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By Eva K

October 4th, 2023

Mouse Diet

A mouse’s diet has an enormous impact on their overall health and welfare, their development, and changes to their microbiomes.

Nutritional Requirements​

The specific nutritional requirements of a mouse will depend on their age, environment, and genetics. 




  • The diet of mice in laboratories is 17-24% protein for adequate performance levels, but this largely depends on their strain and age. 


  • Protein is required for metabolic health and growth and repair of body tissue.


  • A study found that a diet with lowered protein led to the development of mild fatty liver, affecting middle-aged mice more than young mice, whereas the moderate-protein diet suppressed lipid contents and lowered levels of blood glucose and lipids. This shows that the protein content of a middle aged mouse's diet shouldn't be lowered.



  • Lipids are needed to provide essential fatty acids and dietary fat is needed to aid absorption of fat-soluble vitamins ( such as vitamin A, vitamin D, vitamin E & vitamin K) and enhance diet acceptability.

  • However, a high fat, high protein diet should be avoided since it can contribute to or worsen atherosclerosis (a buildup of plaque in and on the artery walls).


~5%, under 10% 

  • Labs consider 2.5% an optimal level, but a high concentration of fiber depresses a mouse’s performance​

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Types of Mouse Diets

Purified diet

  • These evaluate nutrient requirements, nutrient deficiency, nutrient-toxin relationships, or other interests that evaluate specific nutrients

  • Only relatively pure and invariant ingredients are used in these formulations ( for example casein and soybean protein isolate (as sources of protein)), sugar and starch (as sources of carbohydrate), vegetable oil and lard (as sources of fat and essential fatty acids), a chemically extracted form of cellulose (as a source of fibre), and chemically pure inorganic salts and vitamins)​

Chemically defined diet

  • A type of purified diet

  • Individual amino acids are used in place of a protein source, and specific fatty acids replace oils

Natural ingredient diet

  • A diet formulated with agricultural products & by-products such as whole grains (e.g., ground corn, ground wheat), mill by-products (e.g., wheat bran, wheat middlings, corn gluten meal), high protein meals (e.g., soybean meal, fishmeal), mined or processed mineral sources (e.g., ground limestone, bone meal), and other livestock feed ingredients (e.g., dried molasses, alfalfa meal) are often called natural-ingredient diets

  • The variations in the composition of the individual ingredients can produce changes in the nutrient concentrations of natural-ingredient diets (Knapka, 1983). The composition can depend on the soil & weather conditions, use of fertilisers, harvesting & storage procedures and manufacturing methods

Recommended Mixes and Blocks

Mice are omnivores and granivorous. They consume a variety of grains, seeds, and animal meat. On average, a healthy mouse consumes around 5 grams of food a day.


Wild house mice are seen to consume seeds, nuts, grains, leaves and insects, such as beetle larvae and cockroaches. They’re also seen to cache their food in hidden "safe"  areas, nibbling small amounts of food at a time. 


Food restrictions can be introduced to adult, non-breeding mice as they're shown to increase longevity. This should be done by having a fixed schedule every day for feeding, for example, only feeding healthy adult mice at 7 pm each day. Hahn et al. reported that late-life dietary restriction, the switch from dietary restriction to ad libitum at 24 months of age, increased mortality in female mice, and the switch from ad libitum to dietary restriction slightly increased survival (study also considered nutritional memory). Please do not restrict their access to water, since mice should be given clean, fresh water every day.  

This following section was made for British/European mouse owners:


  • Getzoo Color Mouse Food

  • Mixerama Color Mouse (following instructions for selection)

  • Bunny Nature Expert Mouse Mix

  • Rodents in a Cocoon (homemade mix from Poland)

Lab Blocks/Pellets:

  • Oxbow Essentials Mouse & Young Rat Food

  • Science Selective Rat & Mouse pellets (must be supplemented if used due to low protein)

  • Heygates Sow and Weaner Nuts (only to supplement; should be thrown out after 2 months since the probiotic makes them go bad)

Controversy Surrounding Lab Blocks:

An issue that always arises with a mix diet is selective feeding, which can cause deficiencies in the mice. This can be solved by not filling the bowl to the brim and allowing each mouse to eat the mix. The other issue with feeding a mix is that not all mice will eat equal portions, but this can be prevented if each mouse is monitored and fed anything they missed. Feeding them ad lib will worsen the selectivity.


The main issues with pellets are the quality (which can also be said for some mixes), the lack of variety, and the lack of species specificity. Most of these issues arise from the certain pellets themselves being nutritionally poor. Usually, mouse keepers use pellets to ensure all nutritional requirements are fully met and to provide stability to the diet. 

Why a pellet meant for pigs? (Heygates Sow and Weaner Nuts)

These pellets are well-known in the mouse community and used because of the high quality ingredients and value.


The ingredients for the blocks are wheat-feed, wheat, barley, soybean meal (dehulled), limestone flour, and salt. This composition is very similar to the Science Selective, another appropriate and recommended option.

What should I avoid in mixes/pellets?

  • Vague ingredients - they're a telltale sign that the food is low quality! Can be dangerous for animals with allergies.

  • Grass/hay products & straw - they're an empty filler ingredient!

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Safe Foods and Herbs

For a more extensive list, click here.

The following list is non-exhaustive:

  • Apple (without seeds)

  • Pear

  • Croccoli 

  • Lettuce (small amounts)

  • Cucumber

  • Chamomile 

  • Lemon balm

  • Beetroot (colors the urine)

  • Tomato

  • Parsnips

  • Parsley (& parsley root)

  • Dandelion

  • Rosehips

  • Cauliflower

  • Carrots

  • Jerusalem artichoke

  • Turnip

  • Strawberry leaves

  • Watermelon

  • Grapes (sources stating they’re unsafe usually use studies done on canines for whom grapes are toxic)

  • Evening primrose

  • Peas

  • Zucchini

  • Bean sprouts

  • Bell peppers

  • Pumpkin

  • Green beans 

  • Spinach

  • Water chestnut (small amounts)

  • Freeze-dried chicken

  • Mealworms 

  • Gammarus 

  • Grasshoppers (only ones sold for pet consumption, not wild ones)

  • Sunflower petals & seeds

Dangerous Foods


For a more extensive list, click here.

The following list is non-exhaustive:

  • Amaryllis

  • Agave

  • Aloe vera

  • Anthurium

  • Arum

  • Azalea

  • Hogweed

  • Mountain laurel

  • Bittersweet nightshade

  • Wisteria

  • Fenugreek

  • Boxwood

  • Wood anemone

  • Christmas rose

  • Christ thorn

  • Ivy

  • Yew family

  • Ferns

  • Primrose

  • Window leaf

  • Foxglove

  • Laburnum

  • Buttercup

  • Gogwood

  • Hyacinth

  • Lupine

  • Lily of the valley

  • Mistletoe

  • Oleander

  • Daffodil

  • Umbel

  • Black locus

  • Sade tree

  • Wood sorrel

  • Horsetail

  • Snowberry

  • Snowdrop

  • Celandine

  • Daphne

  • Belladonna

  • Juniper

  • Spurge family

  • Miracle shrub

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