A production process and use method of a macrobrachium rosenbergii breeding seawater formula

Abstract

The application discloses a production process and a use method of a marine formula for breeding Macrobrachium rosenbergii, and belongs to the technical field of aquaculture. The marine formula for breeding Macrobrachium rosenbergii comprises sodium chloride, magnesium sulfate, anhydrous calcium chloride, potassium chloride, potassium bromide, boric acid and EDTA in a mass ratio of decreasing order; further comprises a beta-alanine methyl ester derivative and isomalt; and the beta-alanine methyl ester derivative contains a guanidino structure. The marine formula for breeding Macrobrachium rosenbergii can simplify the process flow of configuring artificial seawater, is beneficial to quality control, can improve the growth performance of Macrobrachium rosenbergii, and is suitable for popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, specifically relating to a production process and application method of seawater formula for raising giant freshwater prawns. Background Technology

[0002] Artificial seawater, also known as man-made seawater, refers to a mixture of salts used to raise marine animals or to preserve their organs and tissues in a normal state. Because the osmotic pressure of seawater can vary from region to region, artificial seawater also requires different osmotic concentrations depending on the region and the marine animals being raised.

[0003] There are few commercially available pre-prepared seawater products. During the breeding and rearing of giant freshwater prawns, fish farms mostly purchase ingredients separately according to existing formulas and then prepare their own artificial seawater. This results in problems such as numerous ingredient components, complex raw material varieties, and inconsistent ingredient quality. Furthermore, the preparation process often requires repeated trials to select suitable ingredients, making it complex, error-prone, and lacking in quality control, which is unsuitable for high-efficiency production.

[0004] Patent application CN105210935A discloses a simulated seawater for breeding giant freshwater prawns and its preparation method. The main components of the simulated seawater preparation include NaCl, MgSO4, CaCl2, KCl, NaBr, H3BO3, Na2SiO3, and Al2Cl6. The preparation method includes pre-treatment of freshwater for harmlessness and post-treatment of the simulated seawater for harmlessness. This application enhances the physique of seedlings, removes parasites, improves water quality, and is convenient to prepare. Some components are present in higher concentrations than in natural seawater, such as Ca2+. 2+ The purpose is to provide a good material basis for the seedlings during the molting process, while increasing trace elements to enhance the activity and physical condition of the seedlings.

[0005] However, similar to existing seawater formulations, the ingredients for the above-mentioned simulated seawater often need to be prepared by the manufacturer. The artificial seawater obtained from different batches of different formulations varies greatly, and the materials are prone to absorbing moisture, which is not only unfavorable for packaging, but also causes clumping if stored for a long time, thus affecting transportation and making it unsuitable for use. Summary of the Invention

[0006] The purpose of this invention is to provide a production process and method for a seawater formula for raising giant freshwater prawns, which simplifies the process of preparing artificial seawater, facilitates quality control, improves the growth performance of giant freshwater prawns, and is suitable for widespread application.

[0007] The technical solution adopted by the present invention to achieve the above objectives is as follows: A seawater formula for raising giant freshwater prawns includes sodium chloride, magnesium sulfate, anhydrous calcium chloride, potassium chloride, potassium bromide, boric acid, and EDTA; The composition includes 65-75 parts sodium chloride, 20-28 parts magnesium sulfate, 1-3 parts anhydrous calcium chloride, 0.5-2 parts potassium chloride, 0.1-0.3 parts potassium bromide, 0.5-1.5 parts boric acid, and 0.01-0.05 parts EDTA.

[0008] The above-mentioned seawater formula for raising giant freshwater prawns is used by adding 13-16 kg of the seawater formula per cubic meter of target seawater.

[0009] Preferably, 14.5 kg of seawater formula is added per cubic meter of target seawater.

[0010] Furthermore, when using the seawater formulation, anhydrous calcium chloride can be added. The dosage of the added anhydrous calcium chloride is 0.03-0.06 kg per cubic meter of water.

