On of the single, most important aspects related to keeping your hedgehog happy and healthy is fulfilling their dietary needs. Although most commonly described as insectivores, hedgehogs may also be accurately labeled as obligate carnivores. This means that during the course of a day, a hedgehog will consume a variety of insects, meat, plants, and other matter. However, in the wild, a hedgehog's diet would consist mostly of insects and other "meat" based nourishment, while vegetables, fruits, and other matter would only randomly and occasionally be consumed if the latter were not readily and immediately available. Unlike humans, dogs, and other more direct and obvious omnivores, hedgehogs have a short and simple digestive tract (Johnson-Delaney, n.d.). Much like cats and ferrets, who also will occasionally consume fruits and vegetables given the right circumstances, the length and composition of a hedgehog's digestive tract simply does not allow them to extract and utilize the nutrients in plant matter in the same way as omnivorous animals. In this article, we will examine the various components surrounding the dietary requirements of obligate carnivores, in contrast to the common beliefs concerning the dietary needs of pet African Pygmy Hedgehogs.
Establishing Hedgehogs as Obligate Carnivores
An obligate carnivore is defined as " an animal that necessarily subsists on a diet consisting mainly of meat, because it does not possess the physiology to digest vegetable matter. Such animals may consume other materials (vegetable or mineral) for non-nutritional purposes (Definition.org, n.d.)." Because hedgehogs are considered insectivores, one would assume insects would comprise a large portion of the captive-bred hedgehog's diet as well. The issue here lies within both the variety and availability of nutritionally appropriate protein sources. First, a large portion of what a wild hedgehog would consume would not be insects at all. The Caimbridge English Dictionary (n.d., as cited in Cambridge University Press, 2017) defines an insect as "a type of small animal with six legs, a body divided into three parts, and often two pairs of wings, for example, an ant, beetle, or butterfly." So the term "insectivore" often leads us to leave out the variety of worms, mollusks, and other invertebrates belonging to an entirely different phylum of animals, that would generally account for much of a wild hedgehog's meal. For example, earthworms are an important source of protein and nourishment in a wild hedgehog's diet. Earthworms are of the Phylum Annelida and subclass Oligochaeta, meaning they do not classify as insects. They are extremely high in protein when examined on a dry matter basis and have an amino acid composition that would be considered alike to that of eggs and fish meal (Zhenjun, Xianchun, Lihui, & Chunyang, (1997). These are ingredients commonly found in many commercial cat foods.
That is not to say hedgehogs do not consume many insects as well. Caterpillars are reported to be a hedgehog favorite and although worm-like at the time, would be considered insects as they will eventually evolve into moths or butterflies. According to a study carried out at Wageningen University (n.d., as cited in Scott-Thomas, 2013), insect protein is comparable to that of the more traditional animal proteins, such as chicken and contains all of the essential amino acids we would find in conventional meat sources. Also remember that hedgehogs will naturally consume whole eggs and small, whole prey, such as pinky mice, if given the opportunity.
Unfortunately, there are limited studies which focus on hedgehog health behavior, & nutrition. Breeders, veterinarians, and pet owners alike are left to hypothesize nearly all matters related to maintaining hedgehogs in captivity. It is important to keep in mind that no information appears to exist regarding a hedgehog's ability to adjust protein utilization. But given the likenesses in digestive tract composition, as well as the similarities in nutritional value between the non-conventional protein sources consumed by wild hedgehogs and the more traditional sources commonly consumed by other carnivorous animals, we can conclude that in terms of nutritional requirements, there is a strong connection between insectivorous hedgehogs and other more commonly recognized obligate carnivores, such as cats and ferrets.
One problem with this statement is in order to view hedgehogs in this manner, one must concede to the notion that as a collective whole, breeders, pet owners, and even some veterinarians have not been going about things in the right way. This statement alone is likely to cause a good deal of backlash from those who refuse to keep an open mind. In that event, any and all counter arguments are welcome. However, despite a wide and detailed search, there really is very little information to justify feeding hedgehogs protein and fat levels which are often considered too low for other obligate carnivores. This is in addition to the unbelievable amount of carbohydrates and indigestible protein sources that have been pushed on them for so many years. However, that does not mean one should simply go out and pick a food based on a high protein percentage. There are many factors to consider when selecting a food in order to avoid all of the issues that have scared hedgehog owners away from protein to begin with. Some of the myths surrounding high protein in the diet are in fact valid, but simply neglect to take into account several key factors which override the validity of these myths when applied to the diet of an obligate carnivore.
