Biology Question

[foodchain]

Here's something I have found...some of it applies to this thread, but also to a previous thread on salt treatments. For simplicity, I have cut n pasted.

The second breakdown product in the nitrogen cycle is NO2, which is also toxic to fish. NO2 can enter the bloodstream passively across the gill epithelium. It complexes with hemoglobin to form methemoglobin, resulting in methemoglobinemia or brown blood disease. As in other species, RBC containing methemoglobin are unable to transport oxygen, resulting in a physiologic hypoxia regardless of oxygen content in the water. There are species-specific differences in fishes’ susceptibility to NO2 toxicity (eg, centrarchids [bass, bluegill, etc] are refractory to methemoglobinemia). Marine fish were thought to be protected from NO2 toxicity by salts in their environment; however, red drum have developed brown blood disease in the presence of NO2. A tentative diagnosis of brown blood disease can be made by observing the characteristic chocolate brown color of the gills. Blood samples will also be an abnormal color. Methemoglobin concentrations in the blood can be determined, although this is not necessary for clinical management. A water quality test can confirm the presence of NO2. Fish affected with methemoglobinemia typically show signs of hypoxia, often manifest by piping. The most rapid treatment for NO2 toxicity is a water change, but this may not be feasible in production ponds. Increasing chloride Cl-) concentration in the water creates a competitive inhibition at the gill epithelium between Cl- and NO2. By increasing the concentration of Cl-, so that there are 6 parts Cl- to 1 part NO2, the percentage of Hgb converted to methemoglobin will decrease dramatically, providing immediate relief to the fish and stopping most further mortality within 24 hr. Salt can be used to increase the concentration of Cl-. To determine the amount of salt required, the concentrations of NO2 and Cl- present must be measured, by commercial test kits. The concentration of Cl- needed (mg/L) = (6 ¥ NO2) ? Cl- present. Once the concentration of Cl- needed is known, the volume of water can be calculated in acre-feet (1 acre foot = 1 surface acre, 1 foot deep), and salt can be added to increase Cl- to the desired concentration (4.5 lb of salt will add Cl- at 1 mg/L to 1 acre-foot of water). In aquariums and garden ponds, a water change and filter maintenance are recommended, although salt may still be used to halt mortality.

[foodchain]

For those looking for the whole article, here's the link:

http://www.merckvetmanual.com/mvm/index ... htm&hide=1

I am still looking for a digital referance as requested previously. I will post it as soon as I locate it.

[urbanfarmer]

What is the book and on what page?

I am just curious about the claim that methemoglobinemia leads to permanently sterile fish. Methemoglobin is normally present in fish blood at low concentrations. Moreover, seeing that methemoglobinemia is a completely metabolically reversible process, I don't understand how permanent sterility would occur.

Also, I cannot find any literature that states methemoglobinemia causes sterility in fish. Albeit, I looked briefly, but the search engines and databases returned 0 results. So, I had no hope of finding anything without doing an extensive search.

Thanks, I appreciate your effort.

[foodchain]

I am at the office, I can look when I get home. It listed the effects on liver, kidneys, renal failure, discoloration of blood, heart tissue, coloring of gills, and fins, etc. And as a side note, noted that prolonged exposure would lead to death, sterility, and should be avoided. Then it went on to list treatments and prevention. My problem is it didn't explain it, least ways not the above mentioned points, so I thought I would ask here. You yourself UF are mouch more educated on the 'how comes' and 'whys' of things so I figured this would be a good start. Hence the title of the thread was "biology question". As in I don't know. But I have been reading enough stuff to know, that just because it's printed or online doesn't mean it's true. I will find what your asking for this evening when I get in.

[urbanfarmer]

Yessum. I'm trying to figure it out for you, but I honestly have never heard this nor read about it. If it only notes it briefly, then that may be a dead end as well. I can't think of anyone I can ask that would outright know the answer.

Post the info when you can, and I will try to search for an answer using that.

[bsfman]

For those looking for the whole article, here's the link:

http://www.merckvetmanual.com/mvm/index ... htm&hide=1

Amazing the stuff you can learn accidentally while looking up other stuff! Thanks for posting this link, Foodchain!

I'm currently cycling my new tilapia breeder system using sunfish I caught in my canal. I have 17 large sunfish, roughly 5 pounds worth, that I seeded the new system with 5 days ago. Ammonia spiked to 8ppm but cycled to zero in just 4 days thanks to the old media and bacteria with which I'd innoculated the new system. But nitrites started climbing immediately and are still at levels in excess of 16ppm. I've seen no signs of distress in the sunfish whatsoever. I've been amazed each morning to find no floaters or sick fish in the tank. A line in your article caught my eye: "There are species-specific differences in fishes’ susceptibility to NO2 toxicity (eg, centrarchids [bass, bluegill, etc] are refractory to methemoglobinemia)". I admit, I had to look up what "refractory" meant when used in this context, but it turns out it means "immune, or not affected by".

