Journey of feed through the digestive tract (Part I)
When talking about feed and drinking water additives and the usage of natural products to replace antibiotic growth promoters there is one system where this will have a major impact: the digestive system.
Farmers and food producers have as aim to grow and produce animal products for human consumption; for this goal to be reached the proper maintenance and support of the digestive system will be the most important factor. The digestive system of animals varies from species to species. Animals have evolved to adapt to the different nutrition requirements that they need. From the multipartition of the esophagus from ruminants to the cecal fermentation of rabbits; all digestive systems have their own characteristics and will be the major factor to consider in animal productions. As each system differs in major characteristics between different animal species; in this article, we will focus on one of the birds.
The avian digestive tract has some similarities to that of humans, with some physiological and anatomical adaptations. The digestive tract of poultry is structured by:
- Esophagus – Crop
- Small intestine
- Large intestine
While in previous articles we already talked about the liver (part of the digestive system) or the principle of competitive exclusion which takes effect in the gut, in this article we will focus on the first organs that play a major role in the digestion of feed. From picking up the feed until maceration of it.
Starting with the beak.
Depending on the bird’s diets, beaks present multiple variations that help them adapt to the feeding possibilities of the area where they inhabit.
Poultry species possess a generalist beak that lets them eat multiple things ranging from vegetables, insects, to corns. The beak helps the chicken to pick up the feed but it won’t help them to macerate or break it properly due to the lack of teeth. For that, the avian digestive system has another organ. The beak contains not only part of the digestive system but also the respiratory one; the hard palate presents a slit that communicates the digestive system (covered by salivary glands) and the nasal cavity.
A proper division of the respiratory system and the digestive system comes on the Pharynx where feed and water are sent to the esophagus and the air to the trachea.
–Esophagus (crop and proventriculus)
The esophagus is the connecting path between the mouth and the gizzard, a very flexible and expandable tissue that can carry feed or water. Before the esophagus connects to the gizzard, there are two structures that originate from the esophagus: the crop and the proventriculus.
The crop is located before the esophagus reaches the thoracic cavity, and is a dilatation of the esophagus that allows the animal to eat periodically but allows the chicken to have constant digestion. It works as a temporary reservoir for un-digested feed, while the proper digestion starts on the proventriculus.
The proventriculus or also called the “glandular stomach” is the portion of the esophagus that starts the enzymatic digestion of the feed. Digestive juices conformed of hydrochloric acid and proteolytic enzymes are produced in the proventriculus. For digestion to be optimal, an acid pH is needed in the proventriculus. This section of the esophagus allows the animal to break the feed into smaller particles or molecules of nutrients. Digestive enzymes have a more efficacious effect once the feed is broken down into smaller particles in the ventriculus (Gizzard).
The gizzard or also called “muscular stomach” has the function of breaking the feed into smaller particles after it has been pre-digested by the proventriculus. The gizzard consists of a muscular organ with an inner layer that prevents the particles from damage that can come with the grinding effect of the organ.
The inner layer is called the koilin membrane, an abrasive layer that permits the gizzard to work as a grinding mill, with the help of grit. Grits are hard substance particles that are fed to birds coming usually from crushed stone or crushed shells, this acts as grinding parts inside the gizzard.
This grinding motion, in addition to the acidity and enzyme digestion provided by the proventriculus, breaks the feed components into smaller molecules (nutrients) that the intestines will be able to absorb.
In XVET we count on numerous feed and water additives that help to support the digestive system. Regarding the organs that were mentioned, the products below help us gain and maintain a low pH will support the esophagus, crop, proventriculus, and gizzard; by facilitating the digestion and providing an antimicrobial effect, reducing the possibility of infection.
XVETs water acidifier X-Cid is a synergetic mixture of inorganic and organic acids that provide an optimal pH of the water; maintaining the water lines in better conditions, reducing the possibility of bacterial proliferation in water, and improving the digestion and absorption of nutrients.
Regarding feed solutions, we count on multiple products that fit various production needs. Products such as Cinnacid and Salmo Guard will provide acids and salt of the acids to the feed. This double effect of acidification will provide an effect both at the feed and gut level. Besides the benefits of acids, all XVET’s formulas contain added ingredients for extra benefits to the animals.
In the upcoming article, we will focus on the next portions of the digestive tracts and will give an overview of the different XVET products that can be used to improve their function.