Bamboo-based feed for aquaculture and preparation method thereof

Abstract

The invention belongs to the technical field of aquaculture feeds, and discloses a bamboo-based feed for aquaculture and a preparation method thereof.According to the feed, a bamboo-based raw material subjected to enzymolysis and probiotic fermentation treatment is used as a main material, bamboo polysaccharides, mannan oligosaccharides and galactooligosaccharides are used as auxiliary materials to construct a composite prebiotic system, and the composite prebiotic system is matched with a protein source, a fat source and mineral vitamins; the preparation method comprises the following steps: mixing, extruding, granulating and drying. The preparation method comprises the following steps: crushing the bamboo raw material, carrying out alkali treatment, carrying out synergetic enzymolysis on cellulase and pectinase, carrying out combined fermentation on lactic acid bacteria and yeast, and compounding the functional prebiotics and the nutritional additive. The feed can significantly improve digestibility of bamboo-based crude fibers, enhance intestinal flora balance and nutrient absorption efficiency of aquatic animals, and is helpful for promoting growth, increasing survival rate and improving water quality environment. Compared with the existing bamboo feed, the bamboo feed has the advantages of efficient utilization, functional design and environmental friendliness, and is suitable for various aquaculture animals.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture feed technology, specifically relating to a bamboo-based feed for aquaculture and its preparation method. Background Technology

[0002] With the rapid development of aquaculture, feed, as a major component of aquaculture costs, directly impacts farming efficiency in terms of quality and cost. Traditional aquatic feeds are mostly based on high-protein ingredients such as fishmeal and soybean meal, supplemented with nutrients such as oils, vitamins, and minerals. However, fishmeal is expensive and scarce, plant-based proteins have low digestibility in aquatic animals, and the large-scale use of soybean meal intensifies competition between grains and feed, limiting the sustainable development of aquaculture. Therefore, developing a low-cost, widely available, nutritionally balanced, and environmentally friendly alternative feed is of great significance.

[0003] In recent years, bamboo resources have gradually attracted attention in feed research due to their advantages of rapid growth, high yield, and wide distribution. Bamboo culms, leaves, and shoot husks are rich in crude fiber, polysaccharides, and some functional components, making them potential feed ingredients. However, the lignin and complex polysaccharide structures in bamboo raw materials are difficult for aquatic animals to digest and absorb directly. If added directly to feed without processing, it may reduce feed conversion rate.

[0004] On the other hand, gut health in aquatic animals has a crucial impact on their growth, development, and immunity. Prebiotics, as functional substances that promote the growth of beneficial bacteria and improve gut microbiota structure, are increasingly widely used in feed. Existing studies have mostly used oligosaccharides as prebiotic additives, but systematic research on constructing complex prebiotic systems based on bamboo polysaccharides is still lacking. Summary of the Invention

[0005] To address the shortcomings mentioned in the background art, the present invention aims to provide a bamboo-based feed for aquaculture and its preparation method. The feed uses bamboo-based raw materials treated with enzymatic hydrolysis and probiotic fermentation as the main ingredient, and combines bamboo polysaccharides and oligosaccharides to construct a complex prebiotic system. This system is then scientifically formulated with protein sources, fat sources, vitamins, and minerals. The feed is prepared through mixing, conditioning, granulation, and drying. This method can improve the digestibility and utilization rate of bamboo resources, and enhance the intestinal health and feed conversion efficiency of aquatic animals.

[0006] The objective of this invention can be achieved through the following technical solutions: A bamboo-based feed for aquaculture comprises the following raw materials in parts by weight: 30-60 parts of fermented bamboo-based raw material, 2-10 parts of bamboo polysaccharide, 1-5 parts of oligosaccharide, 20-40 parts of protein source, 3-8 parts of fat source, 1-3 parts of vitamin-mineral premix, and 0.5-2 parts of binder. The bamboo-based raw material is selected from one or more of bamboo culms, bamboo leaves, and bamboo shoot shells.

[0007] More preferably, the method for preparing fermented bamboo-based raw materials specifically includes the following steps: S101. Mix the pulverized bamboo raw material with cellulase and pectinase, and react for 2 to 4 hours at 50 to 60°C and pH 5.0 to 6.0 to degrade the crude fiber and polysaccharide structure and obtain the enzymatic hydrolysis product. S102. Inoculate the enzymatic hydrolysis product with lactic acid bacteria and yeast strains, wherein the lactic acid bacteria are selected from Lactococcus lactis and the yeast is selected from Saccharomyces cerevisiae. Ferment at 30-37℃ for 12-24 hours to obtain the fermentation product. S103. The fermentation product is dried at low temperature to control the moisture content to no more than 10%, thereby obtaining the fermented bamboo-based raw material.