Meeting the Nutritional Requirements of Obligate Carnivores
Obligate carnivores require a high amount of protein in their diet to achieve and maintain prime system function. However there are many myths and misunderstandings which have skewed the truth when it comes to the dietary needs of such animals. Here we will explore the needs of obligate carnivores in contrast to common, popular beliefs surrounding the nutritional requirements of hedgehogs.
The Need for Protein
In order to understand the need for a diet adequate in protein, one must understand the role of protein in the body. Proteins are large molecules which are comprised of chains of amino acids. They are responsible for bodily function and can act as antibodies which function in immunity, enzymes, structural components, transport of atoms and small molecules throughout the body, and will act as messengers to communicate messages between cells. When humans and other animals consume protein, such as in meat, those proteins are broken down into amino acids which then go on to build new proteins in the body of the consumer. The remaining matter is excreted as waste.
Unfortunately for hedgehogs, no concrete studies have been done outside of natural habitat observation regarding their diet. What we do know is that a hedgehog's diet in the wild would closely mimic that of a cat, ferret, or other obligate carnivore that naturally thrives on a high protein, low carb diet. Remember, many of the worms and insects hedgehog's consume have amino acid profiles similar to eggs and larger prey animals. Therefore, using this information we can assume the protein requirements in hedgehogs would be similar to that of a ferret or cat.
So what happens when protein levels dip too low? Keep in mind this may even happen when feeding a high protein food if a large portion of the protein content is derived from vegetable matter, as hedgehogs cannot break down and utilize vegetable protein in the same way as humans or dogs would. This can cause deficiency issues unless the animal eats more food to make up for deficits.
Low protein levels may result in a wide variety of issues which are unusually and unexplainably common to African Pygmy Hedgehogs. For example, when a hedgehog is diagnosed with "Wobbly Hedgehog Syndrome" by a veterinarian and the hedgehog is sent of to a specialist for necropsy upon its death, it is most commonly found the hedgehog has died from something more easily explained. Fatty Liver Disease (FLD) is a fairly common cause of the "false WHS diagnosis", as symptoms can include wobbling and a progressive deterioration period. According to Kneeman, Misdraji, & Coreyon (2012), Non-Alcoholic FLD can be linked to starvation and protein malnutrition. It is common for hedgehogs who go off their feed for any extended period of time to experience signs and symptoms of liver disease or deterioration, but it is also possible that some cases of FLD are caused by chronic protein deficiency based on the hedgehog's genetic makeup and the contents and nutritional profile of their daily diet. In most cases, treatment of FLD and other diseases of the liver rely upon boosting he level of protein in the diet, rather than decreasing these levels.
Among other issues, protein deficiency can also cause weight loss and anorexia, a weak immune system with proneness to chronic, low-grade infection (Sanderson, 2016), and may also lead to obesity when the animal begins to eat unnecessary amounts of food in an attempt to satisfy its nutritional requirements (Tudor, 2013). It is all to common to hear of hedgehogs suffering from low-grade infections and generally insufficient immune systems. Although not among the most common of deadly issues, weakened immune systems could play a role in the development of Wobbly Hedgehog Syndrome in pet hedgehogs, as it is possible the resulting white matter lesions are secondary to infection. Additionally, animals on a low protein diet experience a reduction in glomular filtration rate, which is the amount of blood filtered through the kidneys. A decrease the glomular filtration rate will, in turn, result in a decrease of toxins being removed from the body (Hamilton, n.d., as cited in Scott, n.d.). This leads one to then question why a diet which is relatively low in protein when compared to the natural diet of hedgehogs, would be recommended and encouraged for pets. The main concern among breeders, pet owners, and even some veterinarians is the potential for a high protein diet to cause kidney damage.
Protein Digestibility - The Kidney Damage Conundrum
A very common myth is that feeding your hedgehog a diet with a protein percentage above 35% will inevitably result in renal disease or failure. This is simply false and is a result of an outdated study which was done using rats being fed an inappropriate diet and does not apply to obligate carnivores, such as cats, ferrets, and hedgehogs (Falconer, 2015). Other, outdated studies also exist, but are likewise flawed. None have examined hedgehogs specifically, nor have they taken into account the specific dietary needs for this species, which are not yet fully known.
