Method for zero water replacement in large-size fry culture of takifugu obscurus

Abstract

The application discloses a zero water changing method in large-size fry cultivation of Takifugu obscurus, and the Takifugu obscurus larvae have large feeding and excretion amounts and are sensitive to water quality. The operation steps are as follows: in the process of fry cultivation, vitamin C is added to enhance the resistance of Takifugu obscurus, apple snails are added to clean up excrement and create a good water environment, and the feeding mode of Takifugu obscurus fry is refined. In the above process, the survival rate of Takifugu obscurus fry in the transfer tank can be increased by 18% to 23%, the feeding residual of the Takifugu obscurus fry cultivation tank with apple snails can be effectively removed, the survival rate of Takifugu obscurus fry is improved, and the zero water changing in the process of large-size fry cultivation is realized. The application provides effective technical support for the large-scale production of Takifugu obscurus fry.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aquaculture, and particularly relates to a zero-water-changing method in large-size seed cultivation of Takifugu obscurus. BACKGROUND

[0002] Takifugu obscurus has been a traditional and precious edible fish since ancient times, and ranks among the three fresh fishes in the Yangtze River. The fish has delicious meat and smooth taste, and has conquered a large number of Chinese and foreign diners. In today's rapid economic development, the demand for Takifugu obscurus, a high-grade food material, is increasing, and the prospect of Takifugu obscurus and its processed products is very broad.

[0003] Currently, the survival rate is low in the process of large-size seed cultivation of Takifugu obscurus. The individual of Takifugu obscurus is much smaller than other fish fries, and has a huge appetite and a large amount of excretion, which is easy to destroy the water body for seed cultivation.

[0004] Vitamin C, also known as ascorbic acid, plays an important role in the nutrition physiology and immune system of fish. Vitamin C can participate in the synthesis of collagen, which is an important component of fish muscle and bone. At the same time, vitamin C is an effective antioxidant that can eliminate active oxygen and free radicals, protecting fish cells and tissues from oxidative damage. In addition, vitamin C is an effective immune enhancer that can stimulate fish immune cells and improve their ability to resist pathogens and stress.

[0005] Apple snail, the formal name of which is Planorbarius corneus var in Chinese, is originally from Europe to Central Asia, and has been artificially selected into a common freshwater aquarium snail. Apple snail has strong adaptability to temperature and can survive in the temperature range of 18-28℃. Apple snail is omnivorous and usually feeds on algae, feed debris and fish feces by sticking to the bottom of the tank. Apple snail is hermaphroditic and has strong reproductive capacity, and can reproduce throughout the year under suitable temperature and water quality conditions. At the same time, apple snail has thin shell and no closed lid, so apple snail can also be used as a natural biological bait for puffer fish in the aquarium market.

[0006] At present, the most common method to improve the water quality for Takifugu obscurus fry cultivation is to maintain the water quality by water changing. However, in the process of water changing, the fry is easy to be sucked away, and the change of water quality causes the stress death of Takifugu obscurus fry, which reduces the survival rate in the process of large-size seed cultivation of Takifugu obscurus. Therefore, a zero-water-changing method that can significantly improve the survival rate is urgently needed in the process of Takifugu obscurus seed cultivation to improve the breeding efficiency of Takifugu obscurus. SUMMARY

[0007] Invention purposes: based on the problems in the background art, the purpose of the present application is to provide a zero water changing method in the cultivation process of large-scale dark striped puffer fry, which can effectively reduce the mortality rate in the cultivation process of large-scale dark striped puffer fry and improve the survival rate of fry.

[0008] Technical scheme: the zero water changing method in the cultivation process of large-scale dark striped puffer fry of the present application comprises the following steps:

[0009] Step 1, water quality control of culture pond: oxygenate the culture pond by oxygen stone, and add methylene blue and vitamin C according to the size of the culture pond water body;

[0010] Step 2, apple snail feeding: after the dark striped puffer hatches for 4-6 days, it is transferred to the culture pond, and the apple snail is put into the culture pond within 12-36 hours;

[0011] Step 3, fry feeding: after the dark striped puffer fry is transferred into the culture pond for 1 day, feed it with brachionus calyciflorus; after 8-11 days, feed it with live artemia nauplii; after 12-18 days, feed it with live artemia nauplii and frozen artemia nauplii; after the fry is 1.5-2.5 cm long, feed it with frozen artemia nauplii and eel powder; when the fry is more than 2.5 cm long, feed it with pure eel powder;

[0012] Step 4, transfer out the culture pond: after the dark striped puffer fry is more than 3 cm long and completely feeds on eel powder, transfer it out of the culture pond, and end the dark striped puffer fry cultivation stage.

