Feed for promoting ecdysis growth of procambarus clarkii and preparation method thereof

Abstract

The invention relates to the technical field of aquaculture, in particular to feed for promoting ecdysis and growth of procambarus clarkii and a preparation method of the feed. The feed comprises the following components: fish meal, soybean meal, corn flour, bran, rice bran, fish oil, algae powder, monocalcium phosphate, mountain flour, a vitamin premix, a mineral premix, cholesterol, a phagostimulant, an antioxidant, a preservative, sodium chloride, choline chloride and bentonite. According to the present invention, by adjusting the cholesterol content and the addition amounts of the fish meal, the fish oil and the algae powder, the ratio of the unsaturated fatty acids DHA (docosahexaenoic acid) / EPA (eicosapentaenoic acid) in the feed is optimized, the hormone level in the shrimp body is adjusted, and the ecdysis-related physiological process is promoted, such that the ecdysis frequency and the ecdysis synchronism are improved, the growth speed of the shrimp body is accelerated, and the culture period is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of aquaculture, and particularly to a feed for promoting molting and growth of Procambarus clarkii and a preparation method thereof. Background Art

[0002] Procambarus clarkii, commonly known as crayfish, is an important aquaculture variety. Due to its high economic value and wide market demand, it is widely cultured globally. During the cultivation of Procambarus clarkii, molting is a crucial link in its growth and development. Molting not only affects the growth rate of the shrimp body but also directly relates to the survival rate and final yield of the shrimp.

[0003] Currently, common crayfish feeds on the market are mainly based on the ratio of basic nutrients such as protein, fat, and carbohydrates, supplemented with micronutrients such as vitamins and minerals. Some feeds also add growth promoters, immune enhancers, etc. to improve the growth rate and disease resistance of shrimp. To promote molting, some manufacturers have tried to add exogenous hormones or chemicals to the feed, but these methods have certain risks, such as hormone residues, environmental pollution, and potential harm to the health of the shrimp body. In addition, the existing feeds often focus on the supply of protein and energy in the ratio of nutrient components, while ignoring the proportion of molting-related nutrients such as cholesterol, unsaturated fatty acids (DHA and EPA), resulting in problems such as low molting frequency and asynchronous molting in the shrimp body, which prolongs the cultivation cycle and increases the cultivation cost.

[0004] In summary, there are many deficiencies in the existing technology in promoting molting and growth of Procambarus clarkii. There is an urgent need for a new type of feed that can effectively improve the molting frequency and synchrony, increase the growth rate of the healthy shrimp body, and shorten the cultivation cycle on the premise of ensuring food safety and environmental friendliness. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: how to improve the molting frequency and synchrony of Procambarus clarkii and shorten the cultivation cycle on the premise of ensuring food safety and environmental friendliness.

[0006] In this application, by adjusting the cholesterol content and the addition amounts of fish meal, fish oil, and algal powder, the ratio of unsaturated fatty acids DHA (docosahexaenoic acid) / EPA (eicosapentaenoic acid) in the feed is optimized, the hormone level in the shrimp body is regulated, and the molting-related physiological processes are promoted, thereby improving the molting frequency and synchrony, accelerating the growth rate of the shrimp body, and shortening the cultivation cycle.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A Procambarus clarkii feed contains the following components: fish meal, soybean meal, corn flour, wheat bran, rice bran, fish oil, algal powder, calcium dihydrogen phosphate, stone powder, vitamin premix, mineral premix, cholesterol, attractant, antioxidant, preservative, sodium chloride, choline chloride, bentonite.

[0009] Preferably, the feed contains the following components in mass ratio: fish meal 20 - 30%, soybean meal 30 - 40%, corn flour 10 - 20%, wheat bran 5 - 10%, rice bran 2 - 8%, fish oil 1 - 5%, algal powder 1 - 3%, calcium dihydrogen phosphate 1 - 1.5%, stone powder 0.5 - 1%, vitamin premix 0.5 - 1.5%, mineral premix 0.5 - 1.5%, cholesterol 0 - 1%, attractant 0.3 - 0.8%, antioxidant 0.01 - 0.05%, preservative 0 - 0.03%, sodium chloride 0.1 - 0.5%, choline chloride 0 - 0.3%, bentonite 1 - 5%.

[0010] Preferably, the total ratio of DHA:EPA in the fish meal, fish oil and algal powder is 1 - 2:1, preferably 1.6:1.

