A biological attractant based on Schizochytrium fermentation broth and its preparation method
By preparing a biological attractant based on Schizochytrium fermentation broth, the problems of resource waste and DHA rancidity were solved, providing a green and efficient aquatic attractant that improves the feeding rate and stress resistance of aquatic animals and reduces production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI TIANKAI BIOTECHNOLOGY CO LTD
- Filing Date
- 2026-03-26
- Publication Date
- 2026-05-26
AI Technical Summary
In existing technologies, the fermentation broth of Schizochytrium is not fully utilized, leading to resource waste and environmental pressure. At the same time, DHA is prone to rancidity, resulting in off-flavors and toxicity. Chemical attractants are banned, and there is a lack of green and efficient aquatic attractants.
By using the fermented broth after oil extraction from Schizochytrium, a bio-attractant that does not require the addition of stabilizers was prepared through filtration, sterilization, and pH adjustment. The natural viscosity of algal polysaccharides was used to maintain stability, and the synergistic effect of umami amino acids and DHA was combined to prepare a simple and low-cost bio-attractant.
It significantly improves the feed intake and stress resistance of aquatic animals, improves the breeding environment, reduces production costs, realizes the full-chain utilization of resources, and can still maintain the feeding effect in rainy and low-temperature environments.
Abstract
Description
Technical Field
[0001] This invention relates to the field of aquaculture technology, and in particular to a biological attractant based on Schizochytrium fermentation broth and its preparation method. Background Technology
[0002] In aquaculture, attractants are key additives for improving feed utilization, reducing water pollution, and ensuring the healthy growth of aquatic animals. With the national ban on the use of chemical attractants such as DMPT, developing green, efficient, natural attractants with nutritional functions has become the core direction for the industry's development.
[0003] Schizochytrium is a core microalgae raw material for the industrial production of DHA. The fermentation broth produced after oil extraction is naturally rich in amino acids, algal polysaccharides, DHA, and other active ingredients, as well as minerals such as magnesium, calcium, and sodium, and small molecule peptides, possessing the dual potential of natural appetite stimulant and nutritional supply. DHA, as an essential polyunsaturated fatty acid for aquatic animals, has both tropism-inducing and anti-stress functions. However, DHA is prone to rancidity in the absence of antioxidants. Oxidized DHA not only loses its nutritional value but also produces aldehydes, which then produce an off-odor, causing animals to refuse to eat and even have toxic effects. Currently, this fermentation broth is mostly discarded or simply disposed of, resulting in resource waste and environmental pressure. There are no reports of using it as the sole functional base for preparing aquatic appetite stimulants, and its natural synergistic appetite-stimulating value has not been fully explored. Summary of the Invention
[0004] To address the shortcomings of existing technologies, one objective of this invention is to provide a biological attractant based on Schizochytrium fermentation broth; another objective is to provide a method for preparing the biological attractant based on Schizochytrium fermentation broth; a third objective is to provide a method for using the biological attractant based on Schizochytrium fermentation broth; and a fourth objective is to provide an application of the biological attractant based on Schizochytrium fermentation broth.
[0005] One of the objectives of this invention is achieved through the following technical solution: A bio-attractant based on the fermentation broth of Schizochytrium is obtained by processing the fermentation broth after oil extraction from Schizochytrium. It requires no excipients, stabilizers, or anti-flatulence agents, and has advantages such as simple production process and low cost.
[0006] Furthermore, the fermentation broth after oil extraction from Schizochytrium is the residual fermentation broth after supercritical CO2 oil extraction or enzymatic hydrolysis of Schizochytrium.
[0007] Furthermore, the physicochemical properties of the fermentation broth after oil extraction from the Schizochytrium include: The total amino acid content is 6.8-9.2 g / L, of which umami amino acids (including glutamic acid, aspartic acid, phenylalanine, alanine, glycine and tyrosine) account for ≥40%; the content of algal polysaccharides is 3.1-4.3 g / L, and the content of DHA is 0.53-0.81 g / L; it also contains magnesium, calcium, sodium minerals and small molecule peptides, and has no residues of toxic and harmful substances prohibited in aquaculture.
