Increased small intestinal fermentation is partly responsible for the anti-nutritive activity of non-starch polysaccharides in chickens.
1. The mechanism of the anti-nutritive activities of soluble non-starch polysaccharides (NSPs) in broiler diets was investigated with emphasis on the inter-relationship between viscosity and fermentation along the gut. Isolated soluble NSP were added to a control diet to effect high gut viscosity, and in vivo depolymerisation of the NSP was achieved using a commercial glycanase. 2. Addition of soluble NSPs significantly (P < 0.01) increased gut viscosity, reduced the AME of the diet and depressed the growth and FCE of the birds. Enzyme supplementation of the NSP-enriched diet reversed the adverse effects, increasing (P < 0.01) weight gain, FCE and AME. Comparisons of the viscosities (mPa) in birds fed on the NSP-enriched diet and the same diet supplemented with enzyme were respectively: 11.9 v. 2.3 in the duodenum; 78.3 v. 4.4 in the jejunum and 409.3 v. 10.8 in the ileum. 3. Caecal volatile fatty acid concentration was markedly (P < 0.01) elevated by enzyme supplementation, whereas ileal fermentation was inhibited. 4. Microscopic examination revealed that, among birds fed on the NSP-enriched diet, there had been extensive small intestinal fermentation, which was eliminated by the enzyme supplementation. 5. Addition of a synthetic antibiotic (Amoxil) had no beneficial effects. 6. The current study demonstrated that increased fermentation occurs in the small intestine when a large amount of viscous NSPs is present in the diet and this is detrimental to the performance and well-being of poultry.
Choct
M
M
CSIRO Division of Human Nutrition, Glenthorne Laboratory, Australia.
Hughes
R J
RJ
Wang
J
J
Bedford
M R
MR
Morgan
A J
AJ
Annison
G
G
D000821:Animal Feed; D000818:Animals; D002432:Cecum; D002645:Chickens; D004063:Digestion; D002149:Energy Intake; D005232:Fatty Acids, Volatile / Q000032:analysis; D005260:Female; D005285:Fermentation; D005527:Food, Fortified; D006026:Glycoside Hydrolases; D007413:Intestinal Mucosa / Q000502:physiology*; D007421:Intestine, Small / Q000502:physiology*; D008297:Male; D009753:Nutritive Value; D011134:Polysaccharides / Q000378:metabolism*; D013213:Starch; D014783:Viscosity
D005232:Fatty Acids, Volatile; D011134:Polysaccharides; D013213:Starch; D006026:Glycoside Hydrolases; C020668:glycanase