Non-starch polysaccharide degradation in the gastrointestinal tract of broiler chickens fed commercial-type diets supplemented with either a single dose of xylanase, a double dose of xylanase, or a cocktail of non-starch polysaccharide-degrading enzymes

Abstract

The aim of this study was to examine non-starch polysaccharide (NSP) degradation in the gastrointestinal tract of chickens fed a range of commercial-type diets supplemented with a commercial dose of xylanase, a double dose of xylanase or a cocktail of NSP - degrading enzymes. Cobb 500 broilers (n = 1,080) were fed 12 dietary treatments; 4 diets with differing primary grain sources (barley, corn, sorghum, and wheat) and three different enzyme treatments (commercial recommended dose of xylanase (16,000 BXU/kg), a double dose of xylanase (32,000 BXU/kg) or an NSP-degrading enzyme cocktail (xylanase, β-glucanase, cellulase, pectinase, mannanase, galactanase, and arabinofuranosidase at recommended commercial levels). There were 108 pens, approximately 10 birds per pen, 9 replicates per dietary treatment. The diets were fed as 3 phases, starter (d 0-12), grower (d 12-23), and finisher (d 23-35). On bird age d 12, 23, and 35, performance (total pen body weight, feed intake, and feed conversion ratio corrected for mortality [cFCR]), litter and excreta dry matter content, and ileal and total tract soluble and insoluble NSP degradability and free oligosaccharide digestibility was determined. On d 35, the quantity of NSP in the gizzard, jejunum, ileum and excreta was determined. Results from this study showed that the double xylanase dose and NSP-ase cocktail had positive impacts on starter phase performance in birds fed the corn- and wheat-based diets. In the grower phase in birds fed the barley-based diet, these enzyme treatments improved cFCR and increased litter dry matter content. The NSP-ase cocktail had a negative impact on finisher phase cFCR in birds fed the sorghum-based diet. The double xylanase dose induced a positive impact on NSP degradability and free oligosaccharide digestibility. In conclusion, there appears to be advantages to feeding broilers a double xylanase dose, but lack of consistency when using an NSP-ase cocktail containing many enzymes.

Keywords: enzyme cocktail; grains; non-starch polysaccharide; xylanase.

Figure 1

Effect of grain type and xylanase level (16,000 BXU/kg [Single) or 32,000 BXU/kg [Double]) or NSP-ase cocktail (Cocktail) on total tract degradability of soluble and insoluble non-starch polysaccharides at d 12 (% DM).

Figure 2

Effect of grain type and xylanase level (16,000 BXU/kg [Single] or 32,000 BXU/kg [Double]) or NSP-ase cocktail (Cocktail) on ileal digestibility of free oligosaccharides at d 12 (% DM).

Figure 3

Effect of grain type and xylanase level (16,000 BXU/kg [Single] or 32,000 BXU/kg [Double]) or NSP-ase cocktail (Cocktail) on total tract degradability of soluble non-starch polysaccharides at d23 (% DM).

Figure 4

Effect of grain type and xylanase level (16,000 BXU/kg [Single] or 32,000 BXU/kg [Double]) or NSP-ase cocktail (Cocktail) on ileal and total tract degradability of insoluble non-starch polysaccharides at d23 (% DM).

Figure 5

Effect of grain type and xylanase level (16,000 BXU/kg [Single] or 32,000 BXU/kg [Double]) or NSP-ase cocktail (Cocktail) on ileal degradability of soluble non-starch polysaccharides and total tract digestibility of free oligosaccharides at d 35 (% DM).