[0011] Preferably, the antioxidant is ethoxyquinoline, the attractant is squid liver powder extract, and the preservative is vitamin E - lecithin solution.

[0012] Any of the above - mentioned Procambarus clarkii feeds, and its preparation method includes the following steps:

[0013] S1: Add raw materials in a granulator: fish meal, soybean meal, corn flour, wheat bran, rice bran, calcium dihydrogen phosphate, stone powder, sodium chloride, bentonite, vitamin premix, mineral premix, choline chloride, and mix evenly.

[0014] S2: Atomize and spray fish oil and cholesterol - ethanol solution onto the dry materials using a high - pressure nozzle, and add algal powder for mixing.

[0015] S3: Inject steam for compression granulation, and spray vitamin E - lecithin solution and squid liver powder extract after cooling and drying.

[0016] Preferably, the raw materials in step S1 need to be sieved and dried in advance.

[0017] Preferably, in the cholesterol - ethanol solution in step S2, the mass ratio of cholesterol to ethanol is 1:4 - 6, and an antioxidant needs to be added to the fish oil.

[0018] Preferably, the steam pressure in step S3 is 0.2 - 0.3 MPa, the compression ratio is 1:7 - 9, and the moisture content of the granules after cooling is ≤10%.

[0019] Application of any of the above - mentioned Procambarus clarkii feeds in aquaculture.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) By optimizing the cholesterol content in the feed, the present invention can promote the synthesis of ecdysteroid, increase the molting frequency of Procambarus clarkii, accelerate the growth rate of the shrimp body, and shorten the cultivation period.

[0022] (2) By optimizing the ratio of DHA / EPA, the present invention regulates the physiological rhythm of the shrimp body, promotes the synchrony and success rate of group molting, thereby improving the overall yield and economic benefits.

[0023] (3) The present invention uses natural cholesterol and unsaturated fatty acids (DHA and EPA) as molting-promoting components, avoiding the use of exogenous hormones and ensuring food safety and environmental friendliness. Specific Embodiments

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0025] Example 1

[0026] The contents of DHA and EPA in the fish meal, fish oil, and algal powder involved in this example are as follows in the table:

[0027] Table 1 Contents of DHA and EPA in each component of the raw materials

[0028] Raw materials DHA content EPA content Fish meal (anchovy fish meal from Peru) 1％ 1.3％ Fish oil (anchovy fish oil) 12％ 13％ Algal powder (Schizochytrium sp. algal powder) 30％ 0.3％

[0029] These three raw materials are proportioned as needed into an unsaturated fatty acid mixture so that the total ratio of DHA:EPA in the mixture is 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1.

[0030] The cholesterol involved in this example is provided by cholesterol powder, and the cholesterol content in the cholesterol powder is ≥98%.

[0031] The feed in this example contains the following components in mass ratio:

[0032] Table 2 Contents of each component in the feed

[0033]

[0034] Preparation method of the feed:

[0035] ① Pass the fish meal, soybean meal, and corn flour through an 80-mesh sieve (particle size ≤ 180 μm) to prevent caking and affecting the mixing uniformity; pass the wheat bran and rice bran through a 60-mesh sieve (particle size ≤ 250 μm) to avoid difficulty in pelletizing due to too long fibers. Dry these 5 raw materials (air-dry at 60 °C for 2 hours).

[0036] ② Preheat the fish oil to 42 °C and add the antioxidant ethoxyquinoline; dissolve the cholesterol powder in absolute ethanol (mass-to-volume ratio of 1:5), and the ethanol will volatilize without residue during spraying.

[0037] ③ Add the fish meal, soybean meal, corn flour, wheat bran, and rice bran to the granulator and mix for 5 minutes, then add the trace components (calcium dihydrogen phosphate, stone powder, sodium chloride, bentonite) and mix for 3 minutes. Finally, add the vitamin premix, mineral premix, and choline chloride and mix for 2 minutes (to reduce the degradation of trace components).

[0038] ④ Use a high-pressure nozzle (pressure 0.3 - 0.5 MPa) to atomize and spray the fish oil and cholesterol-ethanol solution onto the dry material, stir synchronously (rotation speed 20 - 30 rpm), and immediately add the algal powder after spraying and mix for 5 minutes (to avoid DHA being exposed to air for too long).

