Procambarus clarkia food baiting fermented feed and preparation method thereof

Abstract

The application discloses a red crawfish food-enticing fermented feed and a preparation method thereof, and belongs to the technical field of feed fermentation and food-enticing. The red crawfish food-enticing fermented feed is prepared by using a complex bacteria liquid system of Hansenula, Saccharomyces cerevisiae, Lactobacillus plantarum and Lactobacillus acidophilus, and a large amount of high-activity esters and acid-smelling food-enticing substances are generated through a double mechanism of "bacteria liquid culture first round ester production + continuous ester production in puffed material", and the food-enticing effect is further improved after synergistic action with conventional food-enticing agents. The red crawfish food-enticing fermented feed provided by the application can significantly shorten the feeding response time of red crawfish, improve the feeding rate, especially in the low-temperature environment of 8-20 DEG C in autumn, winter and early spring, and the effect is outstanding. Meanwhile, the red crawfish food-enticing fermented feed can significantly improve the weight gain rate, survival rate and intestinal digestive enzyme activity of red crawfish, reduce the ammonia nitrogen and nitrite content of the aquaculture water, solve the problems of low feeding of red crawfish, low feed utilization rate and water pollution in the low-temperature period, provide a feed solution with stronger food-enticing effect and green high efficiency, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of feed fermentation and feeding inducement technology, specifically relating to a feeding inducement fermented feed for crayfish and its preparation method. Background Technology

[0002] Crayfish are freshwater crustaceans resembling lobsters, scientifically known as *Procambarus clarkii*, also called red swamp crayfish or freshwater crayfish, native to the Americas. Crayfish are omnivorous, generally feeding on aquatic plants, algae, aquatic insects, and animal carcasses. They are rich in protein, and their meat is tender, delicious, and easily digestible, making them an excellent food for those who are weak or recovering from illness. Furthermore, crayfish meat is rich in magnesium, zinc, iodine, and selenium. Magnesium plays an important role in regulating heart activity, effectively protecting the cardiovascular system, reducing blood cholesterol levels, preventing arteriosclerosis, dilating coronary arteries, and helping to prevent hypertension and myocardial infarction.

[0003] The crayfish farming industry continues to expand, with extruded feed becoming the mainstream feed due to its balanced nutrition, ease of feeding, and high utilization rate. However, crayfish feeding activity is significantly affected by water temperature. When water temperatures drop to 8-20℃ in autumn, winter, and early spring, their metabolic rate decreases, their appetite weakens, leading to reduced feed utilization and increased uneaten feed. Uneaten feed also easily pollutes water bodies, causing water quality deterioration and further affecting crayfish growth and survival. In recent years, due to a sharp increase in market demand, natural crayfish resources have decreased dramatically, and prices have gradually risen, leading to the development of artificial crayfish farming and a rapid increase in the area of ​​rice paddies used for crayfish farming. However, artificially farmed crayfish are smaller, have poorer color, longer growth cycles, are more susceptible to diseases, and have weaker disease resistance, resulting in lower economic benefits for farmers.

[0004] Existing crayfish feed attractant technologies mostly rely on the single or combined addition of conventional attractants such as (dimethyl-β-propionate thiophene) DMPT and betaine, which have problems such as low attractant effect and weakened effect at low temperature. Summary of the Invention

[0005] The purpose of this invention is to provide a fermented feed for crayfish and its preparation method. This addresses the problems of existing crayfish feed attractants, which often rely on single or combined additions of conventional attractants such as DMPT and betaine, resulting in low attractant efficacy and weakened effects at low temperatures.

[0006] In a first aspect, the present invention provides a method for preparing crayfish feed with an appealing fermentation, comprising the following steps: providing a compound bacterial solution; adding a solvent and the compound bacterial solution to crayfish extruded feed and mixing them evenly to obtain a first material; adding dimethyl-β-propionate thiatin, betaine, and enzymatically hydrolyzed fish paste to the first material and mixing them evenly to obtain a second material; fermenting the second material and drying the resulting fermented material to obtain crayfish feed with an appealing fermentation; wherein the compound bacterial solution is prepared by mixing Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus, inoculating them, and fermenting them.