[0011] The above-mentioned seawater formula for raising giant freshwater prawns can be used directly after dilution, simplifying the process of preparing artificial seawater in fish farms and ensuring the consistency of artificial seawater obtained from multiple preparations, thus achieving standardized quality control. Furthermore, it reduces the amount of redundant ingredients used, lowering raw material costs. The processing technology of the giant freshwater prawn raising seawater formula significantly reduces the probability of materials absorbing water and becoming damp, preventing material clumping and facilitating packaging and transportation. In the preparation of the giant freshwater prawn raising seawater formula, the mother salt is prepared first, and then the remaining components are mixed with it. This avoids the generation of a large amount of dust during the mixing process and reduces the probability of materials adhering to the inner wall of the mixer, thereby saving raw material costs and ensuring the quality of artificial seawater obtained using this formula.

[0012] Furthermore, the seawater formulation also includes β-alanine methyl ester derivatives and isomaltitol; the β-alanine methyl ester derivatives contain a guanidine group structure.

[0013] Preferably, in the seawater formulation, the mass ratio of β-alanine methyl ester derivative to isomaltitol is 1:0.5-1.5, and the mass ratio of β-alanine methyl ester derivative to sodium chloride in the seawater formulation is 1:30-120.

[0014] In addition to sodium chloride, magnesium sulfate, anhydrous calcium chloride, potassium chloride, potassium bromide, boric acid, and EDTA, a certain amount of β-alanine methyl ester derivative and isomaltitol are added to the seawater formulation. Using this seawater formulation to prepare artificial seawater for the cultivation of giant freshwater prawns can not only improve antibacterial properties, but also increase the survival rate, weight gain rate, and crude protein content of giant freshwater prawns.

[0015] This is likely due to the presence of guanidinyl groups in β-alanine methyl ester derivatives and the presence of polyhydroxyl groups in isomalt. The combined use of these two substances can interact with various pathogens that may be present in the aquaculture water, such as Vibrio, Aeromonas, and Flavobacterium, thereby preventing pathogen infection of the giant freshwater prawn (Macrobrachium rosenbergii) and reducing the incidence of various diseases such as septicemia, ulceration, tail rot, enteritis, and vibriosis, thus improving the survival rate of the giant freshwater prawn. On the other hand, β-alanine methyl ester derivatives also contain amino and imino structures, are rich in nitrogen, and contain β-alanine ester groups, which reduces the difficulty of contact with pathogens, thereby improving antibacterial properties. The addition of β-alanine methyl ester derivatives and isomalt to the aquaculture water provides a healthy and favorable growth environment for the giant freshwater prawn and also helps to improve its weight gain rate. On the other hand, β-alanine methyl ester derivatives also contain amino and imino structures, are rich in nitrogen (N), and contain β-alanine groups, which themselves contribute to the growth of *Macrobrachium rosenbergii* and provide a nitrogen source for protein synthesis. Furthermore, the presence of amino groups in β-alanine methyl ester derivatives and the polyhydroxy structures in isomaltulitol may promote the expression of related protein genes in *Macrobrachium rosenbergii* cells, thereby promoting the growth of *Macrobrachium rosenbergii* larvae and increasing protein content.

[0016] According to one aspect of the present invention, a method for preparing a β-alanine methyl ester derivative is provided: Benzoyl isothiocyanate was reacted with β-alanine methyl ester hydrochloride. The resulting product was then reacted with NaOH, followed by reaction with CH3I. The final product was then reacted with n-propylamine and N,N-diisopropylethylamine to yield a β-alanine methyl ester derivative. The resulting β-alanine methyl ester derivative contained a guanidine group.

[0017] Specifically, the preparation method of β-alanine methyl ester derivatives includes the following steps: S1. Benzoyl isothiocyanate was added to a DCM solution containing β-alanine methyl ester hydrochloride, the mixture was stirred and reacted, then filtered, and the resulting residue was washed and dried. S2. Add the solid obtained in S1 to NaOH solution to react, then filter, and wash and dry the resulting filter residue; S3. The solid obtained in S2 is then reacted with CH3I, filtered, and the resulting filter residue is washed and dried. S4. The solid obtained in S3, n-propylamine, and N,N-diisopropylethylamine were added to anhydrous DMF and stirred to react. Then, NaCl solution was added and the mixture was dialyzed with deionized water to obtain a β-alanine methyl ester derivative.

