Dynamics Changes of Microorganisms Community and Fermentation Quality in Soybean Meal Prepared with Lactic Acid Bacteria and Artemisia argyi through Fermentation and Aerobic Exposure Processes

Abstract

This study evaluated the effects of Lactiplantibacillus plantarum subsp. plantarum ZA3, Artemisia argyi and their combination, on the fermentation characteristics, microbial community, mycotoxins and crude flavonoids content of fermented soybean meal during fermentation (under anaerobic conditions) and aerobic exposure (under aerobic conditions). The results showed that ZA3, Artemisia argyi and ZA3+ Artemisia argyi groups had lower pH values and higher lactic acid concentrations compared with controls, and additives increased the abundance of Lactiplantibacillus and decreased those of Acetobacter and Enterobacter; in particular, Artemisia argyi and ZA3+ Artemisia argyi reduced the abundance of fungi, such as Aspergillus, Pichia, Fusarium, Cladosporium and Xeromyces. Meanwhile, the contents of mycotoxins were lower in treated groups, and even mycotoxins in the control were significantly reduced after 30 d (p < 0.05). Crude flavonoids that were correlated positively with Lactococcus and negatively with Bacillus, Aspergillus, Enterobacter and Kazachstania were significantly higher in the Artemisia argyi and ZA3+ Artemisia argyi groups (p < 0.05).

Variation of Microbial Community and Fermentation Quality in Corn Silage Treated with Lactic Acid Bacteria and Artemisia argyi during Aerobic Exposure

“…This observation indicated that ZA3 and AA can change fungi community when environment changes from anaerobic to aerobic. It is possible that acid-tolerant bacteria still dominate the bacterial community in the early period of aerobic exposure, and the variation of microbial community might explain the difference in fermentation quality [ 15 , 38 , 39 ].…”

“…The majority of bacteria involved in lactic acid fermentation belong to the Firmicutes. However, once the WCCS silage was exposed to oxygen, Firmicutes were gradually replaced by Proteobacteria, which might be because an increase in pH and decrease in organic acids are not beneficial to the proliferation of Firmicutes [ 15 , 39 ].…”

“…AFB1, DON, ZEA, OA and FUM are the main mycotoxins of concern in WCCS [ 48 ]. Biodegradation with microorganisms and Chinese herbal medicine might be an effective method to eliminate mycotoxins [ 15 , 49 ]. Although LAB are effective in hindering mold growth, increasing in the oxygen concentration could provide the adequate growth conditions for these fungi strains, which would metabolize lactic acid and WSC into CO 2 and water in aerobic condition [ 50 ].…”

“…WCCS fermented 60 d, aerobic exposure of 3 d and 7 d were sampled to analysis the bacterial and fungi communities. Briefly, 10 g of each sample were shaken well with 90 mL of sterile phosphate buffer saline at 150 rpm for 60 min, and then filtered through 4 layers of gauze, and the solution was centrifuged for 10 min at 8000 g to collect microorganism cells for DNA extraction [ 15 ]. Total genome DNA from samples was extracted using CTAB/SDS method, and DNA concentration and purity was monitored on 1% agarose gels.…”

“…Artemisia argyi (AA) is a traditional Chinese herb medicine used for treating diseases such as diarrhea, hemostasis and inflammation, and is one of the most popular plant in China and eastern Asia [ 13 ]. Studies have proved that AA contains varieties of active compounds such as essential oils, polysaccharides, flavonoids, phenols, terpenoids and glycosides, and also contains crude protein (CP), polyunsaturated fatty acid, vitamin C and essential amino acids [ 14 , 15 ]. Flavonoids, which improve the antioxidant capacity of silage, reduce pH, ammonia nitrogen (NH 3 -N) content and the number of undesirable microorganism during fermentation [ 16 , 17 ], acting as free radical scavengers and metal chelators in the organism [ 18 ], performing functions such as bactericidal, boost immunity, antioxidant, antiviral and cardiovascular regulation [ 19 ].…”