Artemia enrichment – How To Enrich Brine Shrimp

Artemia strains differ in size and nutritional quality, particularly in content of highly unsaturated fatty acids (HUFA). In the 1980s researchers found that fish larvae feed strains containing more than 4 percent eicosapentaenoic acid (EPA) 20:5 n-3 yielded significantly better growth in fish than Artemia with less than 3 percent 20:5 n-3. Recent research suggests that docosahexaenoic acid (DHA) 22:6 n-3 is more important nutritionally than EPA.

Premium quality Artemia (usually from San Francisco Bay) are higher in 20:5 n-3 (EPA), but are still lacking in 22:6 n-3 (DHA), which is the most important HUFA for marine finfish larvae. These high EPA Artemia are not equal to HUFA enriched Artemia in terms of nutritional value, but are helpful in bridging the gap between rotifers and enriched day-old Artemia. The premium quality Artemia with high hatching rates, small size and greater HUFA levels are relatively expensive and sometimes difficult to find in quantity.

As an alternative, a hatchery can purchase a commercial enrichment product to treat lower quality Artemia. Here is a simplified formula for Artemia enrichment.

Formula

Ingredients

• 800 ml (27 fluid ounces) deionized water

• 160 ml (5.4 fluid ounces) cod liver oil or other high omega fish oil

• 4 raw egg yolks (Egg yolks can be substituted with soybean lecithin “” 8 g or 5 percent of the weight of the oil.)

• 30 g (0.06 pound) unflavored gelatin

• 10 g (0.02 pound) vitamin premix, including E, C and B complex

• 1 g beta-carotene

Procedure

1. Dissolve gelatin in 800 ml (27 fluid ounces) boiled, deionized water and let it cool to 40 oC (104 oF).

2. Mix the oil in a blender on the highest setting for 30 seconds while adding betacarotene.

3. With blender on, add vitamins and egg yolks. Then add gelatin and blend for 90 seconds.

4. Store the product covered in the refrigerator.

For use with hatching Artemia

Use about 0.5 ml (0.01 fluid ounce) of the enrichment diet per liter of incubation water (assuming 2 g dry cysts per liter of incubation water). After 18 to 24 hours hatching time, add another 0.5 ml of the enrichment diet per liter 2 hours before harvesting. Harvest before Artemia become too large for fish larvae.

For use with hatched, separated Artemia (in seawater)

Use about 0.5 ml of the enrichment diet per liter of separated Artemia (assuming a density of 100 to 150 Artemia per ml) for not less than 4 hours. Aerate the Artemia/diet mix during the enrichment process. Cooling the water with ice may slow the rate at which the Artemia grow during the enrichment process if size is critical to the target larvae.

The drawback to this procedure is that Artemia grow very rapidly, metamorphose to second instar metanauplii, and can become too large for some fish larvae to consume. The recommended solution is to use premium quality, newly hatched Artemia for the younger stages and then switch to enriched metanauplii Artemia as food for older fish larvae.