Artemia Strains Research Articles

INTERNATIONAL STUDY ON Artemia:1 XXI. INVESTIGATIONS INTO WHY SOME STRAINS OF Artemia ARE BETTER FOOD SOURCES THAN OTHERS. FURTHER NUTRITIONAL WORK WITH LARVAE OF THE MUD CRAB, Rhithropanopeus harrisii

AbstractIn a series of studies conducted by members of the International Study on Artemia, differences in nutritional quality were documented between geographical strains of the brine shrimp Artemia. Concomitant with, and possibly related to nutritional effectiveness are differences in biometric traits and biochemical composition. Since these initial experiments could only hint at causal relationships, a series of experiments were carried out to further our understanding of cause and effect.In one experiment we tried to ascertain whether the factors responsible for poor survival in larvae fed some brine shrimp strains are cumulative throughout larval development or whether there are critical periods when larvae are more sensitive. Our results indicate that the factors contributing to poor growth and survival are cumulative.In a second experiment, we contaminated Brazil Artemia with diel‐drin, chlordane and combinations of the two and fed them to mud crab (Rhithropanopeus harrisii) larvae. The levels of contamination were chosen to approximate those suspected of contributing to the poor food value of some brine shrimp strains. In this experiment, however, diel‐drin and chlordane contamination appeared to have no effect on growth and survival of R. harrisii larvae.In a third experiment, we fed Utah strain Artemia on Isochrysis galbana for 24 hours and then fed these brine shrimp to mud crab zoeae. Previous work had shown that this regime made Utah Artemia more suitable as a food source for a prawn. However, in our experiments, it did not improve survival of R. harrisii.

The use of Artemia nauplii for toxicity tests—A critical analysis

Because of their easy hatching from dry cysts and their year-round availability, nauplii of the brine shrimp Artemia salina are most convenient test organisms for toxicity studies. The bioassays mentioned in literature have, however, mostly been carried out with larvae of which neither the exact instar stage nor the geographical origin is known. The incubation of the cysts should always be carried out under strictly controlled temperature conditions since both the onset of hatching and the length of the hatching period are temperature-dependent. Moreover, the experiments should only be carried out with populations of nauplii of the same stage of development since it is demonstrated that second and third instars are significantly more sensitive to toxicants than first instar larvae. It is demonstrated that the sensitivity to chemicals varies from one geographical Artemia strain to another.

The nuclear content of DNA in 3 different strains of Artemia salina Leach (Phyllopoda, Branchiopodidae).

DNS-Messungen an Interphasekernen vonArtemia salina parthenogenetica 2n undArtemia salina anfigonica zeigen ein Mengenverhaltnis von 1.2∶1, wahrend zwischenArtemia salina parthenogenetica 4n undArtemia salina anfigonica DNS Werte im Verhaltnis 2∶1 gefunden wurden.

EFFECTS OF SALINITY AND NUTRIENTS ON MONO- AND DIAXENIC CULTURES OF TWO STRAINS OF ARTEMIA SALINA

1. Two tetraploid strains of Artemia salina were axenized. The bisexual strain from the Great Salt Lake was obtained bacteria-free by serial washes of the wintering eggs in Merthiolate. The parthenogenetic strain from the Comacchio salines was axenized by serial washes of gravid females and nauplii in antibiotics; the yeast infection was eliminated by high salinity.2. Methods for the maintenance of the bacteria-free stocks were defined. Various phytoflagellates were found suitable food organisms for both strains of Artemia when grown in appropriately enriched sea water.3. Two species of Dunaliella were adapted to grow in synthetic salt solutions ranging from 0.5 to 20.5% total salts. These conditions permitted the study of the effect of salinity on egg production of Artemia in diaxenic culture.4. Great Salt Lake Artemia grown at various salinities, in inorganic enrichments and fed ad libitum with salinity-adapted D. viridis and D. salina, failed to deposit eggs in solutions containing less than 3% salts. The Comacchio Artemia was even more sensitive: in low salinities development was inhibited even though the algae were abundant.5. The reduced fecundity of Artemia at low salinities could be reversed by adding organic enrichments, i.e., small quantities of glucose, liver extract, yeast extract and vitamins. The organic enrichment was thought to affect the metabolism of the algae rather than that of Artemia.