[0007] In this invention, the inventors discovered that a complex bacterial culture system of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus generates a large amount of highly active esters and acidic aroma-enhancing substances through a dual mechanism of "first-round ester production in bacterial culture + continued ester production in extruded feed." Furthermore, the synergistic effect with conventional attractants further enhances the feeding effect. The crayfish feeding-enhancing fermented feed provided by this invention can significantly shorten the crayfish feeding response time and increase the feeding rate, especially in the low-temperature environment of 8-20℃ in early autumn and spring. It can also significantly improve the weight gain rate, survival rate, and intestinal digestive enzyme activity of crayfish, and reduce the ammonia nitrogen and nitrite content in the aquaculture water. This solves the problems of low feeding, low feed utilization, and water pollution in crayfish during low-temperature periods, providing a more effective, green, and efficient feed solution with broad application prospects.

[0008] In some implementations, in the step of preparing the compound bacterial solution by inoculating and fermenting a mixture of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus, the Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus are mixed at a viable cell ratio of (0.5-1.5):(0.5-1.5):(0.5-1.5):(0.5-1.5); and the viable cell count of the compound bacterial solution is ≥2×10⁻⁶. 10 CFU / mL.

[0009] In some implementation schemes, the step of preparing the compound bacterial solution by inoculating and fermenting a mixture of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus specifically includes: culturing for 24-36 hours at a temperature of 30-32°C and a rotation speed of 150-180 rpm.

[0010] In some implementations, in the step of adding solvent and compound bacterial solution to crayfish puffed feed and mixing them evenly, the added solvent accounts for 6-10% of the mass of crayfish puffed feed, and the solvent includes sterile water.

[0011] In some implementations, in the step of adding solvent and compound bacterial solution to crayfish puffed feed and mixing them evenly, the mass-volume ratio of crayfish puffed feed to compound bacterial solution is (8-12 kg): (1.9-2.3 L).

[0012] In some implementations, before adding solvent and compound bacterial solution to crayfish puffed feed and mixing evenly, a pretreatment step of crayfish puffed feed is included; wherein, the pretreatment specifically includes: crushing crayfish puffed feed to 1-3mm.

[0013] In some implementation schemes, in the step of adding dimethyl-β-propionate thiatin, betaine, and enzymatically hydrolyzed fish paste to the first material and mixing them evenly, the mass of dimethyl-β-propionate thiatin added accounts for 0.03-0.07% of the mass of crayfish puffed feed, the mass of betaine added accounts for 0.1-0.3% of the mass of crayfish puffed feed, and the mass of enzymatically hydrolyzed fish paste added accounts for 3-5% of the mass of crayfish puffed feed.

[0014] In some implementation schemes, the fermentation process, which involves fermenting the second material and drying the resulting fermented material, specifically includes fermenting for 20-30 hours at a temperature of 28-30°C, a pH of 3-4, and a relative humidity of 65-75%.

[0015] In some implementations, the step of fermenting the second material and drying the resulting fermented material specifically includes drying the fermented material at a temperature of 40-50°C until the moisture content of the fermented material is ≤12%.

[0016] In a second aspect, the present invention provides a crayfish feeding-inducing fermented feed, which is prepared by any of the above-mentioned preparation methods.

