Technique for cultivating single ring spinach seedlings using well brine

Technique for cultivating single ring spinach seedlings using well brine

Commonly known as the sea intestine, the single ring thorn mite is a common species in the phylum of mites, which is widely distributed in the waters of China, Korea, Russia and Japan, and is a long cylindrical link animal with no burrs and light yellow. Monocyclic prickly is rich in protein, amino acids and trace elements, and has good nutritional and health value. Adults are coarse, 100 to 300 mm long, 25 to 27 mm wide, the body surface is covered with granular protrusions of varying sizes, snout conical; abdominal bristles 1 pair, coarse; there is a ring of 9 to 13 brown tail hairs around the anus, which are more tolerant to water quality: -2 to 31 °C water temperature can survive, 8 ~ 26 °C conditions can grow well; survival salinity range of 15 ~ 36; can tolerate pH range of 4.5 ~ 9.5, suitable pH of 7.5 ~ 8.5; dissolved oxygen is higher than 1.14 mg / It can live normally under the condition of liters, and has a strong tolerance to low dissolved oxygen, and can tolerate more than 46 hours when dissolved oxygen is 0.34 to 0.45 mg/l. The main habitat is the intertidal and subtidal zones, and the single ring thorn mite lives in U-shaped burrows and feeds by filtering on suspended material in seawater. In China, South Korea and Japan, it is regarded as a high-grade seafood, and its high nutritional and economic value makes it an important aquaculture resource.

Due to the overfishing of monocyclic spiny aphid in recent years, its natural resources have been seriously damaged, and it is urgent to carry out artificial breeding to meet people's needs, but at present, the development of monocyclic stingray culture technology in China is not mature enough, whether it is seed incubation or adult culture is in the exploratory stage, it is reported that there are two reproductive periods in the year: the large reproductive period in the spring (mid-to-late April to the end of May) and the small reproductive period in autumn (September), during the breeding period, the kidney canal of the female is filled with egg cells and orange The male's sperm-filled kidney tubes are milky white. The average number of eggs carried by females can reach more than 1 million. In this experiment, the seed cultivation of monocyclic thorny aphid was studied by using the treated well brine, in order to provide a new idea for the industrial production of single-ring thorny aphid seedlings by using the abundant well saline water resources in Panjin.

1. Preparation for artificial seedlings of single-ring thorn aphid

1. Seed flies

The specification and quality of the seed mite are directly related to the implementation effect of egg collection and fertilization, which directly affects the development of the larvae, so it is necessary to select a good seed mite. According to the requirements of seedlings, breeding mites growing from the dalian sea area of Liaoning Province and the natural sea area of Hebei were selected, and the fresh individuals weighed 100 to 250 grams and reached 3 years of age. Depending on the needs of seedlings, the collection of seed mites begins in late April. The seed mites are transported dry in a direct incubator, and two ice bottles of 500 ml are placed in the box, and the seed mites occupy 2/3 of the height of the incubator, tie the mouth of the bag, put them into a foam box and transport them to the temporary pond of Panjin Guanghe Crab Industry Co., Ltd. for temporary rearing treatment.

2. Temporary rearing

The temporary density of seed mites with a body weight of 100 to 200 grams was 15 to 20 pcs/m2, and the seed mites weighing 200 to 250 g were stocked according to 10 to 12 per m2, and the water temperature was controlled at (20±0.5) °C, the salinity was (30±2), and the pH was (8±0.2). The seeds can be transported to the temporary pond on the first day without feeding bait, and then fed chlorella paste every day, according to the (20 to 40) × 104 / ml, once in the morning and once in the evening, or you can use the compound to feed according to 2% of the body weight. Change the water once a day at noon, the amount of water is 100%, and the bottom feces are siphoned during the water change. During the temporary period, the individuals who died of ulceration on the surface of the injured body should be fished out in time to avoid spoiling the water quality.

3. Treatment of well brine

The water in an underground brine well in the R&D center of Panjin Guanghe Crab Industry Co., Ltd. in Liaoning Province is pumped into the sedimentation tank for natural precipitation, and the well brine is pumped into the reserve pool before use, and the bleaching powder is disinfected with 100 to 120 mg/l, when the precipitation is completed and the residual chlorine disappears, the EM bacteria are used to adjust the water quality, and the water quality is discharged into the biological treatment tank through two sand filters, and when the indicators such as ammonia nitrogen, nitrite, alkalinity and other indicators reach the breeding water standard, it can enter the nursery for use.

The salinity of seedlings is controlled at 27~30, the water temperature is 16~23 °C, and the pH is 8.0~8.4. Seedling pond disinfection is generally soaked with 100 mg/L bleaching powder, after 7 days of disinfection treatment, the drainage is rinsed with clean water, and the seedlings can be fed after further disinfection and cleaning with hydrochloric acid + hydrogen peroxide.

