A breeding method for inhibiting gonadal development of Pengze crucian carp

Abstract

The present invention relates to the field of fish farming technology, and in particular to a method for inhibiting gonadal development in Pengze crucian carp. The method comprises the following steps: preparing a circular canvas pool, cement pool, or culture barrel with a diameter of 6-10 meters and a height of 1-1.5 meters, equipped with a microporous oxygenation device; cultivating bioflocs in the circular canvas pool, cement pool, or culture barrel to culture Pengze crucian carp; and inhibiting gonadal development in Pengze crucian carp by managing biofloc suspended solids (TSS) concentration, alkalinity, carbon-nitrogen ratio, water quality, and feeding. The present invention, developed based on biofloc technology, can inhibit gonadal development in Pengze crucian carp, addressing the problem of premature gonadal maturation in Pengze crucian carp farming without affecting growth and muscle nutrients, and increasing meat yield. The present invention provides a new aquaculture method for the Pengze crucian carp farming industry that can address premature gonadal maturation, thereby achieving the goal of improving the quality and efficiency of Pengze crucian carp farming.

Description

Technical Field

[0001] The invention relates to the technical field of fish breeding, in particular to a breeding method for inhibiting the gonadal development of Pengze crucian carp. Background Art

[0002] Pengze Crucian Carp ( Carassiu sauratus var Pengze crucian carp is a superior species bred by the Jiangxi Provincial Fisheries Science Research Institute and the Jiujiang Municipal Fisheries Science Research Institute over seven years and six generations since 1983. It is the first high-quality aquaculture variety in China directly derived from wild crucian carp. Pengze crucian carp contains 6.39%-7.25% of eight essential amino acids, accounting for 41.16%-41.92% of the total amino acid content. The total content of all four umami amino acids exceeds 33%, and the edible portion reaches 72.4%, 10% higher than that of common crucian carp. Pengze crucian carp has become a major freshwater aquaculture species in my country. Since the mid-1990s, it has been widely promoted nationwide, especially in northern regions such as Heilongjiang, Jilin, Liaoning, Hebei, and Ningxia. It has achieved significant economic and social benefits, making it one of the leading aquaculture species in China.

[0003] Pengze crucian carp grows 2.5 times faster than regular crucian carp. Generally, fry bred in the first year of breeding reach marketable size (over 250g / fish) by the second half of the following year. However, due to their self-propagation, Pengze crucian carp mature and reproduce independently in the spring of the following year. This leads to three problems in Pengze crucian carp farming. First, gonadal development occurs in the autumn and winter, which consumes a large portion of the nutrient supply, increasing the weight of internal organs such as the gonads and reducing meat yield. Second, growth slows during spring sexual maturity, and their self-propagation leads to stunted growth (poor feeding, with nutrients used for reproduction), resulting in a decrease in growth rate. Finally, after breeding, a large number of fry are produced in the water body, crowding the breeding space and competing for feed, affecting the growth of the farmed fish. Therefore, a breeding method that inhibits gonadal development without affecting growth and nutritional status has been developed to address these issues. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a breeding method for inhibiting the gonadal development of Pengze crucian carp, so as to more accurately solve the problems raised in the above background technology.

[0005] The present invention is achieved through the following technical solution: a breeding method for inhibiting the gonadal development of Pengze crucian carp, characterized in that it comprises the following steps:

[0006] Prepare a circular canvas pool, cement pool or culture barrel with a diameter of 6-10 meters and a height of 1-1.5 meters, equipped with microporous aeration equipment;

[0007] Fill the round canvas pool, cement pool or breeding barrel with water and turn on the microporous aeration equipment to continuously aerate;

[0008] One-time 1.5-2.0kg / m 3 Feed was added in the form of a carbon source at a ratio of total organic carbon to total nitrogen (C:N) of 15:1 to cultivate bioflocs. The bioflocs were cultivated until the total suspended solids (TSS) was 600 mg / L, the ammonia nitrogen in the water was <0.5 mg / L, and the nitrite was <0.05 mg / L. Alternatively, mature bioflocs were added until the TSS was 600 mg / L.

[0009] Put Pengze crucian carp seedlings into the round canvas pool, cement pool or breeding barrel, 2-5g / fish of summer flower, 350-400 fish / m 3 ; Winter slices 25-30g / tail, 55-65 tails / m 3 ;

[0010] TSS management: Measure water TSS once a week and adjust the water TSS level based on the results. Maintain the TSS concentration within the range of 600±25 mg / L. When the TSS concentration is lower than 600±25 mg / L, supplement it with bioflocs with a TSS greater than 600 mg / L. When the TSS concentration is higher than 600±25 mg / L, drain some of the bioflocs and add a corresponding amount of clean water.