[0017] The beneficial effects of this invention are as follows: Unlike existing technologies, this invention uses a compound bacterial culture system of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus to generate a large amount of highly active esters and acidic and aromatic attractants through a dual mechanism of "first-round ester production in bacterial culture + continued ester production in extruded feed." Furthermore, the synergistic effect with conventional attractants further enhances the attractant effect. The crayfish attractant fermented feed provided by this invention can significantly shorten the crayfish feeding response time and increase the feeding rate, especially in the low-temperature environment of 8-20℃ in early autumn and spring. It can also significantly improve the weight gain rate, survival rate, and intestinal digestive enzyme activity of crayfish, and reduce the ammonia nitrogen and nitrite content in the aquaculture water. This solves the problems of low feeding, low feed utilization, and water pollution in crayfish during low-temperature periods, providing a more effective, green, and efficient feed solution with broad application prospects. Attached Figure Description

[0018] Figure 1 This is a flowchart of the preparation method of the crayfish feeding fermentation feed in this invention. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Experimental methods not specified in the examples are generally performed under conventional conditions and as described in the manual, or as recommended by the manufacturer. Unless otherwise specified, the general equipment, materials, reagents, etc. used are commercially available.

[0021] Currently, existing crayfish feed attractant technologies mostly rely on the single or combined addition of conventional attractants such as DMPT and betaine, which have problems such as low attractant effect and weakened effect at low temperatures.

[0022] To address the problems of existing crayfish feed attractant technologies that rely heavily on single or combined additions of conventional attractants such as DMPT and betaine, which result in low attractant efficacy and weakened effects at low temperatures, this invention provides a crayfish attractant fermented feed and its preparation method.

[0023] In a first aspect, the present invention provides a method for preparing crayfish feed with an appealing fermentation, comprising the following steps: providing a compound bacterial solution; adding a solvent and the compound bacterial solution to crayfish extruded feed and mixing them evenly to obtain a first material; adding dimethyl-β-propionate thiatin (DMPT), betaine, and enzymatically hydrolyzed fish paste to the first material and mixing them evenly to obtain a second material; fermenting the second material and drying the resulting fermented material to obtain crayfish feed with an appealing fermentation; wherein the compound bacterial solution is prepared by inoculating and fermenting a mixture of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus.

[0024] The preparation method provided by this invention utilizes a compound bacterial culture system of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus. Through a dual mechanism of "first-round ester production in bacterial culture (where Saccharomyces cerevisiae constructs a semi-anaerobic environment and produces alcohol, Hansenula polymorpha primarily produces esters and alcohols, and Lactobacillus plantarum and Lactobacillus acidophilus produce acids, with alcohol-acid reaction further generating esters) + continued ester production in the extruded feed," a large amount of highly active esters and acidic aroma-enhancing substances are generated. Furthermore, the synergistic effect with conventional attractants further improves the feeding attraction effect. In addition, the crayfish feeding-enhancing fermented feed provided by this invention can significantly shorten the crayfish feeding response time and increase the feeding rate, especially under low-temperature conditions of 8-20℃. This method addresses the challenge of low feed intake in crayfish by enhancing the metabolic activity of probiotics in the compound bacterial solution, thereby boosting intestinal digestive enzyme activity and improving immunity. This leads to increased daily weight gain, reduced feed conversion ratio, and lower mortality. Simultaneously, the enhanced feeding effect reduces feed residue, effectively lowers ammonia and nitrite levels in the aquaculture water, stabilizes pH and dissolved oxygen levels, and maintains ecological balance. The entire process is free of harmful additives, avoiding the risks of intestinal disorders and the transmission of harmful substances through the food chain. Furthermore, the process is simple to operate, easily scaled up, and adaptable to different water temperatures throughout the year, comprehensively improving the economic, ecological, and product safety benefits of crayfish farming.

[0025] In some embodiments, in the step of preparing the compound bacterial solution by inoculating and fermenting a mixture of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus, the Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus are mixed in a viable ratio of (0.5-1.5):(0.5-1.5):(0.5-1.5):(0.5-1.5), preferably 1:1:1:1; and the viable count of the compound bacterial solution is ≥2×10⁻⁶. 10 CFU / mL.