[0008] More preferably, the amount of cellulase used is 0.5-2.0% of the mass of the bamboo-based raw material, the amount of pectinase used is 0.2-1.0%, and the pH is 5.0-6.0.

[0009] More preferably, the bamboo polysaccharide is obtained by hot water extraction, alcohol precipitation, decolorization, concentration and drying of bamboo culms or leaves. The bamboo polysaccharide has a β-(1→3) or β-(1→4) main chain structure and an average molecular weight of 1000 to 10000 Da.

[0010] More preferably, the oligosaccharide is composed of mannan oligosaccharide and galactooligosaccharide in a mass ratio of 1:(0.5 to 1.5).

[0011] More preferably, the protein source is one or more of fish meal, soybean meal, fermented soybean meal, hydrolyzed fish protein, and yeast protein, and the fat source is one or more of fish oil, flaxseed oil, and rapeseed oil.

[0012] A method for preparing bamboo-based feed for aquaculture includes the following steps: S1. Take the fermented bamboo-based raw material, dry it at low temperature, and then pulverize it to a fineness of less than 200 μm using a pulverizer for later use; S2. Add bamboo-based raw materials, bamboo polysaccharides, oligosaccharides, protein sources, fat sources, vitamin-mineral premix and binder to the mixing equipment in sequence, pre-stir for 3 to 5 minutes, and then mix at high speed for 10 to 15 minutes to fully disperse and mix the components to form a uniform wet mixture. S3. The mixed wet material is conveyed to the conditioner, an appropriate amount of water or steam is sprayed in to adjust the moisture content, and it is matured at medium temperature for 5 to 10 minutes. S4. Feed the conditioned and matured material into a twin-screw or ring die extruder for granulation, so that the resulting granules are cylindrical or elliptical in shape, with a length of about 1 to 2 times the diameter of the granules. S5. The freshly extruded pelleted feed is transported to a drying device and dried under low-temperature hot air conditions until the moisture content is ≤10%; after drying, it is cooled by a cold air blower to obtain the bamboo-based feed for aquaculture.

[0013] More preferably, the surface of the dried pelleted feed in step S5 is coated with a coating material selected from fish oil, chitosan solution, and gelatin-sodium alginate composite solution to improve the stability of the feed in water and achieve a slow-release effect.

[0014] More preferably, the feed includes a cooling and sieving step after drying. The cooling step uses a cold air blower to lower the feed temperature to room temperature, and the sieving step uses a vibrating screen to remove powder and unqualified particles to obtain a finished feed with uniform particle size.

[0015] The beneficial effects of this invention are: This invention significantly improves the nutritional utilization efficiency and functional value of bamboo resources in aquaculture by constructing a functional aquatic feed system based on fermented bamboo-based raw materials and centered on compound prebiotics. Cellulase and pectinase are used to synergistically enzymatically hydrolyze bamboo culms and leaves, effectively breaking down their fiber wall structure and releasing soluble polysaccharides, significantly reducing the indigestible portion of crude fiber. Subsequently, Lactococcus lactis and Saccharomyces cerevisiae are inoculated for compound fermentation, further decomposing residual anti-nutritional factors in the bamboo-based raw materials and enriching metabolites such as organic acids, oligosaccharides, and functional peptides, thereby enhancing feed palatability and digestibility. Compared to untreated crude fiber feed, the fermented bamboo-based raw materials obtained by this invention have higher enzymatic hydrolysis and stronger nutrient release capacity, solving the core problem of bamboo materials being "abundant but difficult to utilize." Based on this, the present invention introduces a complex prebiotic system represented by bamboo polysaccharides, mannan oligosaccharides and galactooligosaccharides, which can selectively promote the proliferation of beneficial bacteria (such as lactic acid bacteria and bifidobacteria) and inhibit the growth of harmful bacteria in the intestines of aquatic animals, regulate the intestinal microecological balance, thereby improving the animals' ability to absorb feed nutrients and growth performance, and enhancing their stress resistance and disease resistance. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a bar chart comparing the disintegration time and solubility loss rate of the feed samples of the present invention in water. Figure 2 This is a comparison chart of the daily weight gain rate of the feed samples of the present invention when feeding tilapia. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 Preparation of bamboo-based raw materials by fermentation Add 1000g of bamboo stalk powder to 3000mL of distilled water and stir until homogeneous to form a suspension. Adjust the pH to 5.5 using 1mol / L citrate buffer and preheat in a 55℃ water bath for 10 minutes. Add 15g of cellulase and 6g of pectinase to the preheated bamboo powder slurry and maintain the reaction at 55℃ and pH 5.5 for 3 hours with continuous stirring. After enzymatic hydrolysis, quickly cool to 35℃ and set aside. Add 3g of Lactococcus lactis powder and 1.5g of Saccharomyces cerevisiae powder to the hydrolysis product, mix thoroughly, and allow to stand at 35℃ for static fermentation for 18 hours. After fermentation, pour the mixture into a stainless steel pan, spread it to a thickness of 1-2cm, and dry it in a 55℃ hot air drying oven until the moisture content is ≤10%. After drying, cool to room temperature, pulverize and pass through an 80-mesh sieve to obtain fermented bamboo-based raw material powder.

