Sugars in a chameleon's diet?

[Kaizen]

Yes, sugar is present in all living things. Didn’t mean to imply that wasn’t the case. The bacterial metabolism angle is an interesting one, but if we are talking about fructose, it’s a simple sugar not a complex one. So there’s not too much more to breakdown compared to the well-described breakdown of complex carbs by microbes that you indicate. but maybe the microbes in chameleons do so with fructose and we just aren’t aware of it. And this still leaves us with the interesting issue that it seems veiled chameleons don’t have the fructose transporter homologous to humans and snakes itself. So if this were the case it might mean fructose breakdown is more reliant on microbes in chameleons than other organisms, which would be interesting. Perhaps sucrose is another sugar worth considering in addition to fructose.

Interesting! I wonder if the relative shortness of the chameleon digestive tract would make it difficult to foster a sufficiently large population of commensal gut flora.

 

[DocZ]

Nothing else to add

You guys are smart

 

[Kaizen]

Nothing else to add

You guys are smart

My mom says so too.

 

[DocZ]

My mom says so too.

 

[Klyde O'Scope]

You guys are smart

Fooled you too, eh?

“If you can't dazzle them with brilliance, baffle them with bull.”​

― W.C. Fields (Questionable)

 

[Klyde O'Scope]

Interesting! I wonder if the relative shortness of the chameleon digestive tract would make it difficult to foster a sufficiently large population of commensal gut flora.

I think the operative word there is 'sufficient'. With rare exception (mostly because I can't think of one OTTOMH) I think Nature (capital 'N') provides precisely the gut flora an organism needs it means to.

Kinda like a wizard arriving precisely when he means to.

 

[Kaizen]

I think the operative word there is 'sufficient'. With rare exception (mostly because I can't think of one OTTOMH) I think Nature (capital 'N') provides precisely the gut flora an organism needs it means to.

Kinda like a wizard arriving precisely when he means to.

Agreed. The question is whether nature meant for gut flora to do important digestive work in chameleons, given that it imbued the latter with a relatively short gi tract.

 

[javadi]

Interesting! I wonder if the relative shortness of the chameleon digestive tract would make it difficult to foster a sufficiently large population of commensal gut flora.

Could be! And would be quite interesting if so.

 

[Kaizen]

Could be! And would be quite interesting if so.

I’m just thinking about organisms that rely heavily on gut flora and/or fermentation for digestion. Most seem to have mechanisms for keeping food in the gut longer.

 

[Klyde O'Scope]

Agreed. The question is whether nature meant for gut flora to do important digestive work in chameleons, given that it imbued the latter with a relatively short gi tract.

Following the same line of thinking, I think Nature means for gut flora to do precisely what it does in precisely the space it does it in.

You guys are smart

I think no matter how smart we (humans) think we are or aren't, Nature is smarter.
No matter what we do to circumvent nature, it still finds ways to circumvent our circumventions!

 

[Kaizen]

Following the same line of thinking, I think Nature means for gut flora to do precisely what it does in precisely the space it does it in.


I think no matter how smart we (humans) think we are or aren't, Nature is smarter.
No matter what we do to circumvent nature, it still finds ways to circumvent our circumventions!

That seems reasonable. Without stretching the “deliberacy of nature” fallacy too far, I think you’re right about the de facto status of gut flora. Just to clarify: Do you think the gut flora of chameleons does some heavy digestive lifting, or not?

 

[kinyonga]

@Kaizen said..."Most seem to have mechanisms for keeping food in the gut longer"...like a cecum?

 

[Klyde O'Scope]

That seems reasonable. Without stretching the “deliberacy of nature” fallacy too far, I think you’re right about the de facto status of gut flora. Just to clarify: Do you think the gut flora of chameleons does some heavy digestive lifting, or not?

IDK that Nature does anything deliberately (if I'm interpreting that phrase correctly).

I think gut flora does what lifting it needs to do for survival of the species. For example, to digest a particular 'menu' of 'food' available in a given biome, an organism needs a combination of saliva, gastric juice, pancreatic juice, succus entericus (intestinal juice) and bile, along with associated enzymes and range of pH values—all in balance. Change that 'menu' in a significant way, and the balance may be upset. Fortunately, most animals have the ability to adapt over time and within limits. Enough of a change over enough time could either kill off a species, or bring about an evolutionary change in order to preserve the species.

IDK if I explained that well.

 

[kinyonga]

Apparently the veiled chameleons have a...
"Pyloric valve, located between the stomach and the intestine aids the pushing and stopping of food transmission and a duct that extends from the liver and pancreas enter the intestine to secrete digestive enzymes including "pepsin and trypsin" into the food"...
https://www.123helpme.com/essay/A-Summary-Of-The-Veiled-Chameleon-FJMJ5ALVD26

 

[Kaizen]

Apparently the veiled chameleons have a...
"Pyloric valve, located between the stomach and the intestine aids the pushing and stopping of food transmission and a duct that extends from the liver and pancreas enter the intestine to secrete digestive enzymes including "pepsin and trypsin" into the food"...
https://www.123helpme.com/essay/A-Summary-Of-The-Veiled-Chameleon-FJMJ5ALVD26

Hmm…Sounds like a mechanical means of slowing the movement of digesta through the GI tract. Fascinating! I shall have to bone up on my chameleon digestion! Thanks, K !

