阅读说明：本技术 一种利用低值母本养成优质反季节商品蟹的方法 (Method for breeding high-quality out-of-season commercial crabs by using low-value female parents ) 是由 宣富君 付龙龙 何静 鲍成满 顾成曦 王�华 王淇 常国亮 李嘉尧 管卫兵 聂纯 于 2019-09-26 设计创作，主要内容包括：本发明涉及水产养殖技术领域,具体是一种利用河蟹出苗后的低值母本反季节养成优质商品蟹的方法,其步骤包括：(1)室内温控暂养池构建；(2)所暂养螃蟹的选择、运输及消毒；(3)前期分级淡化；(4)后期生态育肥；(5)捕捞上市。本发明主要基于河蟹生殖生物学和生态养殖学,利用室内温控暂养池为出苗后河蟹体力的恢复、二次排卵及卵巢再次发育提供一个相对稳定优越的养殖环境。本发明可以大大提升出苗螃蟹的经济价值,缓解当下河蟹育苗普遍采用大规格亲本所带来的成本压力,实现反季节销售(4-7月),将对河蟹的育种与养殖等领域产生重要意义。(the invention relates to the technical field of aquaculture, in particular to a method for breeding high-quality commercial crabs out of season by using low-value female parents after the seedlings of river crabs, which comprises the following steps: (1) constructing an indoor temperature control temporary culture pond; (2) selecting, transporting and sterilizing the temporarily-raised crabs; (3) early stage grading desalination; (4) ecological fattening in later period; (5) fishing and marketing. The invention is mainly based on the river crab reproductive biology and ecological breeding science, and provides a relatively stable and superior breeding environment for the recovery of the river crab physical strength after emergence of seedlings, secondary ovulation and ovarian regrowth by utilizing the indoor temperature control temporary breeding pond. The method can greatly improve the economic value of the crab seedlings, relieve the cost pressure caused by the common adoption of large-specification parents when the river crab seedlings are raised, realize out-of-season sale (4-7 months), and have important significance in the fields of river crab breeding, cultivation and the like.)

1. a method for cultivating high-quality out-of-season river crabs by using low-value female parents is characterized by comprising the following steps:

(A) constructing an indoor temperature control temporary culture pond;

a1, selecting a room or a greenhouse which is ventilated, has good lighting and is provided with temperature-controllable equipment indoors;

a2, constructing a temporary culture pond with an independent water inlet and outlet system according to field layout, and arranging a microporous oxygen increasing pipeline at the bottom of the temporary culture pond; fine sand of about 10cm is paved on the bottom of the pool for cement, and the mud bottom needs to be disinfected by quicklime for standby after being desilted;

a3, artificial conceals which are convenient for crabs to avoid in the pool, and each river crab can have 1 artificial crab hole as much as possible;

(B) selecting, transporting and sterilizing;

b1, after the egg-carrying female crabs grow out in a breeding field, selecting individuals with strong vitality, complete footstep and no obvious scars on the body surface as far as possible;

b2, controlling the movement of the temporary crab within 2-3 hours;

b3, soaking and sterilizing the selected crabs in potassium permanganate or iodine preparation for a short time before putting the crabs into the temporary rearing pond;

(C) Carrying out grading desalination treatment;

c1, 1 to 3 days before the feeding, adding water into the temporary rearing pond, preparing the temporary rearing pond into artificial seawater with the salinity of 20 per mill, controlling the water level to be more than 50cm, controlling the dissolved oxygen to be not less than 5mg/L and maintaining the temperature to be 15 to 25 ℃;

c2, after sterilizing, directly placing the crabs into the temporary rearing pond, and controlling the density to be 5-10 crabs/m²(ii) a During the period, water is changed by 1/3-1/2 every 2-3 days;

c3, feeding enough wild fish, snail meat or clam meat which crab likes to eat;

c4, measuring pH, ammonia nitrogen and nitrite regularly, wherein the pH is kept between 7 and 8.5, the ammonia nitrogen is controlled to be below 0.6mL/g, and the nitrite is not higher than 0.01 mg/L;

c5, after temporarily culturing for 5-8 days, gradually reducing the salinity of the water body of the temporarily culturing pool after the vast majority of crabs carry eggs for the second time; in order to reduce stress, adding a proper amount of fresh water into the pond every day for dilution, and maintaining salinity fluctuation at 3-5 per mill until the salinity of the water body is reduced to 0;

