Guinea pigs have a biological make up that creates special nutritional needs for them. Unable to synthesize (create) Vitamin C themselves as most other animals can, guinea pigs must have Vitamin C supplied through Vitamin C fortified guinea pig pellets and fresh vegetables.
Fiber in the appropriate quantity is also essential in the diet of guinea pigs. Additional fiber should be supplied through unlimited amounts of Timothy Hay. Additional Vitamin C can and should be supplied in fresh fruits and vegetables such as the following:
- Leafy greens such as kale, parsley, spinach and chicory
- Red and Green Peppers
- Dandelion Greens (no pesticides, fertilizer or herbicides)
Note: Fruits and vegetables should make up no more than 10-15% of the diet.
The recommended amount of food pellets to feed varies with each manufacturer based on the nutrition each product supplies. Oxbow Essentials for guinea pigs recommends 1/8 cup for mature guinea pigs (in addition to unlimited grass hay). Be sure not to feed rabbit pellets to your guinea pigs. While similar in appearance, rabbit pellets have a different nutritional mix than that needed by guinea pigs.
Commercial pellets should always be used when fresh. The reason fresh pellets should be used is that Vitamin C breaks down in a matter of weeks, which means your guinea pig will not get the full benefit of the Vitamin C. Guinea pigs deprived of appropriate levels of Vitamin C will, over time, develop the disease known as scurvy.
Guinea pigs are finicky eaters and do not easily tolerate changes in the flavor or make up of their diet. Any changes should be gradually introduced over a period of two to three weeks.
Guinea pigs practice coprophagy, that is, they eat their own special feces. As unappealing as it sounds, "cecotropes" (soft feces) supply both Vitamin B and Vitamin K to guinea pigs. Guinea pigs deprived of cecotropes will eventually develop malnutrition and will die.