[0018] More specifically, the preparation method of β-alanine methyl ester derivatives is as follows: S1. Benzoyl isothiocyanate was added to a DCM solution containing β-alanine methyl ester hydrochloride under ice bath conditions, and the mixture was stirred at 25°C and 150 r / min for 24 h. The mixture was then filtered, and the resulting residue was washed with DCM and dried under vacuum at 55°C for 6 h. S2. Dissolve the solid obtained in S1 in ethanol, add NaOH solution dropwise, stir at 25°C and 150 r / min for 24 h, then filter, wash the filter residue with ethanol, and dry under vacuum at 55°C for 6 h. S3. Dissolve the solid obtained in S2 in ethanol, add CH3I dropwise, stir at 40℃ and 150 r / min for 48 h, then filter, wash the filter residue with ethanol, and dry under vacuum at 55℃ for 6 h. S4. The solid obtained in S3, n-propylamine, and N,N-diisopropylethylamine were added to anhydrous DMF and stirred at 60°C and 150 r / min for 72 h. Then, NaCl solution was added and the mixture was dialyzed with deionized water to obtain the β-alanine methyl ester derivative.

[0019] Preferably, in S1, the molar ratio of benzoyl isothiocyanate to β-alanine methyl ester hydrochloride is 1-1.5:1.

[0020] Preferably, in S1, the mass-to-volume ratio of β-alanine methyl ester hydrochloride to DCM is 1 g: 60-120 mL.

[0021] Preferably, in S2, the mass-to-volume ratio of the solid obtained in S1 to ethanol is 1g:15-40mL; Preferably, in S2, the concentration of the NaOH solution is 3.0-6.0 mol / L; Preferably, in S2, the mass-to-volume ratio of the solid obtained in S1 to the NaOH solution is 1g:1-5mL.

[0022] Preferably, in S3, the mass-to-volume ratio of the solid obtained in S2 to ethanol is 1g:30-80mL; Preferably, in S3, the mass ratio of the solid obtained in S2 to CH3I is 1:1-3.

[0023] Preferably, in S4, the mass concentration of the NaCl solution is 15-40%; the mass-to-volume ratio of the solid obtained in S3 to the NaCl solution is 1 mg: 3-8 mL. Preferably, in S4, the MWCO of the membrane used for dialysis is 1000 Da.

[0024] According to one aspect of the present invention, a seawater formulation for raising giant freshwater prawns is provided, comprising sodium chloride, magnesium sulfate, anhydrous calcium chloride, potassium chloride, potassium bromide, boric acid and EDTA in descending order of mass percentage; and further comprising β-alanine methyl ester derivative, isomaltitol and 3-mercapto-2-butanone.

[0025] Preferably, the mass ratio of β-alanine methyl ester derivative to isomaltulitol is 1:0.5-1.5, the mass ratio of β-alanine methyl ester derivative to sodium chloride in the seawater formulation is 1:30-120, and the mass ratio of β-alanine methyl ester derivative to 3-mercapto-2-butanone is 1:0.5-1.5.

