Artificial culture technology of giant salamander

The water source of the farm is pollution-free mountain spring water with clean water quality, moderate water temperature (4 ~ 25℃ for many years), quiet environment and cool climate.

2. Design and construction of aquaculture ponds

We design aquaculture ponds by simulating ecology. This pool is made of bricks and coated with cement. Each swimming pool has an area of 40 square meters and a depth of 50 cm. The pool wall is smooth, and the pool surface is made of cement into a T-shaped escape eaves. Make a hole 30-50 cm high with brick cover and cement board in the pool, and pile pebbles 10-20 cm high in the hole. The slope of the bottom of the pond is 1%, and a sewage pipe is set at the lowest part of the pond. The water inlet pipe is introduced from the middle of the pool. Put a pebble with a width of 20 ~ 30 cm in the pond ditch, which is 10 cm higher than the water surface, so that the giant salamander can find a habitat when the weather is sultry. The whole culture pond is covered with a sunshade net.

Second, the species of giant salamander.

Before the giant salamander fry enter the pond, it should be disinfected and disinfected. If it is a new giant pond, it must be soaked in water for one month before it can be used. Disinfect the pond with quicklime 150g/m2 and the giant salamander with 5% salt solution 15min. The release time is March in spring, the water temperature is 8 ~ 10℃, the density of the first-year catfish is 8 ~ 10 catfish /m2, and the second-year catfish is 5 ~ 6 catfish /m2. Catfish with normal specifications are raised in the same pond.

Third, the daily management

The daily management of giant salamander adult culture mainly includes water temperature and quality regulation, feed feeding, disease prevention and escape prevention.

1. Water temperature regulation

When it is hot in summer, cover it with a sunshade net to keep the water temperature below 25℃.

2. Water quality regulation

The water quality of adult catfish pond is kept fresh, with pH value of 7.2 ~ 8.2, transparency of pond water of 30 cm and dissolved oxygen of 5 mg/L, and sludge and sundries in the pond are cleaned every 7 days.

3. Feed feeding

Giant salamander is a carnivorous animal, and there are four ways to feed it: feeding it regularly, every time in the evening; Positioning, feeding in a relatively stable position; Determine the quality, feed fresh bait without impurities, and live bait is preferably small crucian carp and frog; Quantitatively, the feeding amount is 6% ~ 8% of the total weight of giant salamander, once every two days in summer and autumn and once every five days in winter and spring.

4. Disease prevention and escape prevention

In the artificial breeding environment, the giant salamander does not often get sick because of good management, but skin rot is still the main disease found at present. The symptoms of adult giant salamander are hyperemia and oval erythema, and in severe cases, punctate ulceration occurs, with the largest lesion of 0.8 cm ~ 2. When the giant salamander comes of age, the tips of its limbs fall off, exposing its phalanges. The main reason is that giant salamanders are aggressive and bite each other, causing skin damage and bacterial reinfection. As a result, the giant salamander moves slowly and eats less. Prevention and control methods: separate cultivation according to size and specifications; Frequent examination showed that the sick salamander was treated in isolation and soaked in 0.05 μ g/L furazolidone for 30 minutes every other day/kloc-0 times until it recovered.

In the process of breeding, pay attention to setting an iron fence at the water outlet to prevent the giant salamander from escaping.

Biological characteristics and artificial breeding techniques of giant salamander;

Giant salamander, commonly known as giant salamander, is a specialty of China, so it is also called Chinese giant salamander. The giant salamander is distributed all over China, mainly in the mountains and streams in South China and Southwest China. Common individuals weigh 2-5 kg, with a body length of about 50- 150 cm, and the largest individual can reach10-2-5 kg. The giant salamander has tender meat, delicious taste and rich nutrition, and has high edible and medicinal value. In recent years, due to man-made indiscriminate killing, the natural ecological environment has been seriously damaged, and the resources of giant salamander are decreasing day by day. It is an endangered animal and has been listed as a second-class key protected wild animal by the state. Therefore, it is of great practical significance to carry out the research and discussion on the biological characteristics, artificial reproduction and breeding technology of giant salamander.

