and the roles of their enzymes in starch and hemicellulose degradation during fermentation of TMR silages
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