[0020] II. Preparation of bamboo-based feed for aquaculture The bamboo-based feed for aquaculture contains the following raw materials in parts by weight: 30 parts fermented bamboo-based raw material, 2 parts bamboo polysaccharide, 1 part oligosaccharide, 20 parts protein source, 3 parts fat source, 1 part vitamin-mineral premix, and 0.5 parts binder. The bamboo-based raw material is selected from one or more of bamboo culms, bamboo leaves, and bamboo shoot shells.

[0021] The preparation steps are as follows: Take 300g of fermented bamboo-based raw material, put it into an ultrafine pulverizer, and pulverize it at 8000rpm for 2min to make its average particle size less than 200μm; then place it in a 60°C hot air drying oven to dry for 4h, controlling the moisture content to ≤8%, and set aside for later use. Add 300g of pulverized fermented bamboo-based raw material, 20g of bamboo polysaccharide, 10g of oligosaccharide, 200g of protein source, 10g of vitamin-mineral premix, and 5g of sodium alginate to a mixer, premix at 80rpm for 3min, and then mix at 300rpm for 10min. Transfer the resulting mixed powder to a conditioning machine, spray in 50mL of deionized water and 30g of fish oil, and stir at the same time to adjust the moisture content to 18±1%; set the conditioning temperature to 65°C and maintain for 5min. The conditioned wet material is fed into a twin-screw extruder, ensuring the barrel temperature is stable at 70–75°C. A cylindrical die with a 2mm aperture is installed at the discharge port, and the rotation speed is controlled at 200 rpm to produce cylindrical pellets. The pellets are immediately sent to a hot air drying oven at 55°C and 1.5m / s for 6 hours, until the feed pellet moisture content is ≤10%. The dried pellets are then cooled to room temperature using a cold air blower and sent to a vibrating screen to remove powder and pellets that do not meet the length requirements. Standard pellets within the 2–5mm range are selected for packaging. The screened and dried feed pellets are then loaded into a roller sprayer and evenly sprayed with 10g of chitosan solution. The mixture is then tumbled at room temperature for 5 minutes to promote uniform distribution and air-dried for 30 minutes until the surface is no longer sticky. This is the bamboo-based feed for aquaculture.

[0022] Example 2 The preparation method of the fermented bamboo-based raw material is the same as that in Example 1.

[0023] The bamboo-based feed for aquaculture contains the following raw materials in parts by weight: 60 parts fermented bamboo-based raw material, 10 parts bamboo polysaccharide, 5 parts oligosaccharide, 40 parts protein source, 8 parts fat source, 3 parts vitamin-mineral premix, and 2 parts binder. The bamboo-based raw material is selected from one or more of bamboo culms, bamboo leaves, and bamboo shoot shells.

[0024] The preparation steps for the bamboo-based feed for aquaculture are the same as in Example 1.

[0025] Example 3 The preparation method of the fermented bamboo-based raw material is the same as that in Example 1.

[0026] The bamboo-based feed for aquaculture contains the following raw materials in parts by weight: 45 parts fermented bamboo-based raw material, 6 parts bamboo polysaccharide, 3 parts oligosaccharide, 30 parts protein source, 5.5 parts fat source, 2 parts vitamin-mineral premix, and 1.25 parts binder. The bamboo-based raw material is selected from one or more of bamboo culms, bamboo leaves, and bamboo shoot shells.

[0027] The preparation steps for the bamboo-based feed for aquaculture are the same as in Example 1.