[0026] In the marine formula for raising giant freshwater prawns, in addition to sodium chloride, magnesium sulfate, anhydrous calcium chloride, potassium chloride, potassium bromide, boric acid, and EDTA, a certain amount of β-alanine methyl ester derivative and isomaltitol are added, along with a certain amount of 3-mercapto-2-butanone, which further enhances the antibacterial properties of the resulting artificial marine seawater. This is likely because 3-mercapto-2-butanone contains a thiol group, which, in combination with the guanidinyl group in the β-alanine methyl ester derivative and the hydroxyl group in isomaltitol, can further enhance its effect against pathogens. Furthermore, the combined use of 3-mercapto-2-butanone with β-alanine methyl ester derivative and isomaltitol can further improve the survival rate, weight gain rate, and crude protein content of giant freshwater prawns. This may be because the presence of thiol and carbonyl groups in 3-mercapto-2-butanone, along with the β-alanine ester group and guanidine group in β-alanine methyl ester derivatives, and / or the polyhydroxy structure in isomaltitol, helps to increase the expression of related protein genes in giant freshwater prawns, thereby promoting the growth of giant freshwater prawn larvae and helping to increase protein content.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. A seawater formula for raising giant freshwater prawns is provided, which simplifies the process of preparing artificial seawater in fish farms and helps to achieve standardized quality control of aquaculture water. The processing technology of the giant freshwater prawn raising seawater formula can significantly reduce the probability of the material absorbing water and becoming damp, avoid material clumping, and facilitate packaging and transportation. In the preparation of the giant freshwater prawn raising seawater formula, the mother salt is prepared first, and then the remaining components are mixed with it, which can avoid the generation of a large amount of dust during the mixing process and reduce the probability of material adhering to the inner wall of the mixer, thereby saving raw material costs and ensuring the quality of artificial seawater obtained by using this seawater formula.

[0028] 2. Adding a certain amount of β-alanine methyl ester derivative and isomalt to the seawater formulation, and using this formulation to prepare artificial seawater for the cultivation of giant freshwater prawns, can not only improve antibacterial properties but also increase the survival rate, weight gain rate, and crude protein content of the prawns. β-alanine methyl ester derivative and isomalt can act on various pathogens that may exist in the aquaculture water, reducing the incidence of diseases. β-alanine methyl ester derivative contains amino and imino structures, is rich in nitrogen, and also contains β-alanine groups. Combined with the polyhydroxy structure in isomalt, it may promote the expression of relevant protein genes in giant freshwater prawn cells, thereby increasing the crude protein content of the prawns.

[0029] 3. In the seawater formulation for raising giant freshwater prawns, the combined use of 3-mercapto-2-butanone with β-alanine methyl ester derivatives and isomaltitol can further enhance the antibacterial properties of the resulting artificial seawater, and further improve the survival rate, weight gain rate, and crude protein content of giant freshwater prawns. This may be because the guanidinyl group in the β-alanine methyl ester derivative and the hydroxyl group in isomaltitol interact with the thiol and carbonyl groups in 3-mercapto-2-butanone, further enhancing the interaction with pathogens and improving antibacterial performance. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below with reference to specific 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.

[0031] Example 1 Seawater formula for raising giant freshwater prawns In the seawater formulation, the mass percentages of sodium chloride, magnesium sulfate, anhydrous calcium chloride, potassium chloride, potassium bromide, boric acid, and EDTA decrease in that order. Specifically, sodium chloride accounts for 69.32 parts, magnesium sulfate for 26.34 parts, anhydrous calcium chloride for 2.08 parts, potassium chloride for 1.25 parts, potassium bromide for 0.14 parts, boric acid for 0.83 parts, and EDTA for 0.03 parts.

[0032] Preparation method of seawater formula for raising giant freshwater prawns The group mixing method involves mixing the groups evenly during the feeding process, including the following steps: 1) Mix sodium chloride, potassium bromide and EDTA to prepare a mother salt.

[0033] 2) Mix magnesium sulfate, calcium chloride, potassium chloride, boric acid and the prepared mother salt.

[0034] 3) Add sodium chloride to the mixed salt obtained in step 2) and mix thoroughly to obtain the seawater formula.

[0035] In the obtained seawater formulation, the mass percentages of sodium chloride, magnesium sulfate, anhydrous calcium chloride, potassium chloride, potassium bromide, boric acid, and EDTA decreased sequentially. Specifically, sodium chloride accounted for 69.32 parts, magnesium sulfate for 26.34 parts, anhydrous calcium chloride for 2.08 parts, potassium chloride for 1.25 parts, potassium bromide for 0.14 parts, boric acid for 0.83 parts, and EDTA for 0.03 parts.

[0036] The mass ratio of sodium chloride used in step 1) to step 3) is 1:100.

