A Birds Digestive System

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Avian Digestive System
Wings with small saw-toothed projections vortex generators , like those on the leading edge of owl wings, generate many small vortices instead of large vortices and produces less aerodynamic noise. The crop evolved for birds that are typically hunted by other animals but need to move to the open to find feed. However, the mouth contains glands that secrete saliva, which wets the feed to make it easier to swallow. Here, nutrients begin to be absorbed. Note how particle size of material in the gizzard ventriculus is smaller than in the proventriculus due to the grinding action of the muscular walls plus small pebbles gastroliths. For example, passive absorption of nutrients such as fat-soluble vitamins is not subject to modulation by diet.

Sense organs

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Preventing this situation is a good reason to keep a poultry house free of nails, glass shards, bits of wire, and so on. The small intestine is made up of the duodenum also referred to as the duodenal loop and the lower small intestine. The remainder of the digestion occurs in the duodenum, and the released nutrients are absorbed mainly in the lower small intestine. The duodenum receives digestive enzymes and bicarbonate to counter the hydrochloric acid from the proventriculus from the pancreas and bile from the liver via the gall bladder.

The lower small intestine is composed of two parts, the jejunum and the ileum. The Meckel's diverticulum marks the end of the jejunum and the start of the ileum see Figure 6.

In the egg, the yolk sac supplies the nutrients needed for the embryo to develop and grow. Right before hatch, the yolk sac is taken into the navel cavity of the embryo. The residual tiny sac is the Meckel's diverticulum. Location of the Meckel's diverticulum in the digestive tract of a chicken. The ceca plural form of cecum are two blind pouches located where the small and large intestines join. Some of the water remaining in the digested material is reabsorbed here.

Another important function of the ceca is the fermentation of any remaining coarse materials. During this fermentation, the ceca produce several fatty acids as well as the eight B vitamins thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folic acid, and vitamin B Because the ceca are located so close to the end of the digestive tract, however, few of the produced nutrients are absorbed and available to the chicken.

Despite the name, the large intestine is actually shorter than the small intestine. The large intestine is where the last of the water reabsorption occurs. In the cloaca, the digestive wastes mix with wastes from the urinary system urates. Chickens usually void fecal material as digestive waste with uric acid crystals on the outer surface—that is, chickens do not urinate.

The color and texture of chicken fecal material can indicate the health status of the chicken's digestive tract: The reproductive tract also exits through this area.

When a hen lays an egg, the vagina folds over to allow the egg to leave through the cloaca opening without coming into contact with feces or urine. These microflora aid in digestion. When chicks hatch, their digestive tracts are virtually sterile. If raised by a mother hen, a chick obtains the beneficial microflora by consuming some of its mother's fecal material.

In artificial incubation and brooding, chicks do not have this option. Through the probiotics, the chicks receive the beneficial bacteria they need to fight off infection by pathogenic bacteria, such as salmonella. Intestinal disease in chickens normally occurs when the balance of normal microflora is upset—that is, the normal microflora are overrun by too many foreign organisms. The result is enteritis, or inflammation of the intestines.

Enteritis produces symptoms that include diarrhea, increased thirst, dehydration, loss of appetite, weakness, and weight loss or slow growth. Try asking one of our Experts. This is where you can find research-based information from America's land-grant universities enabled by eXtension.

View publishing information about this page. Jacquie Jacob, University of Kentucky An understanding of the avian digestive system is essential for developing an effective and economical feeding program for your poultry flock and for recognizing when something is wrong and taking necessary actions to correct the problem. Parts of a Chicken Digestive Tract The chicken has a typical avian digestive system.

Digestive tract of a female chicken. Location of the digestive tract in a female chicken. Esophagus The esophagus is a flexible tube that connects the mouth with the rest of the digestive tract. Crop The crop is an out-pocketing of the esophagus and is located just outside the body cavity in the neck region see Figure 3. Location of the crop in a female chicken. Jacquie Jacob, University of Kentucky Although the digestive enzymes secreted in the mouth began the digestion process, very little digestion takes place in the crop—it is simply a temporary storage pouch.

Proventriculus The esophagus continues past the crop, connecting the crop to the proventriculus. Jacquie Jacob, University of Kentucky When allowed to free-range, chickens typically eat small stones. Small Intestine The small intestine is made up of the duodenum also referred to as the duodenal loop and the lower small intestine. Parrots and other birds that eat large, thick, hard shelled nuts need a really strong curved beak to put enough pressure on the nut to crack it.

The curve of the beak also serves as an aide in climbing up branches in trees. It appears as a little lump.

A pouch where food accumulates and stored. It kind of hangs out here while small amounts drop down in to the next organ of digestion; the Proventriculus. The Proventriculus is the first of two parts of the stomach. This first stomach is the one that secretes the juices that help break down the birds food for digestion.

Special glands release digestive juices to soften food so that the birds body can take it apart on a molecular level and use it to keep the bird alive.

Then the food passes to the Ventriculus. This is the more muscular second half of the stomach, more commonly known as the gizzard. Here, food is squashed and smashed and generally just beaten up. The gizzard often contains grit or gravel to help grind up food. The gizzard is very very powerful. Some birds ingest whole seeds that have not been shelled. In cases like this, the gizzards power, along with some hard pieces of grit, break down the shell so the nutrient-filled insides can be processed.

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