Still, some current studies have found that excess digestible protein does not only fail to cause kidney damage, but also will not cause progression of issues with existing renal failure (Finco et al., 1998). However, high phosphorus levels in the diet have been positively identified as a component in the progression of renal disease and may lead to Hyperphosphataemia. Because meats are high in phosphates, it is of upmost importance that animals with chronic kidney disease be fed a diet with balanced calcium-phosphate ratios. The need for a phosphate binder may still apply, even when balanced ratios exist (Thompson, 2016). Some vets do recommend the use of niacin, also known as vitamin B6, instead of traditional phosphate bineders due to a lower risk of toxic effects (Falconer, 2015). But it is important to remember this applies to animals with CKD and not to healthy pets with well functioning kidneys. Even so, in most cases a drastic reduction in protein would be detrimental, even to pets with CKD.
Now one must take into consideration the type of protein being fed in relation to overall digestibility. Because hedgehogs cannot utilize vegetable protein in the same manner as omnivorous animals such as dogs, it is extremely important to exclude foods high in what we will call "indigestible" proteins from the diet in order to reduce the amount of nitrates being passed through the kidneys. Keep in mind it is not that the these proteins are technically indigestible in general, but the term theoretically fits in this case due to the hedgehog's digestive composition. This is where there is some valid concern and confusion surrounding feeding a hedgehog a high protein diet, as often high protein cat foods are high in indigestible proteins, such as peas, soy, and grains. Feeding a food high in vegetable protein and carbs can in fact further stress kidneys that are already damaged to begin with, due to the high amount of nitrate by-products that are excreted (Doctors Foster & Smith Educational Staff, n.d.). However, it is important to refrain from reducing the amount of protein in your pet's diet, regardless of kidney health, without first consulting a veterinarian. Only very specific circumstances warrant modification to protein intake (Peterson, n.d.). Instead, by changing the type of protein you are feeding your pet, you are promoting a healthy cellular environment and allowing your pet's system to work as it was naturally designed.
Determining Digestibility
There are a few various systems by which foods are scaled for degree of digestibility. Each system has its flaws, but one system most commonly used would be the system of "biological value". Each food is given a number, with 100 being the most digestible. Eggs have a biological value of 100. Keep in mind, eggs also have an amino acid composition similar to Earthworms, which is a favorite of wild hedgehogs. Fish and milk follow close behind at a score of 92, chicken scores a 79. Keep in mind that hedgehogs will also naturally eat foods with a low biological value while forging, such as bones. Feeding your hedgehog a steady diet of eggs and nothing else will not do them any favors, but will rather rob them of other important nutrients. The goal is to mimic the natural diet as closely as possible.
Hedgehogs being fed an appropriate diet full of digestible proteins will eat less, produce less stool, and maintain their weight much easier than an animal being fed a diet that is high in fillers and "indigestible proteins." This is because proteins are broken down into useable amino acids and the remaining product is excreted as waste. Let's say a food has a biological value of 79, such as chicken. Although it is more complicated overall, for the sake of argument we will say 79% of what goes in can be utilized, the rest will be excreted. The more efficiently a food is broken down and utilized by the body, the less the body will require to feel satisfied. By feeding digestible proteins, you will naturally reduce the overall fat and calorie intake, thereby leading to a more balanced and healthy weight long term while simultaneously preventing issues associated with protein deficiency and likewise reducing the amount of nitrates being filtered.
When High Protein Goes Wrong. Is there ever a time to lower the protein?
In most cases, any healthy animal with a healthy liver and kidneys will have no issues eating a diet containing the appropriate amount of protein for their species. It is often recommended that obligate carnivores, such as cats, are not put on a reduced protein diet due to the fear of protein malnutrition. In the case of Hepatic Encephalopathy, protein reduction only follows clinical symptoms of the disease and protein is only lowered enough to eliminate physical symptoms and then gradually increased over time in order to maintain the highest protein intake possible (Delaney & Fascetti, n.d.). In the case of end stage CKD, protein reduction may prove beneficial, in addition to lowering phosphorus (Falconer, 2015). Again, this shows even animals that have existing liver and kidney issues are often still encouraged to consume high levels of protein.
