Thoughts on Vitamin D

[boxcat]

I don't have time to fish all this stuff up, I have a lot of other stuff to worry about at the moment but that paper would be eye opening for you.

Also, if that's the attitude you want to take, that's fine. I'm done then. I apologize if this post wasted your time. We have noticed people are having some devastating problems with their crabs. We are trying to propose a theory to right that problem, and some other common captivity issues. I find the attitude in the above quote disheartening.

[Rocky]

I don't think hermit crabs even get that much sun exposure From what I can tell, they're mostly or completely nocturnal. Even mine tended to hide and bury themselves when I had a bright heat lamp, but when I have my moonglo lamp in, they're much more active and willing to come out in the open. Even if the light is out there and available, mine avoid it.
I'd think a hermit crab in it's natural environment would avoid excess sun exposure because of how hot it can get there. They tend to stay hidden in the foliage or buried underground.
I really don't think crustaceans (or critters with an exoskeleton in general) really get vitamin D the same way mammals and reptiles do. Besides the fact that they have this large, thick exoskeleton, what about marine hermit crabs? Or critters like scorpions or lobsters? They have little or no exposure to UVB lighting (especially the marine ones)but they get the necessary vitamin D through their diet, and they're all closely related to hermit crabs.
And what about the random-ness factor? (for lack of a better term) I think mine and wode's environments are pretty darn similar, neither of us provide UVB, but she has problems and I don't. The only difference I can think of is that her Es are much older and larger, and probably sexually mature.
Just my thoughts :dunno: I just really don't see the logic behind it. How would the UVB even penetrate their exo?

[wodesorel]

I would also like to point out

"Vitamin D-binding proteins in the blood have been found as far back in the evolution as amphibians and reptiles. Their presence in more primitive animal forms and plants has not been described, but their existence seems likely."

I missed that on my first read-through.

Vitamin D binding proteins have nothing to do with processing Vitamin D from UVB exposure. They simply transports the D to where it's supposed to go, and that D can come from skin exposure to UVB light or from eating something that contains D.

Again, I'm not seeing any specific proof that states crustaceans - specifically hermit crabs - derive the Vitamin D they require from UVB exposure.


I'm not saying they don't need Vitamin D - all things do. But if there's going to be an argument made that UVB is that incredibly vital to their suvival, then there needs to be proof that they can actually gain something essential from it. It's an expensive set-up, and it's hard to make work with the current style of crabitats. If it's shown that it is absolutely a must then it needs to be listed up there with deep substrate and heat and humidity for sure. However, to this point, there has been no scientific proof that it is necessary to prove them with it, and no scientific proof that they can even utilize UVB.


And please don't forget that kuza has a full-time job, two human babies, and a thousand little babies to take care of right now! Some of us are able to devote more time to the HCA then others, and not being able to drop everything to hunt down proof doesn't make their point of view any less valid. Besides, I'm sure he knew I would hook you up with the paper once he mentioned it.

[kuza]

I get the feeling you may have misunderstood the point of this post. We're not saying Es are not aggressive as a species. We're saying some, maybe all, of the aggression can be explained by a deficiency of this nature. And perhaps other things like jumbos that have been stunted in growth (sound familiar?), or crabs that seem to get smaller with molts. Hermit crabs in general show some symptoms of vitamin D deficiency (see bulleted list).

I don't mind a hearty debate, but we took the time to post scientific references to back up our review of literature and our synthesis of our theory. I (along with, I'm sure, Eugooglizer), would appreciate the same.

I knew wode would come through for us, as she did, thanks wode

[kuza]

Also, if that's the attitude you want to take, that's fine. I'm done then. I apologize if this post wasted your time. We have noticed people are having some devastating problems with their crabs. We are trying to propose a theory to right that problem, and some other common captivity issues. I find the attitude in the above quote disheartening.

Sorry but I was actually serious, I'm in the middle of doing a lot of work on my zoea right now so I seriously didn't have time to look it up. But I had read it and I've personally seen their shell aggression right from day one so I believe it's the species and I will continue to believe that until someone finds some proof to prove otherwise.