[0028] Comparative Example 1 (Prebiotic-free system) The preparation method of the fermented bamboo-based raw material is the same as that in Example 1.

[0029] The bamboo-based feed for aquaculture comprises the following raw materials in parts by weight: 45 parts fermented bamboo-based raw material, 30 parts protein source, 5.5 parts fat source, 2 parts vitamin-mineral premix, and 1.25 parts binder. The bamboo-based raw material is selected from one or more of bamboo culms, bamboo leaves, and bamboo shoot shells.

[0030] The preparation of the bamboo-based feed for aquaculture is the same as in Example 1, except that the prebiotic system composed of bamboo polysaccharides and oligosaccharides is not added during the dry mixing and pre-stirring.

[0031] Comparative Example 2 (Unfermented bamboo-based raw material) The bamboo-based feed for aquaculture contains the following raw materials in parts by weight: 45 parts unfermented bamboo-based raw material, 6 parts bamboo polysaccharide, 3 parts oligosaccharide, 30 parts protein source, 5.5 parts fat source, 2 parts vitamin-mineral premix, and 1.25 parts binder. The bamboo-based raw material is selected from one or more of bamboo culms, bamboo leaves, and bamboo shoot shells.

[0032] The preparation of the bamboo-based feed for aquaculture is the same as in Example 1, except that the fermented bamboo-based raw material is replaced with unfermented bamboo-based raw material.

[0033] Performance testing 1. Basic Nutritional Component Analysis Crude protein (%): The Kjeldahl method was used, in accordance with GB / T 6432-2018 standard. A 2g feed sample was taken and digested with sulfuric acid and a mixed catalyst (copper sulfate + selenium powder). Ammonia was then collected by distillation under alkaline conditions, absorbed with boric acid, and titrated with standard hydrochloric acid. The total nitrogen content was calculated and then multiplied by the protein conversion factor to obtain the crude protein content.

[0034] Crude fat (%): Soxhlet extraction was performed according to GB / T 6433-2018 standard. 5g of dry sample was weighed and placed in an extraction tube. Anhydrous diethyl ether was used as the solvent for reflux extraction in a Soxhlet extractor for 6 hours, during which the fat was dissolved and extracted. The solvent in the extract was evaporated to remove it, and the remaining fat was dried and weighed. The percentage of fat content was calculated based on the initial sample mass.

[0035] Crude fiber (%): Referring to GB / T 6434-2006 standard, take an appropriate amount of dry feed sample and boil it sequentially with 1.25% dilute sulfuric acid and 1.25% sodium hydroxide to simulate the effect of animal gastrointestinal tract on crude fiber. After thorough filtration, drying and calcination in a muffle furnace at 550°C, the difference in residue is the crude fiber content, expressed as a percentage.

[0036] Ash content (%): According to the standard operation of GB / T 6438-2007 ashing method, 2g of pre-dried feed sample was weighed and placed in a heat-resistant ceramic crucible, and then placed in a muffle furnace at 550°C for 4 hours to ashing, so that all organic matter was burned off and only inorganic minerals remained. After cooling, the sample was weighed, and the percentage of residue in the sample was calculated, which is the ash content.

[0037] Moisture content (%): Compliant with GB / T 6435-2014 standard. Weigh 3g of feed sample and dry it in a 105°C constant temperature drying oven until constant weight (the difference between two consecutive weighings should not exceed 0.003g). The weight loss is the moisture content.

[0038] Calcium and phosphorus content (%): Analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES) according to AOAC 984.27. The sample was first ashed at high temperature, and the resulting ash was dissolved in a nitric acid-hydrogen peroxide mixture. After adjusting the volume, the ash was injected into the ICP instrument, and the calcium (Ca) and phosphorus (P) content were determined at specific wavelengths. The results are expressed as percentages.

[0039] The test results are shown in Table 1 below.

[0040] Table 1 Basic Nutritional Components

[0041] As shown in Table 1, the crude protein and crude fat contents in Examples 1-3 were significantly higher than those in the comparative example, while the crude fiber content decreased significantly. This indicates that the fermented bamboo-based raw materials have a positive effect on improving protein availability and feed palatability. In particular, in Example 2, the use of a higher proportion of fermented bamboo-based raw materials and compound prebiotics (bamboo polysaccharides and oligosaccharides) to synergistically construct a nutrient carrier increased the protein content to 25.7% and reduced the crude fiber to 7.2%, demonstrating that enzymatic hydrolysis and microbial fermentation of bamboo raw materials effectively disrupted the lignocellulose structure and released absorbable nutrients. The increased calcium and phosphorus content also reflects the enhanced mineral activation and organic chelation capabilities of the fermentation process. In contrast, Comparative Example 1 lacked prebiotics, and Comparative Example 2 did not undergo fermentation treatment, both showing lower protein content and higher crude fiber content.