First, the biological characteristics of giant salamander

1? morphological character

The giant salamander belongs to Amphibia, Anura and Cryptbranchia. Its body surface is bare, its skin is smooth and elastic, and it is covered with irregular punctate or patchy cyan pigment, and its body color often changes with the change of environment. The abdomen is gray, the head is wide and flat, and the mouth is roughly semicircular. The vomer and mandible have teeth, and the vomer teeth are developed. It is the main tool for catching food. Adults have no gills and breathe with their lungs. Eyes are distributed on the upper and lower sides of the head, with wide and flat eye distance and no eyelids. There are 65,438+0 nostrils on each side, which are small and round and located above the eyes. The vertebral body is biconcave, the abdomen is obese, accounting for about12 of the body length, and there is an inconspicuous degenerated dorsal fin on the back extending to the tail. The giant salamander has a pair of forelimbs and hind limbs. The forelimbs have four fingers and the hind limbs have five toes. The limbs are similar in shape to those of frogs. The movement of giant salamander mainly depends on its limbs. There is a genital hole between the abdomen of the two hind limbs, and the outer end is in line with the excretory hole. The female giant salamander has no fertilization device.

2? Living habits

Giant salamander is a kind of temperature-changing animal, which often lives in streams in deep mountains and forests, likes to move in the middle and lower layers of water and can survive in water at 0 ~ 38℃. The suitable water temperature is 16 ~ 28℃. When the water temperature is lower than 14℃ and higher than 33℃, the food intake decreases, the action is slow and the growth is slow. When the water temperature is lower than 10℃, the giant salamander begins to hibernate and stops eating completely. The requirements for dissolved oxygen and water quality in water are strict. When the dissolved oxygen in water is above 5 mg/L, the water quality is fresh and pollution-free, which is most suitable for the growth of giant salamander. The dissolved oxygen in the water must be kept above 5.5 mg/L, and the water in the nursery pond should be kept in a constant flow state. The suitable PH value is 6.0 ~ 9.0, and the optimum PH value is 6.8 ~ 8.2. In the natural ecological environment, the giant salamander often lives in benthic organisms, lives in seclusion in caves during the day, climbs out of caves at night to forage everywhere, likes darkness, and is afraid of strong light and shock. They often feed on aquatic animals such as small fish and shrimp in streams, and can prey on fish equivalent to their own length 1/2. The fish they eat are generally spike fish, goby fish, puffer fish, betta fish, loach and snakehead, mollusks such as snails and mussels, as well as aquatic insects and voles. Under the condition of artificial breeding, in addition to eating all kinds of wild fish, you can also eat some animal carcasses, animal blood or internal organs. By taming food, you can also eat artificial compound feed.

3? Growth characteristics and reproductive habits

In the natural environment, the giant salamander grows rapidly because of its good water quality and rich feed resources, and the largest individual can reach 10 ~ 15 kg. Under the condition of artificial breeding, the growth rate is the fastest at 2-5 years old, especially at 2 years old, the annual growth multiple of body weight is 6.5-9.8, and the annual growth multiple of body length is about 2.2. The weight growth of pond giant salamander is obviously faster than that of wild population, which is mainly related to the comprehensive nutrition and suitable water temperature in artificial breeding, and it will not hibernate even in severe winter. Under natural conditions, the female giant salamander generally reaches sexual maturity at the age of 4, and under artificial breeding conditions, the female giant salamander reaches sexual maturity at the age of 4-5. When the giant salamander is sexually mature, the milky semen can be discharged by squeezing the abdomen of the male giant salamander, and it can be dispersed by dripping into water. Female giant salamander can produce beaded long-chain banded eggs, which can be fertilized in vitro during reproduction. May-September is the breeding season of giant salamanders. During the breeding season, giant salamanders often make a doll-like cry. The optimum water temperature for incubation and reproduction is 22 ~ 25℃. The artificial propagation of giant salamander has been studied in China for nearly 30 years. So far, the artificial propagation of giant salamander has made little progress and the success rate is extremely low. The source of fry is still mainly natural resources. Therefore, the research on artificial propagation technology of giant salamander is an important topic and main direction in the future.

4? Identification of fish fry in amphibians The suborder Cryptbranchiae in Anura is very similar to Andrias davidianus, salamander and Hydratidae. In recent years, stimulated by the high profits of giant salamander fry, some fry suppliers often mix fish with pearls and often keep giant salamander without spots. In order to distinguish giant salamander from salamander and salamander, their morphological characteristics are compared as follows for reference in identification.