[0013] Further, in step 1, the oxygenation of the culture pond by oxygen stone is specifically: sink the oxygen stone into the bottom of the water body, keep it on all day, and control the oxygen output of the oxygen stone, with dissolved oxygen maintained at 6-9 mg / L. This step can prevent the dark striped puffer fry from suffering from bubble disease.

[0014] Further, in step 1, the methylene blue is a powder, and the water solution concentration is maintained at 1-3 mg / L, and the concentration of vitamin C is 400-600 mg / L. This step can improve the resistance of dark striped puffer fry.

[0015] Further, in step 2, the dark striped puffer is transferred to the culture pond after hatching for 4-6 days, and the water is warmed up when transferring, and the temperature difference between the incubator and the culture pond should be controlled within ±1℃.

[0016] The water warming specifically includes the following steps:

[0017] a. use a thermometer to measure the water temperature of the incubator and the culture pond respectively;

[0018] b. prepare a container that can hold all the fry and a certain amount of water;

[0019] c. Add the incubation pond water into the over-temperature water container, and then gently put the fish into the container;

[0020] d. Slowly stir the water in the container when the water temperature in the container is close to the water temperature in the incubation pond;

[0021] e. Slowly pour the fry along with the container water into the incubation pond when the water temperature in the container is close to the water temperature in the incubation pond.

[0022] Further, in step 2, the releasing density of the apple snails is 30-60 / m 2 Before being put into the culture pond, the apple snails need to be soaked in a 1‰ potassium permanganate solution for 10-20 min for disinfection.

[0023] Further, in step 3, when the Brachionus plicatilis is fed, 10 6 -10 7 ml / ml of Chlorella sp. algal solution is added.

[0024] Further, in step 3, the live Artemia nauplii are just hatched and broken membrane, and are sieved through an 80-mesh sieve, and the density of the Artemia nauplii is kept at 600-800 / L.

[0025] Further, in step 3, the pure eel fish meal has a crude protein content of 45%, and the specific feeding is that the meal and water are kneaded into a dough at a ratio of 1:1 and then put into the culture pond. In the later stage of this step, the darkbarred puffer fish fry has started to independently prey on the apple snail larvae, which further improves the survival rate of the darkbarred puffer fish fry.

[0026] Further, in step 4, the temperature difference between the water in the culture pond and the water transferred out of the culture pond is controlled to be ±2℃.

[0027] Beneficial effects: Compared with the prior art, the present application has the following remarkable advantages:

[0028] (1) Compared with the traditional processing method for large-scale darkbarred puffer fish fry cultivation, the present application controls the whole process from the transfer of the fry into the culture pond to the transfer of the fry out of the culture pond. The darkbarred puffer fish does not suffer from bubble disease in the fry cultivation stage by using the present application to control the water quality. After the transfer of the fry out of the culture pond, the survival rate of the darkbarred puffer fish fry can be improved by 18%. In the later stage of the fry feeding, the darkbarred puffer fish fry has started to independently prey on the apple snail larvae, which further improves the survival rate of the darkbarred puffer fish fry. The survival rate of the fry comprehensively using the present application is 21.2% higher than that of the fry not using the present application;

[0029] (2) The application greatly reduces the mortality rate of large-size P. argus fry during the cultivation process, and the large-size fry cultivation period is zero water change, and the labor cost and material cost are low, the method greatly reduces the death of P. argus fry caused by water quality change, and can effectively improve the survival rate of P. argus fry breeding, so the application has strong practical popularization significance.

[0030] (3) The P. argus cultivated by the method has smooth surface without injury, stable and powerful swimming, active food grabbing after feeding, rapid response to stimulation, and normal shape and color of excrement, which can meet the further operation of breeding, breeding or scientific experiment. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a co-cultivation schematic diagram of P. argus fry and apple snails;

[0032] Figure 2 It is a water temperature change graph of P. argus fry culture ponds in Example 1 and Example 2;

[0033] Figure 3 It is a dissolved oxygen change graph of P. argus fry culture ponds in Example 1 and Example 2;

[0034] Figure 4 It is a pH change graph of P. argus fry culture ponds in Example 1 and Example 2;

[0035] Figure 5 It is an ammonia nitrogen change graph of P. argus fry culture ponds in Example 1 and Example 2. DETAILED DESCRIPTION

[0036] The technical solutions of the application will be further described below with reference to the drawings.