[0026] In this invention, by selecting specific strains for compounding, ester production can be achieved efficiently and synergistically, thereby enhancing the palatability effect; wherein, Saccharomyces cerevisiae constructs a semi-anaerobic environment and produces alcohol, Hansenula polymorpha mainly produces esters and alcohols, Lactobacillus plantarum and Lactobacillus acidophilus produce acids, and the alcohol-acid reaction further generates esters.

[0027] In some implementations, in the step of preparing the compound bacterial solution by inoculating and fermenting a mixture of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus, the fermentation culture specifically includes: culturing for 24-36 hours, preferably 30 hours, at a temperature of 30-32℃ (preferably 31℃) and a rotation speed of 150-180 rpm (preferably 160 rpm).

[0028] In this invention, by controlling the specific parameters of fermentation culture within a certain range, the strain can be better cultured, which facilitates the continuous ester production of the compound bacterial solution and thus significantly improves the feeding effect.

[0029] It is understood that the culture medium used in the fermentation process is a conventional culture medium in the art, and can be conventionally selected according to actual needs. For example, in this invention, the composition of the culture medium used in the fermentation process is as follows: glucose 25g / L, peptone 15g / L, yeast extract 8g / L, potassium dihydrogen phosphate 2g / L, magnesium sulfate 1g / L, pH 6.5-7.0, sterilized at 121℃ for 20min.

[0030] In some embodiments, in the step of adding solvent and compound bacterial solution to crayfish puffed feed and mixing them evenly, the mass of the added solvent accounts for 6-10% of the mass of crayfish puffed feed, preferably 8%; and the solvent includes sterile water.

[0031] In this invention, by controlling the amount of solvent added within a specific range, the state of the material can be adjusted, which facilitates better fermentation and ester production of the subsequent compound bacterial solution, and further significantly improves the palatability effect.

[0032] It is understood that the type of solvent can be conventionally selected according to actual usage needs, as long as it can adjust the state of the material. For example, in this invention, the solvent preferably includes sterile water.

[0033] In some implementations, in the step of adding solvent and compound bacterial solution to crayfish puffed feed and mixing them evenly, the mass-volume ratio of crayfish puffed feed to compound bacterial solution is (8-12 kg):(1.9-2.3 L), preferably 10 kg:2.1 L.

[0034] In this invention, by controlling the mass-to-volume ratio of crayfish puffed feed to compound bacterial liquid within a specific range, the compound bacterial liquid can continuously produce high esters during subsequent fermentation, thereby further enhancing the palatability effect.

[0035] In some implementations, before adding solvent and compound bacterial solution to crayfish puffed feed and mixing evenly, a pretreatment step of crayfish puffed feed is included; wherein, the pretreatment specifically includes: crushing crayfish puffed feed to 1-3 mm, preferably 2 mm.

[0036] In this invention, by controlling the particle size of the crayfish extruded feed within a specific range, it can be mixed evenly with the compound bacterial solution, thereby further improving the utilization rate of the feed.

[0037] In some embodiments, in the step of adding dimethyl-β-propionate thiatin, betaine, and enzymatically hydrolyzed fish paste to the first material and mixing them evenly, the mass of added dimethyl-β-propionate thiatin accounts for 0.03-0.07% of the mass of the crayfish puffed feed, preferably 0.05%; the mass of added betaine accounts for 0.1-0.3% of the mass of the crayfish puffed feed, preferably 0.2%; and the mass of added enzymatically hydrolyzed fish paste accounts for 3-5% of the mass of the crayfish puffed feed, preferably 4%.

[0038] In this invention, by controlling the addition of dimethyl-β-propionate thiophene, betaine, and enzymatically hydrolyzed fish paste within a specific range, their synergistic effect with the compound bacterial solution significantly improves the feeding-inducing effect of crayfish fermented feed.

[0039] In some implementation schemes, the fermentation process, which involves fermenting the second material and drying the resulting fermented material, specifically includes fermenting for 20-30 hours, preferably 24 hours, at a temperature of 28-30°C (preferably 29°C), a pH of 3-4 (preferably 3.4), and a relative humidity of 65-75% (preferably 70%).

