Food calling type river crab feed and preparation method thereof

Abstract

The invention provides the food calling type river crab feed, the application effect of the food calling type river crab feed in river crab culture shows that the food calling type river crab feed has remarkable advantages in the aspects of improving the growth performance, enhancing the immune function, optimizing the intestinal microecology, improving the water quality environment and the like, the use of the fish meal is reduced through the fermented vegetable protein, and the specific composite phagostimulant has the advantages that the utilization rate of the fish meal is reduced; the palatability of the river crab feed with the fish meal content reduced is improved, the feed coefficient is reduced, the unit economic benefit is improved, the problem of environmental pollution in the breeding process is effectively relieved, and the river crab feed has good ecological and economic dual values.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of animal feed, in particular to a food-enticing river crab feed and a preparation method thereof. BACKGROUND

[0002] As an important freshwater aquaculture species in China, the feed industry of river crab has long been facing three core challenges. The quality of feed directly affects the profitability of aquaculture. High-quality feed can provide sufficient and balanced nutrition, promote the healthy growth of aquatic animals, improve survival rate, shorten the breeding cycle, and thus increase the yield of aquaculture. At the same time, high-quality feed can also improve the quality of aquatic products, meet market demand, and enhance the competitiveness of the aquaculture industry. There are various types of aquatic feed in China, including compound feed, single feed, etc., covering the needs of various aquatic animals such as fish, shrimp, crab, and shellfish. At the same time, feed manufacturers have launched various specifications of feed products for different breeding modes, different growth stages, and nutritional needs. In addition, with the progress of science and technology and the development of the feed industry, the production technology of aquatic feed in China has made breakthroughs. Feed manufacturers have invested a lot of research and development efforts in feed formula design, production process optimization, and balanced nutrition, etc., improving the utilization rate and nutritional value of feed, while effectively reducing the cost of aquaculture.

[0003] However, despite the achievements made in the application of aquatic feed in China, there are still some problems and challenges. For example, some breeders do not pay enough attention to the quality of feed and excessively pursue price advantage, leading to the existence of inferior products in the feed market. The rational use and sustainable development of aquatic feed resources are important issues facing the aquaculture industry. With the expansion of breeding scale and the increase of demand, the contradiction between supply and demand of feed resources is becoming increasingly prominent. For example, the problem of high dependence on fish meal. The addition of fish meal in traditional river crab compound feed is generally maintained at 20%-30%, while the global fish meal production is only about 5 million tons per year. China, as the largest consumer, accounts for more than 30%. The scarcity of resources has led to a cumulative increase of 68% in the price of fish meal since 2020, directly pushing up the cost of feed. In summary, developing new feed resources and improving the utilization rate of existing resources is the key to the sustainable development of the aquaculture industry.

[0004] In addition, there is the problem of insufficient feed palatability. Existing feeds mostly use single amino acids or fishy substances as palatability enhancers. In high-density farming environments, this can easily lead to a decrease in feed intake (feeding frequency less than 8 times per day) and a high rate of uneaten feed (more than 25%). Single palatability enhancers often result in industry pain points in crab farming, such as a high feed conversion ratio (generally 2.0-2.5), uneven growth (individual difference coefficient > 25%), and a prolonged farming cycle (40-60 days longer than ideal). The development of aquatic feed palatability enhancers is of great significance for improving the efficiency and sustainable development of aquaculture. First, with the expansion of aquaculture scale and the increase in stocking density, the demand for feed by aquatic animals is constantly increasing. Developing efficient and environmentally friendly feed attractants can improve feed utilization, reduce aquaculture costs, and thus improve the economic benefits of aquaculture. Second, the development of aquatic feed attractants helps improve the aquaculture environment. Traditional aquaculture methods often lead to water pollution and ecological damage. By adding attractants, the feeding efficiency and digestibility of aquatic animals can be improved, reducing feed residue and waste in the water, thereby alleviating environmental pressure. Furthermore, the development of aquatic feed attractants can promote the healthy growth of aquatic animals. Attractants can improve feed quality and palatability, increase aquatic animals' appetite and nutrient absorption capacity, thereby enhancing their disease resistance and growth rate. This is of great significance for increasing the yield and quality of aquatic products and meeting market demand. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a feeding-attracting crab feed and its preparation method. This feeding-attracting crab feed containing specific components significantly increases the feeding efficiency and digestibility of crabs, thereby improving the yield and quality of crabs.

[0006] This invention provides the following technical solution: A feed for attracting crabs, comprising the following components in parts by weight: 5-10 parts by weight of fishmeal, 1-2 parts by weight of attractant, 70-80 parts by weight of fermented compound plant protein, 10-20 parts by weight of whole wheat flour, and 1-3 parts by weight of oil.

