The flow of non-starch polysaccharides along the gastrointestinal tract of broiler chickens fed either a wheat- or maize-based diet

Abstract

The present study characterised the types and amounts of non-starch polysaccharides (NSP) remaining undigested along the gastrointestinal tract (GIT) of broiler chickens offered a typical wheat- or maize-based diet. One-day old Cobb 500 mixed-sex chicks were assigned to 24 pens, with 10 birds/pen and 12 pens/treatment. Birds were offered the experimental diets in 3 phases (starter, day 0 to 10; grower, day 11 to 24 and finisher, day 25 to 35). Excreta and digesta samples from the crop, gizzard, duodenum, jejunum, ileum and caeca were collected at 12 and 35 days of age, and analysed for the NSP flow. The wheat-based diet contained higher levels of soluble NSP than the maize-based diet, whereas insoluble NSP levels were similar between the 2 diets. Detailed analysis of NSP constituents revealed that arabinoxylans were the primary NSP in the wheat-based diet, mostly in insoluble form. Pectins were the predominant NSP in the maize-based diet, followed by arabinoxylans. Overall, birds offered the wheat-based diet presented higher levels of soluble NSP remaining in all gut sections compared to birds offered the maize-based diet, at both 12 and 35 days of age (P < 0.050). Accumulation of insoluble NSP in the gizzard was noted in birds fed both diets, but was more pronounced in birds offered the maize-based diet compared to the wheat-based diet, at both 12 and 35 days of age (P < 0.001). The present study highlights marked differences in the amounts and types of NSP delivered to the different gut sections when feeding wheat-compared to maize-based diets, particularly in the gizzard and the lower GIT of birds.

Keywords: Broiler chickens; Insoluble fibre; Non-starch polysaccharides; Soluble fibre.