Animal and Aquacultural Sciences
Ingestion of bedding material enhances digestive function in poultry
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New research shows that the average particle size in the small intestine of poultry with access to course particles is half the size of the intestinal particles in poultry only having access to fine particles.
Thus, intestinal feed particles in poultry with access to course edible components, either from feed or their immediate surroundings, become finer and are thus easier digestible than in poultry fed fine-grained feed without access to course litter. Feed digestion is therewith a greater challenge for animals lacking a well-developed gizzard.
During the past 50 years, genetic improvement, advances in nutritional science and improved poultry management have resulted in a tremendous increase of productivity. Today’s poultry feed consists of highly concentrated TMR feed, ensuring a constant supply of nutrients that are efficiently digested and utilized. However, commercial poultry feed contains a considerable amount of cereals and legumes, which in turn consist of significant amounts of indigestible fibres. Such indigestible structural components could prove to play a major role in the digestion of other nutrients, and help to increase intestinal capacity in a naturally sustainable way.
Many of us have seen poultry pecking and scratching the ground, picking up stones, leaves, twigs and other materials – in accordance with their natural behaviour pattern. However, new research shows that modern poultry hybrids also bathe in, and especially eat bedding material. On their own, modern laying hens ingest 5-10 g of litter daily, depending on the type of bedding material available. This is equivalent to 5-10 % of the birds’ food intake. Instead of teeth, birds have a gizzard, a muscular stomach that grinds food particles in a moist, acid environment. The gizzard is stimulated by course, and preferably hard particles. The fine-grained, highly concentrated feed now commonly used in poultry operations does not stimulate the gizzard’s development. Thus, the feed passes through the gizzard with little reduction of particle size.
However, hens or chicks with access to such litter material as sawdust, stones or other course or fibrous particles will ingest these particles. As a result, the gizzard’s muscles nearly double their weight, which in turn improves the grinding of ingested food particles. Furthermore, an active gizzard helps to optimize the unique interaction between the gizzard’s grinding function and nutrient absorption in the bird’s intestines. This may help to improve the regulation of feed ingestion according to the animal’s needs, and perhaps lead to a more balanced state of satiation and hunger.
Updated: 14.05.09Printerfriendly version
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