Spawning technique of Loach

Misgurnus anguillicaudatus usually develops and matures at the age of 2 winter. It begins to reproduce in April (water temperature 18 ℃). The water temperature is 18-30 ℃, and the optimum water temperature is 22-28 ℃. It lays eggs in shallow grass with a water depth of less than 30 cm. The eggs produced adhere to aquatic plants or submerged upland grass. The hatched larvae often disperse their lives and do not form groups. Let's take a look at the techniques of inducing labor of Loach.

Life habits

Misgurnus anguillicaudatus is a small bottom fish, which lives in the static or slow water at the bottom of the silt. it has strong adaptability and can live in an environment rich in humus. It can breathe in the intestine when the water is anoxic, and can be buried in the mud after the water body dries up. Feed on all kinds of small animals and lay eggs in batches, the breeding period is mainly from May to June, and the largest individual can be as long as 300mm. It is one of the exported aquatic products.

Parent Loach selection

The parent Loach used for breeding is mainly selected from the adult Loach pond last year, and can also be purchased from the nearby market. The female Misgurnus anguillicaudatus generally requires a body weight of more than 25 grams and a body length of 14 cm. Male Loach weight requirements are not strict, generally weight more than 12 grams, body length more than 10 centimeters. It is required that the body surface color is normal, smooth and disease-free, symmetrical, agile, aged 2-3 years old. When inducing labor, the well-developed female Loach with obvious abdominal ovary outline should be paired with the healthy and lively male Loach, and the female-to-male ratio is 1:2.

Pond condition

Parents of Loach no matter where they come from must be cultivated in the pond for no less than 2 months. The cultivation pond of Loach has an area of 1200-1500 square meters, which can maintain the normal water level of 60-80 cm, transparency of 20 cm and moderate fertility. The parent Loach was thoroughly disinfected with quicklime or bleach powder, tea seed meal and so on before it was put into use. After the medicine disappears, the base fertilizer is applied to improve the water quality, and then the parent Loach is released. The stocking density is 325 kg of parent Loach per mu of water surface and mixed culture of male and female.

Loach pool management

In March, people can be fed artificial feed when the water temperature is higher than 10 ℃. The feed requires a crude protein content of 30,35% and a fat content of 5%, mainly animal protein. The feeding amount is about 1% of the body weight when the pond water temperature is 15 ℃, about 2% of the body weight when the water temperature is 20 ℃, and about 3% of the body weight when the water temperature is above 25 ℃. The feeding time is 8: 9 a.m. and 16-17:00 p.m. Flush regularly once a week, 2 hours each time, deepen the water level by 5 cm, do not change a large amount of water, maintain a certain fatness is conducive to the gonadal development of Loach.

Time of induced labor

The suitable time for induced spawning of Misgurnus anguillicaudatus is from mid-late April to early May, the water temperature is 16 ℃ ~ 18 ℃, and the gonads are easy to be overripe later. There are mainly medical syringes with a capacity of 1ml and matching needles, oxytocin, dissection plates, scissors, knives, tweezers for Loach injection, towels for testicular extraction, hard feathers, 1 1000 ml fine bottle, Green's solution or medical saline, 2 straws with 20 ml or 50 ml, water basins or buckets.

Labor-inducing drug

Through the experimental study, it was found that the effect of the mixture of DOM + chorionic gonadotropin or luteinizing hormone analogue was better, and the price of HCG alone was high, and the effect was not good. The injection dose was 0.5 mg / tail of dioxone + 300 mg / tail of chorionic gonadotropin or 0.5 mg / tail of dioxone + 2 μ g / tail of luteinizing hormone analogue.

Method of inducing labor

First use normal saline to match the dosage of each fish into an injection. Generally, about 20 grams of Loach are injected with 0.5-0.7 ml. During the injection, one person fixed the Loach with the Loach control net, and the other used a medical syringe for injection. The method of intramuscular injection on the back was used. The needle tip was at an angle of 45 °with the Loach body, and the drug was injected into the head with a depth of 0.2 cm. In order to prevent the Misgurnus anguillicaudatus from being hurt too deeply, the needle can be treated by winding cotton thread on the needle tip or putting a small rubber tube on the needle, which is required to expose the needle tip of 0.2 cm.

Spawning and hatching

After the induction of spawning, the parent Misgurnus anguillicaudatus was stimulated to lay eggs with micro-running water. After 12-15 hours at 22 ℃ and 8-10 hours at 25 ℃, Misgurnus anguillicaudatus began to estrus, chase, entangle and lay eggs, and the fertilized eggs fell into the loop from the mesh. After spawning, take away the cage and Loach together, and the fertilized eggs enter the incubation stage. At this time, the current should be increased to flush the Loach eggs that have sunk at the bottom of the loop. At the same time, the loach eggs can be stirred up from below with a stirring board, and the operation lasts for about 30 minutes. After the caking eggs are separated, the flow rate can be reduced, and the flow rate can be controlled at about 10 cm / s. When the water temperature is 22 ℃, 90% of the fertilized eggs hatch Loach seedlings after 41 hours. When the water temperature is 25 ℃, it takes 30 to 32 hours for Loach to hatch.