[0037] Example 1:

[0038] (1) Fish fry culture pond water quality control: use tap water, water depth 40 cm, water temperature maintained at 23℃, dissolved oxygen maintained at 7mg / L, air stone density 1 / m 2 , and reduce the air output of air stone.

[0039] (2) Methylene blue is put in, and the concentration is maintained at 2.5mg / L.

[0040] (3) Vitamin C is put in: vitamin C is put into water at 500mg / L, and the P. argus fry is aerated for 40h before transferring to the culture pond.

[0041] (4) Fry transfer: P. argus is transferred to the culture pond within 4d after hatching, and the water temperature difference between the incubator and the culture pond is controlled within 1℃.

[0042] (5) Put apple snails: 24 hours after the transfer of the fish fry to the culture tank, put 50 apple snails with a shell diameter of 1.5 cm per square meter into the culture tank. 2

[0043] (6) Fish fry opening: 1 day after the fish fry is transferred to the culture tank, feed the fish fry with Brachionus plicatilis, and maintain the density of the rotifers at 30 per milliliter. The feeding is performed for 8 days.

[0044] (7) Fish fry feeding: after the fish fry is opened, the feeding is performed in the following manner:

[0045] After the fish fry is transferred to the culture tank for 8 days, feed the fish fry with live Artemia nauplii, and feed the fish fry twice a day at 9:00 and 17:00.

[0046] After the fish fry is transferred to the culture tank for 15 days, feed the fish fry with live Artemia nauplii and frozen Artemia nauplii, and feed the fish fry twice a day at 9:00 and 17:00.

[0047] After the fish fry is 2 cm long, feed the fish fry with frozen Artemia nauplii and eel meal with a crude protein content of 45%, and the material and water are mixed at a ratio of 1:1 to form a dough, which is then put into the culture tank. The feeding is performed twice a day at 9:00 and 17:00, and the feeding amount is consumed within 30 minutes. The feeding is continuously performed for 10 days.

[0048] When the fish fry is longer than 2.5 cm, feed the fish fry with eel meal with a crude protein content of 45%, and the material and water are mixed at a ratio of 1:1 to form a dough, which is then put into the culture tank. The feeding is performed twice a day at 9:00 and 17:00, and the feeding amount is consumed within 30 minutes.

[0049] (8) Transfer out of the culture tank: when the fish fry is longer than 3 cm and completely feeds on eel meal, transfer the fish fry out of the culture tank, and end the fish fry culture stage.

[0050] The total number of the fish fry before the water transfer is 550, and the number of the surviving fish fry after the transfer is 520. No fish fry has bubble disease during the feeding process. After 40 days, a total of 312 surviving fish fry are collected.

[0051] Example 2:

[0052] Example 2 is basically the same as Example 1, except that:

[0053] Example 1 (1) reduces the air output of the air stone; and Example 2 does not use this step.

[0054] Example 1 (2) puts methylene blue; and Example 2 does not use this step.

[0055] Example 1 (3) puts vitamin C; and Example 2 does not use this step. ​

[0056] Example 1 (5) put apple screw; Example 2 does not use this step.

[0057] Example 2 every day bottom sewage change water 1 / 4, Example 1 does not use this step.

[0058] The batch of puffer fish fry before water is 550, after the conversion pool, 419 survive, 27 fry get bubble disease in the process of feeding, 195 survive after 40d.

[0059] Table 1 Example 1 and Example 2 puffer fish fry breeding process comparison

[0060]

[0061] As shown in Table 1, the survival rate of puffer fish fry in Example 1 is 18.4% higher than that in Example 2; the puffer fish fry in Example 1 has no bubble disease, and the mortality rate of bubble disease of the puffer fish fry in Example 2 is 4.9%; the survival rate of puffer fish fry in Example 1 is 21.2% higher than that in Example 2 after 40d.

[0062] Example 3:

[0063] Example 3 is basically the same as Example 1, the difference is:

[0064] Example 1 (1) the dissolved oxygen is kept at 7mg / L; Example 3 uses dissolved oxygen interval gradient treatment, the dissolved oxygen interval is 3mg-6mg / L, 6mg-9mg / L, 9mg-12mg / L, 12mg-15mg / L.

