Functional nutrition bag for improving cold water fish meat quality and breeding method

Abstract

The invention discloses a functional nutrition bag for improving cold water fish meat quality and a culture method, and belongs to the technical field of aquaculture. The functional nutrition bag comprises the following raw materials in percentage by weight: 25%-50% of schizochytrium limacinum powder, 10%-40% of chlorella powder, 0%-40% of linseed oil and 0%-15% of an amino acid compound. According to the breeding method, the functional nutrition bag and commercially available feed are matched for feeding in the'window period 'before the cold water fishes appear on the market. The innovative functional nutrition bag is combined with a special method, the content of DHA and total n-3 polyunsaturated fatty acid in cold water fish muscles can be remarkably increased, meanwhile, the muscle color and texture characteristics are optimized, a cold water fish product with high quality and high additional value is finally obtained, and synergistic improvement of flavor substances and nutritional quality is achieved. In addition, the non-whole-course feeding mode avoids the cost pressure of whole-course addition of nutrition bags, the economical efficiency is excellent, and market popularization is facilitated.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, and in particular to a functional nutrient package and aquaculture method for improving the quality of cold-water fish meat. Background Technology

[0002] With the significant improvement in the national economic level and the continuous enhancement of residents' health awareness, consumers' dietary concepts are undergoing profound changes. The demand for aquatic products has shifted from "eating enough" to "eating well" and "eating healthily." High-quality, high-nutritional-value functional foods, especially those rich in specific health benefits (such as docosahexaenoic acid, DHA), are highly favored by the market. Rainbow trout, as a cold-water fish and an important economic fish, has delicious flesh and the potential to become a high-end health food. However, the current conventional aquaculture model, which is oriented towards cost reduction and the pursuit of rapid growth, is significantly at odds with this market demand.

[0003] Currently, a common practice to improve the nutritional value of fish meat is to add ingredients rich in n-3 polyunsaturated fatty acids (n-3 PUFAs), such as fish oil or algae products, to the formulated feed throughout the entire aquaculture cycle. While this method can improve the fatty acid composition of fish meat to some extent, it also has significant limitations: Firstly, fish oil, as a major source of n-3 PUFAs, is becoming increasingly scarce, with high and volatile prices, leading to a substantial increase in aquaculture costs; secondly, although algae powder can directly provide DHA, its cost is also high, making large-scale promotion difficult throughout the entire aquaculture cycle; more importantly, this "extensive" method of adding supplements throughout the entire cycle has low nutrient utilization efficiency. During the rapid growth phase of fish, ingested nutrients are mainly used for tissue synthesis rather than the deposition of target functional nutrients, resulting in a waste of supplementary resources. In other words, existing aquaculture methods have the following drawbacks and shortcomings:

[0004] (1) The contradiction between cost and effect: Conventional feeds that are cost- and growth-efficiency-oriented cannot simultaneously ensure high quality and high nutritional value of the product. If growth rate is pursued, it is difficult to achieve a synergistic improvement in flavor substances and nutritional quality. If high-cost fish oil or algae powder is used throughout the process to improve quality, it is not economically viable and farmers cannot afford it, which restricts the improvement of the industry's added value.

[0005] (2) Low nutrient utilization efficiency: Adding functional nutrients throughout the entire growth cycle of fish is a “rough” nutrient fortification strategy. During the rapid growth stage of juvenile fish, the nutrients ingested are used more for protein synthesis and body building, rather than for the enrichment of specific functional components (such as DHA). This results in expensive additives being consumed in non-critical growth stages, leading to low utilization efficiency and waste.

[0006] (3) Unable to meet the demand of the high-end market: Rainbow trout produced by the existing farming model usually have a medium level of beneficial fatty acids such as DHA in their muscle, which cannot be compared with wild products or specially fortified functional foods. It is difficult to meet consumers' demand for "eating well" and "eating healthily" in the high-end market. The products are seriously homogenized and have weak premium capabilities.

