At Purina Animal Nutrition we know it’s important to understand each animal’s digestive system and how it absorbs nutrients, in order to formulate feeds that will provide optimum nutrition.
The rabbit digestive tract greatly resembles that of a horse. Both are “hind-gut fermenters,” meaning that they have an organ called the “cecum” that functions much like the rumen of a cow, but instead of being at the beginning of the digestive tract it is at the end. The cecum is full of special microbes that break down and digest the various fibers and other feedstuffs that enter the cecum.
Because the rabbit has this cecum, it requires a fairly high amount of fiber from the forage in its diet, but because the beginning of the digestive tract is like that of a monogastric animal (such as pigs and humans), the fiber quality must be high. Rabbits will not do well at all on coarse, very mature fiber sources. Good quality fiber is a major energy source for rabbits and an effective tool for maintaining the microbial population in the cecum. Healthy microbial populations in the cecum are critical for proper digestion and optimal gut health.
Path of digestion
Food travels from the stomach to the small intestine, where it encounters enzymes which aid in digestion and absorption of nutrients from proteins, sugars and starches. From there it travels to the cecum, where the microbial breakdown of fiber occurs. It then enters the large intestine, where there is significant water resorption, followed by excretion of the feces.
If the cecum occurs at the end of the digestive tract, how do the nutrients released from the fiber get absorbed? Volatile fatty acids, which are the energy component of fiber digestion, can be absorbed directly through the cecal epithelium. However, other nutrients such as amino acids, vitamins and minerals, are excreted in a special soft fecal pellet known as “night feces” due to the fact that they are excreted only at night. We never see them because rabbits practice coprophagy – they eat these special night feces directly from the anus. This no doubt has a “yuck factor” for humans, but for rabbits it is an extremely efficient way to capture and utilize the nutrients produced by the fermentation of feeds in the cecum.
Like all animals, rabbits need a balance of all the necessary nutrients in order to be optimally productive and healthy. What they need is determined by their stage in life. Young growing bunnies and lactating does will have the highest nutrient requirements (especially energy), while adult rabbits, such as pet rabbits, will have the lowest. Breeds with long fur, such as Angoras, may require more protein and fat to support optimal coat quality. Properly balanced feeds that meet your rabbits’ needs will keep your bunnies healthy and happy throughout their lifetime.