[0065] The batch of puffer fish fry before water is 400, 100 for each concentration, a total of 4 dissolved oxygen intervals. The 40d survival rate of puffer fish fry in different dissolved oxygen intervals is shown in Table 2.

[0066] Table 2 40d survival rate of puffer fish fry under different dissolved oxygen

[0067] Dissolved oxygen range Total number (tail) Survival number after 40d (tail) Survival rate after 40d 3mg~6mg / L 100 33 33％ 6mg~9mg / L 100 58 58％ 9mg~12mg / L 100 24 24％ 12mg~15mg / L 100 12 12％

[0068] Example 4:

[0069] Example 4 is basically the same as Example 1, the difference is:

[0070] Example 1 (2) put methylene blue concentration of 2.5mg / L; Example 4 uses different concentrations of methylene blue gradient treatment, respectively 0mg / L, 1mg / L, 3mg / L, 5mg / L, 7mg / L.

[0071] The batch of dark striped puffer fry before water is 500 in total, 100 for each concentration, and 5 concentrations are set. The 40d survival rate of dark striped puffer fry under different methylene blue concentrations is shown in Table 3.

[0072] Table 3 40d survival rate of dark striped puffer fry under different methylene blue concentrations

[0073] Methylene blue concentration Total number (tail) Survival number after 40d (tail) Survival rate after 40d 0mg / L 100 30 30％ 1mg / L 100 46 46％ 3mg / L 100 51 51％ 5mg / L 100 34 34％ 7mg / L 100 25 25％

[0074] Example 5:

[0075] Example 5 is basically the same as Example 1, except that:

[0076] The concentration of vitamin C in Example 1 (3) is 500mg / L; Example 5 uses different concentrations of vitamin C gradient treatment, which are 0mg / L, 200mg / L, 400mg / L, 600mg / L, and 800mg / L, respectively.

[0077] The batch of dark striped puffer fry before water is 500 in total, 100 for each concentration, and 5 concentrations are set. The 40d survival rate of dark striped puffer fry under different methylene blue concentrations is shown in Table 3.

[0078] Table 4 40d survival rate of dark striped puffer fry under different vitamin C concentrations

[0079] Vitamin C concentration Total number (tail) Survival number after 40d (tail) Survival rate after 40d 0mg / L 100 32 32％ 200mg / L 100 41 41％ 400mg / L 100 53 53％ 600mg / L 100 56 56％ 800mg / L 100 37 37％

[0080] Example 6:

[0081] Example 6 is basically the same as Example 1, except that:

[0082] The density of apple snails in Example 1 (5) is 50 / m 2 ; Example 6 uses different density apple snail gradient treatment, which are 0 / m 2 , 30 / m 2 , 60 / m 2 , 90 / m 2 , and 120 / m 2 .

[0083] The batch of dark striped puffer fry before water is 500 in total, 100 for each concentration, and 5 concentrations are set. The 40d survival rate of dark striped puffer fry under different methylene blue concentrations is shown in Table 3.

[0084] Table 5 40d survival rate of dark striped puffer fry under different apple snail densities

[0085] Apple snail density (ind / m 2 )]]> Total number (tail) Survival number after 40d (tail) Survival rate after 40d 0 100 30 30％ 30 100 48 48％ 60 100 59 59％ 90 100 37 37％ 120 100 21 21％

[0086] As shown in Tables 2-5, the optimal dissolved oxygen interval of the dark striped puffer fry culture pond of Example 3 is 6-9 mg / L; the optimal methylene blue concentration interval of the dark striped puffer fry culture pond of Example 4 is 1-3 mg / L; the optimal vitamin C concentration interval of the dark striped puffer fry culture pond of Example 5 is 400-600 mg / L; and the optimal apple snail stocking density interval of the dark striped puffer fry culture pond of Example 6 is 30-60 snails / m 2 .

