Roles of fibre fermentation in monogastric animals: 2. Training microbiome to enhance fermentation of the major cereal NSPs

Jae Cheol Kim, Technical Manager ASPAC, AB Vista



In the previous edition, benefits of increasing post-ileal fibre fermentation through supplementation of β-1,4-endo-xylanase were introduced suggesting a hypothesis that effective fibre fermentation needs adaptation of microbiota. In this issue, recent AB Vista research will be introduced to demonstrate the importance of adaptation of microbiota to substrate for maximum fibre fermentation.
In a study by Bedford and Apajalahti (2018), caecal digesta was anaerobically collected from 35-day-old broilers fed a wheat-soybean meal-based diet either without or with xylanase supplementation (Econase XT 16000 BXU, n=10). Within 3 hours of the collection, the caecal digesta containing microflora was used as inoculum for an in vitro anaerobic incubation study with varying substrates. Gas production was measured as a means of fibre fermentation capacity from caecal microflora without and with adaptation to the supplemented xylanase (Figure 1).
Results clearly demonstrated that gas production was significantly higher (up to 28%) in caecal microflora pre-adapted to a xylanase diet. This finding suggest that intestinal microflora can be trained to maximize fibre fermentation through supplementation of xylanase. Provision of xylo-oligosaccharides through action of xylanase may have upregulated metabolism of XOS utilising microbiota which increased gas production.


Figure 1.  In vitro gas and butyric acid productions when cecal flora from broilers fed either Control diet or xylanase supplemented diet were used as inocula with various substrates. Broiler chickens were fed a wheat-soy diet which contained a xylanase (Econase XT, AB Vista, UK) at 0 or 16,000 BXU/kg for 35 days of age (Bedford and Apajalahiti, 2018).


Recent in vitro study at University of New England (Morgan et al., 2019) simulated gizzard and ileal digestion with different wheats samples. Although there were variations in short chain XOS production by xylanase depends on wheat samples (8.78 – 12.08 g/100g), the results clearly showed that xylanase (Econase XT) significantly increased short chain XOS (2-5 xylose chain) from 0.1 g up to 12 g per 100g wheat (Table 1). This result explains why the caecal microbiome from birds fed a xylanase supplemented diet adapted to a greater gas production in Bedford and Apajalahti’s study. Collectively, these two studies demonstrated that supplementation of xylanase produces increasing amounts of short chain XOS which augmented caecal bacterial metabolism to a greater fibrolytic activity.

Table 1.  Sum of short chain xylo-oligosaccharide (X2-X5, g/100g) production after in vitro simulation of gizzard and small intestinal digestion in different wheat samples without and with xylanase (Econase XT) supplementation (Morgan et al., 2019).



Subsequent analysis on the pattern of volatile fatty acid production in Bedford and Apajalahti’s study showed that the caecal microflora adapted to a xylanase supplemented diet produced proportionally less acetate, propionate and higher butyrate. Increasing production of short chain XOS and butyric acid production with supplementation of xylanase has implications for intestinal health and energy extraction from the diet in older animals as microbial adaptation to altered substrate through supplementation of xylanase generally takes time (Masey-O’Neill et al., 2014). The burning topic is then whether intestinal microbiota can be trained to reduce the adaptation period and get most of the benefit via improving energy extraction and intestinal health from younger ages. This topic will be discussed in the next issue with in vivo responses from poultry and pig studies.


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Article made possible through the contribution of Jae Cheol Kim and AB Vista