[0008] The second objective of this invention is achieved through the following technical solution: A method for preparing a biological attractant based on Schizochytrium fermentation broth includes the following steps: Step 1: Fermentation broth pretreatment: Take the fermentation broth after oil extraction from Schizochytrium spp., filter it with a 100-200 mesh filter to remove residual algal residue and solid impurities, and obtain a clear fermentation broth that retains water-soluble active ingredients; Step 2: Sterilization and stabilization treatment: Sterilize the clarified fermentation broth at 62-65℃ for 30 minutes, cool it to room temperature, and adjust the pH value to 6.5-7.5. Utilize the natural viscosity characteristics of algal polysaccharides to make the system spontaneously maintain a uniform and stable state without the need to add any stabilizers. Step 3: Concentration and Adjustment: If used immediately on-site, the original liquid (sterilized fermentation broth with a solid content of 8-10%) can be used directly without concentration; if concentration is required, the sterilized fermentation broth should be concentrated under low temperature vacuum (temperature 40-50℃, vacuum degree -0.08~-0.09MPa) according to the application scenario requirements to obtain a concentrated liquid with a solid content of 20-30%, which is a concentrated palatability enhancer; Step 4: Filling and storage: Fill the concentrated or stock solution into a sealed container and store at room temperature away from light. Since there are no live bacteria to metabolize after sterilization, the problem of bloating is completely eliminated, and there is no need to add anti-bloating ingredients.
[0009] The third objective of this invention is achieved through the following technical solution: A method for using a biological attractant based on Schizochytrium fermentation broth involves diluting the biological attractant based on Schizochytrium fermentation broth, mixing it evenly with the feed, and then letting it stand.
[0010] Furthermore, take 0.2% of the fermentation liquid stock solution (add 0.2g of stock solution to 100g of feed), dilute it 10 times with aquaculture seawater (to avoid excessive local osmotic pressure affecting seedling feeding), mix it with the feed, stir for 3 minutes, let it stand for 10 minutes to fully absorb the liquid, and control the moisture content of the feed to within 10% after absorption, without clumping or disintegration. Prepare and use immediately, and seal and refrigerate any remaining feed (4℃) and use it within 12 hours. The fourth objective of this invention is achieved through the following technical solution: A biological attractant based on Schizochytrium fermentation broth, used to maintain a stable feeding effect in rainy and low-temperature environments.
[0011] A biological attractant based on the fermentation liquid of Schizochytrium is used to enhance the stress resistance and growth rate of aquatic animals, strengthen their immunity, produce regular and odorless feces, and improve the aquatic environment of aquaculture.
[0012] The beneficial effects of this invention are as follows: Significant feeding induction effect: The three core components in the fermentation liquid work synergistically, with umami amino acids quickly triggering the taste perception of aquatic animals, algal polysaccharides slowly releasing odor molecules to prolong the feeding induction effect, and DHA enhancing natural attraction. The feeding induction rate of Litopenaeus vannamei is significantly improved, with a feeding rate of over 75% in 10 minutes and complete feeding achieved in 30 minutes. The amount of remaining feed is reduced by more than 85% compared to the control group, and the feeding induction effect can still be maintained under rainy and low temperature conditions.
[0013] Excellent system stability: Relying on the natural viscosity and structural characteristics of algal polysaccharides, there is no need to add stabilizers such as xanthan gum. The product does not separate or settle within 3 months, which is superior to the stability of active ingredients in traditional probiotic attractants, and there is no risk of bloating or packaging breakage.
[0014] It has outstanding nutritional support effects: In addition to its appetite-enhancing effect, it can improve the stress resistance and growth rate of aquatic animals, enhance the body's immunity, and long-term use can increase the survival rate of shrimp by 10-15%, increase the weight gain rate by 8-12%, extend the pond transfer cycle by 2-3 days, produce regular and odorless feces, and improve the aquatic environment of aquaculture.
[0015] Significant economic and environmental benefits: The raw materials are industrial by-products, and the preparation cost is only 1 / 3 to 1 / 2 of that of traditional bacterial fermentation attractants. Moreover, the process is simplified and energy consumption is low. It not only realizes the full-chain utilization of Schizochytrium resources, but also reduces by-product emissions, which meets the needs of industrialized green aquaculture and has broad prospects for promotion. Detailed Implementation
[0016] The following is a further explanation with reference to specific implementation methods: Example
[0017] The fermentation broth after enzymatic hydrolysis and oil extraction of Schizochytrium was analyzed and found to contain the following components: total amino acids 6.8 g / L, including glutamic acid 3.1 g / L and aspartic acid 1.7 g / L, with umami amino acids accounting for 47.8%; algal polysaccharides 4.3 g / L and DHA 0.81 g / L; magnesium 0.32 g / L, calcium 0.18 g / L, and sodium 0.55 g / L. No heavy metals or toxic and harmful substances remained, meeting the raw material requirements.
[0018] Pretreatment: The fermentation broth was filtered using a 150-mesh stainless steel filter at a pressure of 0.1 MPa to remove residual algae residue and solid particles. The clarity after filtration was ≥95%. The supernatant was used as the pretreatment liquid, and the water-soluble active ingredients were found to be 100% retained.