 

[MangoTango]

What follows is sort of a stream of consciousness about this and sharing of some articles and ideas.

I appreciate you bringing this up, as it's been floating around but has little evidence or studies supporting its application to captive husbandry to my knowledge. I think it has mostly been argued by one particular well-known chameleon enthusiast.

I might be accidentally strawmanning this, but the argument as I know it is that the fruits we eat are so full of sugar (fructose) that they are not a natural food item anymore because they're so far removed from what exists in the wild, especially from the natural habitats calyptratus inhabits. Furthermore, there is an argument that chameleons cannot digest the "sugar" in fruits (although sugars in fruits are variable and the term is broad). I take issue with this, as we are not talking about feeding exclusively these fruits in isolation. Sugars are present in many foods and prey items consumed by chameleons (as you nicely point out) and we are talking about feeding a diet comprised of many things. Further, as someone who has published on the impact of diet on immune system and liver physiology, I can tell you it is not about a single ingredient most of the time, but the overall composition of nutrients in the diet. So I can see not exclusively feeding fruit, or not using it for gutload for every single insect, but completely avoiding the ingredients for the above reasons doesn't stack up to me.

I'm not advocating for people to feed their chameleons fruit constantly, but I don't think the reasons why fruits should be avoided (as food, as gutload) are totally solid. I don't bother with fruits except for gutloading on occasion, but I doubt they do much harm. There's also an argument that citrus should be avoided because it causes "breakdown of homeostasis", I have some concerns about that and I don't think it's accurate nor are there any studies that I'm aware of that look into this.

Here's a couple papers that are worth discussing, but do not really support the whole "chameleons can't digest sugar" thing. I unfortunately don't think this has been tested rigorously in chameleons specifically, but here's some stuff in other reptiles that might be able to be extrapolated to chameleons.

https://journals.physiology.org/doi/epdf/10.1152/ajpgi.1985.249.2.G271
One is demonstrating in turtles, chuckawallas and iguanas, that rates of glucose uptake in the intestines are less than mammalian uptake but this is because of differences in overall anatomy and decreased surface area of intestinal mucosa rather than something intrinsic to the biochemistry of the system. However, there is still plenty of glucose uptake in reptiles. Maybe this was taken out of context to argue that chameleons can't digest sugar. Obviously the study was not done in chameleons but there is some reason to believe the findings are similar.

https://journals.physiology.org/doi/abs/10.1152/ajpregu.1996.271.5.R1447
This one just demonstrates that some lizards have ability to run similar metabolic pathways we do, one of which utilizes a metabolite of fructose (F26BP), suggesting that there might be mechanisms to modulate dietary fructose uptake, conversion etc. in reptiles. This does not necessarily mean reptiles (chameleons) uptake fructose, but it at least suggests that the fructose molecule is not totally foreign to their systems.

https://www.ncbi.nlm.nih.gov/gene/6518/ortholog/?scope=8504
Using NCBI blast, one can identify that corn snakes express the gene encoding the enzyme that leads to uptake of fructose (so digestion), which is a bit surprising.

Now, here's where things get a bit interesting.

I am not able to find a homologous glut5 (SLC2A5) gene (encoding the main enzyme that uptakes fructose) in the veiled chameleon genome. This doesn't necessarily mean they don't uptake fructose, but if they do, it might be through a different mechanism. So maybe this is the source of the idea that they can't digest sugar-they don't have a similar gene as the typical fructose transporter. Again, this doesn't mean there's no way for them to take up the fructose, just that it might be a different mechanism.

So, the last bit is the only thing that supports any inability to digest fructose, but it is far from conclusive.

It's an interesting topic. However, even if we were to determine that chameleons cannot uptake any fructose at all and it's sitting idly in their gut (I think this is very unlikely), nobody has demonstrated that this is a bad thing. Further, other species of chameleons have been documented eating fruits in the wild. A lot of steps are necessary to really get at why feeding/gutloading with fruits is a bad idea. I think it's worth considering all of this though and keeping things in moderation. Probably not worth feeding chameleons fruit regularly regardless, as it doesn't seem like a major part of the diet in the wild, IMO.

this was so thorough i love it. incredible research

 

[kinyonga]

I know this thread has been inactive for a few weeks but...
can anyone answer this question..
If a chameleon eats and insect and the insect has enzymes that break down sugars in its gut, will those enzymes continue to work on breaking down sugar while they pass through the chameleons digestive system?

(I think I know the answer but my biology is a little week since I always took physics and chemistry in school.)

 

[Ambilobe123]

I know this thread has been inactive for a few weeks but...
can anyone answer this question..
If a chameleon eats and insect and the insect has enzymes that break down sugars in its gut, will those enzymes continue to work on breaking down sugar while they pass through the chameleons digestive system?

(I think I know the answer but my biology is a little week since I always took physics and chemistry in school.)

I believe that so long as the conditions are similar, the enzymes should continue to work. If the pH or temperature of the chameleon’s stomach/intestines is outside the optimal range for said enzymes, they will either work very slowly or denature entirely.

 

[kinyonga]

Thanks...I hadn't thought about the temperature being a factor...but I get it/remember that temperature could be a factor.