[0007] Therefore, existing technologies struggle to effectively balance the simultaneous improvement of rainbow trout's flavor and functional nutritional value, resulting in a lack of competitiveness and limited added value in the high-end market, thus hindering the industry's transformation and upgrading. In light of this, there is an urgent need in this field to propose a more targeted and economical innovative aquaculture strategy to efficiently and precisely improve the muscle quality of cold-water fish, particularly increasing DHA content, thereby meeting consumers' diversified demands for high-quality aquatic products. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a functional nutritional package for improving the quality of cold-water fish meat, which can efficiently and accurately improve the quality of cold-water fish muscle, especially increase the DHA content, and has the advantages of low cost and high targeting, which can meet the diversified needs of consumers for high-quality aquatic products, thereby overcoming the shortcomings of existing common practices for improving the nutritional value of fish meat.

[0009] To address the aforementioned technical problems, this invention provides a functional nutritional pack for improving the quality of cold-water fish meat. This functional nutritional pack comprises the following ingredients by weight percentage: 25%-50% Schizochytrium powder, 10%-40% Chlorella powder, 0%-40% flaxseed oil, and 0%-15% amino acid complex.

[0010] Further improvements have been made to this functional nutrition pack, which includes the following ingredients by weight percentage: 25%-50% Schizochytrium powder, 10%-40% Chlorella powder, 10%-40% flaxseed oil, and 5%-15% amino acid complex.

[0011] Further improvements were made, with the weight ratio of raw materials Schizochytrium powder, Chlorella powder, flaxseed oil, and amino acid complex being 5:2:2:1.

[0012] Further improvements were made, with the weight ratio of raw materials Schizochytrium powder, Chlorella powder, and flaxseed oil being 3:1:1.

[0013] In a further improvement, the amino acid complex includes one or more of lysine, methionine, threonine, tryptophan, arginine, glutamic acid, glycine, and vitamin C.

[0014] In a further improvement, the amino acid complex comprises lysine, methionine, threonine, tryptophan, arginine, glutamic acid, glycine, and vitamin C in equal mass ratios.

[0015] As a further improvement of the present invention, the present invention also provides a method for improving the quality of cold-water fish meat. This method involves feeding cold-water fish with the aforementioned functional nutrient package for improving the quality of cold-water fish meat, and combining the functional nutrient package with commercially available feed.

[0016] To further improve the process, starting 3-5 weeks before the cold-water fish are put on the market, feed them in an intermittent manner, using the aforementioned functional nutrition pack in combination with commercially available feed.

[0017] Alternatively, starting 3-5 weeks before the cold-water fish are put on the market, feed them with the aforementioned functional nutrition pack every other day instead of one regular commercial feed meal.

[0018] As a further improvement, the cold-water fish is now rainbow trout.

[0019] With this design, the present invention has at least the following advantages:

[0020] The functional nutritional package of this invention is composed of Schizochytrium, Chlorella, plant oils rich in α-linolenic acid (such as flaxseed oil), and amino acid complex in a specific ratio. This allows the DHA content and total n-3 polyunsaturated fatty acid content in the muscle of the produced cold-water fish to be significantly higher than those of conventionally farmed cold-water fish. At the same time, the color and textural properties (such as hardness and adhesiveness) of the muscle are optimized, ultimately resulting in a high-quality, high-value-added cold-water fish product, achieving a synergistic improvement in flavor substances and nutritional quality.

[0021] The breeding method of this invention adopts a "window period" feeding strategy before market launch. That is, only during a specific period before the cold-water fish are marketed, a "partial substitution" feeding mode is used, such as replacing one meal of regular commercial feed with this functional nutrition pack 3-4 times a week, instead of feeding functional nutrition packs throughout the entire process. This avoids the cost pressure of adding nutrition packs throughout the entire process, and precisely targets the key stage of meat quality improvement. The method is highly targeted and innovative.

[0022] This invention combines an innovative functional nutritional package with a special method, and the specific technical effects are as follows:

[0023] (1) Precise and efficient, directly addressing pain points: Traditional technologies either use expensive additives (such as fish oil) throughout the process, resulting in high costs, or the improvement effect is not obvious. This invention provides precise nutritional intervention for the critical period of fat deposition and fatty acid conversion in the later stage of fish growth, achieving the best DHA enrichment effect in the shortest time and with the least amount of additives, with extremely high efficiency.

