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Posted by Thamnophile on March 13, 2003 at 00:25:31:
In Reply to: The long story on Thiaminase and vitamin B1 posted by Brian Macker on March 12, 2003 at 21:33:32:
:Here is the link listing thiaminase in fish. The first list Alewife - Whitefish lists fish known to contain Thiaminase. Fathead minnows(Rosy reds) and Carp(Goldfish) are on the first list. The second list Ayu-Yellowtail are those without thiaminase. This includes trout.
:Guppies and Gambusa (Mosquito fish) are not on either list but I believe neither contains Thaiaminase.
:I am going to post my knowledge on this again. You can skip to the bottom of the page to get the moral of the story.
:Snakes need Thaimine (Vitamin B1) to survive. If they do not get enough they come down with nervous disorders. They can become listless, uncoordinated, twitchy, or have "fits".
:Thiaminase is an enzyme that will break apart Thaimine. Enzymes are normally named after the cheical on which they act with an added suffix of "ase". Thus peptase, that smelly component of vomit and papayas, breaks apart peptides (proteins).
:To break apart the chemical it acts on an enzyme needs contact with it. The length of time, concentration, and the temperature both affect the action of an enzyme. Enzymes are not destroyed in the chemical reaction the cause and can act again and again. Since molecules are constantly moving about at an atomic scale an enzyme is jostled about and will come into contact with more of the host chemical as time passes. Also at higher temperatures molecules move around more quickly and have more energy so enzymes act more quickly. At higher concentrations within a carrier liquid enzymes act more quickly because there are more chances to bump into the target molecule.
:In living animals enzymes are usually separated from other molecules by cell and vacuole walls. Death and freezing can both cause these walls to break down. Freezing does so via the sharp ice crystals as the expand and grow.
:Water with salt (and other dissolved molecules like sugar) in it has a lower freezing temp than those without. The more salt the lower the temp. When salt water freezes the ice that forms is fairly pure and the remaining water becomes more concentrated with salt. Animal blood is dilute salt water. This means that frozen meat will usually still have some liquid water as a highly concentrated liquid broth.
:Using this knowledge I make the educated guess that when fish containing thiaminase are frozen that can break down the cell walls and allow the thiaminase to come in contact with the thiamine and break it down. This may take a longer time because of the low temperatures but this effect is counter balanced by the higher concentration of both thiaminase and thiamine in the remaining unfrozen liquid. I have no empircal data on this but realize that long frozen thiaminase containing fish probably no longer contains any vitamin B1 whatsoever.
:There is a similar problem with dead fish. With death the cell walls begin breaking down and the chemicals come in contact. Although not concentrated the warmer temperatures allow the molecules to wander faster and so have a high chance of bumping into each other and when they do with a fast enough speed to provide energy for the reaction.
:These reactions also can occur in the gut of your pet. Another factor on the performance of enzymes is PH (acidity). The acid conditions in the gut are specifically there to enhance the performance of peptase. It may also help thiaminase to act more efficiently but this I am not sure of. In any case as your pet digests the thiaminase containing fish the cell walls are broken down and the temps are warm. So any vitamine B1 in the gut even present at elevated levels from supplements can and will be broken down. Thus supplements are not as effective during meal time than in between. A snake drinking vitamin B1 between meals on an empty gut has a better chance of adsorbing some than if he gets dusted fish.
:In fact I had a batch of baby snakes that I was feeding B1 supplements in their water. I was feeding them rosy reds. I had three snakes that were particularly attractive so I was paying special attention to them to make sure they had a constant load of food in their gut. They got fed first and I separated them to make sure they got fed the most. Well guess what all three came down with thiminase poisoning first and two died. The other snakes were fine the whole time. I had been feeding my snakes rosies for a long time before that (the entire prior year) and never had a problem. Difference was that normally I didn't worry to much about keeping them well fed. They usually had a period of no fish in the gut and drinking vitamins supplements. That gave them a chance to load their bodies back up with B1 so I didn't lose any snakes prior to this.
:I no longer use fish I use F/T mice. Not after losing an entire years worth of work with the offspring of one adult female by losing the cream-of-the-crop babies.
:Note that I do not believe that thiaminase can pass through the gut wall into the bloodstream of a snake. Enzymes are usually proteins and are usually large. I believe that proteins are broken down into amino acids before being transported across the gut wall.
:Note that even though peptase, which is present in the stomach, would probably act to break down thiaminase there is so much other proteins in a prey item that it is less likely for the thiaminase to be picked out of the crowd and broken down.
:So moral of the story is: If you must use fish use non-thiaminase containing fish like trout (and maybe guppies or gambusa). Don't feed goldfish or rosy reds to you snakes if possible. If you have to make sure they are not frozen or dead. Give your snakes feeding breaks with access to vitamin B1 laced water. I use Reptosol.