[0037] Application method of seawater formula for giant freshwater prawn breeding When using the seawater formula for raising giant freshwater prawns, add 14.5 kg of the seawater formula per cubic meter of target seawater.

[0038] If necessary, anhydrous calcium chloride can be added when using seawater formulations. The amount of anhydrous calcium chloride added is 0.03 kg per cubic meter of water.

[0039] Example 2 The difference between this embodiment and Embodiment 1 is that, in preparing the seawater formulation, after step 3), β-alanine methyl ester derivative and isomaltitol are added, with a mass ratio of β-alanine methyl ester derivative to isomaltitol of 1:1, and a mass ratio of β-alanine methyl ester derivative to sodium chloride in the seawater formulation of 1:100. All other conditions and steps are the same.

[0040] β-alanine methyl ester derivatives contain a β-alanine ester group and a guanidine group. Specifically, the preparation method of β-alanine methyl ester derivatives is as follows: S1. Benzoyl isothiocyanate was added to a DCM solution containing β-alanine methyl ester hydrochloride under ice bath conditions, and the mixture was stirred at 25°C and 150 r / min for 24 h. The mixture was then filtered, and the resulting residue was washed with DCM and dried under vacuum at 55°C for 6 h.

[0041] The molar ratio of benzoyl isothiocyanate to β-alanine methyl ester hydrochloride is 1.2:1. The mass-to-volume ratio of β-alanine methyl ester hydrochloride to DCM is 1 g: 80 mL. When the filter residue is washed with DCM, the mass-to-volume ratio of filter residue to DCM is 1 g: 50 mL, and the washing is performed 3 times.

[0042] S2. Dissolve the solid obtained in S1 in ethanol, add NaOH solution dropwise, stir at 25°C and 150 r / min for 24 h, then filter, wash the filter residue with ethanol, and dry under vacuum at 55°C for 6 h.

[0043] The mass-to-volume ratio of the solid obtained in S1 to ethanol is 1 g: 20 mL; the concentration of the NaOH solution is 5.0 mol / L, and the mass-to-volume ratio of the solid obtained in S1 to the NaOH solution is 1 g: 2 mL.

[0044] S3. Dissolve the solid obtained in S2 in ethanol, and add CH3I dropwise. Stir the mixture at 40°C and 150 r / min for 48 h. Then filter the mixture, wash the residue with ethanol, and dry it under vacuum at 55°C for 6 h.

[0045] The mass-to-volume ratio of the solid obtained from S2 to ethanol is 1 g: 50 mL; the mass ratio of the solid obtained from S2 to CH3I is 1: 2.

[0046] S4. The solid obtained in S3, n-propylamine, and N,N-diisopropylethylamine were added to anhydrous DMF and stirred at 60°C and 150 r / min for 72 h. Then, NaCl solution was added and the mixture was dialyzed with deionized water to obtain the β-alanine methyl ester derivative.

[0047] The mass-to-volume ratio of the solid obtained in S3 to n-propylamine was 1 mg:1 mL; the volume ratio of n-propylamine to N,N-diisopropylethylamine was 1:0.2; and the mass-to-volume ratio of the solid obtained in S3 to DMF was 15 mg:1 mL.

[0048] The NaCl solution has a mass concentration of 20%, and the mass-to-volume ratio of the solid obtained from S3 to the NaCl solution is 1 mg: 5 mL; the MWCO of the membrane used for dialysis is 1000 Da.

[0049] Example 3 The difference between this embodiment and Embodiment 1 is that, in preparing the seawater formulation, after step 3), β-alanine methyl ester derivative and isomaltitol are added, with a mass ratio of β-alanine methyl ester derivative to isomaltitol of 1:1, and a mass ratio of β-alanine methyl ester derivative to sodium chloride in the seawater formulation of 1:60. All other conditions and steps are the same.

[0050] The preparation method of the β-alanine methyl ester derivative is the same as that in Example 2.

