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Ferretone, Other Oil Treats, and Vitamin A & D Toxicity

Jump to a Section:
Ferretone and Furo-tone
Using Other Oils as Treats
Vitamin A Toxicity for the Cautious
Vitamin D Toxicity for the Cautious
References

Ferretone and Furo-tone

Ferretone is a popular oil and vitamin treat/supplement that comes in two brands: the original 'ferretone' from 8-in-1 brand, and the Marshall brand 'furo-tone'. Both are a mix of vegetable oil, cod liver oil, and vitamins.


Not to be confused with other treats and supplements that have similar names:

Ferretvite or furo-vite: pastes of sugars, oils, and vitamins, best suited for ferrets that are off food, underweight, or recovering from medical problems. Some people raise concerns that it is too sugary to be appropriate as an everyday treat for healthy ferrets.

Ferret lax or laxatone: pastes of petroleum jelly (aka vaseline) flavored with sugars and oils, made to help against hairballs and blockages by lubricating the digestive tract.

Vita-sol: a liquid vitamin supplement to be added to drinking water.



Becuase ferretone's guaranteed analysis is listed as "per 3/4 tsp" and furo-tone's is "per 1 tsp", I have converted the 8-in-1 ferretone, and both are listed as "per tsp" in the comparison chart below1:



8-in-1 Ferretone

Marshall Furo-tone
Ingredients Soybean Oil, Cod Liver Oil, Lecithin, Wheat Germ Oil, Vitamin A Supplement, Vitamin D Supplement, Vitamin E Supplement, Pyridoxine Hydrochloride, Biotin, Mono and Diglycerides, and BHT and Propyl Paraben (as preservatives). Canola Oil, Cod Liver Oil, Wheat Germ Oil, Safflower Oil, Lecithin, Pyridoxine Hydrochloride, Vitamin A Palmitate, Tocopheryl Acetate, Biotin, Zinc Sulfate, Methylparaben, and Propylparaben.
Linolenic Acid (Omega 3) mg 180 350
Linoleic Acid (Omega 6) mg 2000 900
Arachiodonic Acid (Omega 6) mg 53 -
Palmitoleic Acid (Omega 7) mg - 40
Oleic Acid (Omega 9) mg 1000 2000
Vitamin A (IU) 1333 931
Vitamin D3 (IU) 100 93
Vitamin E (IU) 10.7 13
Zinc (mg) - 0.7
Choline (mg) 4.3 2.4
Inositol (mg) 1.7 2.4
Vitamin B6 (mg) 0.4 0.3
Biotin (mcg) 17.3 13
Preservatives Used BHT, PropylParaben Methylparaben, Propylparaben


Among ferret owners, the two largest concerns with commercial oil supplements or treats are typically:

1. Preservatives: I don't have any comments to make on preservatives; I think they're a matter of personal discretion.
2. Vitamin A or D toxicity: Further down I'll try to evaluate the potential vitamin toxicity risk in both ferretone and cod liver oil. Pure cod liver oil is another popular treat for ferrets that has even higher vitamin A and D concentrations, and thus sparks a lot of debate regarding vitamin toxicity.

Using Other Oils as Treats

Some ferret owners choose to skip the commercial oil treats and simply offer fish and/or vegetable oils (or homemade oil mixes) to their ferrets. This gives them more control to choose vitamin levels, choose Omega 3 and 6 levels, and avoid certain preservatives. It can also prove to be much less expensive. Most ferrets will gladly accept a variety of oils as 'treats'.

TIP- fish oils can be purchased at some pet supply stores, but also at regular 'human' pharmacies.
Softgel capsules are also often used for ferrets- simply poke a hole in the end of the with capsule pin or needle, and squeeze the capsule to drip the oil out.


Here is a comparison chart for assorted fish and vegetable oils and ferretones.1,2 Keep in mind that different brands of the same kind of oil could have different values since the differences in genetic strains, batches, and processing practices can all affect the end result.
All values are listed as per teaspoon.

Oil Type Total Omega 3 (mg) Total Omega 6 (mg) Vitamin A (IU) Vitamin D (IU)
Cod liver oil 888 42.1 4501 450
Herring oil 534 51.7 0 -
Salmon oil 1589 64.9 0 -
Sardine oil 1084 90.6 0 14.9
Soybean oil 306 2269 0 -
Canola oil 441 839 0 -
Olive oil 34.2 439 0 -
Flaxseed oil 2399 572 0 -
8-in-1 ferretone 180 min 2053 min 1333 100
Marshall furo-tone 350 min 900 min 931 93


Vitamin A Toxicity for the Cautious

*****Notes before reading*****
  • pay close attention to units, it is often easy to confuse IU/kg body weight and IU/kg food.
  • These calculations require some estimation, so consider them with a grain of salt
  • I know that Vitamin A is typically measured in RE or RAE these days, but I have to use IU because that's what pet food labels use.



