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Anti-nutritional compounds such as non-starch polysaccharides (NSP) are present in viscous cereals used in feed for poultry. Therefore, exogenous carbohydrases are commonly added to monogastric feed to degrade these NSP. Our hypothesis is that xylanase not only improves laying hen performance and digestibility, but also induces a significant shift in microbial composition within the intestinal tract and thereby might exert a prebiotic effect. In this context, a better understanding on whether and how the chicken gut microbial population can be modulated by xylanase is required. To do so, the effects of dietary supplementation of xylanase on performance, apparent total tract digestibility (ATTD) and cecal microbiome in laying hens were evaluated in the present study. A total of 96 HiSex laying hens were used in this experiment (3 diets and 16 replicates of 2 hens). Xylanase was added to the diets at concentrations of 0, 45,000 (15 g/t XygestTM HT) and 90,000 U/kg (30 g/t Xygest HT). The diets were based on wheat (~55%), soybean and sunflower meal. The lowest dosage, 45,000 U/kg, significantly increased average egg weight and improved feed efficiency compared to the control treatment (P<0.05). Egg quality parameters were significantly improved in the experiment in response to the xylanase addition. For example, during the last 28 days of the trial, birds receiving the 45,000 U/kg and the 90,000 U/kg treatments exhibited an increase in Haugh units and albumin heights (P<0.05). Compared with the control, the ATTD of organic matter and crude protein were drastically improved in the 45,000 U/kg treatment group (P<0.05). Furthermore, gross energy and the ATTD of crude fat were improved significantly for birds fed 90,000 U/kg group compared to the control. Importantly, 16S rRNA gene analysis revealed that xylanase at 45,000 U/kg dosage can exert a change in the cecal microbiome. A significant increase in beneficial bacteria (Bacilli class; Enterococcaceae and Lactobacillales orders; Merdibacter, Enterococcus and Nocardiopsis genera; Enterococcus casseliflavus species) was documented when adding 45,000 U/kg xylanase to the diet of laying hens. In conclusion, dietary supplementation of xylanase 45,000 U/kg significantly improved laying hen performance and digestibility. Furthermore, microbiome data suggest that xylanase modulates the laying hen bacterial population beneficially, thus potentially exerting a prebiotic effect.

The addition of xylanase to piglet diets is known to improve performance and nutrient digestibility. The present study aimed to assess the impact of new xylanase on the growth performance, nutrient digestibility, and gut function of weaned piglets. A total of 144 pigs, weaned at 28 days (7.48 kg initial body weight, IBW), were assigned to 36 pens and 9 pens per treatment. Dietary treatments were a basal complex control diet, and the basal diet supplemented with 45,000, 90,000 and 135,000 U/kg xylanase. Performance was measured at days 0, 14 and 35. At day 35, samples were collected for assessment of intestinal histology, and volatile fatty acid and ammonia concentrations. After two weeks post-weaning, additional 12 piglets (11.34 kg IBW) were placed in metabolic crates for assessment of apparent total tract nutrient digestibility using a dietary marker. The addition of xylanase at 90,000 and 135,000 U/kg significantly improved average daily gain (333.6 g/day control, 364.86 g/day, 90,000 U/kg, 405.89 g/day, 135,000 U/kg, p < 0.05), G:F (0.557 control, 0.612 90,000 U/kg, 0.692 135,000 U/kg, p < 0.05), and reduced diarrhoea. This was driven improved nutrient digestibility and villus height in the jejunum (372.87 µm control, 432.53 µm 45,000 U/kg, 465.80 µm 90,000 U/kg, 491.28 µm 135,000 U/kg, p < 0.05). Xylanase supplementation also linearly increased faecal butyrate levels and had a quadratic relationship with propionate concentrations. 135,000 U/kg xylanase also reduced ammonia emissions. In conclusion, dietary supplementation with xylanase improved growth performance and feed efficiency in weaning piglets, likely driven by improvements to gut structure and function.

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