Most commercial diets that are available in pet stores and are marketed towards rats are not nutritionally appropriate for them. Anything in the form of a mix, with seeds/nuts/grains, is not appropriate as the staple diet for a rat. It might be suitable for an occasional treat, but not as the main source of sustenance.
As far as commercial diets marketed for rats are concerned, there are only three that meet with general approproval from the pet rat community:
- Harlan Teklad (also referred to as HT or NativeEarth)
- Oxbow Regal Rat
- Mazuri Breeder 6F
Harland TekladHarlan Teklad diets are manufactured as diets for lab rats. As such, they need to be nutritionally complete, because lab rats are fed lab blocks and only lab blocks. Introducing other foods can cause disparity between control and test groups and it is important that dietary variables are kept completely constant so that they do not affect the results of the trial. Thus, not only is the Harlan Teklad diet guaranteed to be as complete as our current knowledge can make it, it is also manufactured consistently across batches.
Harlan Teklad is also available in multiple formulas, each with different protein levels, but the only one commercially available is 18% protein. The other formulas are available from some rescues.
Harland Teklad is the choice among many rat lovers because it is nutritionally complete. However, there are a few drawbacks. First, it is only truly balanced if that is the only food being fed to the rats. Once we introduce anything else (fruit, veggies, cereal, treats, table scraps), that balance goes out the window. Most pet owners enjoy introducing their rats to a variety of healthy foods and a few guilty pleasures.
Second, Harlan Teklad isn't readily available. It can be purchased in very large bags from some online retailers in the form of Native Earth, but that incurs high shipping costs, or it can be purchased from some rat rescues, who buy the larger bags and then divide it up into smaller portions for sale to support their rescue.
Finally, Harlan Teklad is not made with the finest ingredients. Just because it is balanced and consistent does not mean it has to be wholesome. One of the biggest drawbacks is the inclusion of dried corn, which may contain a fungus known as aflatoxin. With last year's very dry summer, aflatoxins are going to be an even more prevalent problem than usual.
Oxbow Regal Rat
Mazuri Rodent Breeder 6F
Other OptionsIf the quality of ingredients is more important to you than the nutritional balance of a food designed specifically for rats, then you have two options. You can look for a high-quality dog food with human grade ingredients that also has the approximate fat and protein contents appropriate for rats or you can attempt a fresh diet.
In general, when selecting a dog food, we like to avoid anything with corn. Read the ingredient list and look for human grade ingredients and avoid anything with byproducts and artificial preservatives/chemicals/additives.
We look for something with a fat content close to 6%. Ideal protein content depends on the gender, age, and fitness of the rats. For large males, 14% is ideal. For females, 16% is ideal. For young ones, 18% or even higher is okay. However, it is unlikely that you will find any dog food with protein contents so low. Innova Low Fat used to be at 18%, but then changed its formula and went up to 20%. Blue Buffalo Healthy Weight comes in at 20%, which is about as good as I have been able to find. Dogs, in general, need more protein than rats, and the dog foods are formulated accordingly. The best dog foods for rats tend to be low-fat, weight maintenance, or senior varieties. However, all is not lost. When feeding a dog food, it is usually recommended that the diet be supplemented with other foods, including cereal/grain mixes, that can help bring down the total protein content in the diet. In other words, dog food should not be fed as the only source of nutrition.