[0051] Example 4 The difference between this embodiment and Embodiment 1 is that, in preparing the seawater formulation, after step 3), β-alanine methyl ester derivative and isomaltitol are added, with a mass ratio of β-alanine methyl ester derivative to isomaltitol of 1:1, and a mass ratio of β-alanine methyl ester derivative to sodium chloride in the seawater formulation of 1:40. All other conditions and steps are the same.

[0052] The preparation method of the β-alanine methyl ester derivative is the same as that in Example 2.

[0053] Example 5 The difference between this embodiment and Example 1 is that, in preparing the seawater formulation, after step 3), β-alanine methyl ester derivative and isomaltitol are added, with a mass ratio of β-alanine methyl ester derivative to isomaltitol of 1:1, and a mass ratio of β-alanine methyl ester derivative to sodium chloride in the seawater formulation of 1:100. Furthermore, 3-mercapto-2-butanone is additionally added, with a mass ratio of β-alanine methyl ester derivative to 3-mercapto-2-butanone of 1:0.5. All other conditions and steps are the same.

[0054] The preparation method of the β-alanine methyl ester derivative is the same as that in Example 2.

[0055] Example 6 The difference between this embodiment and Example 1 is that, in preparing the seawater formulation, after step 3), β-alanine methyl ester derivative and isomaltitol are added, with a mass ratio of β-alanine methyl ester derivative to isomaltitol of 1:1, and a mass ratio of β-alanine methyl ester derivative to sodium chloride in the seawater formulation of 1:100. Furthermore, 3-mercapto-2-butanone is additionally added, with a mass ratio of β-alanine methyl ester derivative to 3-mercapto-2-butanone of 1:1. All other conditions and steps are the same.

[0056] The preparation method of the β-alanine methyl ester derivative is the same as that in Example 2.

[0057] Comparative Example 1 The difference between this comparative example and Example 1 is that, in preparing the seawater formulation, after step 3), a β-alanine methyl ester derivative was added, and the mass ratio of the β-alanine methyl ester derivative to sodium chloride in the seawater formulation was 1:50. All other conditions and steps were the same.

[0058] The preparation method of the β-alanine methyl ester derivative is the same as that in Example 2.

[0059] Comparative Example 2 The difference between this comparative example and Example 1 is that, in preparing the seawater formulation, isomaltitol was added after step 3), and the mass ratio of isomaltitol to sodium chloride in the seawater formulation was 1:50. All other conditions and steps were the same.

[0060] Test case The seawater formulations obtained in Examples 1-6 and Comparative Examples 1-2 were used to prepare aquaculture water for the culture of giant freshwater prawns. 14.5 kg of the seawater formulation was added per cubic meter of target seawater. The giant freshwater prawns used had a body weight of 1.2 ± 0.5 g. The water temperature during the culture period was 25 ± 2.5℃. Aeration was maintained throughout the culture period, with 2 / 3 of the water changed daily. The prawns were fed a formulated feed free of sulfonamides three times a day at 8:00, 14:00, and 20:00. The daily feed amount was 5%-20% of the giant freshwater prawn's weight, and the specific amount needed to be adjusted according to the prawns' feeding behavior.

[0061] The survival rates of giant freshwater prawns cultured using the seawater formulations obtained in the various embodiments and comparative examples for 8 weeks are shown in Table 1.

[0062] Table 1. Survival rate of giant freshwater prawns in each embodiment and comparative example.

[0063] Referring to the data in Table 1, the survival rates of *Macrobrachium rosenbergii* in Examples 2-6 and Comparative Examples 1-2 were all improved compared to Example 1. Specifically, compared to Example 1, the survival rates of *Macrobrachium rosenbergii* in Examples 2-6 and Comparative Examples 1-2 increased by 5.2%, 7.3%, 9.3%, 10.7%, 11.5%, 3.8%, and 2.8%, respectively. It is evident that adding β-alanine methyl ester derivative and isomaltitol to the seawater formulation used for *Macrobrachium rosenbergii* farming can significantly improve the survival rate of *Macrobrachium rosenbergii*.