[0087] As shown in Tables 2-5, the optimal dissolved oxygen interval of the dark striped puffer fry culture pond of Example 3 is 6-9 mg / L; the optimal methylene blue concentration interval of the dark striped puffer fry culture pond of Example 4 is 1-3 mg / L; the optimal vitamin C concentration interval of the dark striped puffer fry culture pond of Example 5 is 400-600 mg / L; and the optimal apple snail stocking density interval of the dark striped puffer fry culture pond of Example 6 is 30-60 snails / m Figures 2-5 As shown in Tables 2-5, the optimal dissolved oxygen interval of the dark striped puffer fry culture pond of Example 3 is 6-9 mg / L; the optimal methylene blue concentration interval of the dark striped puffer fry culture pond of Example 4 is 1-3 mg / L; the optimal vitamin C concentration interval of the dark striped puffer fry culture pond of Example 5 is 400-600 mg / L; and the optimal apple snail stocking density interval of the dark striped puffer fry culture pond of Example 6 is 30-60 snails / m

[0088] The above has specifically described the preferred embodiments of the present application, and any equivalent changes and modifications made within the scope of the present application shall be included in the scope of the present application.

Claims

1. A method for zero water change during the cultivation of large-sized pufferfish fry, characterized in that, Includes the following steps: Step 1, Water quality control in the culture tank: Aeration is achieved in the culture tank using oxygen stones, and methylene blue and vitamin C are added according to the size of the culture tank. Step 2, introduce apple snails: After the dark-spotted pufferfish hatch and the membrane emerges, they are transferred to the culture tank. Apple snails are then introduced into the culture tank within 12 to 36 hours. In step 2, the dark-spotted pufferfish are transferred to the culture tank 4-6 days after hatching. During the transfer, the water temperature in the incubation equipment and the temperature difference in the culture tank should be controlled within ±1℃. The temperature and water passing process specifically includes the following steps: a. Use a thermometer to measure the water temperature in the hatching tank and the rearing tank respectively; b. Prepare a container large enough to hold all the fish fry and a certain amount of water; c. Add the water from the rearing pond to the acclimation container, and then gently place the fish into the container; d. When the water temperature in the container is close to the water temperature in the cultivation tank, slowly stir the water in the container; e. When the water temperature in the container is close to the water temperature in the rearing pond, slowly pour the fish fry along with the water in the container into the rearing pond; In step 2, the stocking density of the apple snails is 30-60 snails / m². 2 Apple snails need to be disinfected by soaking in a 1‰ potassium permanganate solution for 10-20 minutes before being placed in the culture tank. Step 3: Feeding the fry: One day after transferring the fry to the culture tank, feed them with Brachycercus calycifolium; 8-11 days after transferring to the culture tank, feed them with live Artemia larvae; 12-18 days after transferring to the culture tank, feed them with a mixture of live and frozen Artemia; when the fry reach a total length of 1.5-2.5cm, feed them with a mixture of frozen Artemia and eel meal; when the fry reach a total length of over 2.5cm, feed them with pure eel meal. Step 4: Transfer out of the rearing pond: After the pufferfish fry reach a length of 3cm or more and have completely consumed eel meal, transfer them out of the rearing pond to end the pufferfish fry rearing stage.

2. The method for zero water change during the cultivation of large-sized pufferfish seedlings according to claim 1, characterized in that, In step 1, the oxygenation of the culture tank by oxygen stones specifically involves: submerging the oxygen stones at the bottom of the water body and keeping them on all day, while controlling the gas output of the oxygen stones to maintain dissolved oxygen at 6~9 mg / L.

3. The method for zero water change during the cultivation of large-sized pufferfish seedlings according to claim 1, characterized in that, In step 1, the methylene blue is in powder form, and the aqueous solution concentration is maintained at 1~3 mg / L. The concentration range of vitamin C is 400~600 mg / L.

4. The method for zero water change during the cultivation of large-sized pufferfish seedlings according to claim 1, characterized in that, In step 3, the amount of Brachiosa calyx rotifer added when feeding is 10 6 ~10 7 Chlorella vulgaris solution per ml.

5. The method for zero water change during the cultivation of large-sized pufferfish seedlings according to claim 1, characterized in that, In step 3, live brine shrimp larvae are fed, which are newly hatched larvae that have broken through the membrane. They are sieved through an 80-mesh sieve, and the brine shrimp density is maintained at 600-800 per L.

6. The method for zero water change during the cultivation of large-sized pufferfish seedlings according to claim 1, characterized in that, In step 3, the crude protein content of the pure eel powder feed is 45%, and the feed-to-water ratio is 1:

1. The feed is kneaded into a dough-like consistency and then placed into the rearing tank.

7. The method for zero water change during the cultivation of large-sized pufferfish seedlings according to claim 1, characterized in that, In step 4, the temperature difference between the water transferred out of the culture tank and the water inside the culture tank should be controlled within ±2℃.

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