Second, artificial breeding of giant salamander

1? Construction of aquaculture pond

According to the topographical features, the giant salamander culture pond can be designed into two types: rectangular and oval, with an area of 200-300m2. Do a good job in the installation of inlet and outlet pipes. The design of the inlet pipe should be higher than that of the drain pipe, generally about 820cm away from the bottom of the pool. The duckbill can be installed at the inlet of the water inlet pipe, with the wide edge as the outlet, and the duckbill outlet is about 1cm. Determining the number of duckbills according to the size of the aquaculture pond can not only reduce foreign debris, but also increase the width of the water surface and promote the water circulation in the pond. Drainage pipes should be installed near the bottom of the pool to facilitate the removal of deposited dirt. Pool height 2? 5 ~ 3m, the wall of the pond shall be leveled with cement, and it shall be as smooth as possible. A number of artificial caves are built with bricks, cement boards and other materials, the length, width and height are 2 ~ 4m, 1m and 0.5m respectively, and they can also be interconnected, but the walls of the caves should be kept smooth as far as possible to avoid scratching the skin of giant salamander. The soil quality of the cave and the bottom of the pool is better, and the ratio of pebbles with a thickness of 20cm to river sand can be 5∶ 1, and a bait table should be set above the cave. The bait platform is required to be flat, and its area accounts for about 1/20 ~ 1/30 of the culture pond, and the slope ratio on both sides is 1: 5. A shade shed was built above the bait table with blue fiber tiles to prevent the giant salamander from being frightened when eating. After the new culture pond is completed, the pond water should be filled to a depth of about 2m, drained after 3-4 days, and then filled with fresh water. Repeat for 3-4 times, and when the alkalinity of cement completely disappears and a layer of attachment appears on the wall of the pond and the hole, the giant salamander can be released. In order to ensure the supply of fresh bait for the giant salamander, a bait pond can be built nearby, and a certain number of fish, mollusks and frogs with strong reproductive ability and easy feeding are often stocked in the bait pond as bait for the giant salamander.

2? Catfish stocking

In order to prevent pathogenic microorganisms on the surface of giant salamander from being brought into the giant salamander pond, the stocked giant salamander fry were disinfected with gentian violet solution with the concentration of 65438 0%. The method is to prepare the mixture according to the ratio of liquid medicine 1∶ 100, and then soak the giant salamander fry in 65438+ liquid medicine. The stocking density is 10m2, 5-6 giant salamanders with specifications of 8- 10 cm and 3-4 giant salamanders with specifications of 1 1-20 cm are released. At present, most species of giant salamander are collected from nature, and their specifications vary greatly. Therefore, it is necessary to do a good job of screening fry when stocking, and try to stock giant salamanders with the same specifications in each breeding pond to avoid bullying and killing each other and improve the survival rate of giant salamanders.

3? baiting

Giant salamanders feed on animal bait. Besides protein, the bait should also be rich in zinc, iron, calcium, phosphorus and various trace elements. When artificial feeding, the types of bait should be as wide as possible and well matched. In addition to feeding a certain amount of fresh bait such as wild fish, shrimp, tadpoles and snails, animal viscera, blood clots and leftovers should also be properly fed. According to the individual size and feeding situation of giant salamander, the feeding method is as follows: firstly, wash the animal viscera, grind the animal viscera into the required fineness with a meat grinder and put it on the bait table. Before each feeding, the bait table should be cleaned to ensure the cleanliness and hygiene of the bait table. It is not allowed to throw animal viscera, blood clots and leftovers directly into the water, which will not only reduce the utilization rate of bait, but also easily cause water pollution. When feeding fresh bait, fish, shrimp, snails or tadpoles can be directly put into the culture pond to let the giant salamander prey freely, which can greatly improve the utilization rate of bait and increase the food intake. The giant salamander has the habit of lying down during the day and going out at night, so the feeding time should be set in the evening. The giant salamander should avoid being disturbed during feeding, because the giant salamander will "spit" after being frightened and stimulated.