(D) ecological fattening stage;

d1, performing freshwater fattening stage, and performing ecological breeding on the crabs, wherein the water level is controlled to be more than 50cm, the dissolved oxygen is kept to be more than 5mg/L, and the temperature is maintained at 15-25 ℃;

d2, fertilizing and water cultivating algae, and adjusting the dosage in time according to the water quality;

d3, adding aquatic weeds, and planting common aquatic weeds such as waterweeds or goldfish algae in the temporary culture pond directly at the mud bottom; the float grass is tied up on the sand bottom and then sinks into the pool bottom, and the pool bottom is ensured to cover the float grass by more than 50 percent;

d4, putting fresh mollusks such as snails, corbicula or mussels which are favored by crabs into the pool simultaneously except the c3 for normal feeding, and putting 3-5kg per square meter; during the period, water is changed by 1/4-1/3 every 3-5 days;

d5, measuring pH, ammonia nitrogen and nitrite regularly, wherein the pH is kept between 7 and 8.5, the ammonia nitrogen is controlled below 0.6mL/g, and the nitrite is not higher than 0.01 mg/L;

d6, completely dispersing eggs held by the crab abdomen after temporary rearing for 15-20 days;

d7, after temporarily keeping for 30-40 days, the crab ovary grows again, and the index of part of individual ovary reaches more than 5;

(E) fishing and marketing.

2. the method as claimed in claim 1, wherein the step b2 is carried out by selecting night or early morning transportation.

3. the method as claimed in claim 1, wherein the step c3 is carried out by adding 0-4mL/Kg of commercially available immune liver-protecting liquid during feeding.

4. The method as claimed in claim 1, wherein the step d2 is implemented by supplementing commercially available probiotics, calcium, magnesium and vitamins as nutritional factors.

5. the method as claimed in claim 1, wherein the step d2 of water culture is performed by using amino acid water extract and unicellular algae species at a ratio of 0.3mL/m³The super-strong spore milk and the stock solution of the lactic acid bacteria are used for supplementing water microorganisms, and the dosage is adjusted in time according to the water quality condition to supplement probiotics.

6. the method as claimed in claim 1, wherein the non-ovulated river crabs are sold as crabs with an ovary index of 6 to 10 in vivo within 1 week of temporary rearing in step E; after temporary rearing for 10-20 days, at the moment, the ovary of the river crab is not developed, and the hepatopancreas account for the main body and are sold in the form of 'June yellow'; after the crab is temporarily cultured for 30-40 days, the ovary of the crab develops again, the ovary index is more than 5, and the crab is sold as a pasty crab.

Technical Field

the invention relates to the field of aquaculture, in particular to a method for breeding high-quality commercial crabs out of season by using low-value female parents after the seedlings of river crab breeding farms emerge.

Background

river crabs, the academic name of Eriocheir sinensis (Eriocheir sinensis), have made great breakthrough in artificial breeding technology in the 80 s of the 20 th century, the breeding and cultivation scale of the river crabs is continuously enlarged, the annual yield is maintained at about 80 million tons at present, and the total yield is nearly 500 hundred million. Of these, germplasm degradation and centralized marketing are two important issues facing the development of the river crab industry. The former is caused by adopting small-sized parent seedlings in large scale in order to reduce the cost in a seedling raising field, and the latter is caused by that the marketing time of river crabs is mainly concentrated at the bottom of 10 months to 12 months.

In recent years, more and more farmers recognize the importance of large-specification parents, and accordingly river crab breeding units increase the specifications of river crab parents year by year. Taking 2018-2019 as an example, most of the seedling farms have more than 4 parents (200g) which are high in cost and are rated according to price quotations (4 parents: 85 yuan/parent, 5 parents: 300 yuan/parent, 6 parents 1000 yuan/parent; correspondingly, 6 males: 60 yuan/parent, 7 males: 260 yuan/parent, 8 males: 1000 yuan/parent). Investigation finds that around the Qingming festival of each year, most of the seedlings in the field are sold at low price of 10-20 Yuan in a short time regardless of the size of the parent after the parent grows. The reasons are the following two points: 1) the egg-carrying overwintering constitution of the batch of female crabs is often weak after 3-4 months of egg-carrying overwintering, and the female crabs are easy to die after being careless for management; 2) generally, the emerging river crabs can generate secondary spawning within a short time (generally 3 to 5 days) under the stimulation of seawater, do not have cream and have lower value.

