how much iodine?

[wheezo]

i read that you don't really need iodine.
but if i were to add some kent marine iodine into freshwater tanks.
what would be the correct dosage?

what would occur if i added the amount stated on the bottle?

[Mustafa]

Why add it if it's totally unnecessary?

[jwarper]

I found a very nice article on iodine in marine aquaria. Doesn't exactly apply here, but it is an interesting read nonetheless.

http://www.advancedaquarist.com/issues/mar2003/chem.htm

[Mustafa]

At least the saltwater people are trying to match the Iodine content of seawater although, again, it's totally useless to do that under aquarium conditions. Saltwater shrimp don't just suck up Iodine from the water...they get it from their food.

The situation is completely different in freshwater. Freshwater is variable in different river systems....there is no measurable "Iodine" content in freshwater systems that is more than tiny trace amounts found everywhere else...even in soil. Some creeks are just pure rain water more or less...no Iodine there either. And again....freshwater shrimp don't just suck up Iodine from the water...hence it's useless to add it. Their food provides them with whatever they need.

I've said this a million times, so I won't repeat the rest of my speech here....

Mustafa

[wheezo]

So it's totally unnecessary but would it be harmful?

[jwarper]

Large amounts will harm animals. Small micro amounts won't. Since it is unneccsary though, why put any in? Saltwater aquarists use it only to provide a more natural environment. There is a small (micro) amount of iodine in seawater, and all plant an animal life in the sea contains small amounts of this iodine in their bodies. Which is why it is thought to be "necessary" for salt aquariums. Freshwater aquariums have no need for the iodine.

[IKnowShrimp]

I found calcium iodate in certain brand of fish food and kelp (rich in iodine)is used as the main ingredient in a couple of brands for freshwater shrimp food.

It won't make sense to use them as ingredient if they are not useful for shrimps.

[Mustafa]

Right...and just because some companies put some ingredients in their food that happen to have Iodine *must* absolutely mean that shrimp need Iodine *in the water*, right? Think about your own statement for a second. As I've said many times before, the trace amounts of Iodine that every living thing seems to need are taken in through food.

[wheezo]

okay, so the dosage described on kent iodine for saltwater would apply for freshwater? or would that be too much?

yea... why add it if they don't need it... i'm asking because i already added it a few weeks ago.

the questions i started this thread with was never answered.
and i already knew it was not really needed... as stated.

[frugalfish]

The dosage is not intended for freshwater applications only marine. As for what would happen...other than over dosing inhabitants with iodine I wouldn't know. Probably the best thing to do is go to the Kent Marine website and try asking the company directly. Actually with any product it's easy to just contact the manufacturer and ask about how to use it best.

[chlorophyll]

For freshwater to have the same content of iodine as seawater does is quite unnatural, so yes that dosage is more likely going to be harmful than helpful.

However, since toxicity of iodine in freshwater animals doesn't appear to be an area of solid knowledge around here, I'll just add that my personal thought is that you shouldn't worry about it being devastating to your shrimp. I would do some (many, even) healthy and sensible water changes over several days if you haven't already been doing this though. As some of us feed foods that happen to actually contain iodine within it, with no apparent ill-effects, it's not something that's just plain poison. Generally we humans need to to eat seafood to prevent iodine deficiency. Seafood reflects the iodine content in seawater and I wouldn't worry about feeding freshwater animals pieces of marine shrimp either. As a staple, I probably wouldn't do it.... although most fish foods are highly shrimp meal, and I believe this is marine shrimp.

[IKnowShrimp]

Right...and just because some companies put some ingredients in their food that happen to have Iodine *must* absolutely mean that shrimp need Iodine, right? Think about your own statement for a second.

Why would manufacturer use iodine intensive ingredient if iodine is not needed, right? If you work in a large industrial before, you will know all production is optimal for profit and more profit. Everything is cut to the lean, cut to just meet it purpose only. So why would a company want to use calcium idote or even use Kelp as the main ingridient?

Until a researcher comfirm the study on freshwater shrimp and iodine relationship, I think all these debate is a waste of time.