This is valuable info to anybody starting up a new system! The ubiquitous sunfish may be the perfect candidate for cycling a system. It always seems to take longer to deal with nitrites than ammonia with a new cycle. What better fish to use than one impervious to nitrite in doing so? Just use an amount of sunnys (by weight) equal to the poundage of tilapia, catfish, perch, koi, or whatever fish you plan to ultimately introduce. When the system equilibriates, remove the sunfish and either repatriate them or eat them, then introduce your intended species!

Viola!

[foodchain]

I have another breif reference I just found.
This one is online, but also does not explain it. It will not let me cut n paste...stupid site. But I can give directions.

http://www.thetropicaltank.co.uk/cycling2.htm

Now scroll down to NITRATE, last sentence of first paragraph.
It seems though that in the searching, that there's a lot of contradictory information out there.
The common thought seems to be, that amonia, nitrites, and nitrates all have "ill" effects. Though there is some dispute as too how much. Some sites say nitrates and nitrites have 0 effect, others state there shouldn't be any measurable levels at all or "ILL" effects will be result.
In reading an aquaculture PDF, it states that different species have diffent tolerances. And that warm water fish typically tolerate it better than cold water....didn't know this, but have noticed some species of fish handle stresses differently.

Anyway. I also found that PH plays a major role in determining how much salt is needed, and at what concentration to relieve the symptoms.

Not to beat a dead horse, but there are current (in the last few years...2000-present) that state ANY salt can be used, and the some is better than none, while there's articles in the SAME time period that are ademant that only CL I think it said can be used. At the end of this I have learned one major point.

There's a lot of information and disinformation out there. Alot of it is contradictory to each other, and sometimes to themselves. I have a head ache now.

[foodchain]

More info: For all those that like to pee in their tanks.... And for those looking to better understand what exactly amonia does and doesn't do.

http://www.americanaquariumproducts.com ... Cycle.html

Also covers cycling types, effects, and myths. Hope all this info helps someone.

It doesn't resolve my original question. For that answer, it appears that people are making guesses. Whether educated or not is yet to be determined. But none the less, they publish it...and people take it as the truth as they don't know better.

On that note. Please please don't ever take what I say as the bonified, this is it, truth. I am not saying don't trust me. Just please understand that a lot of this in my opinion is more art than science. I can tell you what I have done, what I have tried, what I have read/heard. Somethings work, somethings work repeatedly, something are supposed to work and don't. I don't know why.

What I have posted here have been my findings from reading and researching. I haven't tried any of this brown blood disease stuff, however in veiw of there being no clear answer I may try an experiment to find out. But I don't know how to limit the variables to just one.

As the above research has proven that PH, Temp, and species all play variables in the equation.
UF, or anyone give me input here?

On a side note, I did learn that if you have a 'salty' well. You are less prone to brown blood disease or nitrate/nitrite poisoning. At least that's what the posting said. I don't have a salty well, so I don't have a end all fact discussion on that.

[urbanfarmer]

I have another breif reference I just found.
This one is online, but also does not explain it. It will not let me cut n paste...stupid site. But I can give directions.

http://www.thetropicaltank.co.uk/cycling2.htm

Now scroll down to NITRATE, last sentence of first paragraph.
It seems though that in the searching, that there's a lot of contradictory information out there.
The common thought seems to be, that amonia, nitrites, and nitrates all have "ill" effects. Though there is some dispute as too how much. Some sites say nitrates and nitrites have 0 effect, others state there shouldn't be any measurable levels at all or "ILL" effects will be result.
In reading an aquaculture PDF, it states that different species have diffent tolerances. And that warm water fish typically tolerate it better than cold water....didn't know this, but have noticed some species of fish handle stresses differently.

Anyway. I also found that PH plays a major role in determining how much salt is needed, and at what concentration to relieve the symptoms.

Not to beat a dead horse, but there are current (in the last few years...2000-present) that state ANY salt can be used, and the some is better than none, while there's articles in the SAME time period that are ademant that only CL I think it said can be used. At the end of this I have learned one major point.

There's a lot of information and disinformation out there. Alot of it is contradictory to each other, and sometimes to themselves. I have a head ache now.

Yes, the Cl- ion is what combats the nitrite toxicity. Some species are very sensitive to it while others could care less (do we love Tilapia or what).

Although the link you provided is from a source I would never even consider as a reference, it does state that nitrate affects breeding. Sterility implies the organism loses its ability to reproduce altogether. There are many factors that can affect breeding, some, seemingly innocuous, such as temperature, light, or sound.

[foodchain]

True, I never claimed the source was trustable. Just noted the reference. Starting to think a lot of this stuff is word of mouth more than concrete facts. Frustrating.