2. Fertilization and incubation

1. Insemination

This experiment adopts the method of artificial dissection and egg collection, cuts the mouth of the single ring thorn mite with scissors, squeezes by hand, squeezes the sperm and egg gonadal ducts, collects them separately into the container, and waits for backup (so that the gonads can be stored separately through the fullness of the gonadal ducts), and the operation time is appropriate at 30 minutes. Depending on the nursery plan, sperm eggs can be harvested intensively. The method of artificial dissection can effectively control the amount of sperm and does not lead to excessive sperm malformations. In general, the eggs collected by 100 gonadally full females only need the sperm volume of 1 gonad full male to match.

Before sperm egg collection, prepare a 200-liter plastic square trough with 200 liters of treated well brine. According to the density of 200 to 300 / ml, the collected eggs are slowly poured into the fertilization groove, micro-oxygenated, the semen is slowly added to the fertilization groove, evenly stirred, and synchronous microscopy is carried out, and the sperm is stopped when there are 10 to 15 sperm around an egg. Agitate every 2 to 3 minutes, after 10 minutes the fertilized membrane is lifted and the egg nucleus disappears. The first polar body appears after 1 hour, and the second pole body appears about 1.5 hours. After fertilization, the embryonic body develops in the membrane, and after the fertilization membrane is lifted, the fertilized eggs are evenly distributed to the incubation tank for incubation. The density of the incubation tank should be 4 to 5 pcs/ml. Generally, the fertilization rate of this method can reach more than 90%, and the method is simple and easy to control.

2. Incubation

Embryonic development is divided into the following 4 stages.

Fertilized eggs: after monocyclic spiny cockroach and egg fertilization, a fertilization membrane appears on the surface of the egg, and the fertilization membrane forms a clear perioval cavity with the egg membrane, the egg nucleus disappears, and a radial structure appears in the peri-egg cavity, followed by the appearance of the first and second polar bodies.

Cleft phase: Monocyclic spiny mite ovation is completely clefted and isochronous. Clefts begin 1.5 to 2 hours after fertilization and pass through 2 or 4 cell stages. The third hiccup is performed in 3.2 to 3.8 hours, which is a significant spiral hilare. 8 dividing balls are formed, arranged in two layers, the upper and lower division balls are almost equal in size, and 32 cell stages are formed in 4.5 to 4.7 hours, and the division groove is still clearly visible. The fissure continues, the dividing ball becomes smaller and smaller, and gradually blurs into the multicellular phase.

Blastocyst stage: 7.2 to 8.1 hours after fertilization, the blastocyst stage develops into a blastocyst stage, and the single ring spinyropod blastocyst is a luminal blastocyst. The blastocyst wall consists of almost equal splitting spheres.

Intestinal embryonic stage: 10 to 13 hours after fertilization to develop into the primary intestinal embryo stage, the formation process of the primary intestine is in the form of unipolar binding outsourcing, plant electrodehemisphere inverted, resulting in the plant polar hemisphere cell population inverted into the endoderm. The embryo body begins to rotate within the membrane for 15 to 18 hours. 20 to 24 hours after fertilization, the membrane is broken out and enters the pre-single round of larvae.

3. Larval stage management

Larval development goes through three stages, the larval stage, the solitary larval stage, and the helminth stage.

Carrier-wheel larvae: The larvae of the carrier-wheel larvae are pear-shaped, with apical cilia bundles at the top of the upper hemisphere at the top of the brain plate, and perianal ciliary chakras around the posterior anus of the lower hemisphere. The larval digestive tract is not yet formed and is filled with oil droplets. At this time, it has phototropism. After 48 h of fertilization, the larvae form a bow-shaped bowel tube. The mouth is located below the ciliary chakra and the anus is located at the posterior end of the lower hemisphere. The parietal ciliary bundle disappears. The anterior region of the upper hemisphere and the body surface around the lower hemisphere anus are densely packed with short ciliary wheels. At water temperature at 18 to 22°C, the larvae of the pods develop after 16 to 18 days to a pair of abdominal spines in the lower abdomen of the larvae of the larvae, and the anterior ciliary chakra appears in front of the anus.

Sonodal larvae: The lower hemisphere of the larvae rapidly elongates and appears segmented, developing into somatic segments, and finally the elongated lower hemisphere forms 12 body segments, the anterior hairy wheel disappears, the digestive tract becomes elongated, and the body cavity sphere appears in the body cavity. In the water, the body segments elongate slowly but still float in motion.

Helminth stage: 25 to 30 days after fertilization, the larvae switch from planktonic to benthic life. The upper hemisphere begins to degenerate and become smaller, the ciliary chakra of the mouth disappears, the lower hemisphere continues to elongate, and the body segments disappear into torso. Soon the degeneration of the cilia on the surface of the body disappears, the body cavity enlarges, and the digestive tube becomes longer and coiled in the body cavity. A pair of tubular sacs appear on either side of the base of the rectum, which is sand-diving at this time.