[0040] In this invention, by controlling the specific parameters of the fermentation process within a certain range, the compound bacterial solution can be better cultivated, which facilitates the continued high ester production of the compound bacterial solution and thus significantly improves the palatability effect.

[0041] In some implementations, the step of fermenting the second material and drying the resulting fermented material specifically includes drying the fermented material at a temperature of 40-50°C (preferably 45°C) until the moisture content of the fermented material is ≤12%.

[0042] It is understandable that the drying temperature and the moisture content of the fermented material can be adjusted according to actual needs, as long as a good quality crayfish-attracting fermented feed can be obtained. For example, in this invention, the drying process preferably includes drying at a temperature of 40-50℃ until the moisture content of the fermented material is ≤12%.

[0043] In a second aspect, the present invention provides a crayfish feeding-inducing fermented feed, which is prepared by any of the above-mentioned preparation methods.

[0044] The crayfish feed provided by this invention has a high ester content, thus it has a good feeding effect.

[0045] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0046] Please see Figure 1This is a flowchart illustrating the preparation method of the crayfish feeding-enhancing fermented feed according to the present invention. Specifically, the preparation method of the crayfish feeding-enhancing fermented feed includes the following steps: providing a compound bacterial solution; adding solvent and compound bacterial solution to crayfish extruded feed and mixing evenly to obtain a first material; adding dimethyl-β-propionic acid thiatin, betaine, and enzymatically hydrolyzed fish paste to the first material and mixing evenly to obtain a second material; fermenting the second material and drying the resulting fermented material to obtain the crayfish feeding-enhancing fermented feed.

[0047] Example 1 A method for preparing a crayfish-attracting fermented feed includes the following steps: S1. Take Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus strains, mix them at a live cell ratio of 1:1:1:1, and inoculate them into 10L of special culture medium (250g glucose, 150g peptone, 80g yeast extract, 20g potassium dihydrogen phosphate, 10g magnesium sulfate, add water to a final volume of 10L, pH 6.8, sterilize at 121℃ for 20min). Then, incubate at 31℃ and 160rpm on a shaker for 30h to obtain a total effective live cell count of 2.3×10⁻⁶. 10 CFU / mL compound bacterial solution; S2. Take 10kg of crayfish puffed feed and crush it to a particle size of 2mm. Add 800g of sterile water and 2.1L of the compound bacterial solution prepared in step S1 to the crayfish puffed feed, stir evenly, and adjust the moisture content of the material to 29% to obtain the first material. S3. Transfer the first material prepared in step S2 into a fermentation tank and ferment it for 24 hours at 29°C and 70% relative humidity, keeping the pH value around 3.4 throughout the process; then dry the fermented material at 45°C until the moisture content is 10% to obtain crayfish feed.

[0048] Example 2 A method for preparing a crayfish-attracting fermented feed includes the following steps: S1. Take Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus strains, mix them at a live cell ratio of 1:1:1:1, and inoculate them into 10L of special culture medium (250g glucose, 150g peptone, 80g yeast extract, 20g potassium dihydrogen phosphate, 10g magnesium sulfate, add water to a final volume of 10L, pH 6.8, sterilize at 121℃ for 20min). Then, incubate at 31℃ and 160rpm on a shaker for 30h to obtain a total effective live cell count of 2.3×10⁻⁶. 10 CFU / mL compound bacterial solution; S2. Take 10kg of crayfish puffed feed and crush it to a particle size of 2mm. Add 800g of sterile water and 2.1L of the compound bacterial solution prepared in step S1 to the crayfish puffed feed, stir evenly, and adjust the moisture content of the material to 29% to obtain the first material. S3. Add 5g of dimethyl-β-propionate thiatin, 20g of betaine, and 400g of enzymatically hydrolyzed fish paste to the first material prepared in step S2, and mix well to obtain the second material. S4. Transfer the second material prepared in step S3 into a fermentation tank and ferment it for 24 hours at 29°C and 70% relative humidity, keeping the pH value around 3.4 throughout the process; then dry the fermented material at 45°C until the moisture content is 10% to obtain crayfish feed.