On the other hand, at the moment, no crabs are sold on the market basically, and if the batch of crabs can be kept for 1 week temporarily, the price can be doubled (about 120g of female crabs, the salt city field can reach 60 yuan/jin in 2019). Therefore, if technical breakthrough can be realized, risks can be avoided, the batch of the emerged crabs can be temporarily cultured for 1-2 months, even 3 months or longer, so that the batch of the emerged crabs can become high-quality commercial crabs for sale again, the potential economic value is huge, the cost of breeding the crabs by adopting large-size parents in a breeding unit can be directly reduced, the offspring quality of the whole river crab breeding industry can be improved, the blank period that no crabs exist in 4-7 months can be filled, an 'out-of-season' breeding mode is formed, the balanced marketing of the river crabs is realized, and the development of the whole river crab industry is facilitated.

However, no report is available on a method for breeding high-quality out-of-season commercial crabs by using low-value female parents after the emergence of seedlings in river crab breeding farms.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a method for cultivating low-value female parents into high-quality commercial crabs based on the reproductive biology and cultivation ecology of river crabs by combining outdoor observation and indoor cultivation experiments for a long time, so that the anti-season sale of the river crabs is realized, and the cost of cultivating the seedlings by adopting large-size parents in a nursery site is effectively reduced.

in order to realize the aim, the invention provides a method for cultivating high-quality out-of-season river crabs by using low-value female parents, which comprises the following steps:

(A) constructing an indoor temperature control temporary culture pond;

a1, selecting ventilation and good lighting, and arranging an air conditioner or a room or a greenhouse with other temperature-controllable equipment in the room;

a2, constructing a temporary culture pond with an independent water inlet and outlet system according to field layout, and arranging a microporous oxygen increasing pipeline at the bottom of the temporary culture pond; fine sand of about 10cm is paved on the bottom of the pool for cement, and the mud bottom needs to be disinfected by quicklime for standby after being desilted;

a3, placing tiles, bamboo tubes, plastic tubes and other artificial shelters which are convenient for crabs to avoid in the pool, and enabling each river crab to have 1 artificial crab hole as much as possible;

(B) Selecting, transporting and sterilizing;

b1, after the egg-carrying female crabs grow out in a breeding field, selecting individuals with strong vitality, complete step and no obvious scars on the body surface as far as possible;

b2, controlling the movement of the temporary crab within 2-3 hours; the crabs can be transported at night or in the morning, so that the water loss of the body surfaces and gill cavities of the crabs is reduced as much as possible;

b3, soaking and sterilizing the selected crabs in potassium permanganate or iodine preparation for a short time before putting the crabs into the temporary rearing pond;

(C) carrying out grading desalination treatment;

c1, 1 to 3 days before the feeding, adding water into the temporary rearing pond, preparing the temporary rearing pond into artificial seawater with the salinity of 20 per mill, controlling the water level to be more than 50cm, controlling the dissolved oxygen to be not less than 5mg/L and maintaining the temperature to be 15 to 25 ℃;

c2, after sterilizing, directly placing the crabs into the temporary rearing pond, and controlling the density to be 5-10 crabs/m²(ii) a During the period, water is changed by 1/3-1/2 every 2-3 days;

c3, feeding enough wild fish, snail meat or clam meat which crab likes to eat; when the crab feed is fed, a certain amount (0-4mL/Kg) of immune liver-protecting liquid (such as Gandankang) rich in active antibacterial peptide, active yeast, vitamins and other components can be added in the market at the same time, so that intestinal tracts of the crabs are improved, and the resistance is enhanced;

c4, measuring pH, ammonia nitrogen and nitrite regularly, wherein the pH is kept between 7 and 8.5, the ammonia nitrogen is controlled to be below 0.6mL/g, and the nitrite is not higher than 0.01 mg/L;

c5, after temporarily culturing for 5-8 days, gradually reducing the salinity of the water body of the temporarily culturing pool after the vast majority of crabs carry eggs for the second time; in order to reduce stress, adding a proper amount of fresh water into the pond every day for dilution, and maintaining salinity fluctuation at 3-5 per mill until the salinity of the water body is reduced to 0;

