Kinetics of starch digestion and performance of broiler chickens
Keywords: starch, digestion rate, broiler chickens, peas, tapiocaStarch is stored in amyloplasts of various plants like cereals and legumes and seeds of these plants are used as feedstuffs for farm animals. Starch is the major energy source in broiler feeds. The properties of starch from different origin vary condiderably and these properties determine its resistance to enzymatic digestion. The objective of the research project described in this thesis was to study starch digestion behaviour and to investigate whether its digestion rate affects performance of broiler chickens. A digestion experiment pointed out that starch digestion of various native feedstuffs is not complete in four week old broiler chickens. Differences were observed in site, rate and extent of starch digestion. The major part of starch was digested in the upper small intestine (20 to 98%) and the amount of starch digested in the lower small intestine varied from 36 to 1%. Microbial fermentation of starch entering the hind gut did not occur. An in vitro method that simulates the digestive process in the broiler alimentary tract yielded digestion data that correlated well with in vivo starch digestion. Based on in vitro measurements, starch of various feedstuffs and diets could be divided into rapidly digestible starch, slowly digestible starch and resistant starch. These in vitro measurements pointed out that tapioca pellets were rapidly digestible, whereas native peas and sorghum were slowly digestible. Furthermore, technological treatments involving heat and moisture increased in vitro starch digestion rate considerably. Four growth experiments pointed out that feed efficiency of broiler chickens was better on diets with a slow starch digestion than on diets with a rapid starch digestion. Furthermore, the difference in feed efficiency between birds fed a rapidly digestible starch diet or a slowly digestible starch diet was bigger at low than at high protein levels. This suggests that protein efficiency of broiler chickens is higher on slowly digestible starch diets than on rapidly digestible starch diets. The interaction between starch digestion rate and protein level could not completely explain the difference in feed efficiency between birds on slowly- or rapidly digestible starch diets. Therefore, an improvement in energy efficiency may also be involved. In one experiment, feeding a slowly digestible starch diet resulted in a lower number of Clostridium perfringens bacteria in the caeca of broiler chickens than feeding a rapidly digestible starch diet. Therefore, starch digestion rate may affect the microbial balance in the broiler alimentary tract.
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| Format: | Doctoral thesis biblioteca |
| Language: | English |
| Subjects: | amino acids, animal nutrition, broilers, chicks, fowl feeding, in vitro digestibility, kinetics, nutrition physiology, performance, protein content, starch, starch digestion, aminozuren, diervoeding, eiwitgehalte, gevogeltevoeding, in vitro verteerbaarheid, kinetica, kuikens, prestatieniveau, vleeskuikens, voedingsfysiologie, zetmeel, zetmeelvertering, |
| Online Access: | https://research.wur.nl/en/publications/kinetics-of-starch-digestion-and-performance-of-broiler-chickens |
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