[0049] Comparative Example 1 In this comparative example, a crayfish puffed feed is provided and crushed to a particle size of 2mm.

[0050] Comparative Example 2 In this comparative example, the preparation method of the crayfish feeding-inducing fermented feed includes the following steps: S1. Take 10kg of crayfish puffed feed and crush it to a particle size of 2mm. Add 5g of dimethyl-β-propionic acid thiatin, 20g of betaine, 400g of enzymatically hydrolyzed fish paste and an appropriate amount of sterile water to the above crayfish puffed feed. Dry it at 45℃ until the moisture content is 10% to obtain crayfish feed for attracting consumption.

[0051] Comparative Example 3 In this comparative example, a commercially available crayfish attractant feed is provided.

[0052] Performance testing Furthermore, the esters in the compound bacterial solution prepared in step S1 of Example 2 and the crayfish feed prepared in step S4 were tested, and the results are shown in Tables 1 and 2 below.

[0053] Table 1. Detection results of esters in the compound bacterial solution

[0054] Table 2. Detection results of esters in crayfish feed for attracting feed.

[0055] As can be seen from Tables 1 and 2, the compound bacterial liquid can produce more esters after fermentation, and the content of esters is further increased. The results show that the present invention generates a large amount of highly active esters and acidic and aromatic food-attracting substances through the dual mechanism of "first-round ester production in bacterial liquid culture + continued ester production in puffed feed", which significantly enhances the appetite-attracting effect.

[0056] Furthermore, the pH value and acid-fragrant substance content of single Lactobacillus plantarum, single Lactobacillus acidophilus, Lactobacillus plantarum + Lactobacillus acidophilus combination (dual-strain acid-producing group) and compound bacterial liquid (Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum and Lactobacillus acidophilus) during the fermentation process were detected, and the results are shown in Table 3 below.

[0057] Table 3. Results of pH value and acid-aroma substance content detection for different strains during fermentation.

[0058] As can be seen from Table 3, the compound bacterial solution group can stabilize the pH at 3.4 after 24 hours of fermentation, and the content of acidic and aromatic substances (lactic acid + acetic acid) continues to lead, reaching 4.1 mg / g after 24 hours of fermentation, which is significantly higher than other single or dual bacterial combinations. This proves that the compound bacterial solution system can quickly form a low pH environment and produce acidic and aromatic substances efficiently, providing core support for the palatability effect.

[0059] Application test cases Five hundred healthy crayfish, each weighing approximately 5.6g, were randomly divided into five groups. They were fed with the crayfish feed prepared in Examples 1-2, the crayfish extruded feed in Comparative Example 1, the crayfish feed prepared in Comparative Example 2, and the commercially available crayfish feed prepared in Comparative Example 3 for 30 days. The performance of the crayfish and the condition of the culture water were tested. The results are shown in Tables 4 and 5.

[0060] Table 4. Performance test results of crayfish

[0061] As shown in Table 4, the crayfish fed with the feed-enhancing fermented feed from Example 2 exhibited the best overall growth performance, with a mortality rate of only 3.2%, significantly lower than Comparative Example 1 (18.5%) and other comparative examples. This indicates that the feed-enhancing fermented feed from Example 1 significantly enhances the immunity of crayfish. The average daily weight gain reached 0.273 g / crayfish / day, 3.14 times that of the control group, with a feed conversion ratio as low as 1.02. The intestinal amylase and protease activities were as high as 35.8 U / mg and 41.6 U / mg, respectively, significantly superior to the feeds in Comparative Examples 2 and 3. These results demonstrate that the compound bacterial solution, through the synergistic effect of "dual ester production" and precise pH control, can effectively improve the digestive and absorptive efficiency of crayfish, accelerate growth and weight gain, and simultaneously optimize the intestinal microecological environment, enhancing the body's resistance.

