By Bill Vannerson with contributions from David Kawahigashi and Eric Lund
There was a discussion on several Internet Killifish email lists regarding supplementing newly hatch baby brine shrimp (BBS), Artemia, with vitamins or calcium. The results of that discussion brought two important points to light for fish keepers of any species. One, hobbyists can supplement their BBS to add valuable nutrients to their fish, both fry and adults. Two, the power of the internet can be a valuable resource.
Supplementing live food is nothing new. Many hobbyists have been adding vitamins to their worm cultures before feeding to fish and, to a lesser extent, adult brine shrimp as well. The strategy is to have the supplement ingested by the food and then by the fish when they consume the food.
The debate on the mailing lists started when someone questioned the effectiveness of applying this technique to BBS. Would supplements added to the hatching water be ingested by brine shrimp nauplii and then consumed by the fish? Or would the supplement simply stay suspended in the hatching water without providing and additional value to our fish?
The answer comes down to whether or now newly hatched Artemia will consume the supplement. The answer is yes, but not right away. Artemia a filter feeders but the don’t start feeding until after their second molt, referred to as the instar 2 stage.
According to David Kawahigashi at San Francisco Bay Brand, the commercial fisheries have been practicing this for quite a while. "Supplementing nutritional components, such as vitamins or calcium, into live brine shrimp has been practiced by aquaculture hatcheries for around 10 years. This bio-enrichment or bioencapsulation of brine shrimp nauplii (instar 2 or adults) began using emulsified fish oils containing high HUFA's or highly unsaturated fatty acids for marine finfish and crustacean larvae. This 'breakthrough' enabled the culture of many other new marine species to be developed (flounder, sea bass, tuna, ornamental marine sp.)."
Eric Lund, researcher from Universirty of Wisconsin, Madison, explains, "Briefly, saltwater fish all require a fatty acid that is common in marine fish oils called DHA (docosahexanoic acid) in their diet. They cannot make it from precursors, so it must be present in their food. Freshwater fish have a limited ability to make DHA from a particular precursor fatty acid of the omega-3 variety (linolenic acid), but they too can grow and reproduce well on a diet that includes DHA."
"Brine shrimp are a great food for all small carnivorous fish, but they contain virtually no DHA. Marine fish larvae fed only Artemia exhibit mass mortality a few days after they start feeding. Aquaculture operations get around this problem by adding an emulsion of phospholipids rich in DHA to newly hatched Artemia. The Artemia eat the emulsion (more of it also sticks to the outside of their bodies). The Artemia are then fed to the fish or can then be kept refrigerated for up to 3 days."
Enriching or bioencapsulation Artemia is essential for marine fish, but not for freshwater fish. Then why bother at all? Eric further explains, "I do believe, however, that for some delicate killies [and other freshwater fish] that experience high moralities before sexing out that enriching Artemia may be of some benefit. Another tactic worth trying is to feed enriched Artemia to the adults for several weeks prior to breeding them. In other species, fish eggs with low levels of DHA generally have poorer survivorship to first feeding than eggs that are rich in DHA. Giving females a diet high in DHA allows them to put more DHA into their eggs. As you all know, weak and feeble killie fry can be the result of several factors including inbreeding, bad water conditions and improper incubation conditions, but poor parental nutrition may play a role as well."
The essential fatty acid end product, DHA, is an important component of cell membranes in retinal tissue (eyes), neural tissue and cardiac tissue. Deficiency symptoms include:
Note that things other than essential fatty acid deficiency can cause all of these symptoms. Essential fatty acid deficiency is not a problem with most freshwater fish fed a varied diet. It is possible, however, that supplementation with a lipid emulsion may increase growth rates, fecundity and fry survivorship. So, if you are having problems raising particular species, it may be worth a try.
There are three ways you can feed your fish bioenriched shrimp; buy enriched frozen shrimp, enrich live adult shrimp or enrich newly hatched nauplii.
Bioenriched frozen shrimp are available but may be difficult to find. David Kawahigashi explains, "Although we do not market any enrichment formula, we do enrich and freeze live adult Artemia with a HUFA formula and Spirulina algae for the aquaculture and aquarium markets. However, almost all of the sales for these two enriched products go to the aquaculture market due to the "unawareness" of the benefits of bioenrichment in the aquarium trade."