Kidney stones are an issue that can potentially surface when an animal is fed a diet high in protein. Like cats, hedgehogs consume prey with a high water content and often do not drink enough water to compensate that loss when being fed a dry kibble diet. Highly concentrated urine is often a sign of chronic dehydration. It is of extreme importance to always ensure your pet is provided with fresh water and in most cases, soaking your kibble before feeding may help your pet to avoid kidney stones caused by concentrated urine (Pierson, 2016). Additionally, carbs are likewise implicated in the formation of struvite stones in carnivorous pets and should be avoided (Becker, 2013). Instead, a more natural, meat based diet is critical for overall health and vitality.
Hedgehogs & Fiber
One area where insectivores like hedgehogs differ from other obligate carnivores is their overall dietary fiber requirements. Most carnivorous animals, such as cats and ferrets, do not possess the same need for dietary fiber and therefore, commercial foods have been formulated with a low fiber content. As previously discussed, although hedgehogs have a short and simple digestive tract, they do possess chitinase; digestive enzymes that degrade chitin, which then it to be utilized as a source of dietary fiber. Chitin is found in the exoskeletons of arthropods, such as insects & crustaceans, whereas cellulose is a main component in plant matter and is not as easily utilized. Preliminary studies have shown the addition of powdered chitin to a cat food diet to be a promising step in the right direction when it comes to mimicking the natural diet of the African Pygmy Hedgehog (Graffam, Fitzpatrick, & Dierenfeld, 1997, as cited in American Society for Nutritional Sciences, 1998) . By providing your hedgehog with adequate fiber in a form that is naturally consumed by their wild counterparts, you may potentially reduce some of the more common issues we face when keeping hedgehogs in captivity, such as obesity and related comorbidities.
Choosing a Food
Overall, the benefits of an obligate carnivore maintaining a high protein diet far outweigh any associated risk and may prevent some of the very problems pet owners were trying to avoid by feeding a diet low in protein. Obviously a natural diet is always going to be the best choice for any animal of any species. However, there is an Italian company which recently began selling their food in the United States. It is GMO, grain, and gluten free and contains an amazing 70% meat ingredients, with 95% of protein coming from animal sources. It does not contain peas or hormone altering soy ingredients. Additionally, their kitten formula (which is identical to their adult formula in the same variety), comes in very small pieces which are perfect for tiny hedgehog mouths. Is it perfect? Of course not, but it is by far the best we have found. If feeding a dry kibble is necessary, we highly recommend keeping your hedgehog on Farmina Prime Chicken & Pomegranate formula. You may use either the cat or kitten variety, as both have the same ingredients and nutritional value. The kitten formula simply has much smaller pieces which are much easier for hedgehogs to chew.
Additionally, we recommend adding chitosan powder and probiotics to your hedgehog's food daily. This will help offset the low fiber content of cat food, thereby providing them with something that is much closer nutritionally to their natural diet.
To purchase these products pre-mixed and heat sealed into a stand up zipper bag, please visit our online shop or simply click here.
It is our hope that by furthering our knowledge regarding the dietary needs of the species, we will in turn be able to prevent some of the common and not so common issues we see in hedgehogs young and old.
Note: This post may be periodically updated to reflect new or relevant information regarding dietary care in the African Pygmy Hedgehog. We encourage all to remain vigilant in checking food labels on each bag of food purchased, regardless of brand, as manufactures will occasionally change their ingredients. Therefore, what may once have been a great food for hedgies may no longer be suitable. We also encourage the research any and all information provided on this website by means of other breeders, veterinary guidance, and internet databases. We discourage owners from the well-meaning, yet dangerous practice of forming solid opinions based on one resource alone.