[0042] 2. Water stability and dissolution test Take 5.0g of each feed pellet sample and place it in a 1L beaker. Add 800mL of dechlorinated water (temperature 28±1°C) to simulate the aquaculture environment. Samples are taken out at 0.5h, 1h, and 2h, filtered dry with filter paper, and dried in a 55°C oven to constant weight. The remaining mass is calculated, and the water loss rate (%) is also calculated. The time (min) required for complete particle disintegration is recorded as the disintegration time. The floating or settling rate is determined by observing and recording the particle distribution ratio on the water surface / bottom. Each test is repeated three times, and the average value is taken. The results are shown in Table 2 below.

[0043] Table 2 Results of water stability and dissolution tests

[0044] Table 2 shows that the disintegration time in water for Examples 1-3 was significantly longer than that for the comparative examples, while the solubility loss rate was significantly lower. This indicates that the bamboo-based raw materials have a more stable structure after enzymatic hydrolysis and fermentation. The composite prebiotic system constructed with bamboo polysaccharides and oligosaccharides enhances the cohesiveness and film-forming properties of the particles, thereby improving their stability in water. In particular, Example 2, due to the highest addition of bamboo-based components and prebiotics, had the longest particle retention time in water and the lowest solubility loss rate of only 6.1%, effectively reducing nutrient loss. Comparative Example 1, without the addition of prebiotics, had a loose internal structure and was prone to disintegration after absorbing water and swelling; Comparative Example 2, without fermentation treatment, had a high crude fiber content and loose particles, resulting in poor stability.

[0045] 3. Aquaculture performance verification test Three hundred juvenile tilapia with an average weight of 10 ± 0.5 g were randomly divided into 5 groups, with 3 replicates per group and 20 fish per replicate. They were placed in identical rearing tanks and fed twice daily for 45 days. Weight was recorded every 10 days for total weight gain and feed intake. Daily growth rate (DGR), specific growth rate (SGR), and feed conversion ratio (FCR) were calculated. Survival rate was recorded, and three fish were dissected to observe gastrointestinal color, fullness, and mucosal integrity. The results are shown in Table 3 below.

[0046] Table 3 Results of Aquaculture Performance Tests

[0047] Table 3 shows that Examples 1-3 all exhibited good breeding performance, especially in terms of daily growth rate (DGR), specific growth rate (SGR), and feed conversion ratio (FCR), which were significantly better than the control group. In Example 2, due to the highest addition of bamboo-based raw materials and compound prebiotics, the nutrient supply was more sufficient, and the feed digestibility was higher. Its SGR reached 2.12%, and the FCR decreased to 1.35, indicating that the feed required per unit of weight gain was the least, resulting in the best economic benefits. At the same time, the feed intake rate and survival rate were also higher than those of the control group, indicating that the feed was palatable and the animals' health was more stable. Gastrointestinal anatomy results showed that the intestinal mucosa of the experimental group was intact and reddish in color, while the intestinal walls of Control Group 1 and Control Group 2 were rough and the mucosa was pale, respectively.

[0048] 4. Water quality impact analysis and testing After the aquaculture trial ended (day 45), 300 mL of mixed water samples (top, middle, and bottom layers) were collected from each group at a fixed time every morning. Ammonia nitrogen (NH3-N), nitrite (NO2⁻), chemical oxygen demand (COD), suspended solids (SS), dissolved oxygen (DO), and pH were measured using national standard methods such as GB / T 13271-2014, HJ 535-2009, and HJ / T 399-2007. Each water sample was tested three times, and the average was taken. The results are shown in Table 4 below.

[0049] Table 4 Water quality test results (mg / L, pH / DO are original values)

[0050] As shown in Table 4, Examples 1-3 showed significantly lower levels of ammonia nitrogen, nitrite, COD, and suspended solids (SS) compared to the comparative example. In particular, Example 2 showed a reduction in NH3-N to 0.28 mg / L and COD to 15.7 mg / L, indicating minimal release of water pollutants and superior environmental friendliness. The fermented bamboo-based raw materials and compound prebiotic system used in this patent effectively improved the digestibility and utilization of protein and fat in the feed, reduced undigested components in feces, and its lower crude fiber structure reduced the release of non-degradable residues. Furthermore, the higher DO value compared to the comparative example indicates lower dissolved oxygen consumption after feed decomposition, a more stable aquatic ecosystem, smaller pH fluctuations, and a neutral-to-alkaline pH, suitable for the growth of farmed animals.

