Week 13: Rodents


Small Mammals and Birds Nutrition

Lecture Notes

Now, we'll start with rodents


Rodents

Lecture Notes

Rodents are mammals that come in a variety of sizes. From this small field mouse or to the large capybara from South America.


Rodent Diet

Lecture Notes

The diet of rodents is dependent upon the species. Species such as rats, mice, and gerbils are omnivores (meaning they eat meat and plants), while guinea pigs and chinchillas are herbivores (meaning they only eat plants). We'll talk about the hamster in a few minutes. Almost all rodents practice coprophagy, or the act of eating feces. It might sound gross, but it represents an important aspect of their nutrition. Rodents have very developed hind guts, in which they can ferment plant materials producing some aminoacids and vitamins. The problem is that aminoacids and vitamins cannot be absorbed in the large intestine, therefore they eat their feces to ingest those newly formed nutrients that were not present initially in what they ate. It's important to understand that those are not nutrients that were not absorbed the first time they went through the intestine, but nutrients that were formed after the absorptive section of the intestine.


Feeding

Lecture Notes

It is recommended to feed rodents a species-specific pelleted food to meet their nutrients needs. Some experts recommend not to use mixtures of foods to prevent rodents from selecting only what they like, thus promoting a healthy food intake, and preventing nutritionally related diseases. Fresh vegetables, fruits, and seeds may be provided as a treat, but it is important to only provide these in small quantities and to remove any leftover fresh treats daily to prevent mold growth. Rodents are generally very selective about their food choices and may avoid any new foods. It is important to slowly transition rodents to a new diet over the course of 1-2 weeks.


Rat and Mouse

Lecture Notes

Rats and mice are omnivorous species. They are hind-gut fermenters, meaning fermentation of fiber occurs after the stomach and small intestine. Because of this, they practice coprophagy to consume valuable nutrients that were newly formed in the hindgut and would be lost in the feces. Most commercially available pellets provide all the nutrients a rat or mouse needs. It is better to provide hard pellets and some supplemental grains, because they beneficially wear down incisor teeth. Their diet maybe supplemented with seeds, fresh vegetables, and fruits. However, it is important to limit their intake to prevent them from preferring the treats and not consuming the pelleted diet. In addition, too many treats can cause nutritionally related diseases. It is important that food is available at all times. We have to remember that they have a very fast metabolism and the lack of food can affect them seriously in a short period of time.


Hamster and Gerbils

Lecture Notes

Hamsters and gerbils tend to eat small, frequents meals. They have a higher protein and fat requirement than the rat and mouse, therefore some scientists consider them omnivores. However, hamsters require fiber, whereas mice and rats don't, making other scientists consider them as herbivores. This is one reason why you shouldn't feed your hamster rat or mouse food. On the other hand, gerbils are considered omnivores with no doubt. One aspect we must be aware of is that hamsters, using special pouches in their cheeks, will hoard food and store it in their hiding/sleeping place, while gerbils tend to hoard food by burying it in their bedding. This practice allows them to store food for later. Because they hide their food, it is important to limit the amount of fresh fruits and vegetables to what they can consume when provided. If those fresh products are hoarded, they could mold and make your pet sick.


Chinchillas and Guinea Pigs

Lecture Notes

Chinchillas and guinea pigs are both herbivorous species. As with rabbits, they have a higher fiber requirements. It is best to feed these animals a commercial pellet diet that is supplemented with a high quality hay, such as Timothy hay. Fresh forages should be avoided because of their high moisture content and can lead to softer feces and even to diarrhea if the forage is very young in maturity. If you want to feed fresh forages, it is recommended to let them sit and dry for 24 h after cutting them.


Guinea pigs

Lecture Notes

Guinea pigs are unique in their lack of ability to synthesize vitamin C, therefore have a dietary requirement. They are one of the few non-primate mammals with a vitamin C requirement. Because of this trait, guinea pigs are often used to the study scurvy, a disease that results from a vitamin C deficiency. It is important to feed commercial guinea pig pellets because they all contain vitamin C, whereas rabbit, mouse, or rat food won't probably contain it, and consequently they should be avoided . You can supplement their diet with fruits and green leafy vegetables to provide extra vitamin C. Alfalfa hay and alfalfa-hay based products can lead to kidney stones in adult guinea pigs. Therefore, it is best to feed Timothy hay and Timothy hay based pellets.


Sources

Lecture Notes