  • How much is too much?

    There are no AAFCO nutrient profiles for ferrets, and in several hours of research I was unable to find any reported claim for a maximum daily vitamin A tolerance for ferrets. This means it is likely that no one has done the research to determine this, and that the best I can offer is comparisons from other species. Here's what I was able to find:

    -  According to the AAFCO nutrient profiles for cat food, a food must contain at least 9,000 IU/kg of food to be considered suitable for kittens, and no more than 750,000 IU/kg is allowed. Lower amounts are given for dogs: 5,000-250,000 IU.3

    -  The book "Nutrient requirements of dogs and cats" by the National Research Council proposed 213,333 IU (64,000 micrograms retinol) per kg of food as a safe upper limit for dogs, based on several studies4

    -  According to the FDA, "The lowest reported adverse effect level (of Vitamin A) in experimental animals appears to be in the range 25,000 to 60,000 IU per kg body weight per day for periods of 3 to 5 weeks".5 Note that carnivores are known to tolerate much higher levels of vitamin A than non-carnivores, and they did not describe which species were studied.



    How much does a ferret already get from their regular diet?

    Here's some math to determining how much Vitamin A a ferret gets from their kibble alone:
    I ran a survey on ferret.com forums and found that their average ferret ate about 30-35g of kibble per day. If anyone has information from a bigger sample size, please let me know and I'll update my math. Keep in mind also that if you have a large ferret, they'll be eating more than that.

    750,000 IU per kg = 750 IU per gram of food. 750 IU/g x 35g = 26,250 IU. Therefore, an average ferret eating a kitten food that is as high in vitamin A as is permitted by AAFCO nutrient guidelines would be consuming 26,250 IU of vitamin A per day.

    This is the extreme case though, and getting an idea of the vitamin A levels in a "typical" food is important as well. Unfortunately, most foods do not cite Vitamin A levels in their guaranteed or nutrient analysis. I took a small sample from the brands I could find that do list these levels (a full chart of these is available at the bottom of this page). They ranged from 12,100 IU/kg to 26,000 IU/kg with an average of 19,473 IU/kg.8 This average value translates to a ferret getting about 681 IU of vitamin A per day when eating a "typical" food.



    TL;DR, Conversions, and Simplification

    I realize that that's a lot of numbers to look at, so I'll provide a summary of everything with all of the numbers converted to "consumed per day" values:





    Conclusion

    Existing information is not complete enough for me to make a fair call predicting exactly how much vitamin A a ferret can safely consume daily.

    I will say that I personally believe that with typical foods (~20,000 IU/kg vitamin A), ferretone in the amounts directed on the bottle or even a teaspoon of cod liver oil daily should probably not pose any threat of vitamin A toxicity.
    I might however consider being cautious with these treats if you are feeding a brand of food that you have reason to believe is well above this "typical" Vitamin A level. I would also be cautious regarding the potentially bigger threat of vitamin D toxicity (see below).




    Vitamin D Toxicity for the Cautious

    *****Notes before reading*****
  • pay close attention to units, it is often easy to confuse IU/kg body weight, IU/kg food, and IU/1000 kcal of food.
  • These calculations require some estimation, so consider them with a grain of salt



  • How much is too much?

    Again, there are no AAFCO nutrient profiles for ferrets, or available information regarding suggested maximum Vitamin D intake levels.  Here's what I found to compare from other species:

    -  According to the AAFCO nutrient profiles for cat foods, a food must contain at least 750 IU/kg of food to be considered suitable for kittens, and no more than 10,000 IU/kg is allowed. For dogs: 500 - 5,000 IU/kg.3

    -  The book "Nutrient requirements of dogs and cats" by the National Research Council proposed 440 to 1100 IU (11-27.5 micrograms cholecalciferol) per 1000 kcal of food (~1760-4400 IU/kg food if we assume the food is 4000 kcal/kg) as a safe upper limit for dogs, and no more than 800 IU (20 micrograms cholecalciferol) per 1000 kcal food (~3200 IU/kg food) for growing puppies. 4

