Melody
Aug 1st 2009, 05:45 AM
These studies began waaaayyyy back in the day (the early 50's I believe). As it is with some studies from way back when, the information isn't brought to the modern hobby level where keepers of these fish may benefit. That's what I'm here for. :GEEK:
The following related studies were done for cancer research. It seems that thyroidal tumors spontaneously appear in captive populations of Monty's (and later found in X. pygmaeus), whereas they aren't found in the wild.
The first study suggests that the Monty Swordtails may need considerably more iodine than other Xiphophorus species, even those found in the same region. The second study takes that theory and runs with it. I love it when they do that. ::D:
A later study determined that the presence, growth rate of the tumors and the age at which they developed, were negatively influenced by inbreeding (Berg, Edgar & Gordon, 1953). So now we're dealing with two factors in the same condition - nutritional requirements and inbreeding.
Further study of stimulants and inhibitors was conducted and I have also included that study for it's use in possible treatment and prevention.
These studies are referred to again in the late 70's, when P. furmosa (Amazon Molly) thyroid issues were studied (Woodhead & Scully, 1977), so the research continued to be applicable and is probably the latest we have on the specific species topic to this day (if anyone knows of something more recent regarding Monty's, Pygmaeus or further research on thyroidal maladies due to inbreeding, by all means bring us up to speed).
I found the iodine requirement link to be particularly intriguing because I have always been opposed to one commercial food or diet for all fish species. Even on a basic level that makes no sense, but these things need to be proven at an advanced level as well.
Regardless, if it is due (all or in part) to a particularly high iodine requirement, or if the tumors themselves result in that need in order for the fish to recover, we have a concern that should be passed along to the increasing number of hobbyists keeping these fish.
Shrimp (particularly marine shrimp) are a great source of iodine and all seaweed species are noted for their high iodine content. Although all seaweed species contain iodine, the type and amount of iodine in each does vary widely. The most commonly found in grocery stores, Nori, is one of the lowest. Pacific Laminaria (brown) species are a top source of water soluable iodine, while other seaweed species have more organic iodine. Water soluable iodine is heat sensitive and seaweed must be stored properly to retain it. You're not going to reliably find that in pet grade seaweed, so go to the health food store where seaweed iodine content and proper storage is assured in products intended for human consumption. Forget about looking for seaweed-sourced iodine in heat processed fish foods - the heat vaporizes it out before it's dried. Synthetics are not as bio-available as food sources. It isn't always easy to sell hobby fish on the tougher texture of seaweed, but it can be blended into other foods or presoaked in an attractant such as garlic or 'shrimp juice' from frozen shrimp. There is no end to the benefits of seaweed as a whole, so it's well worth the effort of getting it into our aquatic creatures.
Potassium iodide can be added to the environment through the addition of marine salt, which I've used for years in freshwater without issues (low doses). Liquid iodide supplements are also available if you want to increase the dose without increasing the marine salt.
Since little is known about the uptake and utilization of iodine, I suggest covering all your basis in both diet and environmental sources. Don't go overboard though - too much of a good thing is... well... too much. :wideeyed:
Spontaneous Thyroidal Tumors in the Swordtail Xiphophorus montezumae (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Spontaneous_Thyroidal_Tumors-Xiphophorus_montezumae.pdf)
Xiphophorus montezumae Iodine Utilization by Tumorous Thyroid Tissue (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Xiphophorus_montezumae_Iodine_Utilization_by_Tumor ous_Thyroid_Tissue.pdf)
Progressive Growth Stages in the Development of Spontaneous Thyroid Tumors in Inbred Swordtails Xiphophorus montezumae (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Xiphophorus_montezumae-Growth_Stages_of_Thyroid_Tumors.pdf)
Comparative Effects of Thyroidal Stimulants and Inhibitors of Normal and Tumorous Thyroids in Xiphophorin Fishes (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Xiphophorus_montezumae-Effects_Thyroidal_Stimulants_&_Inhibitors.pdf)
I would be very interested in hearing from any hobbyists who think they may have encountered these tumors (mass die-offs, etc), and would appreciate it if all keepers watch for signs of it. It may be an inherited weakness and I feel we should explore that as well, since hobby fish are so heavily inbred and responsible breeding practices aren't always followed in spite of my preaching...lol. The damage is often done by the time we receive the fish, so don't fear negative feedback. That's not the point of discussions here anyway.
---------------------------------------------------------
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Thank you for respecting the effort that I have put into our content.
