Like humans and other mammals, guinea pigs need vitamin C to keep their bodies functioning properly. Also like humans, but unlike other rodents and other animals, guinea pigs are unable to produce their own supplies of vitamin C. This means that they must get 100% of their requirements from the food and supplements you feed them.
Problems Caused by Vitamin C Deficiency
When guinea pigs don't have enough vitamin C in their diets, it can lead to a number of diseases and ailments:
Scurvy - This can cause your pets to become lethargic and depressed, and also exhibits symptoms including open wounds and loss of teeth.
Bone deformities - Similar to rickets in humans, this makes your guinea pigs' bones weak and twisted. This can make it difficult for them to move about, and can increase the chances of them breaking a limb.
Immune system problems - Vitamin C deficiency causes a general weakening of the immune system, leaving your cavy exposed to catching other, more common diseases. This also makes it more difficult for your pets to fight off and recover from diseases.
Vitamin C Requirements
Guinea pigs require roughly 10-20mg of vitamin C per kilogram of body weight per day. A typical adult male weighs around 1.2kg, with a female weighing around 1kg, giving average daily requirements of roughly 18mg and 15mg respectively. You should adjust vitamin C amounts for younger, growing guinea pigs according to their weight.
Pregnant sows require roughly double this amount, to take into account the fact that they are also providing nutrients to as many as 6 babies.
Remember that this is not an exact science, and don't worry about trying to calculate exactly how much vitamin C you are feeding your guinea pigs. Just give them a varied diet containing plenty of foods rich in vitamin C and you will be meeting their needs perfectly.
Fresh Vegetables and Fruit
These are the best sources of vitamin C, and also contain many other essential nutrients to help keep your cavies fit and healthy. Particular favourites are bell peppers, Romaine (cos) lettuce, and dandelion leaves, but it's best to include a range of fruit and vegetables in their diet on a daily basis.
Dried foods such as pellets or food mix also contain a certain amount of vitamin C. This is typically much lower than what you'd find in fresh foods, but many guinea pig foods have added vitamin C to make up for this. Together with vegetables and fruit, this will provide your guinea pigs with most, if not all, of their daily vitamin C requirements.
Vitamin C Supplements
If your pets still aren't getting enough vitamin C, you can top up their intake using supplements. These typically come in 2 forms - tablets, and supplements that you dissolve in their water.
Tablets are considered better because you can make sure they are eaten by the right animal. Where possible, buy the chewy type, as guinea pigs seem to love the taste, and will happily eat them up.
Water-soluble supplements aren't as effective as tablets because vitamin C quickly degrades in light and water, meaning that your pets will get very little value from them. They can also make the water taste funny, which can put your pets off drinking it, potentially leading to other serious health issues.
It's worth quickly mentioning multivitamins for guinea pigs. There are a few of these available on the market, but they can do more harm than good. While your cavies may need a vitamin C supplement, they usually do not have any trouble getting their other vitamins from a healthy diet. Multivitamins can lead to excessive levels of these other vitamins, which can cause health problems.
By taking care with their diet, it is not difficult to meet your guinea pigs' vitamin C needs. The best advice is to give them a varied diet with plenty of fresh vegetables, and the rest will usually take care of itself.