[0011] Alkalinity management: Measure water alkalinity weekly and control it at 180-200 mg (CaCO3) / L. When the alkalinity of the aquaculture water is lower than 180-200 mg (CaCO3) / L, add sodium bicarbonate to control the alkalinity.

[0012] C / N ratio management: Measure the total nitrogen concentration in the water body weekly. Based on the measured total nitrogen concentration, take C / N=15 as the management target and use glucose as the carbon source to maintain the C / N ratio of the water body at 15;

[0013] Feeding management: Feed the fish with extruded feed at 2%-3% of their body weight three times a day. Adjust the feeding amount according to the fish's feeding habits. The fish should eat the feed within 1 hour after feeding. Remove any remaining feed after 1 hour.

[0014] Water quality management: Measure dissolved oxygen daily to ensure it is not less than 5 mg / L and the pH value is 7.1-8.5; measure ammonia nitrogen, nitrite nitrogen and nitrate nitrogen once a week and control them within the appropriate range, among which ammonia nitrogen <2.0 mg / L, nitrite <0.5 mg / L, and nitrate nitrogen <300 mg / L.

[0015] Furthermore, the microporous aeration equipment adopts a 1.5kw Roots blower. One Roots blower controls 3-4 canvas pools, cement pools or breeding barrels, so that the microporous aeration can stir the water body and the biological flocs do not sink but remain in a suspended state.

[0016] Furthermore, in the TSS management, the TSS concentration is maintained in the range of 600±25 mg / L. When the TSS concentration is lower than 600±25 mg / L, biofloc with TSS greater than 600 mg / L is used for supplementation. When the TSS is higher than 600±25 mg / L, part of the biofloc is discharged and a corresponding amount of clean water is added.

[0017] Furthermore, the puffed feed includes the following components: crude protein 35%-36%, crude fat 7%-8%, crude ash 9%-10%, and moisture 8%-9%.

[0018] Furthermore, the ammonia nitrogen concentration is controlled below 2.0 mg / L, the nitrite nitrogen concentration is controlled below 0.5 mg / L, and the nitrate nitrogen concentration is controlled below 300 mg / L.

[0019] Beneficial effects of the present invention:

[0020] (1) A new breeding method has been developed in Pengze. Biofloc breeding not only saves water resources, but also increases breeding density and yield.

[0021] (2) Biofloc technology was used to cultivate Pengze crucian carp. By controlling the TSS concentration of the aquaculture water, managing the water quality, and adjusting the alkalinity, the gonadal development of Pengze crucian carp was suppressed. This solved the problem of premature puberty in Pengze crucian carp cultivation, with a gonadal maturity coefficient of 1.92%. The meat content of Pengze crucian carp was significantly increased (the body weight ratio was reduced by 16.18%) without affecting the growth rate.

[0022] (3) The nutritional composition of the muscle of cultured Pengze crucian carp is stable, and there is no significant difference in the nutritional composition of the muscle of Pengze crucian carp compared with that of the muscle of cultured Pengze crucian carp using other methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic flow chart of a breeding method for inhibiting gonadal development of Pengze crucian carp proposed in the present invention;

[0024] Figure 2 This is an anatomical diagram of Pengze crucian carp cultured in a TSS 600 mg / L concentration group in a culture method for inhibiting gonadal development of Pengze crucian carp proposed in the present invention;

[0025] Figure 3 This is an anatomical diagram of a control group of Pengze crucian carp cultured in a culture method for inhibiting gonadal development of Pengze crucian carp proposed in the present invention;

[0026] Figure 4 Partial gonadal images of the blank group (top) and TSS 600 mg / L concentration group (bottom) cultured Pengze crucian carp in a culture method for inhibiting gonadal development of Pengze crucian carp proposed in the present invention. Implementation Method

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] Reference Figure 1 The present invention provides a method for inhibiting the gonadal development of Pengze crucian carp, which comprises the following steps:

[0029] S1: Prepare a circular canvas pool, cement pool, or culture barrel with a diameter of 6-10 meters and a height of 1-1.5 meters, equipped with a microporous aeration device. The microporous aeration device uses a 1.5kW Roots blower. One Roots blower controls 3-4 culture barrels or canvas pools. The microporous aeration device maintains agitation of the water, preventing the bioflocs from sinking and keeping them suspended.

[0030] S2: Fill the round canvas pool, cement pool or breeding barrel with water, start the Roots blower to continuously inflate, and add feed (1.5-2.0kg / m 3 ) Cultivate bioflocs by adding carbon sources at a C:N ratio of 15:1 until the TSS reaches 600 mg / L, ammonia nitrogen <0.5 mg / L, and nitrite <0.05 mg / L. Alternatively, add mature bioflocs until the TSS reaches 600 mg / L.