I'm very stubborn because I've seen my crabs do things people claim they never have when they have owned crabs much longer than I have, so it's obvious I'm watching my crabs much more closely than they are. And their attitude didn't change over time, they acted the same way day 1 as they do on day 540. The only time things change is seasonally, and it's cyclical.

[CallaLily]

I'm very stubborn because I've seen my crabs do things people claim they never have when they have owned crabs much longer than I have, so it's obvious I'm watching my crabs much more closely than they are. And their attitude didn't change over time, they acted the same way day 1 as they do on day 540. The only time things change is seasonally, and it's cyclical.

Admittedly, I don't sit and watch them for 8+ hours a day but I think it's unfair of you to say other crabbers missed certain behaviors only because they're not watching enough. It is also possible their crabs just haven't displayed these behaviors.

I haven't had my crabs for a large amount of time (just coming up on 5 yrs) but I'm one of the few not noticing aggressive behavior and I do not provide UVB lighting or supplement vitamin D often (very, very occasionally I will use the calcium plus d3 powder I have for my lizards). I do find this thread interesting but like Kuza, I have read enough aggressive E posts to think it is species related. I think some of the reasons I've missed this behavior in my Es (aside from the possibility of just that....missing it) is I've only had a small group of younger, smaller crabs.

[kuza]

That is very possible, I don't expect everyone's crabs are mating just because I've seen it. Or that they are all aggressive just because I've seen that, since not all my E's are aggressive and not all my crabs are mating. So everything I bring up is mainly observation and second hand info.

[Rocky]

Also, if that's the attitude you want to take, that's fine. I'm done then. I apologize if this post wasted your time. We have noticed people are having some devastating problems with their crabs. We are trying to propose a theory to right that problem, and some other common captivity issues. I find the attitude in the above quote disheartening.

Hey dude, we're still people I'm working ten hours a day, kuza has family (and young children to boot, ouch) If you want to debate about this, and you did initiate a debate, then by all means But we don't all have the time to dig through the internet for certain thing.
And thoughts, observations and experiences are just as valid as scientific papers (or so I think) We're the hobbyists, after all. We (as a community) are the ones who put a lot into our crabbing, and we pay a lot of attention to the behaviours of our crabs, what we can do to change certain behaviours and how certain changes effect them. All together, we're putting a heck of a lot more time, money and effort into learning about our little guys than any researcher.
Besides, I'm poking through all that stuff and I'm not seeing anything that says hermit crabs, or even crustaceans, require UVB specifically as a source of vitamin D. I'm seeing "Hermit crabs need vitamin D" and "Animals in general need vitamin D" but not "Hermit crabs require UVB exposure"
Sorry, I'm just not seeing it :dunno:

[boxcat]

I don't think hermit crabs even get that much sun exposure From what I can tell, they're mostly or completely nocturnal. Even mine tended to hide and bury themselves when I had a bright heat lamp, but when I have my moonglo lamp in, they're much more active and willing to come out in the open. Even if the light is out there and available, mine avoid it.

That's interesting. My Es are usually very active during the day. The article that Wodes posted mentions that some Ecuadorians spend the day under logs and in the shade. You still get UVB exposure in the shade-- you can even get a sunburn if you sit in the shade during the summer! Water reflects UVB light as well-- everyone knows to put sunscreen on your face if you go swimming. Just some thoughts. (thoughts, guys-- not conclusions.)

I'm not saying they don't need Vitamin D - all things do. But if there's going to be an argument made that UVB is that incredibly vital to their suvival, then there needs to be proof that they can actually gain something essential from it. It's an expensive set-up, and it's hard to make work with the current style of crabitats.

The article you linked me said that compressus is active during the day in humid areas. I don't know why everyone keeps saying hermit crabs are not active during the day; indeed, that "eye-opening" article mentions this activity! And please, please reread my original post. Who's saying UVB is required? We're saying vitamin D supplementation via diet should be considered-- perhaps UVB as well. Kuza himself mentions his crabs "bask" in the UVB light. Mine do too-- but they never did in the solely fluorescent light. Maybe that's important. Maybe it's not.

