RE: de venomized
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by earthguy on September 5, 2007
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Why would you question my education just because I had other things to do at that particular juncture other than a literature search for fun? To clarify - the enzymatic activities of snake venoms are well known. Some break down tissues and fluids into smaller components. If you want to be technical that is what we refer to as chemical digestion. If that happens before a snake ingests it's prey, and if it then speeds and/or aids the process, then why not call it digestion?
Anyway, if I get some time I'll do a literature search. Until that time (or until such time that I see more than one abstract to the contrary)I will go with what my education tells me.
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RE: de venomized
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by earthguy on September 5, 2007
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Admittedly, the setup for the article that you mentioned was better, but here is one article that supports my assertion that venom could be important in digestion:
Digestive properties of the venom of the Australian Coastal Taipan, Oxyuranus scutellatus (Peters, 1867).
Toxicon; Sep2006, Vol. 48 Issue 4, p422-428, 7p
Abstract: The digestive properties of Australian elapid snake venoms have not been studied to any great extent. To address this, the in vitro digestive properties of Oxyuranus scutellatus (Australian Coastal Taipan) venom were investigated in a simulation of the in vivo conditions using the parameters reported for the stomach of snakes and representative prey for this species. The amount of soluble protein released was measured over time using a bicinchoninic acid (BCA) assay. Dismembered mouse hindlegs were injected intramuscularly with 0.1ml O. scutellatus venom (concentration 10mg/ml) and maintained in a micro-anaerobic, acidic environment (–1.7) at 25°C. The bathing liquid was sampled every 24h for 7 days, and assayed for soluble protein. Statistical analysis revealed that O. scutellatus venom increased the rate at which proteins were released when compared to a negative control suggesting the potential importance of envenomation in the digestion of whole prey
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RE: de venomized
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by vanerka on September 5, 2007
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Just to add.... I know snake and arachnid venom is a little different but dont spiders bites turn their preys intestines into mush to help them be able to eat their prey? Ive always assumed it atleased helped since venom is simply modified saliva, right? Correct me if im wrong but i just thought i would add my 2 cents...
Thanks Eric
p.s. both sides are being well debated... I just love a good debate.. :)
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RE: de venomized
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by EPARR1 on September 5, 2007
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Arachnids are a whole different story and for the most part unrelated to this topic.
I'll accept venom does aid digestion in some species. I just wanted to someone to back it up for a change.
Thanks Earthguy I'm not questioning your education. I would bet you are more educated than myself.
I have seen this comment posted far to often on many forums. The thing that gets me fired up 90% of the people posting it have no clue what there talking about. When asked why they think venom aids digestion more often then not they answer the question with a question. LOL
At any rate was a good debate and thanks for the info if you find any more please post it. This venomoid topic is always a touchy situation. LOL
Take Care
Eric G.
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RE: de venomized
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by FlaSnakeHunter on September 6, 2007
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Earthguy...the paper that you cited was an “in vitro” simulation, therefore, it is, at best, a fairly insignificant predictive model for which few actual conclusions may be drawn. On the other hand, the paper that EPARR1 cited was an “in vivo” study, the merits of which are highly significant and which support and verify the empirical observations by many herpetologists.
In fact, over the course of 40 years of captive husbandry and propagation of hundreds, perhaps thousands, of venomous snakes, including both indigenous and exotic species from Elapidae, Viperidae and Colubridae, my empirical observations would indicate that the role of venom with regard to digestion is minimal, at best. I base this upon the practice of utilizing frozen/thawed food items wherein the feeding animal does not inject venom; they simply locate the head (not always) and begin to swallow the mouse, rat or rabbit...the introduction of venom into the food item is completely bypassed. At no time have I observed anything less than spectacular growth and optimal health. Therefore, the proper and only conclusion is that these animals are receiving superb nutrition despite the lack of venom circulating in a prey item prior to it's death.
To me, it appears that venom is an agent that acts to subdue and kill a prey item.
Furthermore, in many species, neonates feed on reptilian and/or amphibian prey items and, when sufficient growth has occurred, they begin to feed on mammals. The interesting point about this is that their venom is prey specific, i.e. the venom of these neonates has a more profound effect in terms of subduing and killing the reptiles and amphibians that comprise their diet and, when they begin to feed on mammals, their venom has also changed to the extent that it has a greater impact on their mammalian prey with respect to subduing and killing.
Venom-prey specificity seems to be a direct indication as to the role of venom in subduing and killing prey items rather than for any role in prey digestion. This makes sense from an evolutionary standpoint for two reasons: 1) Prey items may pose a considerable risk of injury to the snake, thus, injecting venom and immediately releasing the prey item minimizes the risk, and; 2) Once injected with venom, the snake must be able to find the prey item, and, if said prey item is not subdued quickly, it may travel too great a distance for the snake to find it.
Now, for a moment, let's assume that venom does have a significant role in the digestion of prey items. Wouldn't it then be correct to assume that without the venom, malnutrition and/or marginal health would ensue and the animal would not experience robust health, growth and propagation ?? In reality, this is diametrically different than what actually happens insofar as captive specimens maintained continuously on frozen/thawed food items do experience robust health, growth and propagation.
Very interesting subject…
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RE: de venomized
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by earthguy on September 6, 2007
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Marty,
I admitted that the in vivo paper was probably more accurate. Your observations that F/T mice are digested without injection is flawed in that you would have to conclusively show that the snake didn't envenomate in the process of swallowing (viperidae espeically use their front fangs like fingers to move the prey down the esophagus). Also from an evolutionary standpoint how do you explain the presence of 'venom' in the far more advanced colubridae if not as a digestive aid?
On a side note, have you ever seen a bad EDB bite? The necrotic tissue aroud it looks pretty well 'digested' to me ;)
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RE: de venomized
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by EPARR1 on September 6, 2007
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Correct me if I'm wrong but EDB and WDB venom very simailiar. I took that if it played no role in digestion in the WDB. You could also assume the same for the EDB.
I'm no venom expert so be nice with the reply. lol
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RE: de venomized
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by earthguy on September 6, 2007
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Different species. Venom can vary drastictically even within a species between two different populations. And, as was previously mentioned, venom composition can change within a given snake with age/size to accomodate different prey items (which, incidentally, I see as a pretty strong argument for venom as a digestion aid).
On another point, I don't think that captive venomoids can be used as an indicator for the use of venom as a digestive aid. It would be my guess (and on, I don't have any data to back this up) that our well cared for pets get more nutrition (on average) than a wild snake. There are also probably fewer stressors (possible predators) All of that plays into how well an organism can process their food.
One more point - I'm really enjoying this little debate. It's been a while since something like this has popped up on the forum.
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RE: de venomized
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by Buzztail1 on September 6, 2007
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It seems to me that we are getting caught up in semantics.
If venom breaks down tissue into easier to digest liquids, then it would be safe to say that venom injection AIDS in the digestive process.
Where we seem to be getting lost is the mistaken belief that AIDS IN THE DIGESTIVE PROCESS = REQUIRED FOR DIGESTION.
Clearly the ability of venomoids to thrive disproves this. That does not disprove the AIDS in digestion theory. It merely proves that venom injection is NOT a NECESSARY part of the digestive process.
I hope I have stated my belief clearly. It's easy to mix this one up.
Venom aids digestion but is not required for digestion.
Just my own beliefs
R/
Karl
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