[0062] Table 5 Results of aquaculture water condition monitoring

[0063] As shown in Table 5, the crayfish feeding with the fermented feed from Example 2 resulted in the best environmental indicators for the aquaculture water. The ammonia nitrogen content was 0.19 mg / L and the nitrite content was 0.02 mg / L, both the lowest and significantly lower than Comparative Example 1 (ammonia nitrogen 0.61 mg / L, nitrite 0.16 mg / L). The dissolved oxygen content reached 6.9 mg / L, and the pH value remained stable within the suitable range of approximately 7.4, superior to Comparative Examples 2 and 3. These results indicate that the fermented feed prepared in this invention has a strong feeding effect, reduces uneaten feed residue, and the probiotics in the compound bacterial solution can degrade harmful substances in the water, maintaining the ecological balance of aquaculture and solving the problem of water pollution caused by uneaten feed in traditional feeds.

[0064] Furthermore, the feeding activity of the crayfish fermented feed prepared in Examples 1-2, the crayfish extruded feed in Comparative Example 1, the crayfish fermented feed in Comparative Example 2, and the commercially available crayfish feeding feed in Comparative Example 3 was tested at different water temperatures. The results are shown in Table 6 below.

[0065] Table 6. Results of feeding activity tests at different water temperatures

[0066] As shown in Table 6, under different water temperature conditions, the crayfish fed with the fermented feed from Example 2 exhibited optimal feeding activity, with particularly outstanding advantages in low-temperature environments (8-20℃): the feeding response time was only 5.8 min, shortened by 77.4% compared to Comparative Example 1 and by 68.1% compared to Comparative Example 2; the 2-hour feeding rate reached 91.2%, which is 2.15 times that of Comparative Example 1 and far exceeds other comparative examples. In normal temperature (20-25℃) and high temperature (25-30℃) environments, the feeding response time in Example 2 was 2.3 min and 1.5 min, respectively, and the 2-hour feeding rates were 96.8% and 98.5%, respectively, both at leading levels. The results indicate that the feeding system constructed by this invention through "dual ester production + precise pH 3.5 control" is adaptable to different water temperature environments throughout the year, and can especially solve the industry pain point of low crayfish feeding during low-temperature periods.

[0067] Furthermore, the feeding effects of the crayfish feeding-inducing fermented feed prepared in Examples 1-2, the crayfish extruded feed in Comparative Example 1, the crayfish feeding-inducing fermented feed in Comparative Example 2, and the commercially available crayfish feeding-inducing feed in Comparative Example 3 were tested in different months, and the results are shown in Table 7 below.

[0068] Table 7 Results of appetite stimulation effects in different months

[0069] As shown in Table 7, throughout the year, the average daily feed intake of crayfish fed with the fermented feed from Example 2 was significantly higher than that of Comparative Examples 1-3 in all monitored months. The advantage was most pronounced in the low-temperature months of early autumn / winter and spring, such as January, March, and November: the average daily feed intake in January was 0.36 g / fish, which was 3.27 times that of Comparative Example 1 and 111.8% higher than that of Comparative Example 2; the average daily feed intake in March and November reached 0.41 g / fish and 0.41 g / fish respectively, far exceeding Comparative Examples 1 and 3; in the high-temperature and normal-temperature months (May, July, and September), the average daily feed intake in Example 2 remained above 0.48 g / fish, consistently leading the way. This fully verifies that the fermented feed for crayfish prepared by this invention is suitable for the aquaculture needs of different months throughout the year, especially meeting the feeding needs of aquaculture during the low-temperature period of early autumn / winter and spring, providing strong support for stable aquaculture throughout the year.