[Veneer]

Some articles (general information on iodine supplements; their potential utilization by [marine] shrimp ; the biochemistry of molting in freshwater shrimp; trace element utilization by various crustacea; the endocrinology of molting in freshwater shrimp; etc.), divided among web pages, "white paper" abstacts, and aquaculture/mariculture reports:

Chemistry and the Aquarium (one section is specifically devoted to shrimp):

Who uses iodine: Shrimp

As one moves up the food chain to more sophisticated organisms, data on their ability to take up iodine from the water column becomes very sparse. Shrimp are known to have a need for iodine to grow, but that is only known in terms of a dietary requirement. The shrimp, Penaeus chinensis O'sbeck, for example, grows optimally when the diet contains 0.003% iodine.56

Shrimp apparently incorporate substantial amounts of iodoorganics into their bodies. The shrimp Pandalus borealis, for example, incorporates between 0.04 and 2 ppm iodine as iodoorganic compounds depending on the particular body tissues examined. Their roe were somewhat higher, up to 4 ppm iodine as iodoorganic compounds.57 Shrimp shells and other parts can contain up to 17 ppm by dry weight iodine, the majority of which is iodoorganic compounds58, but the values are still far lower than for other inverts like macroalgae, sponges, or gorgonia.

Still, the amount contained says nothing about whether iodine is an important requirement. I could find no scientific studies that showed that shrimp need iodine from the water column, but neither could I find any that demonstrates that they do not.

An Iodine Supplement FAQ from WetWebMedia.


A discussion of iodine supplementations with some intriguing commentary concerning crustacean molting:

(An excerpt):

Ron Shimek wrote in last months FAMA that Iodide is poison and is dangerous to use. He stated there is not scientific proof that Iodide is even used by corals and that hobbiest [sic] test kits and [sic] not accurate and you can not [sic] maintain levels equivalant to the sea by use of these kits.

Investigating the Composition of the Exoskeleton of Macrobrachium rosenbergii - an inquiry into the particulars of this freshwater prawn's molting cycle.


Stable Amorphous Calcium Carbonate Is the Main Component of the Calcium Storage Structures of the Crustacean Orchestia cavimana - though this study centered about a terrestrial organism, the points made about biominerals, ion reservoirs, and calcium storage strategies should remain in broader consideration.

One of the carbohydrates that shrimp meet in natural environment might be chitin. And the question was raised [sic] is the chitin used by shrimp better than other CBH? Chitinase activity was measured in a 332 number of species and bacteria living in the gut showed chitinolytic activity for a number of species too. Gwinn and Stevenson (1973) have speculated that in Orconectes limosus, the major energy source is chitin, because chitin resorbed by the hypodermis before molting provides sufficient material for
both new chitin synthesis and energy for molting (1.4 kJ which represents around 25% of energy accumulated in intermolt period).

Chitin

Chitin digestion and assimilation occur and make a significant nutritional contribution to shrimp (Clark et al. 1993). Shrimps reared under experimental conditions tend to ingest exuvia of newly molted shrimp with a kind of avidity, which seems to be in relation to the fact that a diet is well-balanced or not. Some diets containing shrimp meal showed poor growth performance and glucosamine could have a beneficial action a new exoskeleton synthesis (Kitabayashi et al. 1971) even though the levels tested (0.5-0.8%) represent a small percentage. Dietary supplies of glucosamine could be insignificant
compared to the metabolic supply provided that a substantial amount of glucose be available ammonioemia in hemolymph is given to be high (1.6-1.9 mg/ 100 cc in the blood of lobster or crayfish; Florkin, 1966). However, Ross Stevenson (1983) mentioned a pathway for glucosamine involved G6-P
and F1-P. And this is contrast with the fact that glucose phosphorylation capacity of shrimp is low (probably less that in fish) and most likely, metabolism of glucose is poor in comparison to mammals.
In fishes, level of chitinase in blood and lymphomyeloid tissues is suppressor to the one in gastrointestinal tract [sic], indicating a diffusion role rather than a digestive capability for chitin. In shrimp such a statement do [sic] not apply.

Chitin synthesis in shrimp cannot be considered out of the molting cycle, which shows the evolution of organic reserves in the digestion gland. Renaud (1949) clearly demonstrated in crabs the variation in glycogen. Also Cuzon (1976) reported this in M. japonicus, and again glycogen in hypodermis, which
indicates an intense metabolic activity including important transport of nutrients from an organ to another, starting in stage C of the intermolt period and in preparation to the next molt. Such transfer [sic] imply hemolymph which dispatch nutrients to different tissues in which metabolism will be oriented according to a given period of the molt cycle.

(From http://www.uanl.mx/publicaciones/maricu ... gcuzon.pdf)


I do not deny that iodine is necessary, in trace quantities (as obtained via foodstuffs), for freshwater shrimp; the potential endocrinological effect of iodine metabolization is, to my knowledge, an uninvestigated branch of inquiry:

Artificial production techniques are based on the ability to induce reproduction and spawning in captivity, but knowledge concerning the basic mechanisms of these physiological processes is insufficient. In this research, the involvement of various endocrinological factors in the control of molting and reproduction were investigated in M. rosenbergii. Ecdysteroids which control molting, were additionally found to accumulate in maturing ovaries and to be present in newly-laid eggs, indicating a potential role in ovarian development and embryogenesis in this species. In addition, juvenile hormone (JH)-related substances were investigated, revealing the presence of the JH precursor, methyl farnesoate (MF) in the hemolymph. (MF) was seen to fluctuate during the molting cycle, suggesting that this hormone has a role in molting in addition to reproduction.

