Why Rabbits Need Fiber in their Diets

When deciding on which foods are suitable for rabbits, there is always an emphasis on going for foods that are high in fiber and low in starches and sugars. Why is it necessary to these lagomorphs? Does it have any benefits?

Understanding the rabbit’s digestion system

The digestive systems of a bunny depend on low energy and low protein diets food sources. Therefore, for them to get enough proteins and energy, they need must have a high food intake.

Why rabbit's need high fiber foods
Why rabbits need high fiber foods?

Their small size means more energy is required since they have a higher metabolic rate. Also, being small and as a prey animal, they need to be alert and have energy to escape since they are often sought for by many predators.

We have the details of their digestion process if you are interested in knowing more. This post will focus on the role of fiber, and it will help you understand why the recommended rabbit’s diets must have it in larger quantities.  

Benefits – soluble vs. insoluble

Fiber forms part of the cell walls for plants and helps to keep the structure and shape of plant cells. Mammalian enzymes cannot digest it. However, some bacteria found in the gut can break some of it down to form short chain fatty acids.

Fiber is divided into dietary and functional types. The functional one is then extracted, manufactured or isolated while dietary is the one found in the foods we eat.

These two types can either be soluble such as lignin and hemicellulose or insoluble ones including cellulose. The former dissolves in water while the latter does not.

As Extension.org reports, “bacteria can digest or ferment the soluble fiber fraction and are not capable of fermenting the insoluble fiber fraction.” Once digested or fermented it becomes a source of energy for the bacteria in the cecum for their growth. The bacterial cells will later be a source of protein as well as the B vitamins in cecotrophy.

The breakdown of the soluble fiber to short-chain fatty acids which intestinal cells use as a source of energy provides various health benefits which lower some risks or symptoms of conditions and disease such as gastrointestinal disease and colon cancers

On the other hand, the insoluble type can only be broken down but not digested and it cannot be terminated either.  Therefore, the rabbit’s digestive system separates it from the soluble fiber that goes to the cecum for fermentation.

This insoluble one is not without uses. It improves satiety (feeling full after eating), prevents constipation but most importantly aids food movement inside the GI tract.

Bottom line: You must give your bunnies diets that have high fiber so that the soluble can be used as a fermentation substrate while the insoluble one will play the roles we have just mentioned.

Going on further, as already mentioned, bunnies depend on high fiber, and low protein diets and they can sort the fermentable and non-fermentable food since it will remove non-fermentable foods fast to avoid carrying them for a long time. To do they need a lot of fiber

Therefore, rabbits do not require feeds that have been ground finely or have high sugars as they will overwork the gut. You should know that the “rabbit’s digestive system is set up to ingest cellulose in the form of tough, woody stems and fibrous vegetation,” notes Rabbit.org.

Also, expect an impacted cecum as rabbits cannot deal with the glucose, carbohydrates and indigestible protein overload. However, having fiber will stimulate cecal-colic motility and avoid it.

Furthermore, large indigestible fiber helps reduce not only hairballs or hair accumulation on the bunny’s gut but also reduces instances of enteritis.

Finally, foods like Small Pet Select 2nd Cutting “Perfect Blend” Timothy Hay, Kaytee Timothy Hay, among other grassy hay, that have high fiber together with exercise will increase the rate at which it passes through the body since movements increase peristalsis. Therefore, such diets and exercise can reduce hairballs

Minimum required

For optimum health and proper working of a rabbit’s digestive system, it’s food should have at least 14% fiber and the amount needed can be higher for adult bunnies.

Risks of low fiber diets

Maybe to understand further, we need to consider the consequences of giving your bunnies diets that have low fiber. It will make everything more apparent to you.

  • Obesity
  • GI stasis especially with diets with high starch
  • cecal-colic motility problems


Option bunny health requires you to strike a balance between the nutrients provided and fiber content. Do not comprise either since your furry friend needs both the two. It will ensure they remain healthy and fit.

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