[0070] In summary, this invention utilizes a compound bacterial culture system of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus to generate a large amount of highly active esters and acidic aroma-enhancing substances through a dual mechanism of "first-round ester production in bacterial culture + continued ester production in extruded feed." Furthermore, the synergistic effect with conventional attractants further enhances the feeding-enhancing effect. The crayfish feeding-enhancing fermented feed provided by this invention can significantly shorten the crayfish feeding response time and increase the feeding rate, especially in the low-temperature environment of 8-20℃ in early autumn and spring. Simultaneously, it can significantly improve the weight gain rate, survival rate, and intestinal digestive enzyme activity of crayfish, while reducing the ammonia nitrogen and nitrite content in the aquaculture water. This solves problems such as low feeding, low feed utilization, and water pollution in crayfish during low-temperature periods, providing a more effective, green, and efficient feed solution with broad application prospects.

[0071] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0072] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a fermented feed to attract crayfish, characterized in that, Includes the following steps: Provide compound bacterial solution; After adding solvent and the compound bacterial solution to the crayfish puffed feed and mixing them evenly, the first material is obtained. Add dimethyl-β-propionate thiophene, betaine, and enzymatically hydrolyzed fish paste to the first material and mix thoroughly to obtain the second material; The second material is fermented, and the resulting fermented material is dried to obtain the crayfish feeding-inducing fermented feed. The compound bacterial solution is prepared by mixing Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus, inoculating the mixture, and then fermenting it.

2. The preparation method according to claim 1, characterized in that, In the step of preparing the compound bacterial solution by inoculating and fermenting a mixture of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus, the Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus are mixed at a viable cell ratio of (0.5-1.5):(0.5-1.5):(0.5-1.5):(0.5-1.5); and the viable cell count of the compound bacterial solution is ≥2×10⁻⁶. 10 CFU / mL.

3. The preparation method according to claim 1, characterized in that, In the step of preparing the compound bacterial solution by inoculating and fermenting a mixture of Hansenula polymorpha, Saccharomyces cerevisiae, Lactobacillus plantarum, and Lactobacillus acidophilus, the fermentation culture specifically includes: culturing for 24-36 hours at a temperature of 30-32℃ and a rotation speed of 150-180 rpm.

4. The preparation method according to claim 1, characterized in that, In the step of adding solvent and the compound bacterial solution to crayfish puffed feed and mixing them evenly, the added solvent accounts for 6-10% of the mass of the crayfish puffed feed, and the solvent includes sterile water.

5. The preparation method according to claim 1, characterized in that, In the step of adding solvent and the compound bacterial solution to crayfish puffed feed and mixing them evenly, the mass-volume ratio of the crayfish puffed feed to the compound bacterial solution is (8-12 kg): (1.9-2.3 L).

6. The preparation method according to claim 1, characterized in that, Before adding the solvent and the compound bacterial solution to the crayfish puffed feed and mixing them evenly, the process also includes a pretreatment step for the crayfish puffed feed. The pretreatment specifically includes crushing the crayfish puffed feed to 1-3mm.

7. The preparation method according to claim 1, characterized in that, In the step of adding dimethyl-β-propionate thiatin, betaine, and enzymatically hydrolyzed fish paste to the first material and mixing them evenly, the mass of dimethyl-β-propionate thiatin added accounts for 0.03-0.07% of the mass of the crayfish puffed feed, the mass of betaine added accounts for 0.1-0.3% of the mass of the crayfish puffed feed, and the mass of enzymatically hydrolyzed fish paste added accounts for 3-5% of the mass of the crayfish puffed feed.

8. The preparation method according to claim 1, characterized in that, In the step of fermenting the second material and drying the resulting fermented material, the fermentation process specifically includes fermenting for 20-30 hours at a temperature of 28-30℃, a pH of 3-4, and a relative humidity of 65-75%.

9. The preparation method according to claim 1, characterized in that, In the step of fermenting the second material and drying the resulting fermented material, the drying process specifically includes drying the fermented material at a temperature of 40-50℃ until the moisture content is ≤12%.

10. A fermented feed to attract crayfish, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

Images