And please don't forget that kuza has a full-time job, two human babies, and a thousand little babies to take care of right now! Some of us are able to devote more time to the HCA then others, and not being able to drop everything to hunt down proof doesn't make their point of view any less valid.

I am a busy person as well. I took the time out of my schedule to partner up with Eugooglizer and write this up. It took a long time. Why did I do it? Because this is an important topic to me. Scientific proof is being asked of me, yet when I ask it of others I'm told you don't need to provide it? Can we at the very least level the playing field here?

If you want anecdotes, I can provide those as well. I've owned hermit crabs since August 1st of 2005. I have fed them a quality vitamin D supplement since day 1. I have never had a deformed molter, an attacked molter, and certainly no overly-aggressive crabs. Eight years later, I still have one of my original crabs, an "exotic" no less. That's my anecdote.

I am lucky in that I work out of my home and I sit in front of my crab tank for about 8-12 hours a day.... [...] I'm also on the forums 24x7, I'm seriously glued to the internet

Serious question though kuza, regarding this:

The only time things change is seasonally, and it's cyclical.

How do your crabs know what season it is? I'm a bit skeptical of the "breeding season" idea in general, because in captivity there's no change in photoperiod, no change in heat/humidity, no moon cycle, no tide... there certainly isn't a hermit crab breeding season in Canada, so they're not just looking out the window for clues. What's the basis, other than perceived behavioral change, for this "breeding season"? I'd be interested to learn more about this, though this may be the wrong board for the topic.

Hey dude, we're still people I'm working ten hours a day, kuza has family (and young children to boot, ouch) If you want to debate about this, and you did initiate a debate, then by all means But we don't all have the time to dig through the internet for certain thing.

Again, if you guys are going to ask me to cite more sources (please see my previous cited sources), it is entirely reasonable for me to ask the same of you.

Besides, I'm poking through all that stuff and I'm not seeing anything that says hermit crabs, or even crustaceans, require UVB specifically as a source of vitamin D. I'm seeing "Hermit crabs need vitamin D" and "Animals in general need vitamin D" but not "Hermit crabs require UVB exposure"

I guess I don't understand how this turned from "our opinion is that hermit crabs should get a vitamin D supplement" to "every hermit crab needs to have access to UVB light right now!" That's not what we're saying, and it's not what I'm saying. I invite you to reread my original post, if you are not too busy, that is.

Some more interesting articles I found via the magic of Google Scholar:

June 1999, a revolutionary article arguing that "crustaceans serve as an ideal model for the study of calcium homeostasis." For those of you playing the home game, calcium homeostasis involves for the most part three hormones: calcitonin, parathyroid hormone, and vitamin D. Serving as a model organism means we can essentially study the process in humans, only in a different species (usually one where we can gauge changes easier [exoskeleton] or faster).


October 2004 (originally published in French), confirmation that crustaceans are now a model organism for the movement and storage of calcium, involving in part the use of vitamin D. This is the exact same process as biomineralization of human bones. To say vitamin d is not involved is to outright not understand the biochemistry behind this confirmation:
"Another advantage of crustaceans based on the presence of calcifying epithelial (but descaling), developing (and resorbing) structures of calcium storage, and whose study to better understand how similar fabrics encountered in vertebrates. Similarly, shellfish are excellent models for understanding the hormonal regulation of calcifying systems, especially in addition to a possible role of some ecdysteroids, hormone controlling calcium metabolism trilogy vertebrates (calcitonin / parathormone / Vitamin D) could also be functional in crustaceans." (translated from the original French article)

"Another characteristic of calcium metabolism in crustaceans are the calcium-transporting epithelia very similar to some vertebrate ones, and in this way they represent also good models to understand how they function."-- English publication

"Furthermore crustaceans are convenient models for studying the hormonal regulation of the calcium turnover with the possible involvement of vertebrate-type hormones such as calcitonin/CGRP and vitamin D presumably evolving from invertebrate counterparts"-- English translation


Simple abstract, states the obvious: that vitamin D interacts in a crustacean's body to regulate calcium:
"These results, together with other data, are discussed to determine the possible functions of vitamin D3, or related molecules, in the calcium turnover within the different compartments of the body, according to the successive stages of the molt cycle."


