The small furry market is an increasingly important sector for pet food manufacturers and covers a number of different animal species, but not all small furry animals are equal when it comes to nutrition. For example, rabbits, guinea pigs, chinchillas and degus can be considered as ‘fibrevores’ whilst rats, mice and hamsters are omnivores and ferrets are obligatory carnivores. Clearly their nutritional requirements and thus digestive physiology vary widely between small furry pets. 

Small animal nutrition, particularly in relation to rabbits, is a topic of discussion which has been hotly debated over recent months, with the PFMA holding a rabbit symposium in June for its members in order to provide the latest information on rabbit nutrition and welfare and the publication of a number of recent scientific papers assessing the efficacy of diet type on rabbit nutrition and welfare. 

Nutritional Requirements of Rabbits                                                                                          

Fibre (particularly long fibre) is an essential part of the pet rabbit’s diet and is required to maintain normal gut function, dental wear and to provide substrate for normal fermentation in the caecum.   This is normally provided in the form of good quality hay. Fibre can come from either a compound feed and/or forages although the advice should always be to feed good quality hay alongside anything else. It must be reiterated that quality of the hay is absolutely vital. Their diet therefore contains large amounts of cellulose, which is hard to digest. Rabbits solve this problem by caecal fermentation and passing two distinct types of faeces: hard droppings and soft black viscous pellets (cecotrophes also known as ‘night faeces’), the latter of which are immediately eaten.  This double-digestion process enables rabbits to use nutrients that they may have missed during the first passage through the gut, as well as the nutrients formed by microbial activity and thus ensures that maximum nutrition is derived from the food they eat. 

Rabbits are hindgut digesters. This means that most of their digestion takes place in their large intestine and ceacum (a secondary chamber between the large and small intestine containing large quantities of symbiotic bacteria that help with the digestion of cellulose and also produce certain B vitamins). In rabbits, the ceacum, along with the large intestine, makes up roughly 40% of the rabbit's digestive tract.

The calcium content of rabbit foods also needs to be carefully considered as rabbits continue to absorb calcium from their food, even if they no longer have a requirement for it. Limiting calcium to around no more than approximately 1%* of the total diet and ensuring a balanced calcium:phosphorus ratio of between 1.5:1 and 2:1 is advisable. An imbalance of calcium along with insufficient enrichment (such as gnaw sticks or similar) does have the potential to lead to dental problems.

It is important that feeding guidelines for prepared rabbit feeds are not only clear and followed by the pet owner, but indicate that it should be fed alongside forage (for example, high quality hay) as a source of long fibre, suitable fresh vegetables in small quantities, fresh water and supplementary snacks or treats high in indigestible fibre (gnaw sticks or similar). By prepared feed, which should be nutritionally balanced, high in fibre ingredients and well balanced for palatability of components, requiring to be fed in conjunction with other feed ingredients, it is generally required to market prepared feed for rabbits as “complementary”, rather than “complete”, for which the PFMA have published some recommended statements for inclusion on rabbit foods. 

Nutritional Requirements of Guinea Pigs, Hamsters and Ferrets

The Guinea pig is well known for its requirement for dietary vitamin C which makes its nutritional requirements stand out from all other common small furry pet species.  Typically a minimum supplementation of 200mg/kg is recommended. As with rabbits, the calcium content of guinea pig diets should be moderated as by not doing so can lead to urinary tract problems. Guinea pigs (along with chinchillas) also require access to good quality forage (hay and/or grass) and treats to help ensure they can wear their teeth down and avoid dental issues. Hamsters have a higher requirement for vitamin A than other small pet species. Ferrets are obligate carnivores and need to eat a diet consisting mainly of meat or materials derived from animals. The nutrient requirements of ferrets are less well understood than for cats; however ferrets need a higher level of quality protein, more fat and less fibre than a cat. Supplementation of taurine in prepared diets for ferrets is normally recommended, typically at levels similar to that for cats (1000mg/kg in dry foods and 2000mg/kg in canned foods).  

Although there are no published requirements (for example, FEDIAF nutritional requirements) for these or any other pet small animal species (with the exception of rabbits), the best source of information for nutritional requirements of most small animal species is the NRC Nutritional Requirements of Laboratory Animals, 1995. Although there will be variation and differences in nutritional requirements of laboratory animals versus their domesticated pet equivalents, this source of information gives best guidance to assist in formulating the most appropriate nutritionally balanced feeds for our small furry animal companions.

Conclusion

The number of peer reviewed publications available that define the nutritional requirements of small pet animals varies widely from rabbits which are relatively well studied to degus where little published data exists and other species in between these two. It is fair to say that the scientific community has historically been predominantly focused on the nutrient requirements of dogs and cats with little or no investment in studying other pet species.  However, over recent years FEDIAF has published nutrient requirements for pet rabbits which represent a significant step forward for the industry (FEDIAF, 2013) and the PFMA has created a number of helpful fact sheets and tools relating to small animal nutrition, diet and welfare. The key is to extend the activity of creating nutritional guidelines to other popular species but data is required to perform the required robust reviews.  It is clear that nutritional requirements vary widely from one species to another, but until published nutrient requirements become available, we as nutritionists will continue to rely upon our expertise to translate the nutritional requirements of laboratory species to our pets. 

*Based on a 12% moisture content of the feed, assuming 10MJ DE/kg

For further information on this article please contact your Pet Nutrition Account Manager (contact details below), or, alternatively, please e-mail info@premiernutrition.co.uk 

Andrew Miller              Andrew.Miller@premiernutrition.co.uk        +44(0)7969 246642

Sara Rowley               Sara.Rowley@premiernutrition.co.uk          +44(0)7786 436712

Cara Freeston-Smith  Cara@premiernutrition.co.uk                       +39 345 892 3860

Graham Yeo               Graham.Yeo@premiernutrition.co.uk           +44(0)7753 796215