[0024] (2) Cost reduction and efficiency improvement, economical and practical: This invention adopts a "partial substitution" aquaculture strategy, using nutrient packs only in the most critical fattening stage, which significantly reduces the total amount of functional additives used and the overall aquaculture cost. This makes the technical solution for producing high-quality cold-water fish highly economical and worth promoting, and easily accepted by aquaculture farmers.

[0025] (3) Synergistic effect and comprehensive quality improvement: The ingredients in the functional nutrition pack are scientifically and rationally proportioned. Schizochytrium provides DHA directly, Chlorella is rich in a variety of nutrients, which may promote the body's health and metabolism as well as pigment deposition in the muscles. ALA provided by flaxseed oil can be converted into DHA in the fish as a precursor, and the amino acid complex can help improve the flavor and texture of the muscle. The combination of ingredients in this invention achieves the synergistic absorption and deposition of n-3 polyunsaturated fatty acids from different sources, which is better than that of a single ingredient, and at the same time improves the texture of the meat.

[0026] (4) Simple operation and easy to promote: This breeding method does not require changing the existing mainstream breeding equipment and feed system of farmers. Only the feeding content needs to be adjusted in the period before the market is ready. It is simple to operate, easy to understand and implement, and very suitable for rapid promotion and application in existing farms.

[0027] (5) Product differentiation and high added value: The aquaculture method of this invention can directly produce cold-water fish products of the "functional food" level rich in DHA, which is significantly differentiated from ordinary products, meets the needs of the high-end market, and significantly improves the added value of the industry. Attached Figure Description

[0028] The above is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Figure 1 A schematic diagram illustrating the correlation analysis between DHA in muscle and DHA in feed in this embodiment of the invention.

[0030] Figure 2 A schematic diagram illustrating the correlation analysis between EPA in muscle and EPA in feed in an embodiment of the present invention. Detailed Implementation

[0031] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that a more thorough understanding of the invention will be achieved and that the full scope of the invention will be conveyed to those skilled in the art.

[0032] This embodiment describes the functional nutrient package and aquaculture method for improving the quality of cold-water fish meat, taking rainbow trout meat as an example, to illustrate the technical solution of the present invention in detail. This should not be construed as limiting the invention in any way. Specific embodiments are as follows.

[0033] 1. Preparation of different functional nutritional packs

[0034] This embodiment prepared eight different formulas of DHA-rich nutritional packs:

[0035] (1) Nutrition pack A: Composed of 100% Schizochytrium powder, of which the DHA content in Schizochytrium is ≥55%.

[0036] (2) Nutrition pack B: It is composed of Schizochytrium powder and soybean oil in a mass ratio of 7:3.

[0037] (3) Nutrition pack C: It is composed of Schizochytrium powder and rapeseed oil in a mass ratio of 7:3.

[0038] (4) Nutritional pack D: It is composed of Schizochytrium powder and peanut oil in a mass ratio of 7:3.

[0039] (5) Nutritional pack E: It is composed of Schizochytrium powder and flaxseed oil in a mass ratio of 7:3.

[0040] (6) Nutrition pack F: It is composed of Schizochytrium powder and Chlorella powder in a mass ratio of 7:3.

[0041] (7) Nutritional pack G: It is composed of Schizochytrium powder, Chlorella powder and flaxseed oil in a mass ratio of 3:1:1.

[0042] (8) Nutritional Pack H: Composed of Schizochytrium powder, Chlorella powder, flaxseed oil, and amino acid complex in a mass ratio of 5:2:2:1. The amino acid complex contains lysine, methionine, threonine, tryptophan, arginine, glutamic acid, glycine, and vitamin C, and the components are mixed in the same mass ratio.

[0043] All the above-mentioned nutrition packs are mixed according to the corresponding raw material ratios and then processed into pellets with a similar particle size to commercially available feed using the same pelleting process for feeding purposes.

