Oyster shells tested for heavy metals?

[Katanahamon]

Wondering if oyster shells are tested for heavy metals..I’m going to offer my girls some pure calcium instead, there are several sources out there..oysters likely have high levels given where they live both naturally and farmed..I found some calcium from Coyote Creek..

 

[DobieLover]

Wondering if oyster shells are tested for heavy metals..I’m going to offer my girls some pure calcium instead, there are several sources out there..oysters likely have high levels given where they live both naturally and farmed..I found some calcium from Coyote Creek..

There have been studies that collect that data. Most of the heavy metals will collect in the soft tissue of the oyster. Cadmium will be higher in the shell than the soft tissue of the the oyster because it can replace calcium. Overall, I wouldn't be too concerned about it.

 

[U_Stormcrow]

There have been studies that collect that data. Most of the heavy metals will collect in the soft tissue of the oyster. Cadmium will be higher in the shell than the soft tissue of the the oyster because it can replace calcium. Overall, I wouldn't be too concerned about it.

Additionally, high heavy metal concentrations in the water oysters filter (and thus potentially absorb to become part of themselves) tend to lead to population collapse, which then results in harvesting moratoriums, which prevent those shells from entering the stream of commerce in the first place.

While there are other, also "natural" sources of calcium, such as limestone rock, there is absolutely no guarantee that those non food grade sources are any less contaminated with trace elements, heavy metals, sources of radioactivity, etc.

So @Katanahamon, good thought. But I'm not sure it warrants abandoning normal practice absent more information. Do you propose to feed your chickens Citrical? Are you prepared to make adhjustments for the greater bioavailability of Calcium Citrate over Calcium Carbonate? How will you measure that? Or have you secured a reasonably priced source of Dicalcium Phosphate? DO you know dosage, or will you be offering freee choice?

Questions. Always Questions. A little knowledge can be a dangerous thing.

 

[U_Stormcrow]

/forgot to add. Commercial oyster farming involves seeding the beds with reclaimed oyster shells, so even if there has been a recent source of heavy metals introduced to a watershed (typically, overflow from flooding at a coal power plant or similar in a coastal area), the very very very vast majority of any shell harvested in the years immediately following will likely have been deposited (created) by older oysters before the spill occured.

 

[Katanahamon]

Additionally, high heavy metal concentrations in the water oysters filter (and thus potentially absorb to become part of themselves) tend to lead to population collapse, which then results in harvesting moratoriums, which prevent those shells from entering the stream of commerce in the first place.

While there are other, also "natural" sources of calcium, such as limestone rock, there is absolutely no guarantee that those non food grade sources are any less contaminated with trace elements, heavy metals, sources of radioactivity, etc.

So @Katanahamon, good thought. But I'm not sure it warrants abandoning normal practice absent more information. Do you propose to feed your chickens Citrical? Are you prepared to make adhjustments for the greater bioavailability of Calcium Citrate over Calcium Carbonate? How will you measure that? Or have you secured a reasonably priced source of Dicalcium Phosphate? DO you know dosage, or will you be offering freee choice?

Questions. Always Questions. A little knowledge can be a dangerous thing.

Thanks..yeah, I may be overthinking, but, being bottom feeders that are usually in polluted areas, even farmed ones, and their slow process for laying down shell, I just don’t see how the can’t have badness. Coyote Creek sells calcium for chickens, it looks good, I think it’s a clean form, I’ll offer free choice..I have a few more weeks to figure it out..

 

[U_Stormcrow]

EVERYTHING will have badness in it. The question is only "how much"?

 

[Katanahamon]

EVERYTHING will have badness in it. The question is only "how much"?

Maybe a more useful study would be chickens’ tumors or sickness correlated with diet. It’s sad there aren’t more vets for chickens, and more studies on virtually every aspect of their biology and behavior, excepting the ones the poultry industry has done to maximize their weight. They did discover a link between soy and ovarian tumors, that’s why you see the non soy foods offered, and wow, I got a small test bag of organic Modesto non corn, non soy, whole grain layer feed, it looks great! I’ve been using their non corn, non soy organic chick starter. I’m sorry these post upside down..I’ve discovered that when you select a smaller pic size to post, they turn upside down..

 

[U_Stormcrow]

and studies that say the opposite

I happen to like Soy in my feed (though my current feed doesn't have it, at the insistence of my major buyer) because its one of the few plant sources of complete proteins, providing limiting amino acids that grains like corn, wheat, and oats lack in quantity.

My current feed starts with wheat middlings and sunflower seeds, but needs porcine meat and bone meal, plus menhaden fish meal to become nutritionally complete.

 

[Katanahamon]

and studies that say the opposite

I happen to like Soy in my feed (though my current feed doesn't have it, at the insistence of my major buyer) because its one of the few plant sources of complete proteins, providing limiting amino acids that grains like corn, wheat, and oats lack in quantity.

My current feed starts with wheat middlings and sunflower seeds, but needs porcine meat and bone meal, plus menhaden fish meal to become nutritionally complete.

But this study doesn’t say the opposite..they used an isolated compound, genistein that was supplemented in concentrated form. They didn’t feed a diet of whole soy..edit..it’s the estrogenic compounds in soy that are the culprit..I’m all for the genistein part though..!

 

[Sequel]

I think it’s a good idea to look for other sources of calcium for your chickens. The shellfish farms have been struggling for years due to ocean acidification from dissolved carbon dioxide, which affects the ability to grow shells. Then this summer we had excessive heat and extremely low tides which they said on the news “cooked the oysters on the beach”. I haven’t been able to find plain oyster shell in the feed stores locally, only the Purina brand ones that are formed into little gritty rocks. Contaminated or not we will probably continue to face increasing shortages or even none at all.