[0031] S3: Release Pengze crucian carp seedlings into the round canvas pond, cement pond or breeding barrel, with 2-5g of summer flower per tail and 350-400 fish / m 3 ; Winter slices 25-30g / tail, 55-65 tails / m 3 ;

[0032] S4; TSS management: Measure water TSS once a week and adjust the water TSS level based on the results. Maintain the TSS concentration within the range of 600±25 mg / L. When the TSS concentration is lower than 600±25 mg / L, supplement it with bioflocs with a TSS greater than 600 mg / L. When the TSS concentration is higher than 600±25 mg / L, drain some of the bioflocs and supplement with a corresponding amount of clean water.

[0033] S5; Alkalinity management: Measure the alkalinity of the aquaculture water weekly and control it at 180-200 mg (CaCO3) / L. When the alkalinity of the aquaculture water is lower than 180-200 mg (CaCO3) / L, add sodium bicarbonate to control the alkalinity.

[0034] S6; C / N ratio management: Measure the total nitrogen concentration in the aquaculture water every week. Based on the measured total nitrogen concentration, set a C / N ratio of 15 as the management target and use glucose as the carbon source to maintain the water C / N ratio at 15;

[0035] S7: Feeding management: Feed the fish an extruded feed at 2%-3% of their body weight daily. The nutritional composition of the extruded feed includes: 35%-36% crude protein, 7%-8% crude fat, 9%-10% crude ash, 8%-9% moisture, and the remainder is crude fiber and carbohydrates. Feed three times a day, adjusting the feeding amount based on the fish's feeding habits. Ensure that the fish consume the feed within 1 hour of feeding. Remove any remaining feed after 1 hour.

[0036] S8; Water quality management: Measure dissolved oxygen daily to ensure it is not less than 5 mg / L and the pH value is 7.1-8.5; measure ammonia nitrogen, nitrite nitrogen and nitrate nitrogen once a week, and control the ammonia nitrogen concentration below 2.0 mg / L, the nitrite nitrogen concentration below 0.5 mg / L, and the nitrate nitrogen below 300 mg / L.

[0037] (1) At the end of the cultivation, after 4-5 months of cultivation, the survival rate of summer flowers can reach more than 90%, and the yield is 8-9kg / m 3 The size can reach 20-30g / tail; after 4-5 months of cultivation, the survival rate of winter slices reaches about 95%, and the yield is 15-18kg / m 3 The specifications are about 300-400g / tail.

[0038] (2) The gonads of Pengze crucian carp in winter are basically underdeveloped, with a maturity coefficient of about 1.5%. The gonads of adults raised in winter with gonads developed to stage III or above account for less than 30% of the total individuals, and the gonads of the remaining individuals have not developed to stage III. The overall gonad maturity coefficient is less than 2%, and the organ-to-body ratio (total weight of internal organs / body weight) is 8%-9.5%.

[0039] (3) The crude protein content of adult fish muscle is 20.18%, crude fat is 2.71%, crude ash is 2.01%, and water content is 74.77%.

[0040] (1) Experimental design

[0041] Four biofloc groups (TSS of 200 mg / L, 400 mg / L, 600 mg / L, and 800 mg / L) were selected for the experiment. The control group was a recirculating aquaculture system with three replicates in each group and a stocking density of 63 fish / m3 The stocking specifications were all 25-30g / tail; each group was fed with extruded feed at 2% of the fish body weight three times a day. The environmental monitoring conditions during the experiment were: water temperature (26.5±1.5) ℃, dissolved oxygen not less than 5 mg / L, pH value 7.26±0.1, and the experimental breeding lasted for 60 days.

[0042] (2) Experimental results

[0043] 1. Changes in water quality

[0044] The changing trends of water quality indicators among different concentration groups were basically consistent. The ammonia nitrogen in the floc culture group showed a trend of first increasing and then decreasing, and finally the ammonia nitrogen concentration stabilized in the range of 0.02 mg / L-0.4 mg / L. During the same period, the TSS concentration of 200 mg / L group>400 mg / L group>600 mg / L group>800 mg / L group. The highest ammonia nitrogen value of each group occurred on the 20th day, and the ammonia nitrogen in the 200 mg / L group reached a maximum of 0.38 mg / L. The nitrite nitrogen concentration fluctuated in the range of 0.03-0.35 mg / L, which was within a reasonable range. The changing trend of the floc culture group was consistent. The nitrate nitrogen concentration gradually accumulated over time, and the changing trend of each group was consistent. The final nitrate nitrogen concentrations of the TSS concentration groups of 200 mg / L, 400 mg / L, 600 mg / L, and 800 mg / L were (114.89±2.06), respectively. The final concentrations of phosphate were (28.31±1.98) mg / L, (29.87±2.32) mg / L, (30.72±3.54) mg / L and (33.24±5.78) mg / L, respectively. In the control group, due to frequent water changes, the ammonia nitrogen and nitrite nitrogen in the water were maintained at around 0 mg / L, the nitrate nitrogen was below 1.5 mg / L, and the phosphate concentration was below 0.5 mg / L.

