Open AccessChanges in chemical composition, structural and functional microbiome during alfalfa (Medicago sativa) ensilage with Lactobacillus plantarum PS-8
Author(s) -
Lijun You,
Weichen Bao,
Caiqing Yao,
Feiyan Zhao,
Hao Jin,
Weiqiang Huang,
Bohai Li,
LaiYu Kwok,
Wenjun Liu
Publication year - 2022
Publication title -
animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 28
eISSN - 2405-6545
pISSN - 2405-6383
DOI - 10.1016/j.aninu.2021.12.004
Subject(s) - silage , fermentation , lactobacillus plantarum , food science , biology , neutral detergent fiber , dry matter , lactic acid , bacteria , microorganism , amylase , inoculation , zoology , biochemistry , horticulture , enzyme , genetics
Improving silage production by adding exogenous microorganisms not only maximizes nutrient preservation, but also extends product shelf life. Herein, changes in the quality and quantity of Lactobacillus plantarum PS-8 (PS-8) -inoculated alfalfa ( Medicago sativa ) during silage fermentation were monitored at d 0, 7, 14, and 28 (inoculum dose of PS-8 was 1 × 10 5 colony forming units [cfu]/g fresh weight; 50 kg per bag; 10 bags for each time point) by reconstructing metagenomic-assembled genomes (MAG) and Growth Rate InDex (GRiD). Our results showed that the exogenous starter bacterium, PS-8 inoculation, became the most dominating strain by d 7, and possibly played a highly active role throughout the fermentation process. The pH value of the silage decreased greatly, accompanied by the growth of acid-producing microorganisms namely PS-8, which inhibited the growth of harmful microorganisms like molds (4.18 vs. 1.42 log cfu/g) and coliforms (4.95 vs. 0.66 log most probable number [MPN]/g). The content of neutral detergent fiber (NDF) decreased significantly (41.6% vs. 37.6%; dry matter basis). In addition, the abundance and diversity of genes coding microbial carbohydrate-active enzymes (CAZymes) increased significantly and desirably throughout the fermentation, particularly the genes responsible for degrading starch, arabino-xylan, and cellulose. Overall, our results showed that PS-8 was replicating rapidly and consistently during early- and mid-fermentation phases, promoting the growth of beneficial lactic acid bacteria and inhibiting undesirable microbes, ultimately improving the quality of silage.