Digestion
Rabbits are herbivores (plant eaters) and belong to the group of folivores (leaf eaters).
In the wild they mainly eat from grasses, wild herbs, trees and bushes and, in very little amounts, field crops, lichens and mushrooms.
They prefer the petaled parts of the plants and the new shoots. Even bark and roots are enjoyed. This natural nutrition provides them with very important nutrients such as essential amino acids.
The healing effect of some plants strengthens the immune system and protects against disease.
Gastrointestinal System
Rabbits eat up to 80 meals daily. The constantly eaten, fresh petaled, nutrition ensures that the food does not stay too long in their digestive tract. This prevents digestive problems and the spread of pathogens.
The digestive tract of rabbits is very long.
- It is made to ingest and digest petaled food.
- The digestive tract separates digestible and lightly fermentable components of digestible fibers.
- Eliminates bad fermentable components (rough/indigestible fibers).
Ingestion
Rabbits select the young and nutritious parts of plants. Due to the positioning of their eyes, they are unable to visualize the food while they eat. Therefore they have developed highly movable, sensitive lips that allow them to locate food as they eat.
Chewing
- Grinding and chewing masticatory movement
They have long incisor teeth located at the front of the jaw. At the sides of the jaw are molars and pre molars. Rabbits typically have a grinding and chewing masticatory movement with their molars. This is called mastication. This abrasive movement is effective in wearing down the ever growing teeth. Saliva is mixed and added to the bolus (ingested food).
Esophagus
The bolus, after being chewed, passes into the esophagus. In rabbits, this serves only to transport the bolus and no digestive processes take place.
Stomach
- Vermicular movement underdeveloped
- Is weakly muscled
- Need constant input of new food – pushes food into the small intestine
- Is normally never empty because it needs new input to keep food moving to exit stomach
- Therefore stop of food input can lead to bolus staying too long in stomach – leads to life threatening bloating of the stomach (tympanites) Link to medical conditions coming soon
Food will be broken down, by the enzyme pepsin and hydrochloric acid, into its separate components. In rabbits, the vermicular movement (peristalsis) for the intermixing and the onboard transfer of the bolus into the intestines is underdeveloped. The stomach is weakly muscled in rabbits and it is thought the churning of food material is caused indirectly by the rabbit’s physical movement.
The onward transportation of food from the stomach into the intestine occurs primarily via the constant input of new food. This is the reason why rabbits may never fast. Every new input of food into the stomach will be just piled up and not mixed through.
A rabbit’s stomach is never empty. If there is no food ingested to continue the digestive process, bloating occurs as the food ferments in the stomach.
There is a strong muscle located at the pyloric orifice (exit of the stomach). This muscle takes care of the mixing of the bolus and indicates the onward movement into the small bowel (intestinum tenue).
Small Intestine
In the small intestine the proteins, fats and carbohydrates will be broken down by the pancreas. This is done via pancreatic enzymes and secretions. The nutrients are absorbed through the small jejunal brush border (intestinal walls).
Large Intestine
- Two different digestive phases, the soft feces (cecotropic phase) and the hard feces.
- Cecotropes are feces rabbits naturally eat and are important for them to get all of their nutrients
The large intestine is separated into the appendix (appendix vermiformis), cecum and hind gut (colon and rectum). Rabbits have proportionally the largest cecum of any mammal.
At the appendix (fusus coli) the digestible fibre is separated from the non digestible fibre. With the help of liquid these particles are washed along the gut wall into the appendix. Particles can only enter the appendix if they are smaller than 0.3-0-5mm and are easily digestible. Here the fine digestible fibre will be combined with bacteria into cecotropes.
The cecotrope is a mix of bacteria, protein and fatty acids. 
They are also called ‚soft feces’ and are not considered waste material. The appendix takes the function of fermentation. This mechanism is called cecotrophy.
The cecotrope is different in appearance to the normal round dry fecal pellets. Cecotropes are soft, grape shaped, and they are connected, also having a characterizable smell and a mucous layer. They are swallowed by the rabbit whole, directly from the anus.
The unrefined undigestible fibre will leave the digestive system as hard, round fecal pellets. A certain amount of hard to digest fibre is very important and necessary to keep the peristaltic movement functioning. Without unrefined fibers there is a risk that the bolus becomes stuck.
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