This article explains the use of vitamin D in crustaceans during the molting process.
"Quantitative differences in 1,25(OH)2D3-like immunoreactivity were noticed from one stage of the molt cycle to another. These results, together with other data, contribute to evidence that immunoreactive 1,25(OH)2D3-like molecules may be involved in the regulatory processes of calcium metabolism in this terrestrial crustacean and suggest an involvement of these substances in the regulation of calcium movements in the posterior caeca."
Human antisera was used to identify 1,25(OH)2D3


I am not saying that hermit crabs can exclusively gain vitamin D from UVB light. I am saying that virtually every organism on the planet, including deep sea fish (which never see the sun) have the ability to produce vitamin D via their integument, whatever that may be. I don't think it is highly unreasonable to suggest crustaceans can do the same; again, just because we haven't looked doesn't mean it isn't there. I personally set up UVB lights in my tank on the off-chance they need them to produce vitamin D; however, I believe my hermit crabs are getting enough from their diet. I DON'T think they would have enough from their diet alone if I did not supplement that diet, even though it is just as healthy and high-quality as any crabber on this board feeds.

Furthermore, calcium and vitamin D are both directly related and proportional to each other in any bodily system. The body needs both. Again, I do not think it unreasonable to suggest that because we supplement a HIGH amount of calcium for our hermit crabs, they may also need a HIGH amount of vitamin D (dietary or maybe UVB) to be healthy, to not have personality issues, and to not "shrink" as they get older. Maybe some species are more resistant to others-- that would certainly be an explanation as to why Es anecdotally show more aggression in captivity than others.

If someone is able to provide scientific evidence that hermit crabs CANNOT synthesize vitamin D via their integument, please pipe up! Do you know the implications that may have in medicine? Research like that can potentially lead to treatment of things like seasonal affective disorder, and may revolutionize how we treat vitamin D deficiency in humans. Until then, all I know is it is easy for humans the become vitamin D deficient without sun exposure, even with a good diet. It's not too much of a stretch to say captive animals can also become vitamin D deficient, even with the quality diets we currently feed.

Those are my thoughts. I feel as though some members are taking this very personally. I'm not trying to criticize care. I'm not trying to say "my care is better than yours." I am taking EIGHT YEARS of experience and trying to help some fellow crabbers. How much does a vitamin D supplement cost? Maybe $5, $7 if you buy something like Repashy. Maybe this is something we need to look into, that we've missed-- we as a community. As Rocky said, we ARE the hobbyists, we need to do this kind of research. My own personal experience tells me there may be something to this. If you don't agree, that's fine, but please hold yourself to the same standards you are holding me. This is all in the name of crab care guys, I am not trying to point the finger and say someone is doing something wrong!

[kuza]

I don't mean to be rude but I really doubt anyone on this planet is as busy as I am right now. Both my wife and I work full time (both leads at work and working 6 days a week most weeks) and we have 2 young kids (2 and 5) to take care of. Do you have kids? It's a LOT of work. I only get to sleep about 5 hours each night because of how busy I am. And I knew wode had that article handy and would help me out, so it was coming, does it matter if it comes from me?

And my crabs all molt through the winter months, every year, and the room they are in has a huge window, in fact my whole house is windows so they will be able to tell when the days are longer. Even on the equator the sun changes sides throughout the year. And only in the summer are my straws making zoea constantly, they didn't do it in the winter and this pair has been together for over a year.

None of this info is scientific, I do not have the time to go that deep into it, I'm just going based on the information readily available to me and if something new comes up or you figure this out, I'll be happy you had the time to do it.

Why don't you just share with us what vitamin D supplement you use and we can try it out, maybe it will help.

[boxcat]

I don't mean to be rude but I really doubt anyone on this planet is as busy as I am right now. Both my wife and I work full time (both leads at work and working 6 days a week most weeks) and we have 2 young kids (2 and 5) to take care of. Do you have kids? It's a LOT of work. I only get to sleep about 5 hours each night because of how busy I am. And I knew wode had that article handy and would help me out, so it was coming, does it matter if it comes from me?