Larval stage: 40 to 50 days after fertilization, the anterior segment of the worm-like larva develops into a semi-tubular snout, and 11 tail hairs are lined up in a ring around the anus at the posterior end of the body. The body is 5 to 6 mm long, and the juveniles can quickly dive sand underwater and form U-shaped tunnels. From the observation, in addition to the fact that the gonads are not mature, the morphology and ecology are similar to adult mites, which is the juvenile mite.

1. Density

The density of larval stage of the spindrock is 1/ml. After hatching, siphon and cage collection can be used to collect the carrier-wheel larvae and distribute the seedlings according to the density. The density of the sonolar larval stage is controlled at 0.5 pcs/ml. The density of the worm stage is controlled at 0.2 to 0.3 /m2, which can be determined according to the actual situation.

2. Bait

In the larval stage and the solitary larval stage, the bait can be fed to single whip golden algae and chlorella, and the auxiliary bait can also use marine red yeast. Use monastic algae in the early stage of the worm stage, and use the compound in the middle and late stages, pay attention to the use of 300 mesh mesh filtering and feeding. The early feeding is according to (2 to 4) × 104 pcs/ml, the medium-term feeding (4 to 8) × 104 pcs/ml, and the late feeding (8 to 14) × 104 pcs/ml, depending on the amount of phytoplankton in the water. Feeding twice a day, 1 time in the morning and once in the evening, the initial compound of the worm period is 0.2 to 0.5 g/m3, and the late compound is 5~6 g/m3, which is increased or decreased according to the feeding situation. The amount of residual bait can be determined by the aspiration process and by observing the fullness of the intestine.

3. Water quality management

The larval stage and the body joint stage mostly use the method of pre-hydration, water replacement after filling to the full water level, 10 to 15 cm per day, 20 to 30 cm per day after full water level, and EDTA, anti-stress drugs, and microecological preparations after hydration. It can also be replenished once in 3 to 4 days, each time at 20% to 30%, do not change the water after reaching the full water level, use a micro-ecological preparation every 1 day, and use a 300 mesh sieve silk mesh for drainage before and during water change.

Daily microscopic examination is performed to observe the viability of the seedlings and observe whether there is damage to the driving force and body wall of the flagellar to prevent the seedlings from being too concentrated on the surface layer of the pond. It can be raked once a day in the morning and once in the evening, stirred up and down once, so that the larvae are evenly distributed to facilitate the normal growth of the larvae.

During the worm stage, water can be changed once every 5 to 7 days, and microecological preparations can be used every 2 days to stabilize water quality. Each water change is about 30%, depending on the change of water quality.

4. Adhesion base treatment and delivery timing

Selection and treatment of attachment groups: The attachment bases used in this experiment are fine sand, and the diameter of sand grains is more than 0.5 mm. Before use, the sand under the 40 mesh sieve is used for backup, disinfected when entering the body joint period, generally soaked with potassium permanganate for 48 hours, and repeatedly cleaned until the water quality becomes clear before it can be put into use.

Attachment base release time: In the single ring thorn mite seedlings, the attachment base release time is particularly important, the release time is late, the body node period turns to the bottom movement period, and the sand is easy to press the seedlings to the bottom and cause the accumulation to die. The optimal time for the insertion of the adhesion base is 4 to 5 days after the appearance of 12 body segments, and it can also be observed when the upper hemisphere begins to degenerate and become smaller, the cilia chakra is about to disappear, the lower hemisphere continues to elongate, and the body segment disappears into a torso. The thickness of the sand can be 1 to 2 mm, evenly splash the sand into the pool, using the method of self-settling, before the sand is poured, the oxygen is stopped before the seedlings float before the operation.

5. Enemy defense

The main predator is copepods, especially the large number of copepods often infringe on the helminth stage of single ring thorny insects, and the predator defense can use 0.3 mg/l "special killing No. 1" (surface penetrator), change the water 20% to 30% after 12 hours of administration, and use microecological preparations for water transfer at 24 hours. The use of 300 mesh and cotton mesh bags can reduce the entry of water fleas into the nursery pond. In recent years, due to the large number of insecticides, some copepods, that is, some water fleas, have developed strong resistance and are difficult to kill, which should be paid great attention to.

Fourth, seedlings out of the pond

When the worm culture reaches about 5 mm and 60,000 to 80,000 /kg in 20 to 30 days, it can be released from the pond. Use a 100 mesh mesh screen to collect seedlings and sand at the sewage outlet, and then use a 30-40 mesh mesh screen to sift the sand and collect the seedlings. The general output is 0.5 to 0.6 kg/m2.