Dairy

[Guest]

Calcium for certain, fats that they need. Milk protein is 96% digestible by them. We'll see. Everyone that I caught around the dish last night is still alive, so time will tell...

[Guest]

Wow Kerie! Good luck! Those pictures make me want to try it with my crabs. I can't bring myself to do it though, I'll probably try it once I hear an OK from you You're such a a good researcher!

[Guest]

I’m really, sincerely not trying to be a pain, but we don’t have enough information to say that dairy protein is 96% digestible. It has been noted that casein, one kind of dairy protein, is 96% digestible by other crustaceans. This makes sense given the fact that isolated casein contains no lactose, but casein in milk is not isolated, and it’s only a part of the protein in milk. The other main dairy protein, whey, is loaded with lactose and is not fed to captive crustaceans. So given the fact that casein is not the only milk protein, and differs greatly from the other, it would be a bit hasty to say that all dairy protein is 96% digestible, especially since it’s the other protein that I have reservations about.

Even the digestible casein may not be a particularly good protein source for crustaceans. Farm-raised seafood is not really an example to follow in regards to crustacean nutrition, given the hormones, antibiotics and other chemicals they’re pumping our seafood full of, but I digress. A study by Eleni Mente and Dominic F. Houlihan of the University of Aberdeen in Scotland compared different sources of protein (seafood meal, seafood & soybean meal and casein) for crustaceans and found:
“…casein diet caused a decrease in growth and an increase in the mortality. The amino acid profiles of the whole-body protein of L. vannamei compared with casein diet showed a deficiency of asparagine, alanine, threonine and arginine concentrations. This is in line with the results of the low growth rates.â€

[Guest]

Kerie, is it too soon to post those "other" results? Is she ready yet with her report?

[Guest]

I’m really, sincerely not trying to be a pain, but we don’t have enough information to say that dairy protein is 96% digestible.

I got my info from an aquaculture scientist, but I misspoke, it's actually 99.1% digestible:

"I am not readily familiar with hermit crab diets. However, casein is used
frequently in dietary studies of shrimp.

See for example, Lazo et al. 1998. Evaluation of three invitro enzyme
assays for estimating protein digestibility in the Pacific white shrimp,
Penaeus vannamei. J. World Aquaculture Society 29(4): 441-450.

Casein in vivo digestibility was reported to be 99.1 % for this shrimp by
Akiyama et al.,

see: Bulletin of the Japanese Society of Scientific Fisheries 55:91-98.
Gary J. Burtle"

Again, I'm not telling anyone else to try this. But after a year of food experiments and research I am completely confident that not only will crabs eat dairy, they can benefit from its nutrients as an occasional treat.

You don't like it? Fine, don't serve it. I will continue to do so. I only use organic food with no hormones or antibiotics.

And, Lisa, she's got a lot on her plate but I'm hoping she'll have the info for us soon.

[Guest]

I think it's a good point to emphasize the ammount of additional chemicals, hormones, and antibiotics that are in commercial milk. The milk that you get at the grocery store has a lot of stuff in there that is probably NOT good for your crabbies. (or you either)

[Guest]

I got my info from an aquaculture scientist, but I misspoke, it's actually 99.1% digestible: "I am not readily familiar with hermit crab diets. However, casein is used frequently in dietary studies of shrimp.

Right, you’ve established that casein is digestible, I don’t have questions about that at all. But casein is only one kind of milk protein, the one that doesn’t contain lactose. The other kind of milk protein, whey, is the one I’m still looking for info on because that’s the one with all the lactose. They’re both present in milk. So it’s perfectly accurate to say that the dairy protein casein is 99% digestible, but not that milk protein, as a whole, is 99% digestible (it may be, but I haven’t seen that research yet).

It’s also important to note that digestibility doesn’t mean it has benefits. After all, people have fed crabs Doritos before and seen them eagerly consumed, I wouldn’t say that makes them healthy. In my last post, I quoted a study that showed that a casein diet increased mortality, lowered growth rate and decreased amino acid levels in crustaceans when compared to other protein sources. I think that deserves some looking into.

You don't like it? Fine, don't serve it. I will continue to do so.

Fair enough, but I also want to make sure this forum provides all the information so people can make an educated decision.

Kerie, is it too soon to post those "other" results? Is she ready yet with her report?

By all means, if someone has some "other" research on lactose digestion by crustaceans I’d love to see it. I’ve really been struggling to find any research on this issue at all. My university finally figured out that I graduated in May and won’t let me use their electronic databases to get journal articles anymore, darn them.

[Guest]

the point is, none of them KNOW. I've asked around to many different scientists. No studies have been done. They don't come out and say, no, either. I'm a member of the Crustacean Society, I pick the brains of the actual scientific members a lot.

It's all conjecture on the part of hobbyists. Which is why my food group does feeding trials - to find out about such things.

All this time I've heard dairy will "kill crabs" if they eat it. And that has now officially been proven wrong. Digestibility is a different matter, but since I'm not proposing that their diets be based wholly on dairy, but rather dairy won't hurt as a treat now and then, I'm not as worried about it.

[Willow]

What kind of milk are you giving them? I'm sure it's organic. Is it whole, 2%, 1%, skim? Probably whole, since you mentioned fats, but I just wanted to ask.

[Guest]

Full fat Horizon organic. Another member of my group is feeding organic half and half right now.