(D) ecological fattening stage;

d1, performing freshwater fattening stage, and performing ecological breeding on the crabs, wherein the water level is controlled to be more than 50cm, the dissolved oxygen is kept to be more than 5mg/L, and the temperature is maintained at 15-25 ℃;

d2, fertilizing and water cultivating algae, and adjusting the dosage in time according to the water quality; can be supplemented with commercial probiotics, calcium, magnesium and vitamin nutrition factors;

d3, adding aquatic weeds, and planting common aquatic weeds such as waterweeds or goldfish algae in the temporary culture pond directly at the mud bottom; the float grass is tied up on the sand bottom and then sinks into the pool bottom, and the pool bottom is ensured to cover the float grass by more than 50 percent;

d4, putting fresh mollusks such as snails, corbicula or mussels which are favored by crabs into the pool simultaneously except the c3 for normal feeding, and putting 3-5kg per square meter; during the period, water is changed by 1/4-1/3 every 3-5 days;

d5, measuring pH, ammonia nitrogen and nitrite regularly, wherein the pH is kept between 7 and 8.5, the ammonia nitrogen is controlled below 0.6mL/g, and the nitrite is not higher than 0.01 mg/L;

d6, completely dispersing eggs held by the crab abdomen after temporary rearing for 15-20 days;

d7, after temporarily keeping for 30-40 days, the crab ovary grows again, and the index of part of individual ovary can reach more than 5;

(E) fishing and marketing;

the temporarily-cultured river crabs are in the blank period (5-7 months) of large-size commercial crabs, and can flexibly come into the market according to the physique and market price of the temporarily-cultured river crabs, so that the out-of-season sale is realized.

Further, the step ofd2, water culture of algae is carried out by using commercially available amino acid fertilizer water paste and unicellular algae seed according to the ratio of 0.3mL/m³commercial ultra-strong spore milk and lactic acid bacteria stock solution are used for supplementing water body microorganisms, and the dosage is adjusted in time according to the water quality condition to supplement probiotics.

furthermore, in the step E, the ovarian index of the unovulated river crabs in vivo is between 6 and 10 within 1 week of temporary culture, and the river crabs can be sold as cream crabs; after temporary culture for 10-20 days, at the moment, the ovary of the river crab is not developed (in the 2-3 stage), the hepatopancreas account for the main body and can be sold in the form of 'June yellow'; after the crab is temporarily cultured for 30-40 days, the ovary index of the crab is more than 5, and the crab can be sold as a cream crab.

the invention has at least the following 5 advantages:

1) the cost is low, and the acquisition price is only 9-10 months in the current year (4 two mothers, calculated according to the acquisition price in 2018, less than 1/10);

2) the breeding period is short, generally, adult crabs need 2 years for breeding, and the price can be doubled by using the young female crabs for temporary breeding for 1 week, so that even if half of the death rate is reached, the profit is still considerable;

3) compared with the non-egg-laying female crabs in the same period of cultivation, the crab-laying female crabs have obvious advantages, the eggs of the latter are aged, the taste is rough, and the taste of the crabs is lack, and the temporarily-cultivated crabs are shorter than the first ovary development time because of living in brackish water (with the salinity of 20 per thousand or more) for a long time before emerging, and biochemical detection shows that the difference of the nutrient components of the ovaries developed twice is not large, and the difference is not obvious;

4) The 'out-of-season' breeding mode (4-7 months) of the invention does not affect the normal production of the river crabs at all, can obviously improve the additional value of the parents, is beneficial to the large-scale use of the large-scale parents in the nursery, and ensures the quality of the seedlings;

5) The cultivation process is relatively simple and is easy to master by farmers.

the invention is mainly based on the river crab reproductive biology and ecological breeding science, and provides a relatively stable and superior breeding environment for the recovery of the river crab physical strength after emergence of seedlings, secondary ovulation and ovarian regrowth by utilizing the indoor temperature control temporary breeding pond. Through the technical practice of the inventor, the temporarily-raised crabs generally complete secondary ovulation within one week by regulating and controlling the conditions of salinity, water quality, nutrition, dissolved oxygen, temperature and the like, egg grains held by the abdomen are quickly removed through the grading desalination process, and then the low-value female parent of the nursery field can be re-cultured into high-quality commercial crabs through ecological fattening for 1-2 months. The method can greatly improve the economic value of the crab seedlings, relieve the cost pressure caused by the common adoption of large-specification parents when the river crab seedlings are raised, realize out-of-season sale (4-7 months), and have important significance in the fields of river crab breeding, cultivation and the like.

Detailed Description

the following examples are provided to illustrate specific embodiments of the present invention.