Discussion on artificial breeding techniques of giant salamander

The technology of artificial breeding of amnesty is a problem that we are all paying close attention to. Now we will talk about a few superficial views on the specific issues in the work of artificial multiplication. It is not necessarily right, it is only for reference.

First, the large-scale artificial breeding model

At present, there are mainly the following farming modes for domestic giant salamander breeding: 1. Single-cultivation: Constructing indoor cement raising ponds, with different sizes (0.5-1.5 m), divided by individual size according to the principle of one pond, one by one. Habitat small pond; 2, polyculture, oval or rectangular cement pool, an area of ​​8-16 m, 8-10 per pond rearing; 3, imitation of natural ecological function pool feeding, that is, the implementation of male and female breeding, and simulate the natural ecological environment, Develop operating points for aquaculture techniques, including technical measures such as light transmission, air permeability, and flowing water stimulation. The aquaculture pond has a water depth of about 0.2m. It has been observed that polyculture feeding is slightly better than monoculture, but mutual fights and bites occur from time to time, and the chance of mutual infection of the disease is high, and it is not conducive to observation. Monoculture overcomes the shortcomings of polyculture, but also because male and female long-term can not get information exchange, is not conducive to gonadal development; imitation of natural ecological function pool breeding, to overcome the shortcomings of polyculture, monoculture, so that both male and female in the breeding process, both interoperable Information, without killing each other, is very beneficial to gonadal development. In addition, there are outdoor imitation of natural ecological breeding models and indoor three-dimensional pots, this model is more common in Shaanxi Hanzhong.

Most of the juveniles used plastic water or aquaculture. According to the observation, hydroponics is not as good as running water, and food intake, growth, and survival rate are all lower.

Second, on the issue of artificial oxytocin production

Xiao Hanbing et al.'s "Study on the annual changes of the gonads of the big pupa under aquaculture conditions" pointed out that under the culture conditions, the synchronicity of bullous maturation is enhanced, both showing the growth of gonads in the late spring and early summer and reaching the peak in summer. The gonads are at the end of the breeding process in late autumn. During the degradation and absorption stage, the annual cyclical pattern of winter stagnation and development changes to reach the peak of gonad maturation at the end of July.

Yang Aisheng et al pointed out in the article “Histological observation of gonads of bullous maggots”: Through the histological observation of gonadal development of bullae, the law of seasonal changes of gonadal development was known. The observation results showed that the female ovaries entered the mature stage of stage IV and appeared the highest The percentage was 41% in summer, followed by 31% in late spring, 11% in autumn, and 51% in the fall. From the point of female gonad development, the mature season is mainly summer. Of course, there are mature people in spring and autumn. , But most of the spring is the beginning of IV, its ovaries are not full, and the eggs have not yet grown. Its maturity coefficient is also much lower than summer. Autumn is the end of the mature season, as most of the ovaries are now moving towards a degenerative stage. Therefore, generally speaking, there are mature ovaries from May to October, but the main maturation season is summer.

Yang Yuqing et al. pointed out in the article “Observing Observations on Gonad Development in Female Bully” that once the measurement was completed on June 10, 2000, four females with the largest egg diameter (about 3.2 mm in egg diameter) were tested for oxytocin production. As a result, only one production was achieved, the number of eggs laid was less than 100, the size of eggs was small, and the quality was relatively poor. The inducing rate reached 63.9% and 68%, and the egg was bright in color with good elasticity. This indicated that the spawning peak of the oviposition spawning group was in mid-late July.

Yang Yuqing used the color Doppler meter to determine the egg size of the female pupa and determine the range of egg diameters for the spawning quail. The correlation equation between the measured value of pre-natal scans of female eggs and their postpartum measured values ​​was Y=0.69X+3.09 (n=56, r=-0.9984). Y represents the measured value and X represents the prenatal scan value. It is considered that the best spawning egg diameter for the prenatal scan is 3.94.5 mm, which is larger or smaller than the egg diameter for both mature and immature eggs.

From the physiological point of view, we found that the peak of sexual maturity of female bulls was in the middle or late July, and that the maturation of females was gentle, while the growth rate of male bulls matured and developed rapidly and quickly. Is this the physiological measurement value of male bulls susceptible to the outside? The influence of environmental conditions fluctuates, or the male's own development is easily affected by external environmental conditions such as water temperature, etc. In the summer high water temperature (23 degrees and 25 degrees), the waiting period for the mature of the testis of O. grandis is shortened and remains to be further observed. However, the practice of artificial reproduction of giant salamanders proved that the post-expiration male mastiff can acquire mature (living) sperm for 13 days after the effect period at a water temperature of 23 degrees and 25 degrees, and move it to a water temperature of 1618 degrees. The time to harvest mature (living) sperm can be extended to 1012 days, indicating that the male reproductive maturity is related to water temperature. Therefore, in order to ensure the success of artificial breeding of giant salamanders and to minimize the differences between males and females, the summer feeding temperature should be controlled within 23 degrees.

Third, on the artificial oxytocin and oxytocin drugs

In the natural world, male and female mature individuals, through mutual information exchange, seek pairing, can spawn and ejaculate, complete the task of breeding offspring, and in artificial breeding conditions, to make their eggs spawn, must from the exogenous hormone The role can only be completed. The production practice shows that there is a lot of room for raising the artificial cocooning rate of cockroaches. The reason for this is related to the cultivation of intimacy, the production season, the selection, formulation and dosage of oxytocin. The key is intimacy training, only the well-developed carcass, select the appropriate season, using appropriate exogenous hormones for artificial oxytocin, in order to achieve the desired oxytocin effect. According to our observations, the construction of a natural ecological function pool, the implementation of male and female breeding, feeding live food, appropriate lighting and water stimulation, supplemented with trace additives are the main technical measures of intimacy culture.

