Feeding guinea pigs excess blueberries will have an adverse effect on them and rather cause problems to the guinea pigs. Some of the problems include:
Obesity
The sugar content level of blueberries is quite high for guinea pigs, thus, feeding guinea pigs many blueberries can make them fat and overweight. It is thus important that you only feed guinea pigs blueberries in small amounts because blueberries contain much sugar.
Acidity
Blueberries also contain some acids which when taken in large quantities can be harmful to guinea pigs. When you feed blueberries to your guinea pigs, they run a risk of this and can develop mouth sores along with some other complications.
Excess blueberries can cause stomach problems
Excessively feeding blueberries to your guinea pig will do it more harm than good due to the presence of fiber in blueberries. Although fiber aids digestion, excess of it would cause problems to the digestive system rather than helping it. It can cause diarrhea, anorexia and other stomach problems.
With all these problems your guinea pig face if you feed it excess blueberries, it is very important that you only feed your guinea pigs blueberries as a treat and the serving size you give to your guinea pig should be small. Once or twice in a week is enough, make sure your guinea pig is not allergic to blueberries and that it also likes it before feeding it.
This makes it safe for guinea pigs to eat blueberries. Blueberries are good for your guinea pig in a small quantity.