Jay - you still refer to investigation done on naups and larvae stage of marine fish where at least EPA and DHA is important and not is biosynthesised from Omega 6 fatty acids either from the naups or the marine larvae. I agree with you about this
However - lately it has been shown that it is not all marine larvae that needs enrichment - please
see this article
But you still says that a sole diet of frozen adult artemia will kill fish eventually. (however a progress from your earlier statement that it is lethal) You still says that my success with my feeding is caused of the fresh water cyclops I used - a cyclops that not I and not you have any knowledge at all about the content of EPA and DHA. Neither no one of us know the HUFA content of frozen mysis that we use.
To be clear - I have used only frozen artemia, a combination of adult artemia and fresh water cyclops, at work I have used a combination of adult artemia and mysis and a friend of me (one of the best reefers we have had here in Sweden) - only used frozen adult artemia for + 10 years, The reason why I change from 100 % frozen artemia to 50/50 artemia/cyclops is because that the cyclops contain huge amount of axtansantin and I also have rather much filter feeders
Even if naups can be low (or have a huge variety in concentrations) of EPA and DHA will it not say that well feed adult Artemia do no have enough amount of these essential fatty acids. If they have or not have enough of EPA and DHA depends of their ability to convert ALA into EPA and DHA by themselves. Nowadays we know that at least Artemia franciscana have some capacity for this (from
here and
here)
We know that marine larvae can' t produce these fatty acids that is very important in the development from larvae to fry - but that' s not the same as that a fry or semi adult do not have this ability. As an example - I have bred many freshwater species from egg to adult only using not enriching naups with no problems. Even species that have a larvae stage (grass carp) but in that case - I think that enrichment have a better outcome. IMO - it is the larvae stage that´s sometimes need EPA and DHA from the outside - marine fishes that release fry (read Banggai cardinalfish) seems not so sensitive for enrichment or not. There have also been shown during the last decades that at least some marine species can synthesize both EPA and DHA from ALA (the common omega 3 in plant and algae) This article is
rather interesting
Now to the most important question - do you - in general - need enrichment when you use adult frozen artemia as only source? You probably have seen the large and great review
THE USE AND NUTRITIONAL VALUE OF ARTEMIA AS A FOOD SOURCE* The question is - did you reach page 59 and the chapter The use of on-grown and adult Artemia ? (the previous 58 page deal with the the EPA and DHA problem in artemia napuli and how to enrich them (EPA = 20:5w3 and DHA = 22:6w3)
Some quotes
In contrast to the very extensive documentation dealing with the use of Artemia nauplii as a food source, similar literature on the application of on grown and adult Artemia is very limited.
it is only during recent years that reliable techniques have been developed for mass production of pre-adult and adult Artemia. Nevertheless, several arguments support the use o f on-grown and adult Artemia as a food source.
My bold
As compared with freshly hatched nauplii the nutritional value of on-grown and adult Artemia is superior, i.e. protein content increases from an average of 47% in nauplii to 60% on a dry weight basis in adults; furthermore, protein quality improves as adults are rich in all essential amino acids (see later). In contrast to other food organisms, the exoskeleton of adult Artemia is extremely thin which facilitates digestion of the whole animal by the predator
Contrary to what is found in wild adults, the fatty-acid profile of brine shrimp cultured on feeds of terrestrial origin (e.g. agricultural waste products) does not show significant levels of the essential fatty acids 20:5w3 and 22:6w3
From page 58 - there is a lot of descriptions including adult artemia according nutritional values.
However I would be glad to change my mind if you could show any reference based on data where it is shown that use of only wild caught frozen adult artemia (as Ocean Nutritions frozen artemia) will back up your claim
The question was brine shrimp as a sole diet, and that will kill fish eventually.
Sincerely Lasse