Culture of Artemia

* Artemia, also known as saltwater amphibian, amphibian shrimp, brine shrimp, also known as saltwater insects, is a small crustacean worldwide distribution.

* Artemia nauplii has been used as feed for marine juveniles since 1958 in China.

* Since the founding of the People's Republic of China, China has also been a major source of Artemia resources.

I. Biology of Artemia

* (1) Reproductive habits

* Artemia reproduces by parthenogenesis and hermaphroditism.

* parthenogenesis: under good environmental conditions; parthenogenesis; parthenogenesis; parthenogenesis; parthenogenesis; parthenogenesis; parthenogenesis; parthenogenesis; parthenogenesis; parthen

* Gender reproduction: under adverse environmental conditions.

* Some strains can only have parthenogenesis or sexual reproduction.

* Reproductive capacity: female 5-10 times per lifetime, 2-300 eggs per pregnancy

(generally 80-150), 30-40 indoors at a time.

(2) Life History of Artemia

* During the development of Artemia, there are metamorphosis stages, including eggs, nauplii, post-nauplii, pseudo-adult larvae and adults.

* Development: eggs naupliums adults? (Shelling growth);

* Life: 2-3 months, up to 9 months.

* Artemia is molting growth (12-15 molting times in a lifetime) and develops metamorphosis. There are great individual differences from nauplii hatched by eggs to adult stage.

* The newly hatched nauplii have a large amount of yolk within 1-2 days, rich in protein and fat and other nutrients. It is a good diet for fish, shrimp and crab larvae.

1. The eggshell of Artemisia sinensis is thick, grayish brown and 200-280 m in diameter.

2. nauplii

* hatching:

* Body length 0.3-0.4 mm

* Body width 0.25-0.3 mm

* Three pairs of appendages and one eye

3. Artemia adults

* The total length is 1.2-1.5 cm, divided into head, chest and abdomen.

* Head: 5 pairs of appendages

* Chest: 11 pairs of appendages

* Abdomen: without appendages

(3) Ecological conditions

* 1. Distribution: Wide range and abundant resources in China

* They are distributed all over the world except the North and South Poles. They are mainly distributed in saline lakes or saline fields with high salinity.

* Hebei, Liaoning, Shandong and Inner Mongolia are rich in resources in China.

2. Salinity

* Life 10-242

* Tolerance 1-340

* Optimum 30-50

* Salinity has a significant effect on the size and body color of Artemia. Under the condition of salinity of 30-50, Artemia is large, light, and the higher the salinity, the smaller the individual and the darker the body color.

3, temperature

* Artemia can adapt to a wide range of temperatures, survive at - 3 ~ 42 degrees C, grow at 15 - 35 degrees C, and hatch at the optimum temperature of 30 degrees C. Growth and development were slow when the temperature was less than 15 C.

* Able to withstand drastic changes in temperature. If the egg-holding female cultured at 25 C was transferred to - 2 C immediately and parked for 2 days, the Artemia could still survive.

4. Dissolved oxygen consumption is low, above 1 mg/L.

5, pH

Adaptation 7.5-8.5 Adaptation 7.5-8.5

6. Bait

* Typical filter-feeding animals, omnivorous (bacteria, yeast, unicellular algae, small protozoa, organic debris);

* The selectivity of the bait is poor, and the size of the bait below 50um is more suitable.

* 7. The sport larvae have strong phototaxis and can be collected by light inducement.

2. Treatment of Artemia eggs

(1) Saturated brine method - specific gravity method:

Eggs - saturated saline water sediment: sand and stone with a large proportion.

Floating Freshwater Floating: Impurities such as grass.

???

Bottom sinking: eggs salvage sea water washing

Dehydration, air drying sieving processing and packaging (large plastic barrel or tin packaging).

(2) washing method:

* (1) Rough screen filtration;

* (2) Use 40-60 mesh net to wash (remove big impurities);

* (3) Use 80-100 mesh net to wash (remove small impurities);

* (4) Seawater washing dehydration, air drying sieving processing and packaging.

3. Storage

* (1) Low temperature;

* (2) Vacuum or nitrogen filling;

* (3) In saturated brine.

2) Selection of dormant eggs

* Look at the origin: Tianjin, the United States.

* Understanding the treatment technology: the treatment needs to be washed with seawater and treated at low temperature.

* 1. Discrimination of Appearance Quality

* (1) Color and odor: brown and lustrous in the eye, no caking in the hand;

* Can disperse, the nose smells no mildew and fishy smell;

* (2) Sediment content: using clean saturated saline water to distinguish and deposit at the bottom of the test tube

* It's not good to have too many things and turbid water.

* (3) Crushed and empty shells: observed by magnifying glass or microscope: round or flat.

* Whether there is broken shell or not and the proportion.

* (4) Size: The number of eggs per gram was measured.

* Number of oil droplets: Take 10 eggs and squeeze them with two slides to see if there are oil droplets.

* Good eggs with oil droplets;

* Bacterial content: microbial culture.

4. Quality Identification Criteria

* (comparison at 35 salinity and 25 temperature)

* Incubation rate:%

* (2) Incubation efficiency: number of nauplii per gram;

* (3) Incubation speed: T0 (the first larva appeared), T90 (90% hatched);

* T10 (10% hatched); T0 about 20-26 hours, the shorter the better. The difference between T10 and T90 indicates the synchronization of hatching, the closer it is, the better.

* (4) Incubation yield: 18-250,000 grains per gram, referring to the total dry weight of hatched nauplii;

* (5) Water content: water content is 5-8%.

* Nutritional value - breeding effect. For example, sea eggs are better than salt lake eggs.

(3) Shelling of dormant eggs

* 1. Shelling principle:

* The eggshell of Artemia is composed of lipoprotein and orthoheme, which can be oxidized by hypochlorite.

* 2. The significance of shelling of Artemia eggs:

> It can play a disinfection role.

> (2) Preventing water pollution;

> (3) Increasing hatching rate;

> (4) Increase the energy of nauplii;

> There is no need to separate the eggshell, which saves labor and time, and brings convenience to production.

3. The process of shelling Artemia eggs:

* Water treatment (1h) water washing and filtration to prepare shelling solution (6-15min) water washing and filtration to remove chlorine (1-2% Na2S2O3) flushing and filtering.