Enriching live adults is not difficult. Just add the supplement to brine shrimp 12-16 before feeding fish.
Adding supplements to newly hatch brine shrimp is a little more complicated. Baby brine shrimp will not ingest the supplements until after the instar 2 stage begins, about 12 hours after the nauplii hatch. However, most fish breeders prefer to feed newly hatched Artemia as close to hatching as possible in order to maximize the nutritional value.
Once the cyst hatches, the nauplii begin to consume stored protein reserves, just as newborn fry live off of their egg sac. The longer you wait to feed them, the less nutritional value that’s passed on to the fish. The only way to counter act this is to feed the Artemia. This is not usually done because of difficulties in raising nauplii to adulthood. It’s just not worth the effort when one can readily purchase adult brine shrimp.
A compromise solution is to maintain two separate sources of baby brine shrimp, one that is bioenriched and one that is not but has higher protein reserves. Follow your normal routine for collecting and feeding from hatcheries that are not enriched. Reduce the amount you would normally feed and replace with a portion from the enriched hatcheries. Since enriching requires extra time, you may want to set up multiple hatcheries to alternate. You also may store enriched Artemia in the refrigerator for up to three days.
Here’s a quick checklist of the steps required to produce bioenriched Artemia:
David mentions, "I am now working on bioenriching Haematococcus algae (super high astaxanthin for color enhancement) and some anti-bacterials into our live Artemia for product development. Because Artemia are non-selective and continuous filter-feeders, pretty much anything can be taken into the gut of a live Artemia, as long as the particle size is between 5-50 microns. Vitamin supplements must be in a non-soluble form as Artemia cannot "drink" soluble components."
Eric Lund is also working on some new research at UWM that he’s not at liberty to discuss in detail.
An interesting footnote to this discussion of supplementing BBS is the role the Internet and email lists played in bringing the subject to light and collecting the information for this article.
The whole issue of enriching Artemia began as a relatively benign question posted to an Internet email lists. In a few days, input from hobbyists and experts, who are also hobbyists, poured in, adding to the collective knowledge of the group. The dynamics of this information exchange and the speed at which it was disseminated is a prime example on how the power of the internet can benefit the hobby. For those of you not familiar with email or the Internet, I’ll explain.
An author of a message sends it to the list server via standard email services from his or her local Internet service provider (ISP). An ISP is company that provides Internet connection, including companies such as America Online (AOL), CompuServe and a whole host of others both large and small. The list server replicates the message and sends it out to all of the subscribers. So if there are 500 people subscribing to a particular list, then 500 people will receive a copy of the email message.
Anyone on the list can respond to the original message either privately to the originator or back to the list server, where everyone can see the response. It’s best to respond back to the list if the topic of the email is of public interest, that way everyone can benefit from the shared knowledge of all of the responses. The collection of messages and the responses is referred to as a thread, as in a string of correspondence.
Subscribers to a list can be from anywhere in the world. I have seen contributions from Alaska to Australia, Hungary to Hong Kong, South America to Singapore. The only place I haven’t seen a message from is Antarctica, but I’m sure it could happen.
There are several lists that I subscribe to:
There are a bunch of others, including one focusing on brine shrimp alone. Visit FishLinkCentral for a more comprehensive source of lists.
Because threads are open conversations between fish folks from around the world, subscribers can benefit from the knowledge and opinions of some of the best experts available. David and Eric happen to be two extremely knowledgeable experts on supplementing Artemia that participate on several email lists. When the original question was posted, they both decided to freely join in and share their knowledge and expertise. Most hobbyists probably would not have known them or the expertise using traditional means of communication, such as letters (referred to as "snail mail" by Internet users). And if someone did know them, the response most likely would have been addressed to single individual, not to hundreds around the world. And the exchange was quick! Within days, literally hundreds of hobbyists learned about the benefits of supplementing BBS.
There has been a lot of fanfare regarding the information age and the Internet. But here is a small, but powerful demonstration of one of the true benefits to the information superhighway.