[0019] Sterilization and stability: Sterilize at 63±2℃ for 30 min, cool to room temperature and adjust pH to 7±1. The system is stabilized by utilizing the natural viscosity of algal polysaccharide (viscosity 26mPa・s), and no stabilizer needs to be added. Concentration on demand: For immediate on-site use, the original solution (9% solids content) is used; for long-term storage, low-temperature vacuum concentration (43℃, vacuum degree -0.08MPa) is used to concentrate the solution to a solids content of 23%. Storage conditions: Store at room temperature, away from light, and sealed. The retention rate of core components (umami amino acids, algae polysaccharides, and DHA) is ≥85% within 6 months, with no risk of bloating.
[0020] Experiment Example 1: Comparative Experiment on the Feeding Inducing Effect of Litopenaeus vannamei Experimental subjects and groups Litopenaeus vannamei larvae, in their initial state (0.9-1.0 cm in length, 0.052 ± 0.01 g in weight), with a healthy and disease-free initial survival rate of 97.2%, were selected as the experimental subjects from a conventional seedling farm in Hainan. The experiment was divided into three groups, with three replicates per group. The control group was fed a basal diet without any added attractants; the commercially available attractant group received 0.1% of a commercially available attractant (mainly composed of betaine and amino acid complex, 2.5 yuan / kg, added according to the dry weight of the feed) in their basal diet; and the Schizochytrium fermentation liquid group received 0.2% of the concentrate (cost 0.8 yuan / L) in their basal diet. Each group contained 300 Litopenaeus vannamei larvae, with 100 larvae per replicate. The culture containers were 300L glass aquariums, and the culture environment for all three groups was consistent with routine management practices.
[0021] 1. Method of adding palatability enhancers The basic feed pellets have a diameter of 0.2mm, are water-soluble and stable, and are suitable for the feeding characteristics of seedlings. The addition process is strictly standardized.
[0022] Commercially available attractant group: Mix commercially available attractant powder with feed in a certain proportion, dry mix evenly, and let stand for 5 minutes to allow it to be absorbed and adhered; Schizochytrium fermentation liquid group: Take the original liquid obtained in Example 1 at a ratio of 0.2%, dilute it 10 times with aquaculture seawater (to avoid excessive local osmotic pressure affecting seedling feeding), mix it with feed and stir for 3 minutes, let it stand for 10 minutes to fully absorb, and control the moisture content of the feed to within 10% after absorption, without clumping or disintegration. Prepare and use immediately, and seal and refrigerate the remaining feed (4℃) and use it within 12 hours. Control group: No palatability enhancers were added; the animals were fed basic feed directly.
[0023] 2. Aquaculture environment control The rearing environment for Litopenaeus vannamei larvae is as follows: salinity 27±2‰, temperature 26±0.5℃, dissolved oxygen ≥7.5mg / L, 1 / 5 of the water is changed daily, Tongwei compound probiotics (Bacillus subtilis + nitrifying bacteria) are used to condition the water, ammonia nitrogen ≤0.12mg / L, nitrite ≤0.04mg / L, and transparency 35-40cm. 3. Feeding and daily management Litopenaeus vannamei larvae are fed 5 times a day (7:00, 10:00, 13:00, 16:00, 19:00), with a feeding amount of 6%-9% of their body weight (6% initially, increasing by 1% every 5 days, based on the condition that the amount of uneaten feed 1 hour after feeding is ≤3%). Uneaten feed is collected at 3 fixed locations around the feeding point using a 60-mesh ultrafine sieve. 1 hour after feeding, the sieve is gently lifted, the uneaten feed is rinsed with sterile water, dried at 65℃ for 3 hours, and then weighed.
[0024] The experiment lasted for 45 days. During this period, water quality indicators were tested every 7 days using a portable water quality analyzer. Every 15 days, 25 shrimp were randomly sampled from each group for indicator testing.
[0025] 4. Comparison of results from the three groups of experiments (1) Comparison of feeding effects The feeding response time in the *Schizochytrium* fermentation liquid group was (36.8±3.2s), which was 43.6% shorter than that in the control group (65.3±4.8s), and there was no significant difference compared with the commercially available attractant group (39.5±3.5s). The cumulative feeding rate in the *Schizochytrium* fermentation liquid group over 2 hours was (89.2±2.3%), compared with (72.3±3.5%) in the control group and (87.5±2.8%) in the commercially available group. The feeding time in the *Schizochytrium* fermentation liquid group was (22.5±1.3min), compared with (23.7±1.7min) in the commercially available group, which was 46.2% shorter than that in the control group (41.8±2.5min).