[0007] In a preferred embodiment, the feed comprises the following components in parts by weight: 10 parts by weight of fishmeal, 1 part by weight of attractant, 73 parts by weight of fermented plant protein, 15 parts by weight of whole wheat flour, and 1 part by weight of oil; particularly preferably, the above feed formulation components are used during the juvenile crab stage.

[0008] In a preferred embodiment, the feed comprises the following components in parts by weight: 5 parts fishmeal, 2 parts attractant, 75 parts fermented plant protein, 15 parts whole wheat flour, and 3 parts oil; particularly preferably, the above feed formulation is used during the adult crab stage.

[0009] Preferably, the palatability enhancer comprises the following components in parts by weight: .

[0010] More preferably, the palatability enhancer comprises the following components in parts by weight: .

[0011] Preferably, the fermented compound plant protein is prepared by compound plant protein co-fermentation technology, and its raw materials include the following components in parts by weight: .

[0012] More preferably, the fermented compound plant protein is prepared by compound plant protein co-fermentation technology, and its raw materials include the following components in parts by weight: .

[0013] In a preferred embodiment, the plant protein is obtained through a plant protein co-fermentation process, the specific steps of which include: crushing and mixing soybeans, broad beans and corn in the prescribed amounts, and adjusting the carbon-nitrogen ratio with bran for the remainder; adding an appropriate amount of combined bacterial strains, and fermenting at a controlled temperature to obtain a compound plant protein.

[0014] Preferably, the combined strain is selected from a combination of Bacillus subtilis, Saccharomyces cerevisiae, and Lactobacillus plantarum; more preferably, the ratio of Bacillus subtilis, Saccharomyces cerevisiae, and Lactobacillus plantarum is 2:1:1; the amount of the combined strain is preferably 3-5%.

[0015] In a preferred embodiment, the plant protein is obtained through a plant protein co-fermentation process. The specific steps include: mixing the formulated amounts of soybeans, broad beans, and corn powder with wheat bran evenly, adding sterile water to adjust the moisture content to 55-60%, adding 4% (v / w) of a combination of Bacillus subtilis, Saccharomyces cerevisiae, and Lactobacillus plantarum (2:1:1), maintaining the pH of the system at 6.0-6.5, controlling the dissolved oxygen content at 15%-20%, fermenting at 35-38℃ for 60-72 hours, and after fermentation, using low-temperature vacuum drying, pulverizing, and sieving to obtain fermented compound plant protein.

[0016] Preferably, the oil is one or a combination of fish oil, soybean oil, soybean lecithin, rapeseed oil, and flaxseed oil; more preferably, it is a combination of fish oil and soybean lecithin, and the ratio of the combined oil can be adjusted appropriately according to the growth period of the crab.

[0017] The beneficial effects of this invention are: This invention significantly increases the feeding frequency and duration of crabs by adding specific compound attractants, and significantly reduces the feed conversion ratio. The attractant-type crab feed of this invention significantly improves the weight gain and survival rate of crabs and significantly shortens the breeding cycle. Furthermore, the addition of fermented plant protein with specific compound components can reduce the proportion of fishmeal in the feed to below 10%. During the juvenile crab stage (stages III-V), a 10% fishmeal addition is sufficient to ensure the cholesterol and phospholipids required for shell development; during the adult crab stage (stages VI-VIII), the fishmeal addition can be reduced to 5%, resulting in an overall cost reduction of approximately 25% compared to traditional crab feed formulations. While reducing costs, the added fermented plant protein provides small molecule peptides to compensate for the difference in amino acid supply caused by the reduction in fishmeal, eliminating the need for additional amino acids, multivitamins, and other ingredients. Through the fermentation process, the total number of viable bacteria in the material is ≥10. 8 With a CFU / g concentration, crude protein digestibility is increased by 20-30%, and the degradation rate of anti-nutritional factors phytic acid and trypsin inhibitors is ≥50%, significantly improving the intestinal health of crabs. In particular, mixed feeds with fermented broad beans exhibit a significant improvement in intestinal health. The phenolic substances and nucleotides produced during broad bean fermentation, combined with the amino acids in soybeans, form a complex feeding signal, increasing feed intake. Simultaneously, the rapid absorption of broad bean protein shortens the molting interval of crabs by 1-2 days. The antimicrobial peptides produced during broad bean fermentation inhibit Vibrio growth, significantly increasing the proportion of beneficial bacteria and stabilizing intestinal pH, thus enhancing intestinal health, immunity, and stress resistance, and improving overall feed palatability. Fermented feed also increases nitrogen retention by 25%, stabilizing ammonia nitrogen concentration in the aquaculture water below 0.3 mg / L, reducing chemical oxygen demand (COD) by 40%, and decreasing water change frequency by 50%. The high proportion of plant protein feed combined with low-dose feeding attractants creates an environmentally friendly aquaculture model, significantly improving overall economic benefits. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and not for limiting the scope of the invention. Unless otherwise specified, all materials and raw materials used in the present invention are commercially available.