[0051] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A bamboo-based feed for aquaculture, characterized in that, It contains the following raw materials by weight: 30-60 parts of fermented bamboo-based raw material, 2-10 parts of bamboo polysaccharide, 1-5 parts of oligosaccharide, 20-40 parts of protein source, 3-8 parts of fat source, 1-3 parts of vitamin-mineral premix, and 0.5-2 parts of binder; The bamboo-based raw material is selected from one or more of bamboo culms, bamboo leaves, and bamboo shoot shells.

2. The bamboo-based feed according to claim 1, characterized in that, The preparation method of the fermented bamboo-based raw material specifically includes the following steps: S101. The pulverized bamboo raw material is mixed with cellulase and pectinase and reacted at 50-60℃ and pH 5.0-6.0 for 2-4 hours to degrade the crude fiber and polysaccharide structure and obtain the enzymatic hydrolysis product. S102. Inoculate the enzymatic hydrolysis product with lactic acid bacteria and yeast strains, wherein the lactic acid bacteria are selected from Lactococcus lactis and the yeast is selected from Saccharomyces cerevisiae. Ferment at 30-37℃ for 12-24 hours to obtain the fermentation product. S103. The fermentation product is dried at low temperature to control the moisture content to no more than 10%, thereby obtaining the fermented bamboo-based raw material.

3. The bamboo-based feed according to claim 2, characterized in that, The amount of cellulase used is 0.5-2.0% of the mass of the bamboo-based raw material, the amount of pectinase used is 0.2-1.0%, and the pH is 5.0-6.

0.

4. The bamboo-based feed according to claim 1, characterized in that, The bamboo polysaccharide is obtained by hot water extraction, alcohol precipitation, decolorization, concentration and drying of bamboo culms or leaves. The bamboo polysaccharide has a β-(1→3) or β-(1→4) main chain structure and an average molecular weight of 1000 to 10000 Da.

5. The bamboo-based feed according to claim 1, characterized in that, The oligosaccharide is composed of mannan oligosaccharide and galactooligosaccharide in a mass ratio of 1:(0.5 to 1.5).

6. The bamboo-based feed according to claim 1, characterized in that, The protein source is one or more of fish meal, soybean meal, fermented soybean meal, hydrolyzed fish protein, and yeast protein, and the fat source is one or more of fish oil, flaxseed oil, and rapeseed oil.

7. A method for preparing bamboo-based feed for aquaculture, wherein the bamboo-based feed for aquaculture is as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Take the fermented bamboo-based raw material, dry it at low temperature, and then pulverize it to a fineness of less than 200 μm using a pulverizer for later use; S2. Add bamboo-based raw materials, bamboo polysaccharides, oligosaccharides, protein sources, fat sources, vitamin-mineral premix and binder to the mixing equipment in sequence, pre-stir for 3 to 5 minutes, and then mix at high speed for 10 to 15 minutes to fully disperse and mix the components to form a uniform wet mixture. S3. The mixed wet material is conveyed to the conditioner, an appropriate amount of water or steam is sprayed in to adjust the moisture content, and it is matured at medium temperature for 5 to 10 minutes. S4. Feed the conditioned and matured material into a twin-screw or ring die extruder for granulation, so that the resulting granules are cylindrical or elliptical in shape, with a length of about 1 to 2 times the diameter of the granules. S5. The freshly extruded pelleted feed is transported to a drying device and dried under low-temperature hot air conditions until the moisture content is ≤10%; after drying, it is cooled by a cold air blower to obtain the bamboo-based feed for aquaculture.

8. The method for preparing bamboo-based feed for aquaculture according to claim 7, characterized in that, The surface of the dried pelleted feed in step S5 is coated with a coating material selected from fish oil, chitosan solution, and gelatin-sodium alginate composite solution to improve the stability of the feed in water and achieve a slow-release effect.

9. The method for preparing bamboo-based feed for aquaculture according to claim 7, characterized in that, After drying, the process also includes cooling and sieving steps. The cooling step uses a cold air blower to lower the feed temperature to room temperature, and the sieving step uses a vibrating screen to remove powder and unqualified particles in order to obtain finished feed with uniform particle size.

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