[0045] 2. Nutritional composition of farmed fish

[0046] From the results in Table 1, there was no significant difference in the nutrient composition of Pengze crucian carp muscle between the TSS floc culture group and the control group, except that the crude fat was slightly higher.

[0047] Table 1 Nutrient composition of Pengze crucian carp muscle under different TSS concentrations

[0048] Note: Different letters indicate significant differences

[0049] 3. Growth parameters and gonadal development of farmed fish

[0050] Table 2 shows the growth of Pengze crucian carp in the 200 mg / L, 400 mg / L, and 600 mg / L TSS concentration groups. There were no significant differences in weight and length compared to the control group. However, the weight gain rate of the control group and the 600 mg / L TSS group was significantly higher than that of the other experimental groups. The weight gain rate and final weight of the 800 mg / L TSS group were significantly lower than those of the other experimental groups and the control group. Gonadal weight and visceral-to-body ratio were lowest in the 600 mg / L and 800 mg / L TSS groups, and highest in the control group. The maturation coefficient was lowest in the 600 mg / L and 800 mg / L TSS groups, followed by the 400 mg / L TSS group, and highest in the control group.

[0051] Table 2 Growth performance of Pengze crucian carp under different TSS concentrations

[0052] Of course, the present invention may have many other implementations. Based on this implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present invention.

Claims

1. A breeding method for inhibiting the gonadal development of Pengze crucian carp, characterized in that: The following steps are involved: Prepare a circular canvas pool, cement pool or culture barrel with a diameter of 6-10 meters and a height of 1-1.5 meters, equipped with microporous aeration equipment; Fill the round canvas pool, cement pool or breeding barrel with water and turn on the microporous aeration equipment to continuously aerate; One-time 1.5-2.0kg / m 3 Feed was added in the form of a carbon source at a ratio of total organic carbon to total nitrogen (C:N) of 15:1 to cultivate bioflocs. The bioflocs were cultivated until the total suspended solids were 600 mg / L, the ammonia nitrogen concentration in the water was <0.5 mg / L, and the nitrite concentration was <0.05 mg / L, or mature bioflocs were added until the TSS was 600 mg / L. Put Pengze crucian carp seedlings into the round canvas pool, cement pool or breeding barrel, 2-5g / fish of summer flower, 350-400 fish / m 3 ; Winter slices 25-30g / tail, 55-65 tails / m 3 ; TSS management: Measure TSS in water bodies once a week and adjust the TSS level according to the results. The TSS concentration should be maintained within the range of 600±25 mg / L. When the TSS concentration is lower than 600 mg / L, use biofloc with TSS greater than 600 mg / L to supplement. When the TSS concentration is higher than 600 mg / L, remove some biofloc and add the corresponding amount of clean water. Alkalinity management: Measure water alkalinity weekly and control it at 180-200 mg CaCO3 / L. When the alkalinity of the aquaculture water is lower than 180 mg CaCO3 / L, add sodium bicarbonate to control the alkalinity. C / N ratio management: Measure the total nitrogen concentration in the water body weekly. Based on the total nitrogen concentration, take C / N=15 as the management target and use glucose as the carbon source to maintain the C / N ratio of the water body at 15; Feeding management: Feed the fish with extruded feed at 2%-3% of their body weight three times a day. Adjust the feeding amount according to the fish's feeding habits. The fish should eat the feed within 1 hour after feeding. Remove any remaining feed after 1 hour. Water quality management: Measure dissolved oxygen in water every day to ensure that it is not less than 5 mg / L and the pH value is 7.1-8.5; measure ammonia nitrogen concentration, nitrite and nitrate nitrogen once a week and control them within the appropriate range, among which ammonia nitrogen concentration is <2.0 mg / L, nitrite <0.5 mg / L, and nitrate nitrogen <300 mg / L.

2. A method for inhibiting gonadal development of Pengze crucian carp according to claim 1, characterized in that: The microporous aeration equipment adopts a 1.5kw Roots blower. One Roots blower controls 3-4 circular canvas pools, cement pools or breeding barrels, so that the microporous aeration can stir the water body and the biological flocs do not sink but are always in a suspended state.

3. A breeding method for inhibiting gonadal development of Pengze crucian carp according to claim 1, characterized in that, The puffed feed comprises the following components: 35%-36% crude protein, 7%-8% crude fat, 9%-10% crude ash, and 8%-9% moisture.

4. A breeding method for inhibiting gonadal development of Pengze crucian carp according to claim 1, characterized in that: The ammonia nitrogen concentration is controlled below 2.0 mg / L, the nitrite concentration is controlled below 0.5 mg / L, and the nitrate nitrogen concentration is controlled below 300 mg / L.

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