[0044] 2. Experimental Design and Grouping

[0045] Prepare 900 healthy rainbow trout of uniform size (initial average weight 198±2.5g) and randomly distribute them into 30 rearing tanks, with 30 trout in each tank, and 3 tanks in each treatment group.

[0046] Control group 1: fed commercially available rainbow trout feed throughout the entire process.

[0047] Control group 2: fed commercially available rainbow trout feed throughout the entire process.

[0048] Experimental groups 1-8: In addition to commercially available feed, the above-prepared nutritional packages A, B, C, D, E, F, G and H were fed separately.

[0049] All experimental groups received the same routine care as the control group, being fed commercially available feed twice daily until they appeared to be satiated. In addition, the experimental groups were fed an equal amount of corresponding nutritional supplement pellets every other day (approximately 3-4 times per week) instead of one regular meal of commercially available feed.

[0050] 3. Aquaculture Management and Sample Collection

[0051] The culture experiment lasted for 8 weeks. All groups were managed under the same environmental conditions (water temperature, dissolved oxygen, and photoperiod). Dorsal muscle samples were collected from experimental fish in each treatment group at weeks 2, 4, 6, and 8 of the culture experiment.

[0052] The collected samples were used to measure the following indicators:

[0053] Fatty acid composition and content: The content of fatty acids such as DHA and EPA in muscle was determined by gas chromatography, which is the core indicator for evaluating the effectiveness of the nutritional package.

[0054] Composition and content of free amino acids: Comparison of the content of flavor amino acids in different groups.

[0055] Muscle texture properties: The hardness, elasticity, chewiness, adhesiveness, and cohesiveness of the muscle are determined using a physical property analyzer.

[0056] Flesh color: Objectively assessed using a colorimeter.

[0057] Muscle antioxidant capacity: Relevant indicators of muscle antioxidant capacity were detected using a kit.

[0058] By comparing the differences in the above indicators among different treatment groups at different time points, the best nutritional pack formula and the optimal time of action for improving the quality of rainbow trout meat (especially the DHA enrichment effect) can be selected.

[0059] 4. Experimental Results:

[0060] 4.1 Feed content was significantly correlated with muscle fatty acid content.

[0061] After the experiment, a correlation analysis was performed between the DHA data in the feed administered to each experimental group and the DHA data obtained from the muscle of rainbow trout. The results are attached. Figure 1 and attached Figure 2 As shown.

[0062] From the appendix Figure 1It can be seen that the DHA content in rainbow trout muscle is significantly positively correlated with the corresponding DHA content in the feed, with a correlation coefficient of 0.899. (See attached...) Figure 2 It can be seen that the EPA content in rainbow trout muscle is significantly positively correlated with the corresponding EPA content in the feed, with a correlation coefficient of 0.888. The results indicate that nutritional regulation of the feed can effectively increase the deposition level of target fatty acids in the muscle.

[0063] 4.2 Differences in fortification effects among different nutritional supplement formulas

[0064] Table 1 lists the DHA and EPA content in the muscle of rainbow trout from different experimental groups at different time points.

[0065] Table 1. Results of DHA and EPA content in the muscle of rainbow trout from different experimental groups at different time points.

[0066]

[0067] As shown in Table 1, throughout the entire experimental period, the DHA and EPA content in rainbow trout muscle remained at the lowest levels in control groups 1 and 2, which were fed only commercially available feed. Among the experimental groups, group 1 (with nutrient pack A) had the highest DHA content in rainbow trout muscle; groups 7 and 8 (with nutrient packs G and H respectively) showed the next best DHA enrichment effects, with little difference between the two groups; while groups 5 and 6 (with nutrient packs E and F respectively) had the next lowest DHA content, with no significant difference between the two groups. Regarding EPA deposition, groups 5 and 7 (with nutrient packs E and G respectively) showed the most significant effects, exceeding the other groups. The results indicate that different nutrient pack formulations have significantly different effects on enhancing the DHA and EPA content in rainbow trout muscle.