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The following related studies were done for cancer research. It seems that thyroidal tumors spontaneously appear in captive populations of Monty's (and later found in X. pygmaeus), whereas they aren't found in the wild.
The first study suggests that the Monty Swordtails may need considerably more iodine than other Xiphophorus species, even those found in the same region. The second study takes that theory and runs with it. I love it when they do that. ::D:
A later study determined that the presence, growth rate of the tumors and the age at which they developed, were negatively influenced by inbreeding (Berg, Edgar & Gordon, 1953). So now we're dealing with two factors in the same condition - nutritional requirements and inbreeding.
Further study of stimulants and inhibitors was conducted and I have also included that study for it's use in possible treatment and prevention.
These studies are referred to again in the late 70's, when P. furmosa (Amazon Molly) thyroid issues were studied (Woodhead & Scully, 1977), so the research continued to be applicable and is probably the latest we have on the specific species topic to this day (if anyone knows of something more recent regarding Monty's, Pygmaeus or further research on thyroidal maladies due to inbreeding, by all means bring us up to speed).
I found the iodine requirement link to be particularly intriguing because I have always been opposed to one commercial food or diet for all fish species. Even on a basic level that makes no sense, but these things need to be proven at an advanced level as well.
Regardless, if it is due (all or in part) to a particularly high iodine requirement, or if the tumors themselves result in that need in order for the fish to recover, we have a concern that should be passed along to the increasing number of hobbyists keeping these fish.
Shrimp (particularly marine shrimp) are a great source of iodine and all seaweed species are noted for their high iodine content. Although all seaweed species contain iodine, the type and amount of iodine in each does vary widely. The most commonly found in grocery stores, Nori, is one of the lowest. Pacific Laminaria (brown) species are a top source of water soluable iodine, while other seaweed species have more organic iodine. Water soluable iodine is heat sensitive and seaweed must be stored properly to retain it. You're not going to reliably find that in pet grade seaweed, so go to the health food store where seaweed iodine content and proper storage is assured in products intended for human consumption. Forget about looking for seaweed-sourced iodine in heat processed fish foods - the heat vaporizes it out before it's dried. Synthetics are not as bio-available as food sources. It isn't always easy to sell hobby fish on the tougher texture of seaweed, but it can be blended into other foods or presoaked in an attractant such as garlic or 'shrimp juice' from frozen shrimp. There is no end to the benefits of seaweed as a whole, so it's well worth the effort of getting it into our aquatic creatures.
Potassium iodide can be added to the environment through the addition of marine salt, which I've used for years in freshwater without issues (low doses). Liquid iodide supplements are also available if you want to increase the dose without increasing the marine salt.
Since little is known about the uptake and utilization of iodine, I suggest covering all your basis in both diet and environmental sources. Don't go overboard though - too much of a good thing is... well... too much. :wideeyed:
Spontaneous Thyroidal Tumors in the Swordtail Xiphophorus montezumae (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Spontaneous_Thyroidal_Tumors-Xiphophorus_montezumae.pdf)
Xiphophorus montezumae Iodine Utilization by Tumorous Thyroid Tissue (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Xiphophorus_montezumae_Iodine_Utilization_by_Tumor ous_Thyroid_Tissue.pdf)
Progressive Growth Stages in the Development of Spontaneous Thyroid Tumors in Inbred Swordtails Xiphophorus montezumae (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Xiphophorus_montezumae-Growth_Stages_of_Thyroid_Tumors.pdf)
Comparative Effects of Thyroidal Stimulants and Inhibitors of Normal and Tumorous Thyroids in Xiphophorin Fishes (http://www.allnaturalpetcare.com/Animal_Nutrition_Research/Xiphophorus_montezumae-Effects_Thyroidal_Stimulants_&_Inhibitors.pdf)
I would be very interested in hearing from any hobbyists who think they may have encountered these tumors (mass die-offs, etc), and would appreciate it if all keepers watch for signs of it. It may be an inherited weakness and I feel we should explore that as well, since hobby fish are so heavily inbred and responsible breeding practices aren't always followed in spite of my preaching...lol. The damage is often done by the time we receive the fish, so don't fear negative feedback. That's not the point of discussions here anyway.
---------------------------------------------------------
© Please note: While you are welcome to link directly to this thread, the contents are copyright of Melody McKinnon and cannot be copied.
Thank you for respecting the effort that I have put into our content.
---------------------------------------------------------