Otsuka's artificial oxytocin drugs include: HCG, Dom, squid release hormone analogues (SGNRHA), PG and so on. As for the dose problem, in our ripening test, the dose of LHRH 4ug/kg was used to promote the production of eggs in females, and some people used HCG4500iu/kg+LHRHA+PG to give birth to the females. Large doses of large damage to the parent, the small dose of the parental spawning, row of sperm is also unfavorable, the key is based on the physiological characteristics of giant salamander, to take appropriate drug compatibility. Because different drugs have different mechanisms of action, for example, HCG mainly acts on the gonads, promotes maturation and maturation of the parent's gonads, and promotes oxytocin production, while LHRHA mainly acts on the pituitary and promotes the release of luteinizing hormone from the anterior pituitary of animals. (LH) and follicle stimulating hormone (FSH) induce ovulation or ejaculation. All kinds of drugs can work together to achieve the ideal oxytocin effect. Synergistic good spawning, smooth sperm delivery, good egg quality, high fertility rate, and vice versa.

IV. Artificial Insemination of Dashes

The test results show that the fertilization rate of the giant salamander eggs is zero and the high value is 99%. Why is there such a big difference? We believe that: 1. Strengthen intimacy training and improve the quality of sperm and eggs is the basis for improving the fertility rate. If there were 39 females in production in 2003, there were only 3 true puerperae. The rest were dystocia. The quality of the eggs produced was poor. The performance was egg membrane, sparse, soft, sticky, white, and easy to use. Broken, easy to deform the yolk, and a small number of eggs. The males produce spermatozoa, produce teratogens, or produce low spermatozoa. As in the second batch, 32 cockroaches were induced and 7 pigs were harvested. One postpartum sperm of 2.7 kg individuals was microscopically examined. After activation, 70% 80% lived, but the speed was 20% 30% slower than normal spermatozoa. The rest of the individuals are dead spermatozoa, headless sperm, and deformed sperm. The fertility rate of such an egg can be imagined. Even if fertilization is also a phenomenon of false fertilization, in which the egg is activated by sperm, early cell division (two-cell, four-cell) occurs, but the sperm-egg does not achieve true fusion, and the fertilized egg or Or late death, eventually can not hatch seedlings. 2. The ratio of sperm activator formation and fertilization methods can affect the fertilization rate. According to observations, male and female comrades, good egg quality, large spermatozoon vigor, using large sperm stimulant, artificial insemination, fertilization rate as high as 99%, compared with conventional fertilization method, without sperm activator, artificial insemination, fertility rate can be About 30% increase, if the egg itself is of poor quality, its fertility rate is still larger, generally about 60%. 3, select the best male and female oxytocin production season. As we all know, any sexual organism, sperm-egg fusion has an optimal period, will affect the fertilization rate after the pre-period. As for the production season, we believe that the determination of the production season should be carried out during the breeding season (June) with comprehensive feeding levels, water temperature, peace and food intake, and a two-touch method or scientific detection method should be used to determine if the food production season is good. The body surface is smooth, the system is robust, the back abdomen is inflated, and when the hand is soft and elastic, it can be artificially elicited. 4. Operating procedures in the fertilization process, ambient temperature, semen addition time, quantity, sperm dilution ratio and other factors all have a certain influence on the fertilization rate.

V. Artificial Incubation of Fertilized Eggs

When the oocyte develops and divides into a two-cell or four-cell stage, that is, when the short and shallow division groove occurs in the center of the placenta, or when it is in a "ten-frame" structure, we identify it as a fertilized egg. When the water temperature is 210.5°C, the incubation time is 2857D, and the majority is about 35D. The oocyte has a fast water absorption rate, a large volume, and a relatively long incubation time. The appearance and fitness of the eel's pupa are robust and the growth rate is fast. The reasons for this need to be further observed. The blastocyst stage develops to the primitive intestine stage, and the neural plate stage develops to the neural tube stage. It is the peak of two deaths during the embryonic development of the giant salamander. Scientific management and effective avoidance can significantly increase the hatching rate. In the process of hatching, the embryonic body is tumbled, big audio is scared, and trace mineral elements can make the embryo body deformed or even die, especially before and after the neural tube period. We used 0.51.0 mg/L micronutrients for the hatching comparative test. As a result, the egg membrane in the experimental group was clear, and the embryo body development rate was about 10% faster, but the deformed seedlings increased. Most of the congenital malformation embryos die during the hatching process. A few of them can hatch out of seedlings and feed on them. Generally, they die after 610 months.

Sixth, on the disease control

In the natural conditions, Daxies have less disease, but due to the change of ecological conditions and the influence of human factors under the artificial conditions, the diseases increase, and the relevant scientific and technical workers and the farmer's owners should attach great importance. For the prevention and control of disease of giant salamander, we should follow the principle of disease-free treatment, early disease prevention, and prevention-based treatment. Prevention is based on comprehensive technical measures. Governance should be discovered as soon as possible, even if isolated, to clarify the cause, the right medicine.

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