No, but I didn't know wodes had it handy. I'm glad it was posted, but it didn't really add much to the discussion either (one paragraph out of roughly eight pages mentioned a shell fight). I thought the way you brought it up was rude, again mostly because I was being asked for "proof" and you were mentioning an anecdote from memory. It's posted now, so I guess that's neither here nor there.

And my crabs all molt through the winter months, every year, and the room they are in has a huge window, in fact my whole house is windows so they will be able to tell when the days are longer. Even on the equator the sun changes sides throughout the year. And only in the summer are my straws making zoea constantly, they didn't do it in the winter and this pair has been together for over a year.

I'll have to dig it up but I thought I remember Curlz mentioning somewhere that her crabs have dropped eggs all throughout the year. I'm not saying a breeding season doesn't exist, I'm just saying that I don't know if there would be a very stringent season in captivity. From what I've been reading, breeding season in the wild is basically when conditions are favorable (tides, currents, etc). In captivity, these conditions are always favorable, and there is always access to salt water that's a proper temperature and has no predators. I'm just wondering if the "breeding season" in captivity isn't necessarily as marked as we may think it should be.

None of this info is scientific, I do not have the time to go that deep into it, I'm just going based on the information readily available to me and if something new comes up or you figure this out, I'll be happy you had the time to do it.

I'm asking for scientific resources refuting what I have to say about vitamin D. I haven't been able to find any myself, which leads me to believe there may not be any. Obviously our theory is synthesis-- there isn't any published paper out there that says "Hermit crabs need ___ IU vitamin D per day from this source or this will happen." I'm trying to offer an explanation-- if you don't like it, that's fine, but again, hold yourself to the same standards that you hold me.

Why don't you just share with us what vitamin D supplement you use and we can try it out, maybe it will help.

Years ago I used a T-Rex cal/vitD supplement that I'm pretty sure is no longer on the market, right now I use a variety of the cal/vitD and general vitamin supplements available through Repashy. There are other brands out there but that's my go-to and preferred.

[kuza]

I often sound rude because of how busily strung out I am, I don't mean it, sorry. And I'm not sure about breading season yet either, I'll know this winter if my straws keep dropping eggs all year round.

And the article mentions they saw many fights between the crabs but only described one for that article. They are obviously getting lots of vitamin D, so again, I believe it's because they have a shell shortage where they are from so competition for them is instinctual.

[Rocky]

Well, you wanted my thoughts, and those are my thoughts I just don't see it being the cause.

[wodesorel]

I don't use UVB, but I do dust their food regularly with this stuff: http://www.flukerfarms.com/repta-calcium.aspx

My very first post in this topic. I've had my Es since Nov. 2009 - almost four years now. I have always supplemented Vitamin D.

My Es are not deficient.

My Es still have behavioral trouble.

Edit: I still have bad molts now and then.

So....?

[wodesorel]

How do your crabs know what season it is? I'm a bit skeptical of the "breeding season" idea in general, because in captivity there's no change in photoperiod, no change in heat/humidity, no moon cycle, no tide... there certainly isn't a hermit crab breeding season in Canada, so they're not just looking out the window for clues. What's the basis, other than perceived behavioral change, for this "breeding season"? I'd be interested to learn more about this, though this may be the wrong board for the topic.

Captive animals still feel tidal pull from the changes of the moon. They can still sense "real" sunlight through windows versus artificial lighting. They can still feel barometric changes. Being in a glass tank does not mean they are cut off from the rest of the world!

And yes, in the US there is definitely a breeding season. No one has gotten eggs here during the fall, winter, or spring. Only in the summers are people seeing mating and eggs.

Why is Germany different? It could be the species - Violas may mate year-round, while species like Es and PPs mate only once a year. So far they've had the most success with Viola breeding. Germany may have just the right barometric pressures year-round to spur them into mating over and over again. Only time is going to tell us what the key is, and that's only as we continue to observe and more people get lucky with captive breeding.