[0064] Based on the data from Examples 2-4, it can be seen that, within a certain range, the content of β-alanine methyl ester derivative and isomalt in the seawater formulation is positively correlated with the survival rate of giant freshwater prawns.

[0065] Compared to Example 2, the survival rates of giant freshwater prawns in Examples 5 and 6 increased by 5.2% and 6.0%, respectively. This demonstrates that adding 3-mercapto-2-butanone to the seawater formulation can further improve the survival rate of giant freshwater prawns.

[0066] Compared to Example 2, the survival rates of Giant freshwater prawns in Comparative Examples 1 and 2 decreased by 1.3% and 2.2%, respectively. This indicates that, in seawater formulations, the combined use of β-alanine methyl ester derivative and isomaltitol, in addition to basic inorganic salts, has a greater impact on the survival rate of Giant freshwater prawns than adding β-alanine methyl ester derivative alone, which is superior to adding isomaltitol alone.

[0067] After 8 weeks of culture of giant freshwater prawns using the seawater formulations obtained in the various embodiments and comparative examples, the prawns were fasted for 24 hours, and their final body weight was measured. The weight gain rate is shown in Table 2.

[0068] Table 2. Weight gain rate of giant freshwater prawns in each example and comparative example.

[0069] Referring to the data in Table 2, the weight gain rate of *Macrobrachium rosenbergii* in Examples 2-6 and Comparative Examples 1-2 was improved compared to Example 1. Specifically, compared to Example 1, the weight gain rates of *Macrobrachium rosenbergii* in Examples 2-6 and Comparative Examples 1-2 increased by 8.0%, 9.4%, 10.8%, 12.0%, 12.9%, 4.5%, and 3.8%, respectively. It is evident that adding β-alanine methyl ester derivative and isomaltitol to the seawater formulation used for *Macrobrachium rosenbergii* farming can significantly improve the weight gain rate of *Macrobrachium rosenbergii*.

[0070] Based on the data from Examples 2-4, it can be seen that, within a certain range, the content of β-alanine methyl ester derivative and isomaltitol in the seawater formulation is positively correlated with the weight gain rate of giant freshwater prawns.

[0071] Compared to Example 2, the weight gain rate of giant freshwater prawns in Examples 5 and 6 increased by 3.7% and 4.6%, respectively. This demonstrates that adding 3-mercapto-2-butanone to the seawater formulation can further improve the weight gain rate of giant freshwater prawns.

[0072] Compared to Example 2, the weight gain rates of Macrobrachium rosenbergii in Comparative Examples 1 and 2 decreased by 3.5% and 3.8%, respectively. This indicates that, in seawater formulations, the combined use of β-alanine methyl ester derivative and isomaltitol, in addition to basic inorganic salts, has a greater impact on the weight gain rate of Macrobrachium rosenbergii than adding β-alanine methyl ester derivative alone, which is superior to adding isomaltitol alone.

[0073] After 8 weeks of culture of giant freshwater prawns using the seawater formulations obtained in the various embodiments and comparative examples, the crude protein content of the prawns was determined by the Kjeldahl method, as shown in Table 3.

[0074] Table 3. Crude protein content of giant freshwater prawns in each example and comparative example.

[0075] Referring to the data in Table 3, the crude protein content of the giant freshwater prawns in Examples 2-6 and Comparative Examples 1-2 was increased compared to Example 1. Specifically, compared to Example 1, the crude protein content of the giant freshwater prawns in Examples 2-6 and Comparative Examples 1-2 increased by 6.2%, 8.7%, 11.4%, 12.6%, 13.9%, 4.1%, and 3.0%, respectively. It is evident that adding β-alanine methyl ester derivative and isomaltitol to the seawater formulation used for farming giant freshwater prawns can significantly increase the crude protein content of the prawns.

[0076] Based on the data from Examples 2-4, it can be seen that, within a certain range, the content of β-alanine methyl ester derivative and isomaltitol in the seawater formulation is positively correlated with the crude protein content of giant freshwater prawns.