[0019] Example 1: A predatory crab feed was prepared according to the following method: 1) Preparation of fermented compound plant protein: Grind 35% soybeans, 15% broad beans, and 25% corn into fine powder according to the formula and mix them evenly with wheat bran (make up the rest). Add an appropriate amount of sterile water to adjust the moisture content to 55-60%. Add 4% (v / w) of the combined bacterial strain Bacillus subtilis (CMCC63501), Saccharomyces cerevisiae (EBY100), and Lactobacillus plantarum (ATCC8014) (2:1:1). Maintain the pH of the system at 6.0-6.5 and the dissolved oxygen content at 15%-20%. Ferment at 35-38℃ for 60-72 hours. After fermentation, use low-temperature vacuum drying to dry the material, grind and sieve it to obtain fermented compound plant protein. 2) Preparation of attractant crab feed: Weigh out the fish meal (5 parts by weight), fermented compound plant protein (75 parts by weight), and whole wheat flour (15 parts by weight) according to the formula, pass them through a 100-mesh sieve and mix them step by step. Add the attractant (2 parts by weight), fish oil (2 parts by weight), soybean lecithin (1 part by weight), and an appropriate amount of distilled water according to the formula. Use a single screw extruder to make pellet feed (1.5×3 mm), dry it in a 45℃ oven, and store it in a sealed container for later use.

[0020] Here, while keeping the formula consistent, different components of attractants were selected, and different crab feeds were prepared according to the above method. The detailed formula of attractant components and content ratio is shown in Table 1.

[0021] Table 1 .

[0022] Example 2: A predatory crab feed was prepared according to the following method: 1) Preparation of fermented compound plant protein: The plant raw materials soybeans, broad beans and corn in the formula are ground into fine powder and mixed evenly with wheat bran (the remainder is supplemented). An appropriate amount of sterile water is added to adjust the moisture content to 55-60%. 4% (v / w) of the combined bacterial strain Bacillus subtilis (CMCC63501), Saccharomyces cerevisiae (EBY100) and Lactobacillus plantarum (ATCC8014) (2:1:1) is added. The pH of the system is maintained at 6.0-6.5, the dissolved oxygen content is controlled at 15%-20%, and the temperature is controlled at 35-38℃ for fermentation for 60-72 hours. After fermentation, the material is dried by low-temperature vacuum drying, pulverized and sieved to obtain fermented compound plant protein. 2) Preparation of attractant-type crab feed: Weigh out the fish meal (10 parts by weight), fermented compound plant protein (73 parts by weight), and whole wheat flour (15 parts by weight) according to the formula, pass them through a 100-mesh sieve and mix them step by step. Add the attractant (1 part by weight, the component formula is as described in Example 1-1), fish oil (1 part by weight), and an appropriate amount of distilled water in sequence. Use a single-screw extruder to make pellet feed (1.5×3 mm), put it in a 45℃ oven to dry, and seal it for later use.

[0023] Here, while maintaining the same formula, different plant raw materials were selected to prepare different crab feeds according to the above method. The detailed formula of plant raw material components and content ratio is shown in Table 2.

[0024] Table 2 .

[0025] Comparative Example 1: A type of attractant feed for river crabs. Referring to the formula of Example 1-1, the compound plant protein (ratio: 35% soybean, 15% broad bean, 25% corn flour) was pulverized into a fine powder. The formula amounts of fish meal (10 parts by weight), compound plant protein (73 parts by weight), and whole wheat flour (15 parts by weight) were weighed out, passed through a 100-mesh sieve, and mixed step by step. The formula amounts of attractant (1 part by weight, component formula as in Example 1-1), fish oil (1 part by weight), and appropriate amount of distilled water were added in sequence. The feed was made into pellets (1.5 × 3 mm) by a single-screw extruder, dried in a 45℃ oven, and sealed for later use.

[0026] The only difference between Comparative Example 1 and Example 1-1 is that unfermented compound plant protein was added to the feed.