[0039] ⑤ Inject steam, steam pressure 0.25 MPa, conditioning temperature 78 °C, time about 30 - 40 seconds (to make the degree of starch gelatinization reach over 85%). The die hole diameter is 2.0 mm (suitable for the mouth diameter of crayfish), the compression ratio is 1:8 (length-to-diameter ratio), and pelletize. The temperature of the pellets at the discharge port ≤ 85 °C (to prevent thermal oxidation loss of DHA and EPA).

[0040] ⑥ Cooling and drying: The cold air temperature ≤ 30 °C, the moisture content of the pellets after cooling ≤ 10%, the temperature difference between the pellets and the environment ≤ 5 °C (to prevent condensation). Spray the vitamin E - lecithin solution (preparation method: mix 50% vitamin E and 50% pure lecithin evenly by mass ratio of 1:1 and dissolve in 3 times the mass of soybean oil), and spray the extract of squid liver powder (feeding attractant) on the surface of the cooled pellets to improve palatability.

[0041] Feed the prepared feed to Procambarus clarkii, record the molting times and weight changes within 60 days, and the results are shown in the following table:

[0042] Table 3 Experiment on the influence of molting and growth of Procambarus clarkii in 60 days

[0043]

[0044]

[0045] As can be seen from the table, when the addition amount of cholesterol is 0.25% and the ratio of DHA:EPA is 1.6:1, the molting frequency of Procambarus clarkii is the highest, the relative weight gain rate is the highest, and the molting synchronization is the best, which is the optimal ratio of the feed for Procambarus clarkii.

[0046] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention, and any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A Procambarus clarkii feed, characterized in that, It contains the following components: fish meal, soybean meal, corn flour, wheat bran, rice bran, fish oil, algal powder, monocalcium phosphate, limestone powder, vitamin premix, mineral premix, cholesterol, feeding attractant, antioxidant, preservative, sodium chloride, choline chloride, bentonite.

2. The crayfish feed according to claim 1, characterized in that, The feed contains components in the following mass ratios: fish meal 20 - 30%, soybean meal 30 - 40%, corn flour 10 - 20%, wheat bran 5 - 10%, rice bran 2 - 8%, fish oil 1 - 5%, algal powder 1 - 3%, monocalcium phosphate 1 - 1.5%, limestone powder 0.5 - 1%, vitamin premix 0.5 - 1.5%, mineral premix 0.5 - 1.5%, cholesterol 0 - 1%, feeding attractant 0.3 - 0.8%, antioxidant 0.01 - 0.05%, preservative 0 - 0.03%, sodium chloride 0.1 - 0.5%, choline chloride 0 - 0.3%, bentonite 1 - 5%.

3. The feed for Procambarus clarkii according to claim 1, characterized in that, The total ratio of DHA:EPA in the fish meal, fish oil and algal powder is 1 - 2:1, preferably 1.6:

1.

4. The Procambarus clarkii feed according to claim 1, characterized in that, The antioxidant is ethoxyquinoline, the feeding attractant is squid liver powder extract, and the preservative is vitamin E - lecithin solution.

5. A Procambarus clarkii feed according to any one of claims 1-4, characterized in that, Its preparation method includes the following steps: S1: Add raw materials in a granulator: fish meal, soybean meal, corn flour, wheat bran, rice bran, monocalcium phosphate, limestone powder, sodium chloride, bentonite, vitamin premix, mineral premix, choline chloride, and mix evenly. S2: Atomize and spray fish oil and cholesterol - ethanol solution onto the dry materials using a high - pressure nozzle, and add algal powder and mix. S3: Inject steam for compression granulation, and spray the feeding attractant and preservative after cooling and drying.

6. The preparation method of a feed for Procambarus clarkii according to claim 5, characterized in that, The raw materials in step S1 need to be sieved and dried in advance.

7. The method for preparing the feed for Procambarus clarkii according to claim 5, wherein, In the cholesterol - ethanol solution in step S2, the mass ratio of cholesterol to ethanol is 1:4 - 6, and an antioxidant needs to be added to the fish oil.

8. The preparation method of a Procambarus clarkii feed according to claim 5, characterized in that, The steam pressure in step S3 is 0.2 - 0.3 MPa, the compression ratio is 1:7 - 9, and the moisture content of the particles after cooling is ≤10%.

9. Application of the Procambarus clarkii feed according to any one of claims 1 - 8 in aquaculture.

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