[0068] 4.3 The effect of feeding time of nutrient packs

[0069] As shown in Table 1, a longitudinal comparison of data at different time points revealed that by week 4 of feeding with the nutritional supplement, the levels of DHA and EPA in the muscle had significantly increased, exceeding the levels of week 2. Although the values ​​of various indicators continued to increase slightly in weeks 6 and 8, they did not reach a significant level compared to the data from week 4.

[0070] The results showed that a four-week nutrient fortification period could achieve efficient deposition of DHA and EPA, reaching an ideal balance between economic and technical benefits.

[0071] Further comparison of the feeding effects of experimental groups 1-8 with control groups 1-2 showed that all experimental groups significantly increased the DHA and EPA content in rainbow trout muscle, with experimental groups 7 and 8 showing the most significant improvement. The overall DHA and EPA content in their muscle was higher than that of other experimental groups and the commercial feed control group, indicating that the two ratios have significant advantages in promoting the deposition of functional fatty acids.

[0072] Based on the results of this study, it was determined that a 4-week nutrient supplementation period can achieve efficient deposition of DHA and EPA. Therefore, subsequent analysis focused on samples collected in the 4th week to screen for the optimal nutrient supplement combination.

[0073] 4.4 Free amino acid correlation analysis

[0074] The free amino acids in the rainbow trout samples collected in week 4 of the above experiment were further analyzed, and the results are shown in Table 2 below.

[0075] Table 2. Free amino acid content in the muscle of rainbow trout in each group (mg / 100g)

[0076]

[0077] As shown in Table 2 above, compared with the control group fed only commercially available feed, the content of umami amino acids, sweet amino acids, and bitter amino acids in the muscle of rainbow trout in each experimental group was increased, indicating that the nutrient package in this embodiment can effectively improve the overall flavor of rainbow trout muscle. Comparison among different formulation groups revealed that experimental group 8 (nutrient package H: Schizochytridium + Chlorella + flaxseed oil + amino acid compound group) showed the highest content of umami, sweet, and bitter amino acids, demonstrating its comprehensive advantages in flavor enhancement.

[0078] 4.5 Color Analysis of Rainbow Trout Back Muscles

[0079] The color of the back muscles in the rainbow trout samples collected in week 4 of the above experiment was analyzed using a colorimeter, and the results are shown in Table 3 below.

[0080] Table 3 Effects of each group on the muscle color of rainbow trout

[0081]

[0082] Note: In the table, 1 represents muscle brightness, a represents muscle redness, and b represents muscle yellowness.

[0083] As shown in Table 3, there was no significant difference in muscle brightness values ​​among the groups. However, in terms of redness and yellowness values, experimental groups 6-8 (with nutrient packs F, G, and H) that added Chlorella showed significantly higher values ​​than the other groups, indicating that the addition of Chlorella has a clear positive effect on improving muscle color. In contrast, there were no significant differences in redness and yellowness values ​​between the control group 1-2 and the experimental groups 1-5 that did not add Chlorella.

[0084] 4.6 Analysis of the textural properties of rainbow trout muscle

[0085] The muscle texture characteristics of rainbow trout samples collected in week 4 of the above experiment were further analyzed, and the results are shown in Table 4 below.

[0086] Table 4. Effects of each group on the textural properties of rainbow trout muscle

[0087]

[0088] As shown in Table 4, compared with the control groups 1-2, experimental groups 1-8 showed significant improvements in texture indicators such as hardness, chewiness, adhesiveness, cohesion, and adhesion. Simultaneously, shear force and drip loss decreased, indicating improved tenderness. This demonstrates that each nutrient pack effectively improves the physical texture and mouthfeel of the muscle. Among the various nutrient pack combinations, experimental groups 7 and 8 (combined with nutrient packs G and H) performed best in multiple indicators including hardness, chewiness, adhesiveness, cohesion, adhesion, shear force, and drip loss.

[0089] 4.7 Analysis of antioxidant indices in rainbow trout muscle

[0090] Based on the principle that antioxidant indicators can effectively reflect the freshness and quality stability of fish meat, the antioxidant indicators of muscle in rainbow trout samples collected in week 4 of the above experiment were analyzed, and the results are shown in Table 5 below.

