There are three main brands of lab blocks that are considered to be high quality food for pet rats. The companies who manufacturer these diets are Harlan Teklad (Since June 2015, Harlan Teklad has merged with Huntingdon Life Sciences and three subsidiaries under the company name, Envigo), Oxbow Animal Health and Mazuri.
I would not recommend feeding any of the rodent blocks or seed mixes typically sold in pet stores. Manufacturers of rodent diets sold in pet stores do not come close having done comprehensive research into the nutritional needs of rats. The ONLY exception to this are the Oxbow diets which are found in some pet stores (details below).
Before giving an overview of the three major brands of commercial rat diets, I’d like to talk a little about soy and protein.
From the research I’ve done, I believe it is helpful to feed soy, especially to females. Soy has been shown to reduce the occurrences of mammary tumors. After upper respiratory infections, mammary tumors are the second most prevalent health concern for pet rats.
Please Note: There are plenty of people who believe the opposite, that soy actually causes mammary tumors.
There are varying opinions on how much protein should be in a rat’s diet. Many experts believe the need for protein decreases as a rat ages. The ranges recommended throughout a rat’s lifespan are from 23-24% for babies and young rats down to as low as 5% for geriatric rats. I have not, however, seen any commercially available diets that have only 5% protein.
Harlan Teklad lab blocks are designed specifically for lab rats and are one of the highest quality foods you can buy. Even though they look like particle board, Harlan Teklad lab blocks are a nutritionally complete food. They contain all the essential vitamins, minerals, amino acids, fatty acids and macronutrients your rat needs.
However, I have to say I cringe when thinking that these diets were originally and are primarily designed for laboratory rats. (Hence the name “lab blocks”.) I am not a supporter of using any animals for laboratory testing. Unfortunately, this diet is still held in high esteem by many experienced pet rat owners even though the manufacturer created this diet for laboratory rats who suffer and even die during and after being subjected to experimental tests. Not only does Envigo manufacture and sell laboratory animal diets, but they also breed and sell the animals used for scientific experiments. The lab animals they sell range from multiple types and strains of rats to mice, guinea pigs, rabbits and dogs.
As mentioned above, in June of 2015 Harlan Laboratories merged with Huntingdon Life Sciences to form the company, Envigo. Huntingdon Life Sciences is one of the world’s largest animal testing labs. In good conscience, I’ve stopped feeding this diet to my own rats. I am still including the information on Harlan Teklad lab blocks here, however, since many pet rat owners still believe it to be one of the best diets.
Out of the many rodent diets they make, there are three Teklad lab block formulas most widely used for pet rats.
The above two Teklad lab block formulas contain no fish meal, meat meals or meat by-products, no alfalfa meal and reduced or eliminated soybean meal. (Soybean meal is only included in the ingredients of Teklad 2018.) The last two digits of each of the Teklad diets above corresponds to the percentage of protein in each diet. Teklad believes low fat, low protein diets promote longevity and normal body weight in rodents. The Harlan Teklad lab blocks specified above have only 4-6% fat.
Another diet, Teklad 8604, has soybean meal listed as the first ingredient and has a protein content of 24.3%. Teklad 8604 is designed to support gestation, lactation, and growth of rodents. This diet is a good one for young unspayed female rats since soybean meal is listed as the first ingredient.
Oxbow Animal Health offers two rat diets. One is for adults and the other is for young, pregnant or nursing rats.
For adults, Oxbow’s Essentials – Adult Rat Food, is a small kibble with 15% crude protein. This diet was introduced and recommended to me by my rats’ veterinarian. Oxbow’s adult, Regal Rat, diet is nutritionally complete and is low-fat to help maintain an ideal weight. The first five ingredients are Whole Brown Rice, Oat Groats, Wheat Bran, Wheat, and Soybean Meal.
For young rats, Oxbow Essentials Mouse & Young Rat Food contains 18% protein. Besides being used as a rat food,this diet can be fed to mice of all ages. Oxbow’s young rat diet contains added vitamins and minerals and is nutritionally complete. This diet’s first ingredient listed is corn, however, so it’s not ideal. The first five ingredients listed are Ground Corn, Soybean Meal, Wheat Middlings, Soybean Hulls, and Dried Whey. It contains no artificial preservatives, colors or flavors. It’s in the shape of a lab block. (I don’t know why they decided to make the young rat food a big block and the adult food a small kibble!)
I’ve been able to find the Oxbow diets in some, but not all, pet stores. Online, both the adult and young rat diets (Oxbow Essentials Adult Rat and Oxbow Essentials Mouse & Young Rat) can be found at the lowest prices on Chewy.com.
Mazuri’s Rat & Mouse Diet is their only pet rat formulation. They promote it as meeting the nutritional requirements for “breeding and non-breeding rodents”. It comes in the form of a lab block and, at 23%, this diet is very high in protein. Dehulled Soybean Meal is the first ingredient which makes it ideal for female rats if you believe that soy helps prevent mammary tumors (which I do). The Mazuri Rat & Mouse diet is a vegetable-based formulation. Because of the high level of protein, I would only feed this diet to young rats since many experts advocate feeding decreasing levels of protein as a rat ages.
The Mazuri Rat & Mouse Diet can be found for the lowest price on Chewy.com.
Mazuri also makes diets for Zebra, Moose, Polar Bear and even Reindeer.
Last updated 5/7/17