The ferret is an obligate carnivore or, as it also defined, a ‘hypercarnivore’, that is, a species with a strong dietary specialisation for animal prey in which the intake of vegetal foodstuffs in nature is insignificant.
The natural diet of the skunk, the ancestor of the ferret, is small prey such as rodents, which are eaten (whole) several times a day. As adaptations to this diet, ferrets have dentition suitable for seizing and tearing prey, a relatively simple and short bowel with a small diameter and without a caecum, and a fairly fast gastrointestinal transit time (3-4 hours), aimed at absorbing the main nutrients of high biological value, with negligible intestinal flora. The ferret uses fats (not carbohydrates) as its main source of energy.
The precise dietary needs of the ferret are not known and are extrapolated from those of the mink. It is thought the nutritional needs of an adult, healthy ferret are:
- proteins, 30-40%
- fats, 20-30%
- carbohydrates and fibre, nil.
- daily calories, 200-300 kcal/kg
The intake of dry food varies depending on the age, size, gender, etc. of the animal, but, on average, is 140-196 g/day. Water must always be available; the average intake is 75-100 ml/day.
PROBLEMS RELATED TO AN UNSUITABLE DIET
- An excess of carbohydrates leads to obesity and is thought to predispose to insulinoma.
- Fibre can be the cause of inflammatory bowel disorders, which are particularly common in ferrets. The fibre content should not exceed 1.5% of the diet.·
- Fish is not a suitable foodstuff for ferrets: it has an unbalanced amino acid composition, is not well accepted or tolerated and can cause vomiting.
- Vegetal proteins are poorly assimilated and are associated with the development of urinary tract stones (because of the alkalinisation of the urine), a dull coat and stunted growth in the young.
- Commercial wet foods are contraindicated because they predispose to the development of periodontal disorders.
THE DIET IN PRACTICE
In practice, there are various choices of food for ferrets:
- traditional commercial kibble diets,
- commercial foods based only on animal ingredients,
- prey (e.g. quails).
The different types of diet can, of course, be varied and alternated.
Commercial diets
The ideal diet should contain only ingredients of animal origin and should not include fish or cereals. However, there are no commercially available kibbles that fulfil these requirements completely, but only some that approach the needs of the ferret. The diet should contain as little carbohydrate as possible and the fibre content should not exceed 1.5%. The presence of cereal in kibbles is essential for technical reasons (as a binder or “glue” to keep the kibble together) and this ingredient is always present, in percentages varying up to 40%.
When choosing the food an assessment must be made not only of the percentage composition, but also the list of the ingredients: food of animal origin (meat, meat meal, animal fats) should be in first place; rice is preferable to corn. A premium food for kittens may have a similar or better composition than foods specific for ferrets and be suitable for the dietary needs of the mustelids.
It is suggested that ferrets be given at least three different types of high quality, commercially available food to minimise the risk of deficiencies or excesses of some elements and to prevent the ferret become dependent on a single source of food. Wet foods (chunks, paté and tinned) should be avoided because they facilitate the development of dental disorders.
Alimentation with commercial, meat-only diets
Based on the principle that domestic carnivores are physiologically adapted only to the ingestion of animal prey and should be fed consequently, meat-only diets for these animals are beginning to spread. These new diets contain only food of animal origin (muscle, fat, bone), properly integrated with minerals and vitamins, which is raw, frozen or dried and contains no preservatives or chemical additives. Some of these diets are just beginning to be imported into Italy, but are still difficult to find. They could be a valid dietary alternative for ferrets, if they are demonstrated to be suitable.
Prey in the diet
Among American authors, the concept that the ideal diet to give to ferrets consists of prey (mice, rats, chicks) is gaining ground. In the USA this idea is relatively easily translated into practice because frozen mice and small rats, destined for feeding carnivorous reptiles, are readily available. In Italy this type of diet can be problematic not only from a practical point of view (that is, availability) but also as a proposal to submit to the owner, for obvious reasons. A practical alternative would be to give the ferret some quails or chicks to eat (Fig. 1). A diet consisting of whole prey is complete and balanced from a nutritional point of view, is easily digested, provides optimal exercise for the teeth, gums and muscles of mastication and leads to the formation of small, compact faeces (the main nutrients are assimilated rather than excreted in the faeces). The potential danger of this type of diet lies in the possible transmission of pathogenic bacteria; it is, therefore, important that the prey is obtained from safe sources.
Treats
Fresh, cooked meat (also with the fat), homogenised meat baby foods and cooked eggs can be given to ferrets as occasional treats.
Contraindicated foods
Food for dogs, adults cats and poor quality diets for kittens and ferrets are contraindicated because they do not meet the nutritional needs of these mustelids. All food of vegetal origin, food rich in carbohydrates and food containing milk or lactose must be avoided completely.
FREQUENCY OF MEALS
The dry commercial foods can be left available at all times. If prey or fresh meat (raw or cooked) is used, the amounts should be small and given frequently; normally the ferret eats nine or ten small meals a day and stops eating when it has satisfied its own calorie requirements. Food that is particularly palatable or very rich in lipids could interfere with these regulatory mechanisms and lead to obesity, necessitating appropriate rationing. It should be noted that the ferret tends to hide food that it does not eat immediately; in this case, fresh food can rapidly become rotten.
PARTICULAR REQUIREMENTS
In the case of obesity it is not advisable to use diets with a higher fibre content, but rather the overall daily amount of food should be reduced (continuing to give the animal small, frequent meals) and physical activity encouraged. Elderly ferrets should be given food that contains a lower percentage of protein in order not to facilitate renal pathologies. Frail ferrets or those requiring assisted feeding should be fed with specific veterinary diets that are commercially available.
SUPPLEMENTS
A diet of excellent quality does not require vitamin supplements; it is, however, advisable to give small amounts of aromatised laxative paste regularly during the period that the ferret is moulting in order to facilitate the expulsion of ingested hair.