Bunny bellies – managing gut stasis

Gut stasis means that food stops moving through the gastrointestinal tract. This is a very dangerous situation in rabbits – it can even cause death.

Gut stasis is one of the most common problems we see in rabbits. It can occur for several reasons including low-fibre diets, pain, stress and dehydration. Understanding this condition is key to avoiding it, recognising it and treating it correctly if it occurs.

Rabbits and how their guts work

Rabbits are monogastric, hindgut fermenting herbivores. This means that your bunny is a plant eater with one simple stomach (unlike a cow), a simple small intestine (duodenum and jejunum) and large hindgut (caecum and colon) containing bacteria that help to digest food.

Rabbits are also the ultimate recyclers – they eat their own poo.

Let's see how this works. Your rabbit munches on some nice high-fibre food:

  • the teeth start the digestive process by grinding the food and breaking up the plant fibres (cellulose). Rabbits can have up to 120 jaw movements per minute!
  • the stomach mixes the ingested food (ingesta) with digestive juices and breaks it down into smaller bits so it can enter the small intestine. Rabbits can't vomit, so anything that goes into the stomach needs to be able to pass through the rest of the gut
  • the small intestine extracts nutrients (sugars, proteins, vitamins and fatty acids) and adds water to make the ingesta within the gut more liquid
  • the caecum (which is a blind-ended sac at the join of the small  intestine and the hindgut) contains bacteria, yeast and other microbes that break down the digestible fibre to produce amino acids, fatty acids and some vitamins. These are repackaged into nutrient-rich 'caecotrophs' that are then passed into the large intestine (you might know these as 'night faeces' or 'soft faeces')
  • the colon removes water from waste and expels the waste pellets and the caecotrophs through the rectum/anus. There is a unique structure in the upper part of the rabbit colon called a fusus coli, which separates the hard and soft faeces
  • your rabbit knows when the caecotrophs are being expelled (usually 4–8 hours after a meal) and will eat them directly from the anus
  • the caecotrophs are digested in the stomach and the nutrients are absorbed in the small intestine.

Sometimes your rabbit might not eat all the caecotrophs and you'll see some irregularly shaped, greenish 'stools' that are coated in mucus. They tend to have a strong, sort of sweet, smell.

The driving force for the digestive system is indigestible fibre. It stimulates healthy gut motility by causing secretion of a hormone called motilin from the small intestine. Motilin helps stimulate peristaltic contractions of the small intestine, colon and rectum. Your rabbit also needs an appropriate fluid intake to keep things moving through.

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What is gut stasis?

Gut stasis is a slowing or stopping of movement of material through the digestive tract. The two main places where the ingesta tends to be delayed are the stomach and the caecum.

While the passage of ingesta is slow, the normal extraction of liquid from it continues, which causes the ingesta to become thick and dry. This material is harder to move and further slows down gut movement and can cause your rabbit to stop eating and drinking – creating a vicious cycle.

The result is dehydrated impacted material sitting in the stomach or caecum causing all motility to stop.

The bacteria in the caecum will continue to ferment the ingesta and as they do, they produce gas, which can cause painful bloating. In some cases, the normal population of bacteria can be disrupted and 'bad' ones can overgrow.

What causes gut stasis?

The biggest cause of gut stasis is diet. The digestive tract need large amounts of digestible and undigestible fibre with adequate moisture. This translates to a diet that mainly consists of grass hay and leafy greens. Overconsumption of high-energy commercial pellets or starchy food (eg grains and legumes) can slow down gut motility.

An example of an appropriate diet for an adult rabbit:

  • unlimited amount of grass hay (not lucerne hay – lucerne is a legume not a grass)
  • around 1 cup of fresh leafy greens (eg spinach, chard, kale, carrot tops, beetroot tops, parsley, dandelion greens, mustard greens, chicory, endive, basil, mint, coriander, wheat grass)
  • about 1/8 cup of grass based pellets

The grass hay not only provides the indigestible fibre needed by the gut, but also something to wear down your rabbit's constantly growing teeth.

Gut stasis can also be caused by:

  • dehydration (either inadequate water intake or an underlying medical condition)
  • stress or pain – these can not only reduce your rabbit's appetite but also disrupt the fusus coli because it is influenced by stress hormones
  • inactivity – good gut motility is positively influenced by exercise
  • ingestion of foreign bodies – as we mentioned, rabbits can't vomit so if they swallow something that can't be digested, it can form an obstruction

Note that hair balls are not really a problem in rabbits. They do occur but only is there is an underlying problem of dehydration and reduced motility.

What are the signs of gut stasis?

Common signs of gut stasis include:

  • reduced/no appetite 
  • smaller/no droppings
  • hunched or bloated appearance
  • lethargy
  • grinding teeth or grunting

If you see any of these signs, consider it an emergency! Rabbits do die from gut stasis. The earlier you seek treatment, the more likely you are to get a good outcome.

How is gut stasis treated?

Treating gut stasis typically involves the following.

Rehydration

This is one of the most important aspect to treatment. For very mild dehydration, offering fresh greens may be enough. Fluids in the form of critical care gruel, electrolyte solution or diluted fruit juice can be given orally. More severely affected rabbits may need fluids under the skin or intravenously.

Pain relief

Pain can cause gut stasis and gut stasis itself is a painful condition, so pain relief is very important. Relieving pain reduces stress and helps appetite. 

Commonly used medications are:

  • buprenorphine (an opioid medication)
  • meloxicam (a nonsteroidal anti-inflammatory).

Gastric motility medications

Drugs that stimulate the gut to start moving again can be useful. The most commonly used motility modifiers are:

  • ranitidine (Zantac®), which is also an antacid medication
  • metoclopromide, which can also reduce nausea.

Assisted feeding

It's critical to get your rabbit eating again to avoid complications of starvation such as fatty liver disease. The goal is to provide indigestible fibre (to drive gut motility), some carbohydrates (for energy) and enough fluid to correct dehydration.

Make sure your rabbit has access to hay, leafy greens and fresh water. You might also need to syringe feed a high-fibre gruel (eg Oxbow Critical Care®) 3–4 times per day if your rabbit isn't eating well on her own.

Other treatments that might be needed include:

  • nasogastric tube feeding – for rabbits that are critically ill and too weak for syringe feeding. Only very narrow tubes fit down a rabbit's nose, so it's hard to get fibre down these
  • removing the gas/fluid from a bloated stomach – sometimes stuff can be removed via a nasogastric tube, otherwise a larger orogastric (through the mouth into the stomach) tube might be needed. Sedation is usually needed to pass this type of tube
  • surgery – where there is a foreign body, we might need to do surgery to remove it.

Apart from being a very serious condition, gut stasis can be expensive to treat. Just the medications alone can cost around $150–200. If hospitalisation is needed, you could easily spend several hundred dollars and if surgery is needed, this can be thousands.

For the sake of your bunny and your finances – prevention is better than cure and this is as simple as feeding a good diet!

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