[0091] Table 5 Effects of each group on the antioxidant properties of rainbow trout muscle

[0092]

[0093] The results showed that, compared with the control groups 1-2 fed only commercially available feed, the activities of key antioxidant enzymes in the muscle of each experimental group—including glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT)—were significantly increased. Simultaneously, the content of malondialdehyde (MDA), a key indicator of lipid peroxidation end product and oxidative damage, was significantly reduced in the muscle of all experimental groups. These results consistently indicate that the various nutrient packs can effectively enhance the antioxidant defense capacity of fish and delay muscle lipid oxidation, thereby helping to maintain the freshness and shelf life of fish meat. Among the various nutrient pack formulations, experimental groups 7 and 8 (combined with nutrient packs G and H) performed exceptionally well, outperforming other groups in all tested antioxidant indicators, demonstrating the strongest antioxidant protective effect on muscle tissue.

[0094] Based on the experimental data above, it is evident that both nutrient packs G and H exhibit excellent effects in several key quality dimensions, including improving muscle flavor composition, enhancing meat color, optimizing textural properties, and strengthening muscle antioxidant capacity. Among these, nutrient pack H (a combination of Schizochytrium brevicornu, Chlorella vulgaris, flaxseed oil, and amino acid compound) showed the best results. These results confirm that using a combination of specific formulations and a "partial substitution" feeding method can comprehensively and synergistically improve the overall edible quality and commercial value of rainbow trout muscle, while significantly reducing farming costs.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, or alterations made by those skilled in the art using the disclosed technical content shall fall within the protection scope of the present invention.

Claims

1. A functional nutritional package for improving the quality of cold-water fish meat, characterized in that, The ingredients include, by weight percentage: 25%-50% Schizochytrium powder, 10%-40% Chlorella powder, 0%-40% flaxseed oil, and 0%-15% amino acid complex.

2. The functional nutritional package for improving the quality of cold-water fish meat according to claim 1, characterized in that, The ingredients include, by weight percentage: 25%-50% Schizochytrium powder, 10%-40% Chlorella powder, 10%-40% flaxseed oil, and 5%-15% amino acid complex.

3. The functional nutritional package for improving the quality of cold-water fish meat according to claim 2, characterized in that, The weight ratio of the raw materials, Schizochytrium breviscapus powder, Chlorella powder, flaxseed oil, and amino acid complex, is 5:2:2:

1.

4. The functional nutritional package for improving the quality of cold-water fish meat according to claim 1, characterized in that, The weight ratio of the raw materials, Schizochytrium breviscapus powder, Chlorella powder, and flaxseed oil, is 3:1:

1.

5. The functional nutritional package for improving the quality of cold-water fish meat according to any one of claims 1 to 4, characterized in that, The amino acid complex includes vitamin C and one or more of lysine, methionine, threonine, tryptophan, arginine, glutamic acid, and glycine.

6. The functional nutritional package for improving the quality of cold-water fish meat according to claim 5, characterized in that, The amino acid complex comprises lysine, methionine, threonine, tryptophan, arginine, glutamic acid, glycine, and vitamin C in equal mass ratios.

7. A method for improving the quality of cold-water fish meat, characterized in that, The functional nutrient pack for improving the quality of cold-water fish meat as described in any one of claims 1 to 6 is used to feed cold-water fish, and the functional nutrient pack is used in combination with commercially available feed.

8. The method for improving the quality of cold-water fish meat according to claim 7, characterized in that, Starting 3-5 weeks before cold-water fish are put on the market, feed them intermittently using the aforementioned functional nutrition packs in combination with commercially available feed.

9. The method for improving the quality of cold-water fish meat according to claim 7, characterized in that, Starting 3-5 weeks before the cold-water fish are put on the market, feed them with the aforementioned functional nutrition pack every other day, replacing one of their regular commercial feed meals.

10. The method for improving the quality of cold-water fish meat according to claim 7, characterized in that, The cold-water fish mentioned is a rainbow trout.

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