Pretreatment of Rapeseed Meal Increases Its Recalcitrant Fibre Fermentation and Alters the Microbial Community in an in Vitro Model of Swine Large Intestine

Abstract

Background: The aim of current study was to investigate whether degradation of rapeseed meal (RSM) which was modified by a cellulase, two pectinase, or alkaline treatment was improved by the swine gut microbiota compared to untreated RSM, and whether the microbiota composition was changed. Methods: An in vitro study was performed to assess how enzymatic and chemical pretreated rapeseed meal (RSM) influences the fibre fermentation and microbial community in the swine large intestine. RSM was processed enzymatically by a cellulase (CELL), two pectinases (PECT), or chemically by an alkaline (ALK) treatment. 16S rRNA gene sequencing data was performedto evaluate changes in the gut microbiota composition, whereas short chain fatty acid production (ion-chromatography) and non-starch polysaccharides (NSP) composition(using monoclonal antibodies; mAbs) were used to assess fibre degradation.Results: The results showed that ALK, CELL, PECT1, and PECT2changed microbial community composition, increased the abundance of microbial fibre-degrading enzymes and pathways,andincreased acetic acid, propionic acid, butyric acid, and total SCFA production. The increased genera also positively correlated with SCFA production. The cell wall polysaccharide structuresof RSM shiftedafter ALK, CELL, PECT1, and PECT2 treatment. The degradation of NSPduring the fermentation period was dynamic, and not continuous based on the epitope recognition by mAbs.Conclusion: This study provides the first detailed analysis of changes in the swine intestinal microbiota due to RSM modified by ALK, CELL, PECT1 and PECT2. ALK, CELL, PECT1 and PECT2 altered microbial community structure, shifted the predicted functional metagenomic profile and subsequently increased total SCFA production. Our findings that ALK, CELL, PECT1 and PECT2increased fiber degradability in RSM could help guide feed additive strategies to improve efficiency and productivity in swine industry. The current study gave insight into how feed enzyme modulate microbial status, which provides good opportunity to develop novel carbohydrase, particularly in swine feed.

Pretreatment of Rapeseed Meal Increases Its Recalcitrant Fiber Fermentation and Alters the Microbial Community in an in vitro Model of Swine Large Intestine

“…We thank Sanne Verbruggen and Jessica Verhoeven for sharing their experience in running TIM-2, and Rob van Dinter for technical support. This manuscript has been released as a pre-print at Research Square (Long and Venema, 2020).…”