If you’re an invested rat owner, you may have heard that pet rats should not eat citrus fruit.
So, are oranges toxic to rats? Can both male and female rats eat oranges?
Oranges contain d-limonene, a compound that causes kidney tumors in male rats when given in high doses. It is therefore best to avoid offering citrus to your male rats. On the other hand, female rats can eat citrus fruit, so if your mischief is all-female, oranges make a good fruity treat.
This article aims to give you a rundown on how much orange – if any – is safe to feed to your mischief and other important considerations on citrus fruit.
Can You Feed Your Pet Rat Oranges?
Can Rats Eat Citrus Fruits?
Citrus fruits have a reputation as being particularly healthy – and for good reason. They are an excellent source of vitamin C, a crucial vitamin for skin and connective tissue health and for the function of the immune system1.
Next, they boast decent amounts of vitamin B, potassium, magnesium, phosphorous, and copper2.
Other healthy compounds in citrus fruit include different types of antioxidants, which are linked to decreased inflammation and cancer rates3.
Citrus fruits – and oranges in particular – contain healthy fibers, which are known to be good for the gut microbiota4. In citrus fruits, the ratio of soluble to insoluble fiber is higher than in other fruits5. Soluble fibers have a positive effect on blood cholesterol levels6.
Oranges are also low in calories, making them a good snack for overweight individuals7. Citrus fruits have been linked time and time again to reduced blood pressure8, lower incidence of cancer3, and improved brain function9.
So, why aren’t oranges and other citrus fruits a great food for rats? Let’s have a look at a specific issue of male rats with d-limonene, a compound that’s found in citrus fruits and their juices.
Can Male Rats Eat Oranges?
Adult male rats produce a substantial amount of a protein called “alpha 2U-globulin”. The d-limonene that is found in citrus fruits and their juices can bind to alpha 2U-globulin.
Subsequently, the alpha 2U-globulin accumulates in the renal tubules of these rats, causing the formation of so-called “hyaline droplets”. These droplets are the first stage of a specific type of kidney damage in the male rat.
Further down the road, the damaged kidney cells are more likely to turn into cancerous cells, leading to kidney tumors10. Since the alpha 2U-globulin is only produced by bucks, does and dams do not have any issues upon consuming d-limonene containing foods.
But is this really relevant in a pet rat’s daily life?
Will feeding your bucks a slice of orange immediately cause kidney cancer?
Probably not. The amount of d-limonene that has been linked to increased kidney cancer and other kidney damage is very high and was given to the rats in question over long periods of time.
Your rats would need to consume ridiculous amounts of oranges or orange juice to reach the levels in those studies. However, it’s not quite clear whether low doses of d-limonene have any effect on kidney health.
As there is a plethora of healthy fruit and vegetable alternatives to choose from, it’s probably a good idea to just avoid citrus fruits for your male rats altogether – to be on the safe side.
Female rats can consume citrus fruits without any issues.
Are Rats Allowed Orange Peel?
Citrus fruit peel contains the highest levels of d-limonene11. If you absolutely want to feed oranges to your bucks, make sure to remove the peel beforehand.
Does and dams can eat orange peel; however, it’s doubtful that citrus fruit peel is particularly appealing to rats.
Lemons are citrus fruits, too, and they also contain d-limonene. Therefore, the same issues apply as mentioned above for oranges.
What Fruits Can Rats Eat?
Many fruits make great food for pet rats. Berries, such as raspberries, are especially good – they are low in sugar but still taste sweet and contain tons of antioxidants. Other safe options include: apples, pears, apricots, kiwi, watermelon, melon and pineapple in moderation.
Fruit pips and stones are toxic and should not be fed to your mischief. The same applies to avocado skin and pits.
To Sum Up
While oranges are very healthy, they contain d-limonene, which has been linked to kidney tumors in male rats. The amount of d-limonene from occasionally eating a slice of orange is probably irrelevant, but to be on the safe side, I would recommend avoiding citrus fruits altogether for bucks.
Female rats can eat citrus fruit, so if your mischief is all-female, oranges make a good fruity treat.
1. Sorice A, Guerriero E, Capone F, et al. Ascorbic acid: its role in immune system and chronic inflammation diseases. Mini Rev Med Chem 2014;14:444-452. https://pubmed.ncbi.nlm.nih.gov/24766384/.
2. Lv X, Zhao S, Ning Z, et al. Citrus fruits as a treasure trove of active natural metabolites that potentially provide benefits for human health. Chemistry Central journal 2015;9:68-68. https://pubmed.ncbi.nlm.nih.gov/26705419.
3. Cirmi S, Ferlazzo N, Lombardo GE, et al. Chemopreventive Agents and Inhibitors of Cancer Hallmarks: May Citrus Offer New Perspectives? Nutrients 2016;8. https://pubmed.ncbi.nlm.nih.gov/27827912/.
4. Anderson JW, Baird P, Davis Jr RH, et al. Health benefits of dietary fiber. Nutrition Reviews 2009;67:188-205. https://doi.org/10.1111/j.1753-4887.2009.00189.x.
5. Slavin JL, Lloyd B. Health benefits of fruits and vegetables. Advances in nutrition (Bethesda, Md) 2012;3:506-516. https://pubmed.ncbi.nlm.nih.gov/22797986.
6. Surampudi P, Enkhmaa B, Anuurad E, et al. Lipid Lowering with Soluble Dietary Fiber. Curr Atheroscler Rep 2016;18:75. https://pubmed.ncbi.nlm.nih.gov/27807734/.
7. U.S. Department of Agriculture. FoodData Central – Oranges, raw, Florida. 2019. https://fdc.nal.usda.gov/fdc-app.html#/food-details/169918/nutrients.
8. Onakpoya I, O’Sullivan J, Heneghan C, et al. The effect of grapefruits (Citrus paradisi) on body weight and cardiovascular risk factors: A systematic review and meta-analysis of randomized clinical trials. Crit Rev Food Sci Nutr 2017;57:602-612. https://pubmed.ncbi.nlm.nih.gov/25880021/.
9. Kean RJ, Lamport DJ, Dodd GF, et al. Chronic consumption of flavanone-rich orange juice is associated with cognitive benefits: an 8-wk, randomized, double-blind, placebo-controlled trial in healthy older adults. Am J Clin Nutr 2015;101:506-514. https://pubmed.ncbi.nlm.nih.gov/25733635/.
10. Hard GC, Whysner J. Risk assessment of d-limonene: an example of male rat-specific renal tumorigens. Crit Rev Toxicol 1994;24:231-254. https://pubmed.ncbi.nlm.nih.gov/7945892/.
11. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Some Naturally Occurring Substances: Food Items and Constituents, Heterocyclic Aromatic Amines and Mycotoxins. d-LIMONENE. 1993. https://www.ncbi.nlm.nih.gov/books/NBK513608/.
Nina has a degree from the Veterinary School in Zurich, with a special focus on microbiological research. Nina has a passion for sports, nutrition and the outdoors and she loves all pets, but rats have a special place in her heart. When she’s not working or reading and writing about all things related to pet health, she loves to travel and surf.
As a small animal veterinarian, Nina is your go-to expert on pet health and nutrition.