300 ppm will not be the lowest, or the norm, found in the various main brands of fish food that contain ethoxyquin. I feel quite confident in stating that most will be under 150 ppm. So I guess only time will tell. If I come across any additional lab reports from other manufacturers I will post them here on MFK.
There have been a number of posts similar to this one, and a number of threads on MFK going about this issue. I get that people are upset with NF... we are too. For us, it's not so much that we mind the use of a preservative in our fish foods as it is that NF may be lying about it. I looked up the science behind ethoxyquin and it's use in fish. This is what I can share:
-150ppm is the limit for feeds used in animals for human consumption. Most preserved fish foods used in the hobby are not for fish intended for human consumption. Any talk of the FDA or USDA is immaterial since our fish will not be consumed by humans. It's the wild wild west... no regulations apply other than to keep it safe for humans to handle the food.
-Ethoxyquin preserves fat and keeps vitamins C and E intact. Citation: Nutrition and health of aquaculture fish By:Oliva-Teles, A (Oliva-Teles, A.) JOURNAL OF FISH DISEASES Volume: 35 Issue: 2 Pages: 83-108 DOI: 10.1111/j.1365-2761.2011.01333.x Published: FEB 2012
-Ethoxyquin has been shown to negatively impact one freshwater fish species (as far as I can tell). That study focused on an African cichlid that is often raised for human consumption, Tilapia. That study found that the immune system of the fish was affected, but that the effect of ethoxyquin (fed at 150ppm) was not strong enough to cause a significant difference in mortality or disease resistance. Note that many things that a fish experiences in a fish tank cause immunosuppression. For example, being kept in a fish tank, being kept in sub-optimal conditions, being kept with inappropriate companions, etc. The study lasted 30 days... there is no evidence, pro or con, what the effect of ethoxyquin ingestion would be past 30 days in a fish. Citation: The synthetic antioxidant, ethoxyquin, adversely affects immunity in tilapia (Oreochromis niloticus) By:Yama****a, Y (Yama****a, Y.)[ 1 ] ; Katagiri, T (Katagiri, T.)[ 1 ] ; Pirarat, N (Pirarat, N.)[ 2 ] ; Futami, K (Futami, K.)[ 3 ] ; Endo, M (Endo, M.)[ 1 ] ; Maita, M (Maita, M.)[ 1 ] View ResearcherID and ORCID AQUACULTURE NUTRITION Volume: 15 Issue: 2 Pages: 144-151 DOI: 10.1111/j.1365-2095.2008.00577.x Published: APR 2009
- Ethoxyquin containing food might not be palatable to some species... and so fish meal containing it might not be the best food for that species. Most of our fish, but not all, will readily eat Northfin. Citation: Fishmeal quality and ethoxyquin effects on the weaning performance of ballan wrasse (Labrus bergylta) larvae By:Bogevik, AS (Bogevik, A. S.)[ 1 ] ; Kousoulaki, K (Kousoulaki, K.)[ 1 ] ; Skiftesvik, AB (Skiftesvik, A. B.)[ 2 ] ; Opstad, I (Opstad, I.)[ 2 ] AQUACULTURE NUTRITION Volume: 22 Issue: 1 Pages: 46-50 DOI: 10.1111/anu.12225 Published: JAN 2016
-This is an active area of scientific inquiry... but one in which there is very little activity... does that make sense? LOL. There are lots of questions, but not a lot of money/interest to answer them. Such is the way of science.