4? Adjustment of water quality and water temperature

The water quality of the giant salamander pond should always be fresh and pollution-free. In summer and autumn, with the continuous increase of giant salamander individuals and food intake, a large number of excreta will also increase, which will easily lead to the deterioration of water quality. Therefore, in addition to regularly removing the residual bait and excrement in the pond, the water in the pond should be replaced regularly, usually once every 3 to 4 days, and the amount of water to be replaced each time is 1/3 of the water in the pond. If the water source is sufficient, it can ensure a steady stream of water in the giant salamander breeding pond, which is more conducive to the growth and development of giant salamander, especially in the breeding season of giant salamander, the steady stream of water can stimulate the nervous system of giant salamander, promote gonad development and improve the reproductive rate. In addition, a certain number of snails can be kept in the giant salamander pond. Because Ampullaria canaliculata can feed on the humus at the bottom of the pond, it can not only remove the dirt in the pond, but also provide palatable bait for the giant salamander. The transparency of pool water is generally about 35cm, and the dissolved oxygen in water is above 5 mg/L. In order to control the PH value of water to 6? 2—7? 8, according to the specific situation by spraying lime to adjust. Water temperature is also very important for the growth and development of giant salamander, and the optimum water temperature is 22 ~ 25℃. In hot summer, it is ideal to introduce mountain stream or clear spring water into the giant salamander pond as much as possible, and the water depth of the pond is deepened to about 2 m. In order to prevent direct sunlight, some aquatic plants such as water hyacinth, duckweed and water hyacinth can be kept in the pond, and vines can be planted around the breeding pond, which can effectively control the sudden change of water temperature in the pond. In early winter, the water temperature drops below 10℃, and the giant salamander hibernates. Under the condition of artificial breeding, in order to promote the rapid growth and development of giant salamander, a series of methods such as geothermal water, industrial warm water or greenhouse heating are generally used to adjust the water temperature of giant salamander pond, so that the water temperature is always kept at 20 ~ 28℃, so that giant salamander can still eat and grow normally in winter.

5? disease control

In the process of artificial breeding, due to the change of the ecological environment and living habits of giant salamander, the water quality is easy to be polluted, the feeding bait is not comprehensive in nutrition, and the stocking density is relatively increased, which will increase the probability of bacterial infection. Whenever there is a lack of bait, the giant salamander is often easily injured in fighting and biting. According to relevant data, the incidence of artificially cultured giant salamander is several times higher than that of wild population. The common diseases of giant salamander are skin rot and tail rot, which are introduced as follows.

1 Rotten tail disease: When giant salamander suffers from this disease, red spots or spots often appear from the base of tail stalk to the tail end, and the surrounding skin tissue is congested and inflamed, and the epidermis is slightly gray. In severe cases, the diseased tissues and muscles are necrotic, the coccyx is exposed, and dark red or light yellow liquid often oozes from the wound. Sick salamander activity weakened or motionless, did not eat, the tail became stiff, and soon died. The disease can occur in all seasons, and the peak period is from June to August, which mainly harms 1 ~ 3-year-old giant salamander. Control method: spray the whole pond with 0.2 ~ 0.3 ppm chlorine dioxide, including bait table and artificial cave, once a day, 3 ~ 4 days as a course of treatment. For the seriously ill giant salamander, first soak the wound with potassium permanganate solution with the concentration of 15 ~ 25 ppm, and clean the attachments on the surface of the wound with cotton balls. Then externally apply anti-inflammatory drugs such as Xiaozhilong ointment or sulfur ointment to the affected area, once a day/kloc-0, for 5-7 days, with chloramphenicol 2-3g+Kana powder 2g+VC2g+VB2g per kilogram of body weight.

Rot skin disease: It is a disease caused by Aeromonas hydrophila. Its symptoms are: irregular red lumps often appear on the body surface of sick salamanders. At the beginning of the disease, there is a yellowish pustule in the center of the red mass, which gradually spreads to the surrounding skin tissue. Scabies-like lesions were formed after the pustules were punctured, and the lesions were congested, swollen and decadent. At this time, the infection is very fast, and the sick salamander lies in the pool and doesn't eat. If measures are not taken in time, the mortality rate is very high. Prevention and control methods: spray the whole pool with 0.3 ~ 0.4 ppm of strong chlorine essence or 0.2 ~ 0.3 ppm of chlorine dioxide regularly for thorough disinfection and sterilization. The onset period is once a day for 4-6 days. Wash the affected area with 0.3-0.5 ppm malachite green solution or medical hydrogen peroxide, and then apply Xiaozhilong ointment or Fuyankang ointment once a day for 4-7 days. Then, according to the weight of giant salamander, 0.3 ~ 0.4 ml of turtle Baokang injection was injected, and the injection site was generally the soft tissue at the lower end of forelimbs, at a 45-degree angle, once a day/kloc-0, for 3 ~ 4 days. Note: When giant salamanders are found to be sick, they should be put in a separate pool quickly.