[0026] (2) Comparison of growth performance The average survival rate of the *Schizochytrium* fermentation liquid group after 45 days was (86.6±2.3%), which was 14.2% higher than that of the control group (72.4±3.8%) and 8% higher than that of the commercially available attractant group (80.2±3.2%). The average growth rate of the *Schizochytrium* fermentation liquid group was (6.85±0.22% / d), while that of the commercially available attractant group was (6.72±0.25% / d), both significantly higher than that of the control group (5.65±0.23% / d). The feed conversion ratio of the *Schizochytrium* fermentation liquid group was (1.42±0.07), which was not significantly different from that of the commercially available attractant group (1.45±0.04), but was 21.5% lower than that of the control group (1.81±0.08).
[0027] (3) Comparison of immune functions The serum lysozyme activity in the Schizochytrium fermentation broth group was (128.5±8.6U / mL), which was 22.0% higher than that in the commercially available attractant group (105.3±7.2U / mL) and 67.3% higher than that in the control group (76.8±6.5U / mL).
[0028] The experimental results showed that the feeding attraction effect of the fermented broth group of *Schizochytrium* was comparable to that of commercially available feeding attractants, and was significantly higher than that of the control group without feeding attractants. Moreover, the fermented broth group of *Schizochytrium* could improve the immune function and survival rate of Litopenaeus vannamei, and also had the effect of feeding attractants. The overall effect was better than that of the commercially available feeding attractant group.
[0029] Experiment Example 2: Experiment on the feeding attraction effect of Litopenaeus vannamei under rainy weather conditions The feeding response time of the *Schizochytrium* fermentation broth group was recorded under cloudy and rainy weather conditions (water temperature 15℃±1℃) (all other conditions were the same as those of the *Schizochytrium* fermentation broth group in Experiment 1), and the result was 36.9±2.5s. This means that the feeding attractant can maintain a stable feeding effect under cloudy and rainy low-temperature conditions.
[0030] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.
Claims
1. A biological feeding attractant based on Schizochytrium fermentation broth, characterized in that, It is obtained by processing the fermentation broth after oil extraction from Schizochytrium.
2. The biological feeding attractant based on Schizochytrium fermentation broth according to claim 1, characterized in that: The fermentation broth after oil extraction from Schizochytrium is the residual fermentation broth after supercritical CO2 oil extraction or enzymatic hydrolysis of Schizochytrium.
3. The biological feeding attractant based on Schizochytrium fermentation broth according to claim 1, characterized in that: The physicochemical properties of the fermentation broth after oil extraction from Schizochytrium include: The total amino acid content is 6.8-9.2g / L, of which umami amino acids account for ≥40%; the content of algal polysaccharides is 3.1-4.3g / L, and the content of DHA is 0.53-0.81g / L; it also contains magnesium, calcium, sodium minerals and small molecule peptides, and has no residues of toxic and harmful substances prohibited in aquaculture.
4. A method for preparing a bio-attractant based on Schizochytrium fermentation broth as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Fermentation broth pretreatment: Take the fermentation broth after oil extraction from Schizochytrium spp., filter it with a 100-200 mesh filter to remove residual algal residue and solid impurities, and obtain a clear fermentation broth that retains water-soluble active ingredients; Step 2: Sterilization and stabilization treatment: Sterilize the clarified fermentation broth at 62-65℃ for 30 minutes, cool it to room temperature, and adjust the pH value to 6.5-7.5; Step 3: Concentration and Control: If used immediately on-site, the sterilized fermentation broth is used directly as the stock solution; if concentration is required, the sterilized fermentation broth is concentrated under low temperature and vacuum to obtain a concentrated solution with a solid content of 20-30%. Step 4: Filling and storage: Fill the concentrated or stock solution into a sealed container and store at room temperature away from light.
5. A method of using a biological attractant based on *Schizochytrium* fermentation broth as described in any one of claims 1-3, characterized in that, The bio-attractant based on the fermentation broth of Schizochytrium was diluted, mixed evenly with the feed, and then left to stand.
6. The method of use according to claim 4, characterized in that: Take 0.2% of the fermentation liquid stock solution by mass, dilute it 10 times with aquaculture seawater, mix it with the feed and stir for 3 minutes. Let it stand for 10 minutes to fully absorb the liquid. After absorption, the moisture content of the feed should be controlled within 10%, without clumping or disintegration. Prepare and use immediately. Seal and refrigerate any remaining feed and use it within 12 hours.
7. A biological feeding attractant based on Schizochytrium fermentation broth as described in any one of claims 1-4, used to maintain a stable feeding attraction effect under rainy and low-temperature conditions.
8. A biological attractant based on Schizochytrium fermentation broth as described in any one of claims 1-4, used to enhance the stress resistance and growth rate of aquatic animals and strengthen their immunity.