Academic nonsense! (scientific info on thiamine/thiaminase)

[GradStudentLeper]

Do you believe it? It's an honest question - I didn't save any of the citations, but when I looked at studies of thiaminase-producing bacteria in alewives the results seemed inconsistent (didn't always find bacteria where they found thiaminase). If the studies you read had really solid results, that would be interesting.

I think so, at least for the really high values, plus there is a very high level of variation in the amount of thiaminase present.

This is digressing a bit, but incidentally, thiaminase-producing bacteria have also been found in the digestive tracts of some people with chronic thiamine deficiency!

Which raises the question, "have Alewives(and other fish) been found to have a thiamine deficiency with this bacteria"

I will basically have to look at the papers to see if the level of thiaminase is really unrelated to thiamine activity, or if there is something underlying. From the way they do the assay, they might have a confound in their data, in that they grind up the fish, breaking down cell membranes and permitting more thiaminase to come into contact with the thiamine present. If this is the case, one would not necessarily expect the two concentrations to be related... Or so I think.

Also the temporal variability might also be consistent with a bacterial infection. Maybe...

[kapor]

have thiaminase fish meal freeze-drieried?

[aquamentus_11]

The point is: vary your feeder items. While thiaminase-positive fish species might as well be avoided if they can be, they will only cause a problem in an animal that is fed them explicitly or regularly. Try to stay away from those species, but sporadically eating some thiaminase (which they probably do in the wild) isn't going to hurt anyone. As the good doctor said, thiaminase is an enzyme (protein) and will be broken down in the the GI tract. Because of this, you would have to have a lot of it to generate enough thiamine-breakdown products to out-compete intact thiamine at its binding sites in the body of an animal with adequate thiamine levels. Also, you'd need a lot of it and relatively low levels of thiamine for the enzyme to deplete your stores. I could see the combination of these two mechanisms being a potential problem, but I would imagine (and this is just a hunch) that the most serious effect of thiaminase will be seen when your primary thiamine sources are ingested at the same time as the thiaminase: the enzyme will break down thiamine before it ever gets absorbed in its intact form for healthy use. It would help to know what the thiamine metabolites look like and what their affinity for the thiamine receptor is like relative to thiamine itself. Anyway, I'm going to avoid if possible, but not worry too much if I have to give a shiner or two once in awhile. Personally, if a snake is being fed enough thiaminase pos. prey items to cause problems, I would worry about the overall nutritional status of the animal, not just thiamine. Imagine if you only ever ate bananas.