A correct diet plays a fundamental role in the health of guinea pigs; dietary errors cause serious disorders, including metabolic, gastrointestinal and dental problems, which can sometimes be fatal. It should be remembered that the guinea pig is an obligate herbivore (not a granivore) which needs vitamin C; its diet must respect these physiological characteristics. Furthermore, it is very important to avoid abrupt changes in a guinea pig’s diet in order not to cause serious intestinal disorders.
Guinea pigs are very difficult to please with regards to their dietary habits. They can easily refuse to eat a type of food that they did not learn to know when they were young. A change in a food container can also cause them to stop eating.
The diet must contain the following components: 18-20% protein, 12-16% fiber and 3-4% fats. The diet must be based on unrestricted access to good quality hay and fresh vegetables and moderate amounts of good quality pellets for guinea pigs. Among the vegetables offered, precedence should be given to leafy ones, Brassicaceae, peppers, and fruit rich in vitamin C, in order to avoid vitamin deficiency; some examples are: red chicory, lettuce, parsley, chards, broccoli, cabbage, spinach, endives, field plants (in particular dandelions) and citrus fruits.
Rabbit pellets are not suitable for guinea pigs because they do not contain vitamin C. In any case, it should be remembered that vitamin C is very labile and breaks down within about 6 weeks of production. Some products contain stabilised vitamin C, which should last longer. Pellets should be stored in a hermetically sealed container in a refrigerator. Pellets for guinea pigs usually contain 18-20% of protein and 10-16% of fibre. Mixtures of pellets and seeds are commercially available, but these are not appropriate for either guinea pigs or rabbits because they are too rich in fats and carbohydrates and poor in fiber. Furthermore, they do not contain adequate amounts of vitamin C.
Fruit and vegetables must be carefully washed to eliminate traces of pesticides and any contaminating bacteria. Field plants must be collected from areas not exposed to car exhaust fumes, or where pesticides or herbicides could have been used.
A balanced diet provides the required amount of vitamin C. If it is necessary to give supplementary vitamin C, this can be added to the drinking water at a dose of 0.5-1 g/L: the water should be replaced every 12 hours. Vitamin C can also be given directly by mouth in the form of drops. Other types of supplements are superfluous or even harmful.
Water must always be available. It is worth noting that guinea pigs that drink from a siphon water dispenser can block the nozzle with food residues, so the correct function of the dispenser should be checked regularly. Furthermore, guinea pigs like playing with siphon water dispensers, blowing the water just delivered back into them. This can cause contamination of the drinking water as well as obstruction of the dispenser.
The errors to avoid are:
- administration of:
- carbohydrates of any type (bread, biscuits, breadsticks, cereals, cereal flakes, etc.)
- seeds of any type
- snacks for rodents (yoghurt sweets, cereal bars, bars of seeds and honey, etc.)
- milk-based products, because guinea pigs do not tolerate lactose
- the leaves and green parts of potatoes and tomato leaves, since these are toxic
- abrupt changes in the diet;
- changes in food or water containers without monitoring that the guinea pig continues to eat and drink;
- not regularly providing a broad range of vegetables, to avoid the guinea pig from restricting its diet to a few types and not accepting new food stuffs in the future.