[0027] Experiment Example 1: Appetite Intensity Index Test Experimental Methods: The river crabs used in the experiment were purchased from Dongying Huize Agricultural Technology Co., Ltd. Before the formal experiment, they were temporarily held in a holding tank for two weeks with feed without attractants to allow them to adapt to the experimental conditions. During the experiment, river crabs weighing approximately 8g were used in 21 PVC aquariums (100×50×50cm), with 10 crabs in each aquarium, a water level of 15cm, and a water temperature of 20-25℃. The experiment was conducted in the evening. Overfeeding was conducted the day before the experiment, and no feeding was given after waste disposal on the morning of the experiment. The 21 aquariums were divided into 7 groups of three. The control group was fed feed prepared according to the formula and method in Example 1, except that no attractants were added. The experimental groups were fed feeds containing different attractant formulations as shown in Table 1 of Example 1.

[0028] During the experiment, 10 pellets each of the control and experimental feed were gently poured into the bottom of the aquarium, concentrated in an area of ​​about 10 cm in diameter. The number of remaining feed pellets was observed every 15 minutes for a total of 90 minutes. Feed pellets that were dragged outside the area with a diameter of 40 cm were considered to have been ingested. The feeding effect of various feed attractants was represented by the average feeding index calculated after 60 minutes of observation. Feeding index (%) = (number of experimental feed pellets reduced - number of control feed pellets reduced) / number of experimental feed pellets placed × 100. Each treatment was repeated 3 times. After one experiment, the crabs were fed feed without feed attractants for two days before the next experiment was conducted to eliminate the "memory" of the tested feed. The feeding index is shown in Table 3.

[0029] Table 3 .

[0030] According to the appetite stimulant index test, the appetite stimulant of the specific component formulation of the present invention has a significantly increased appetite stimulant index.

[0031] Experimental Example 2: Test of River Crab Growth Performance The aquaculture experiment was conducted at the Aquatic Teaching and Research Base of Dongying Vocational College. One hundred and eighty juvenile Chinese mitten crabs with intact appendages, good vitality, and in the intermolting stage, with an initial body weight of (2.56±0.02) g, were selected for the experiment. These 180 juvenile crabs were randomly assigned to 18 rearing tanks, divided into 6 groups, with 3 replicates per group. The water conditions in each replicate were essentially the same. During the experiment, the crabs were fed three times daily (07:00, 12:00, and 18:00) for a 25-day period. The feeding ratio was 5% of the average body weight of the crabs. Uneaten feed was collected immediately one hour after feeding, dried, and weighed. The amount of feed consumed per tank was recorded, along with the number of dead and molting crabs recorded daily. Two-thirds of the water was changed daily to maintain water clarity. Water quality was measured every three days during the experiment, with a water temperature of 25.5 ± 1.5℃.

[0032] After a 25-day rearing trial, all crabs in each rearing tank were fasted for 24 hours, anesthetized, weighed, and counted to calculate weight gain rate (WGR), survival rate (SR), and feed conversion ratio (FCR). The calculation formulas are as follows: Weight gain rate (WGR, %) = 100×(W2-W1) / W1, where W2 is the body weight of each group of juvenile crabs at the end of the experiment, and W1 is the initial body weight of each group of juvenile crabs. Survival rate (SR, %) = 100 × N2 / N1, where N2 is the number of surviving juvenile crabs in each group at the end of the experiment; N1 is the initial number of juvenile crabs in each group. Feed conversion ratio (FCR) == F / (W) ii -W i ), where F is the total dry matter of the feed ingested, and W ii W represents the total weight of the terminally surviving individuals in each group. i The initial total weight of individuals placed in each group.

[0033] Serum samples were collected from crabs in six treatment groups to measure SOD (superoxide dismutase) activity, ALT (alanine aminotransferase) level, and MDA (malondialdehyde) content, and to compare the differences in immunity and health.

[0034] Table 4 Results of River Crab Growth Performance Test .