    -  The book "Nutrient requirements of dogs and cats" by the National Research Council cites that only one study has been preformed to to estimate a safe dietary maximum dietary concentration of vitamin D in cats.  This study reported that cats and kittens did not show any adverse clinical signs, given a diet of 33840 IU (840 micrograms cholecalciferol) per kg of food for 18 months4

    -  One study found that 5 cats that were showing symptoms of vitamin D toxicity had been fed a diet containing 63,700 IU of vitamin D per kg food since a young age6

    -The book "Vitamin Tolerance of Animals" summarizes the effects of various vitamin D levels on various species from available studies.  The mammalian carnivores presented were:
    Foxes: showed adverse signs at 5,000 IU/kg body weight (0.125 mg/kg) for 3 months and some died at 10,000 IU/kg body weight (0.250 mg/kg).7
    Mink: showed no effect at 7,000 - 15, 000 IU/kg body weight (0.175-0.375 mg/kg) for 2-3 weeks. 7 I'm hesitant to say this since the mink is such a close relative to the ferret, but I think this result may be less relevant due to the short trial (2-3 weeks) and the fact that mink are designed to eat fish-based diets, which could be naturally higher in vitamin D.



    How much does a ferret already get from their regular diet?

    Here's some math to determining how much Vitamin D a ferret gets from their kibble alone:

    As I stated earlier, I ran a small survey on ferret.com forums and found that their average ferret ate about 30-35g of kibble per day.

    10,000 IU per kg = 10 IU per gram of food. 10 IU/g x 35g = 350 IU. Therefore, an average ferret eating a kitten food that is as high in vitamin D as is permitted by AAFCO nutrient guidelines would be consuming 350 IU of vitamin D per day.

    This is the extreme case though, and getting an idea of the vitamin D levels in a "typical" food is important as well. Unfortunately, most foods do not cite Vitamin D levels in their guaranteed or nutrient analysis. I took a small sample from the brands I could find that do list these levels. They ranged from 800 IU/kg to 3,200 IU/kg with an average of 1,722 IU/kg.8 This average value translates to a ferret getting about 60 IU of vitamin D per day when eating a "typical" food.



    TL;DR, Conversions, and Simplification

    I realize that that's a lot of numbers to look at, here's another summary, once again with all of the numbers converted to "consumed per day" values:





    Conclusion
    Existing information is not complete enough for me to make a fair call predicting exactly how much vitamin D a ferret can safely consume daily.

    With AAFCO standards and proposed upper limits being such seemingly low numbers compared to oils and the research I was able to dig up, I'm lead to wonder if I may be missing a piece of the puzzle or if vitamin D is in fact toxic at very easy-to-reach levels.

    My personal opinion is:

    It's interesting that one spoonful of ferretone has more vitamin D in it than a day's worth of "typical" food for a ferret. It's even scarier that a teaspoon of cod liver oil has more vitamin D in it than a day's worth of the most extremely vitamin D-rich kitten food allowed by AAFCO profiles.

    My best guess that if your ferret is eating a "typical" food, ferretone is probably safe to use as directed. I would probably restrict cod liver oil to a maximum of 1/2 tsp per day though, just to be on the safe side. If cod liver oil was only a "once in a while" kind of treat for my ferrets though, I probably wouldn't worry about the risk of toxicity. But that's just how I read the data; you may come to a different conclusion.

    I would probably also be cautious about giving daily pure cod liver oil if I had any reason to believe that my ferret's food was not near "typical" levels for vitamin D. Keep in mind as well that ferret foods (unlike cat or kitten foods) do not have to meet any guidelines for vitamins and minerals, as long as they're not clearly making animals sick.



    References

    1. Ferretone (8-in-1 pet products) and Furo-tone (Marshall pet products) bottle labels
    2. nutritiondata.org
    3. Official 2008 AAFCO nutrient profiles for dogs and cats, sourced from peteducation.com
    4. National Research Council (U.S.): Ad Hoc Committee on Dog and Cat Nutrition. 2006. Nutrient requirements of dogs and cats. National Academies Press.
    5. Database of Select Committee on GRAS Substances (SCOGS) Reviews: Vitamin A, sourced from FDA website
    6. Morita T, Awakura T, Shimada A, Umemura T, Nagai T, Haruna A.  1995.  Vitamin D toxicosis in cats: natural outbreak and experimental study.  The Journal of veterinary medical science 57(5):831-7.
    7. National Research Council (U.S.): Subcommittee on Vitamin Tolerance, Committee on Animal Nutrition.  1987.  Vitamin Tolerance of Animals.  Accessed Online.
    8. Data sourced from respective official product websites:



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