Live Bacillus subtilis natto Promotes Rumen Fermentation by Modulating Rumen Microbiota In Vitro

Abstract

Previous studies have shown that Bacillus subtilis natto affects rumen fermentation and rumen microbial community structure, which are limited to detect a few microbial abundances using traditional methods. However, the regulation of B. subtilis natto on rumen microorganisms and the mechanisms of microbiota that affect rumen fermentation is still unclear. This study explored the effects of live and autoclaved B. subtilis natto on ruminal microbial composition and diversity in vitro using 16S rRNA gene sequencing and the underlying mechanisms. Rumen fluid was collected, allocated to thirty-six bottles, and divided into three treatments: CTR, blank control group without B. subtilis natto; LBS, CTR with 109 cfu of live B. subtilis natto; and ABS, CTR with 109 cfu of autoclaved B. subtilis natto. The rumen fluid was collected after 0, 6, 12, and 24 h of fermentation, and pH, ammonia nitrogen (NH3-N), microbial protein (MCP), and volatile fatty acids (VFAs) were determined. The diversity and composition of rumen microbiota were assessed by 16S rRNA gene sequencing. The results revealed LBS affected the concentrations of NH3-N, MCP, and VFAs (p < 0.05), especially after 12 h, which might be attributed to changes in 18 genera. Whereas ABS only enhanced pH and NH3-N concentration compared with the CTR group (p < 0.05), which might be associated with changes in six genera. Supplementation with live B. subtilis natto improved ruminal NH3-N and propionate concentrations, indicating that live bacteria were better than autoclaved ones. This study advances our understanding of B. subtilis natto in promoting ruminal fermentation, providing a new perspective for the precise utilization of B. subtilis natto in dairy rations.

Effects of microbial preparation on production performance and rumen microbial communities of goat

“…The normal range for rumen fluid is 5.50 to 7.50, too high pH will affect the absorption of VFA by the rumen epithelium, while too low pH is not conducive to the feed fermentation in the rumen (Padilla, 2022). Similar result to Deng et al (2018) research, we found MIP decreased the rumen pH, however, Chang et al (2021) research result was quite the opposite (Deng et al, 2018;Chang et al, 2021), the addition of yeast cultures to high-concentration diet could enhance the pH value of rumen fluid and his result was consistent with Thrune et al (2009) and Dias et al (2018) works (Thrune et al, 2009;Dias et al, 2018).…”

Impact of Probiotics on Dairy Production Efficiency

“…Besides, probiotics could simultaneously affect the rumen fermentation and rumen microbial community structure to improve the digestive metabolism. For instance, the activity of Bacillus subtilis natto reportedly improved the concentrations of ammonia nitrogen, microbial protein and volatile fatty acids (VFA) in rumen fluid connected to the change in 18 genera of rumen fluid ( Chang et al, 2021 ).…”

Effects of Bacillus subtilis Natto NB205 and Its Mutant NBMK308 on Egg Quality in Aging Laying Hens

“…B. subtilis natto is shown to improve animal production and meat quality, with studies indicating that B. subtilis natto N21 in combination with lactic acid bacteria enhances broiler growth performance, feed conversion ratio, and nutrient digestibility [ 11 ]. Cows fed B. subtilis natto exhibit increased milk production, improved rumen fermentation, and a positive effect on the ruminal microbiome [ 12 ], while B. subtilis natto also promotes rumen fermentation by modulating rumen microbiota in vitro [ 13 ]. In TOPIGS pigs, B. subtilis natto supplementation resulted in a decrease in skatole content and an increase in meat tenderness [ 14 ].…”