References
American Society for Nutritional Sciences (1998, December 01). Fiber digestion in the African White-Bellied Hedgehog (Atelerix albiventris): A preliminary evaluation. The Journal of Nutrition, Volume 128, Issue 12, Pages 2671S–2673S. Retrieved on January 1, 2019, from: https://academic.oup.com/jn/article/128/12/2671S/4724330
Becker, K. (2013, September 09). Your pets biologically imperfect food
can lead to struvite stones. Healthy Pets. Retrieved on December 11, 2017, from: https://healthypets.mercola.com/sites/healthypets/archive/2013/09/09/struvite-stones.aspx
Cambridge University Press (2017). Definition of “insect” - English
Dictionary. Cambridge Dictionary. Retrieved on April 08, 2017, from: http://dictionary.cambridge.org/us/dictionary/english/insect
Definition.org (n.d.). Definition of "obligate carnivore" [obligate
carnivore]. Retrieved on April 08, 2017, from: http://definition.org/define/Obligate%20carnivore
Delany, S., Fascetti, A. (n.d.). Nutritional management of liver
failure and hepatic encephalopathy. UC Davis School of Veterinary Medicine. Retrieved on December 11, 2017, from: http://www.vetmed.ucdavis.edu/vmth/small_animal/nutrition/client_info_sheets/encephalopathy.cfm
Doctors Foster & Smith Educational Staff (n.d.). Cat food & protein
facts. Doctors Foster & Smith. Retrieved on December 09, 2017, from: http://www.drsfostersmith.com/pic/article.cfm?articleid=547
Falconer, W. (2015, April 12). Feeding the kidney patient: the low
protein diet myth. Vital Animals. Retrieved on December 11, 2017, from: https://vitalanimal.com/low-protein-diet-myths/
Finco DR1, Brown SA, Brown CA, Crowell WA, Sunvold G, Cooper TL.
(1998, May). Protein and calorie effects on progression of induced chronic renal failure in cats. American Journal of Veterinary Research, 59(5):575-82. Retrieved on May 06, 2017, from: https://www.ncbi.nlm.nih.gov/pubmed/9582959
Johnson-Delaney, C. (2006). Anatomy and physiology of the
gastrointestinal system of the ferret and selected exotic carnivores. Association of Avian Veterinarians. Retrieved on April 08, 2017, from: http://www.aemv.org/documents/2006_AEMV_proceedings_4.pdf
Kneeman, J. M., Misdraji, J., & Corey, K. E. (2012). Secondary
causes of nonalcoholic fatty liver disease. Therapeutic Advances in Gastroenterology, 5(3), 199–207. Retrieved on May 04, 2017, from: http://doi.org/10.1177/1756283X11430859
Peterson, M. (n.d.). Nutritional Management of Feline
Hyperthyroidism: What's the Best Diet to Feed these Cats? Animal Endocrine Clinic. Retrieved on December 09, 2017, from: http://www.animalendocrine.com/wp-content/uploads/2011/01/Nutritional-Management-of-Feline-Hyperthyroidism-VMA-NYC.pdf
Pierson, L. (2016, November). Feeding your cat: know the basics of
feline nutrition. CatInfo.org. Retrieved on December 11, 2017, from: http://www.catfinfo.org
Sanderson, S. (2016). Nutritional requirements and related diseases of
small animals. Merrick Veterinary Manual. Retrieved on May 05, 2017, from: http://www.merckvetmanual.com/management-and-nutrition/nutrition-small-animals/nutritional-requirements-and-related-diseases-of-small-animals
Scott-Thomas, C. (2013, July 08). Insect protein ‘similar to
conventional meat’. William Reed Business Media Ltd. Retrieved on April 08, 2017, from: http://www.foodnavigator.com/Science/Insect-protein-similar-to-conventional-meat
Scott, D. (n.d.). Natural options for kidney disease and failure. Dogs
Naturally Magazine. Retrieved on May 06, 2017, from: http://www.dogsnaturallymagazine.com/kidney-failure-in-dogs-natural-treatment-options/
Thompson, L. (2016, January 16). Answers: phosphorus can be key for
kidneys. Feline Nutrition Foundation. Retrieved on May 06, 2017, from: http://feline-nutrition.org/answers/answers-kidney-disease-phosphorus-and-raw-diets
Tudor, K. (2013, June 27). More study results from the nutrition
symposium. Pet MD. Retrieved on May 05, 2017, from: http://www.petmd.com/blogs/thedailyvet/ktudor/2013/june/more-nutrition-studies-from-research-symposium-30509
Zhenjun, S., Xianchun, L., Lihui, S., & Chunyang, S. (1997).
Earthworm as a potential protein resource. Ecology of Food and Nutrition, 36(2-4), 221-236. doi:10.1080/03670244.1997.9991517
header.all-comments