[0077] Compared to Example 2, the crude protein content of Giant freshwater prawns in Examples 5 and 6 increased by 6.1% and 7.3%, respectively. This demonstrates that adding 3-mercapto-2-butanone to the seawater formulation can further increase the crude protein content of Giant freshwater prawns.

[0078] Compared to Example 2, the crude protein content of Macrobrachium rosenbergii in Comparative Examples 1 and 2 decreased by 1.9% and 2.9%, respectively. This indicates that, in seawater formulations, the combined use of β-alanine methyl ester derivative and isomaltitol, excluding basic inorganic salts, has a greater impact on the crude protein content of Macrobrachium rosenbergii than adding β-alanine methyl ester derivative alone, which is superior to adding isomaltitol alone.

[0079] The conventional operations in the operation steps of this invention are well known to those skilled in the art and will not be described in detail here.

[0080] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the claims.

Claims

1. A seawater formula for raising giant freshwater prawns, comprising 65-75 parts sodium chloride, 20-28 parts magnesium sulfate, 1-3 parts anhydrous calcium chloride, 0.5-2 parts potassium chloride, 0.1-0.3 parts potassium bromide, 0.5-1.5 parts boric acid, and 0.01-0.05 parts EDTA; further comprising a β-alanine methyl ester derivative and isomaltitol; the β-alanine methyl ester derivative contains a guanidine group; the mass ratio of the β-alanine methyl ester derivative to isomaltitol is 1:0.5-1.5, and the mass ratio of the β-alanine methyl ester derivative to sodium chloride in the seawater formula is 1:30-120; The preparation method of the β-alanine methyl ester derivative includes the following steps: S1. Benzoyl isothiocyanate was added to a DCM solution containing β-alanine methyl ester hydrochloride, the mixture was stirred and reacted, then filtered, and the resulting residue was washed and dried. S2. Add the solid obtained in S1 to NaOH solution to react, then filter, and wash and dry the resulting filter residue; S3. The solid obtained in S2 is then reacted with CH3I, filtered, and the resulting filter residue is washed and dried. S4. The solid obtained in S3, n-propylamine, and N,N-diisopropylethylamine were added to anhydrous DMF and stirred to react. Then, NaCl solution was added and the mixture was dialyzed with deionized water to obtain the β-alanine methyl ester derivative.

2. The seawater formula for raising giant freshwater prawns according to claim 1, characterized in that, When using, add 13-16 kg of the seawater formula per cubic meter of target seawater.

3. The seawater formula for raising giant freshwater prawns according to claim 1, characterized in that, In S1, the molar ratio of benzoyl isothiocyanate to β-alanine methyl ester hydrochloride is 1-1.5:1; In S1, the mass-to-volume ratio of β-alanine methyl ester hydrochloride to DCM is 1 g: 60-120 mL.

4. The seawater formula for raising giant freshwater prawns according to claim 1, characterized in that, In S2, the solid obtained from S1 is dissolved in ethanol and then reacted with NaOH solution, with a mass-to-volume ratio of 1g to 15-40mL. In S2, the concentration of NaOH solution is 3.0-6.0 mol / L; the mass-to-volume ratio of the solid obtained in S1 to NaOH solution is 1 g: 1-5 mL.

5. The seawater formula for raising giant freshwater prawns according to claim 1, characterized in that, In S3, the solid obtained from S2 is dissolved in ethanol and then reacted with CH3I; the mass-to-volume ratio of the solid obtained from S2 to ethanol is 1g:30-80mL. In S3, the mass ratio of the solid obtained from S2 to CH3I is 1:1-3.

6. The seawater formula for raising giant freshwater prawns according to claim 1, characterized in that, In S4, the mass concentration of the NaCl solution is 15-40%; the mass-to-volume ratio of the solid obtained in S3 to the NaCl solution is 1 mg: 3-8 mL.

7. The seawater formula for raising giant freshwater prawns according to claim 1, characterized in that, It also includes 3-mercapto-2-butanone, wherein the mass ratio of the β-alanine methyl ester derivative to 3-mercapto-2-butanone is 1:0.5-1.5.

Images