(From http://ss.jircas.affrc.go.jp/kanko/seik ... /4-13.html)


Continuing along this track of thought, "liquid iodine" supplements' alleged effects on shrimp molting (if, in fact, valid) may come through interference with "molting" and "molt-inhibiting" hormones:

In M. rosenbergii and most other species of decapod crustacea including crabs and lobsters, the physiological processes of molting and reproduction are inextricably linked and under the control of various hormones. Crustaceans, which are arthropods, bear much endocrinological similarity to insects, and differ greatly from vertebrate species. However, compared with insects, which have been studied more widely, little is known about endocrinological mechanisms in Crustacea.

It is well-established that ecdysteroids such as 20-hydroxyecdysone serve as “molting hormone* in Crustacea and are excreted from a tissue known as the Y-organ. On the other hand, peptides (molt-inhibiting hormone: MIH) originating in the sinus gland complex of the eyestalks exert negative influence on molting. In M. rosenbergii, molting occurs approximately once per month accompanied by growth of the animal. In females, reproduction occurs in synchronization with the molt cycle during which vitellogenin (yolk protein) is produced and ovaries develop and mature. This process is also under the inhibition of an eyestalk hormone: vitellogenesis-inhibiting hormone (VIH). In hatcheries and on prawn farms, the technique of eyestalk ablation has long been employed to induce female maturation; the basis of this is the removal of the eyestalks and thus the removal of the source of these inhibitory hormones.

While much progress has been made regarding negative control of molting and reproduction, it is unclear whether positive control mechanisms exist. Regarding molting, it is still not known what causes ecdysteroid titers in the hemolymph (crustacean blood) to surge just before a molt. It is also not known how the negative effects of VIH are lifted, enabling the animal to produce vitellogenin for uptake into the ovaries. In insects, juvenile hormone (JH), which is a larval developmental hormone, also appears in the adult female to stimulate yolk protein production and uptake. At JIRCAS, we are interested in the functioning of juvenoid substances in M. rosenbergii and are attepting to determine whether such hormones exert similar influences in crustacean species. At present, we have detected a JH-precursor molecule, methyl farnesoate (MF) (Figures 2a,b), in the hemolymph of M. rosenbergii. It was expected that MF would be present in only females undergoing ovarian maturation, but it was detectable in both females and males without connection to reproductive events. MF was also seen to fluctuate during the molting cycle, suggesting involvement together with ecdysteroids in regulating molting.

(From Molting and reproduction in the giant freshwater prawn, Macrobrachium rosenbergii: Endocrinology and potential aquaculture applications)

[chlorophyll]

Does anybody know the typical iodine levels found in inland freshwater systems? While being instructed in endocrinology, the professor claimed that people living inland who get no seafood or iodine supplementation (eg. iodized salt) are at true risk of iodine deficiency because food sources of iodine inland is so negligible. And I hadn't really questioned it.

In my 412 page "Textbook of Limnology" by Gerald Cole (1994), the index points to a single page in reference to "iodine." On that page, the only information on iodine are afterthoughts at the ends of two paragraphs: That it is a needed inorganic micronutrient in "some (but not all) algae," and that it is among boron, cadmium, rubidium, and poisons lead, arsenic, and mercury in the list of elements that "could" be a minor element in a given lake's water.

Seems like this minimal mention of the element suggests iodine's basic lack of importance in freshwater ecosystems, or, possibly it just reflects still (at least in 1994) poor understanding in the area of study.

[chlorophyll]

Why would manufacturer use iodine intensive ingredient if iodine is not needed, right? If you work in a large industrial before, you will know all production is optimal for profit and more profit. Everything is cut to the lean, cut to just meet it purpose only. So why would a company want to use calcium idote or even use Kelp as the main ingridient?

You may have answered your own question. Since it has become so widely accepted (whether correctly or mistakenly) that shrimp benefit from iodine supplementation, it is most definitely profitable to note an iodine source in the "shrimp food". And it likely isn't very expensive to incorporate either.
In fact the word "kelp," associateed with iodine or not, is an attractive (read: marketable) natural ingredient many aquarium hobbyists would like to see ... if not for any truly educated reason, just because it's kelp and kelp grows in the sea.

On this iodine issue, we should be considering mainly what the typical environmental conditions of freshwater shrimps' natural habitats are, and what they eat out there. Does that water and those food sources always contain iodine, and how much?