Just a quick follow up as I emailed NLS and this is what the response was.
Preservatives and Why They Are Necessary
Mentioning the topic of pet food preservatives seems to cause a lengthy debate in almost any pet-keeping circle, especially if the use of ethoxyquin comes up.
The whole ethoxyquin scare started from a single rumour, which became so blown out of proportion via internet chat forums that it eventually turned into another urban myth. The only reason that this preservative ever came into question, was due to a study performed on rats back in 1987 where the dose level of 5,000 ppm ethoxyquin, which is FAR higher than approved levels in pet food, suggested a carcinogenic potential. Ethoxyquin has since been blamed for a myriad of problems, none of which have ever been proven.
Considering the outcry over this preservative by dog owners worldwide, one would think that by now there would be a plethora of data/studies that actually proved that this preservative caused at least some type of long-term health issue in pets. There is not a single documented case where ethoxyquin used at approved levels has been found to cause any type of long term negative health condition in a dog, cat, fish, or otherwise. One would think that with all of the hysterical anti-ethoxyquin crusades that have taken place over the past 20 yrs or so that at least one non-biased study would be able to prove that this substance can cause serious long term health issues in pets, even when used at appropriate or approved levels. Yet to date, there is not a single shred of scientific evidence that supports such a view.
The fact is that this single preservative has probably saved countless lives of pets from suffering from serious health issues caused by rancid fat.
Without preservatives the oil found in fish food would become rancid in very short order. What many hobbyists do not understand is that all fish meal based products will contain ethoxyquin. There is simply no getting around that. The manufacturer may have ethoxyquin listed on their label as a preservative, yet may, or may not even be adding this ingredient at their end. New Life International Inc. does not directly add ethoxyquin to any of our foods.
The United States Coast Guard regulations (Subpart 148.04 -9) requires any vessel entering US waters that contains fish meal, to have the fish meal preserved with ethoxyquin. This is required by law for the safety and health issues that can arise if fish meal is not preserved properly. I personally know of no manufacturer that makes their own in-house fish meal on site, which means that if fish meal is being used in a food, any type of pet food, there will be at least a small amount of ethoxyquin in the final formula.
When used accordingly, there is absolutely nothing wrong with using ethoxyquin as a preservative. The FDA approved the use of ethoxyquin as a preservative for both humans and pets, and for decades the maximum amount allowed in pet food was 150 PPM.
In July 1997, after assessing the results of the latest study on ethoxyquin, the FDA's Center for Veterinary Medicine asked that the maximum amount of the preservative be voluntary reduced to 75 parts per million in complete dog foods. The FDA stated that the earlier limit of 150 ppm "may not provide an adequate margin of safety in lactating female dogs and possibly puppies." The reason being that lactating female dogs generally consume far more food (2-3 times) than non lactating females, hence an increased level of every substance in any food will occur. The study showed ethoxyquin levels of 150 ppm had no adverse health effects at maintenance levels, but that by reducing the max amount to 75 ppm it would create an additional safety margin for lactating females and their puppies.
To date, the FDA has found no scientific or medical evidence that ethoxyquin used at approved levels is injurious to human or animal health. Also, the FDA has found no documentation of the claims of harm to any animal. Not even one.
Please keep in mind that almost everything and anything can become toxic at high enough levels, including fat-soluble vitamins. No nutritionist would recommend completely eliminating vitamin A, B, D, E and K from the diet just because high levels can be toxic, yet this exact type of logic is what's used when most people discuss preservatives such as ethoxyquin. When used in small amounts to prevent rancidity, preservatives are valuable and important components of the diet.
Makes me wonder what kind of levels could we get in a closed Aquarium that is fed 2 to 4 times a day and ad in what may come back from fish waste. I wonder what kind affects it has on Corals and Infert's?