PUT EXTRA MONEY IN YOUR POCKET
https://www.ebates.com/r/SYBIL414?eeid=29041

Liver Problems in 9 Year Old Fennec Fox

For species less common than reds and arctics.

Moderators: Ash, TamanduaGirl

User avatar
Ranger
Posts: 37
Joined: Sun Feb 11, 2007 10:53 pm
Contact:

Re: Liver Problems in 9 Year Old Fennec Fox

Postby Ranger » Sat Dec 10, 2016 5:19 pm

I don't know if I mentioned this, but I also spoke with the vet over the phone today, and sent her the care sheet for fennecs found in this forum. She said she'd find it an interesting read and will be researching more about my fennec's diet. I should expect a call back on Monday.

Its so interesting seeing the relationship between retinol toxicity and taurine deficiency. Interestingly, there is such a metabolite called "retinotaurine", which is the two molecules combined.

I wanted to do a lot more research on the subject, so I cracked open my old $175 biochemistry book. It has next to nothing on retinol and not a mention of taurine in the index.
User avatar
TamanduaGirl
Site Admin
Site Admin
Posts: 10336
Joined: Wed Mar 22, 2006 11:42 pm
Location: Oregon, USA
Contact:

Re: Liver Problems in 9 Year Old Fennec Fox

Postby TamanduaGirl » Sat Dec 10, 2016 6:32 pm

The more info the vet has the better. This book though on red foxes can be helpful http://www.nap.edu/openbook.php?isbn=030903325X
Since it has suggested amounts of nutrients for a fox species and signs of deficiencies for those nutrients it's still useful with lack of specific fennec info. I thought I cited it in the care sheet references but don't see so I'll have to remedy that.

One site that I used to love listed a lot of nutrients and how they reacted with each other in the body(for humans though), it was really interesting but I think it's gone now.
User avatar
Ranger
Posts: 37
Joined: Sun Feb 11, 2007 10:53 pm
Contact:

Re: Liver Problems in 9 Year Old Fennec Fox

Postby Ranger » Sat Dec 10, 2016 6:38 pm

Do you have a citation for retinol toxicity in fennecs or foxes in general? That's really new. I've never heard it before, but it sounds super important. If I could get a source, that would be great.
User avatar
TamanduaGirl
Site Admin
Site Admin
Posts: 10336
Joined: Wed Mar 22, 2006 11:42 pm
Location: Oregon, USA
Contact:

Re: Liver Problems in 9 Year Old Fennec Fox

Postby TamanduaGirl » Sat Dec 10, 2016 9:27 pm

Not specifically. But the problems commonly seen in fennecs can all be linked to chronic over consumption of retinol so anecdotally at least it is strongly implicated.

Aside from the nutrition book there is not much in depth on the effects of specific nutrients in foxes. Page 26 mentions the studies with retinol and red foxes. The problem is they were just looking for acute toxicity in the last study that is about toxicity. The idea that lower chronic subtoxicity will still cause problems is a relatively new concept to medicine in general. Included in the signs of acute toxicity though were exostoses, decalcification and bone fractures.

However the book does give a recommended dose at which point retinol starts being stored in the liver and anything over that then is excess and many diets give 100's of times more than that recommendation of 100iu/kg body weight. If you ever feed a rat it's over 10k more IU than recommended per Kg and a mouse(which people love to feed is nearly 60K more than recommended.

There is a study on retinol in anteaters causing spinal lesions and spinal fusion from chronic excess but it's mostly irrelevant as they have remarkably low needs. One thing of not is outward signs of toxicity were not noticed till "olad age", around 9yrs, but x-rays did show spinal changes early on. After years on the diet then they began showing signs of trouble with tails held curled and rear end paralysis. Similar issues are also seen in possums when fed too much retinol, more obvious more quickly due to their shorter lifespan and rapid growth. And someone more knowledgeable about reptiles said is a known issue with them as well.

In cats retinol toxicity causes spinal lesions too but they tend to start near the neck instead of the rear, dog are more prone to weak bones and lesions that could appear at any joint.

Vitamin A toxicity in the cat causes hyperostosis of the spine, but experimental vitamin A intoxication in the dog had the opposite effect and caused bone resorption and fractures. MADDOCK, C.L.; WOLBACH, S.B.; MADDOCK, S.: Hyper-vitaminosis A in the dog. J Nutr 39: 117-137, 1949

http://jfm.sagepub.com/content/7/6/363.short
This is similar to the fennec in Japan that has cat food as part of it's diet. It also present with a forelimb weakness. X-rays showed spinal lesions. They attributed it to old age however and made no changes. Annual x-rays showed the spinal issues progressively getting worse.

There have been other fennecs that had presented with foreleg tremors or foreleg chewing, which, I think, could be a result of the upper spine issues. If more owners did more extensive tests it would be helpful to all in the long run.

And then the fact that too much retinol is linked to problems you commonly see in fennecs like the liver and kidney issues.

With fennecs were talking sub-clinical over consumption of retinol till their senior years, in most cases so these studies in rats are meaningful as 18 months is nearly their whole lifespan.