[0035] After a 25-day rearing cycle, the crab feed of this invention significantly promoted the growth performance of crabs, with an average weight gain of 105.99%, a survival rate of 96.67%, and a feed conversion ratio reduced to 1.24%. Furthermore, serum immune and antioxidant indicators are important physiological parameters for assessing the functional status of aquatic animals. The SOD activity in the crab feed group of this invention reached 161.5 U / ml, a significant increase, indicating enhanced ability to scavenge free radicals and help alleviate oxidative stress. The significantly elevated serum ALT in the crabs may indicate changes in the hepatopancreas. Cellular damage: When the hepatopancreas becomes inflamed or necrotic due to poisoning, infection, or other reasons, intracellular ALT is released into the bloodstream, leading to elevated serum ALT levels. In the crab feed group of this invention, ALT levels were as low as 18.9 U / L, further indicating a low degree of hepatopancreas cell damage. Low or significantly reduced serum MDA levels generally indicate a balanced oxidative-antioxidant system and good health in the crab. In the crab feed group of this invention, MDA levels were reduced to 2.6 nmol / ml, indicating reduced lipid peroxidation damage and a more stable metabolic state. The organic acids, soluble peptides, and probiotic metabolites abundant in the feed of this invention can regulate the intestinal flora, activate the non-specific immune system, and enhance immune cell function. Optimization of the flora structure stabilizes the intestinal environment. Beneficial bacteria inhibit pathogen colonization by occupying adhesion sites, competing for nutrients, and secreting antibacterial substances, thereby enhancing the development of intestinal villi and further improving nutrient absorption.

[0036] The application effect of the feed for crabs in crab farming shows that it has significant advantages in improving growth performance, enhancing immune function, optimizing intestinal microecology, and improving water quality. Fermented plant protein reduces the use of fishmeal, and the specific compound attractant improves the palatability of the crab feed after reducing the fishmeal content, reduces the feed coefficient, increases the unit economic benefits, and effectively alleviates environmental pollution problems in the farming process, thus possessing good ecological and economic value.

Claims

1. A baited Eriocheir sinensis feed, characterized in that, The feed comprises the following components in parts by weight: 5-10 parts by mass of fish meal, 1-2 parts by mass of an attractant, 70-80 parts by mass of fermented complex plant protein, 10-20 parts by mass of whole wheat flour, and 1-3 parts by mass of oil and fat; wherein the attractant comprises the following components in parts by weight: 。 2. The attractant crab feed as described in claim 1, characterized in that, The feed comprises the following components in parts by weight: 10 parts by mass of fish meal, 1 part by mass of an attractant, 73 parts by mass of fermented plant protein, 15 parts by mass of whole wheat flour, and 1 part by mass of oil and fat.

3. The bait-type feed for Potamobius that is claimed in claim 1, wherein The feed comprises the following components in parts by weight: 5 parts by mass of fish meal, 2 parts by mass of an attractant, 75 parts by mass of fermented plant protein, 15 parts by mass of whole wheat flour, and 3 parts by mass of oil and fat.

4. The feed of any one of claims 1 to 3, wherein the feed is a bait type feed for Eriocheir sinensis. The attractant comprises the following components in parts by weight: 。 5. The attractant crab feed as described in any one of claims 1-3, characterized in that, The fermented complex plant protein is prepared by a complex plant protein synergistic fermentation technology, and raw materials thereof comprise the following components in parts by weight: 。 6. The feed bait according to claim 5, wherein the feed bait is a feed bait for Eriocheir sinensis. The fermented complex plant protein is prepared by a complex plant protein synergistic fermentation technology, and raw materials thereof comprise the following components in parts by weight: 。 7. The bait-type feed for potamobius that is set forth in claim 5, wherein The plant protein is obtained by a plant protein synergistic fermentation process, and the specific steps comprise: crushing and mixing formula amount of soybeans, broad beans and corn, and adjusting the carbon-nitrogen ratio with the remaining bran; adding an appropriate amount of combined strains, controlling temperature for fermentation, and obtaining the complex plant protein.

8. The bait-type feed for Potamobius that is claimed in claim 7, characterized by the fact that, The combined strains are selected from Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus plantarum, and are further preferably in a ratio of 2:1:1; and the combined strains are preferably used in an amount of 3-5%.

9. The bait-type feed for Potamobius that is claimed in claim 8, characterized by the fact that, The plant protein is obtained by a plant protein synergistic fermentation process, and the specific steps comprise: crushing and mixing formula amount of soybeans, broad beans and corn with bran, adding sterile water to adjust the moisture content to 55-60%, adding 4% (v / w) of combined strains Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus plantarum (2:1:1), maintaining the system pH at 6.0-6.5, controlling the dissolved oxygen content at 15%-20%, controlling the temperature at 35-38°C for fermentation for 60-72 hours, after the fermentation is completed, vacuum drying the material at low temperature, crushing and sieving, and obtaining the fermented complex plant protein.

10. The bait-type feed for potamobius marmoratus according to claim 1, wherein The oil and fat is one or a combination of fish oil, soybean oil, soybean lecithin, rapeseed oil and flaxseed oil; and is further preferably a combination of fish oil and soybean lecithin, and the ratio of the combined oil and fat can be appropriately adjusted according to the growth period of the river crab.