Nonneoplastic changes in Fischer 344. rats treated for 18 months with isotretinoin consisted of increased mortality, decreased food consumption and body weight gain, altered gait, decreased hemoglobin concentration and hematocrit, in-creased serum alkaline phosphatase activity, and increased serum concentrations of triglycerides, phosphate, and urea nitrogen. Microscopic changes included focal fibrosis and areas of focal chronic inflammation in the heart, adrenal medullary hyperplasia, arteritis, arterial calcification, focal tissue calcification, and focal osteolys is of the bone. The severity of these gross and microscopic effects was dose-related, with minimal effects noted at the low dose of 2 mg/kg/day,

Rats are relatively intolerant to etretinate, thus requiring a much-reduced dosing regimen relative to the doses of isotretinoin that were given chronically. Nonneoplastic findings in rats treated with etretinate for 18 months 11 were confined mainly to the high-dose group (3 mg/kg/day) and consisted of bone fracture, elevated serum alkaline phosphatase activity, and slight reductions in total red blood cells and hemoglobin concentration. Minimal microscopic changes were noted only in the high-dose group and consisted of increased hematopoiesis in the spleen and mesenteric lymph nodes and an increased incidence of cystic endometrial hyperplasia in the uterus of female rats.

Found in this http://www.sciencedirect.com/science/ar ... 2282700544 Along with lots of other retinol studies complied but less relevant since shorter term. Issues varied by species, dose, types of retinol and length of time being given larger than needed amounts.

That's all mostly skeletal though.

Subclinical hypervitaminosis A causes fragile bones in rats ☆ http://www.sciencedirect.com/science/ar ... 8202009109
That actually goes into liver and kidneys some. Liver enlarges with excess retinol and if too much is given for the liver to handle the kidneys store retinol too. My conclusion: Since retinol is stored as a fat this could harm those organs by making them fatty.

This is interesting though as it says foxes store more retinol in their kidneys than their livers http://www.vetres.org/articles/vetres/a ... v0603.html
So again storing retinol could lead to fatty kidneys. And damage typically done to the liver first in other species could be done to the foxes kidneys first instead. It would be nice to see more studies on that to verify since that is so unusual.

Also saw some studies that kidneys have to convert retinol to retinoic acid meaning they are partly responsible for removing it from the blood stream. And kidney patients given retinol got toxicity for that reason. My conclusion: so chronically giving more than needed means the kidneys are chronically over working.

Chronic vitamin a tox and liver damage: http://www.nejm.org/doi/full/10.1056/NE ... 8292910903
http://www.sciencedirect.com/science/ar ... 2288701656
User avatar
Ranger
Posts: 37
Joined: Sun Feb 11, 2007 10:53 pm
Contact:

Re: Liver Problems in 9 Year Old Fennec Fox

Postby Ranger » Sun Dec 11, 2016 3:18 am

Wow, this is very helpful, thanks. It would seem there really is ample evidence that chronic over exposure is generally bad, though what may be considered bad for one species may differ from another. If it is also very bad for reptiles, with similar problems, then this is a trait highly preserved across hundreds of thousands of species. I bet birds have these problems, too. These are great insights!
User avatar
Ranger
Posts: 37
Joined: Sun Feb 11, 2007 10:53 pm
Contact:

Re: Liver Problems in 9 Year Old Fennec Fox

Postby Ranger » Tue Apr 04, 2017 12:55 pm

I am sad to say that on March 31st, 2017, I had to put my fox to sleep. I picked him up from the vet on March 27th after a vacation, and they said to keep an I on him because he didn't seem "quite right" that day. Over the nest few days, he progressively got worse, with paralysis overtaking his body. The vet said he had a stroke, and needed supportive therapy. The next day he was so bad that we ended up doing an after hours emergency euthanasia. Watching him gasp for air was traumatic, to say the least. By the time we brought him to the vet, he had grown cold, but was still struggling to breath, with his heart racing like crazy. The vet injected him with a blue liquid, and within moments, my baby was dead. The poor guy was such a fighter that he even gave one final grand kick with his still working back legs as lethal injection did its job. April 14th, 2017 was going to be his 10th birthday.

During his last few months, his liver problems did improve significantly over time, but he may have had unchecked blood pressure issues. Unfortunately, between a regular vet and an ophthalmologist vet, nobody had cuffs small enough for fennecs. The only way my vet knows of to check the blood pressure of a fennec is possibly a veterinary Doppler, and they aren't common for vets to have.

The reason we think he had high blood pressure was his retinal detachment with hemorrhages of the back of the eye, glaucoma and a stroke. These issues were probably preventable, but they were also very unexpected.

Next time a fennec is in my life, high levels of taurine will be given, along with examination for hypertension, and treatment if necessary. I am convinced that low taurine lead to his liver infection, which ravaged his body over the past year.
User avatar
Ash
Site Admin
Site Admin
Posts: 7917
Joined: Fri Oct 08, 2010 11:38 am
Location: Utah

Re: Liver Problems in 9 Year Old Fennec Fox

Postby Ash » Tue Apr 04, 2017 2:45 pm

I'm so sorry, Ranger... :cry: He was a special little guy to you, and I'm sorry you lost him. At least you know he is no longer suffering. My heart goes out to you.
3 red fox, 4 pectinata iguanas, nile monitor, BW tegu, sailfin dragon, leachie gecko, 6 snakes, 2 salamanders, 3 tarantulas
User avatar
Ranger
Posts: 37
Joined: Sun Feb 11, 2007 10:53 pm
Contact:

Re: Liver Problems in 9 Year Old Fennec Fox

Postby Ranger » Tue Apr 04, 2017 9:50 pm

Thank you.

Return to “Fennecs, Swift, Corsac, Gray and other rare foxes”

Who is online

Users browsing this forum: No registered users and 1 guest