Soft pellet feed special for sub-adults under condition of separate breeding of male and female river crabs and use method of soft pellet feed

Abstract

The invention belongs to the technical field of aquatic feed and culture, and particularly relates to special soft pellet feed for sub-adults under the condition of separate culture of male and female river crabs and a use method of the special soft pellet feed. The soft pellet feed is prepared from the following main raw materials: steam fish meal, soybean meal, fermented soybean meal, peanut meal, rapeseed meal, chicken meal, euphausia superba meal, yeast extract, high gluten flour, rice bran, choline chloride, compound vitamins, compound minerals, monocalcium phosphate, sodium humate, sodium diacetate, haematococcus pluvialis powder, soybean lecithin oil, refined fish oil and soybean oil. The main nutritional ingredients comprise water, crude protein, total fat, total carotenoid, energy and the like. When the soft pellet feed is used for feeding, the survival rate, the weight gain rate, the feeding rate and the gonad development after reproduction and shelling are improved, the breeding pollution is reduced, and the economic benefit of river crab breeding is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aquatic feed and aquaculture, and specifically relates to soft granular feed for female crabs and soft granular feed for male crabs at the sub-adult stage under the condition of separate breeding of female and male river crabs, and a use method thereof. BACKGROUND

[0002] Eriocheir sinensis (hereinafter referred to as river crab) is the most important farmed crab in China. The national yield of adult crabs in 2023 was about 888,600 tons, with an annual output value of more than 50 billion yuan. Pond culture is the main way of river crab culture in China. The pond culture process of river crab usually takes two years. In the first year, large-eyed larvae are cultured into juvenile crabs. In the second year, juvenile crabs are cultured into adult crabs with basically mature gonads. The adult crab culture stage usually goes through 5 molts, and the last molt is also called reproductive molt. River crabs before reproductive molt are called sub-adults, and river crabs after reproductive molt no longer change their secondary sexual characteristics and are called adult crabs. After reproductive molt, river crabs start rapid development of gonads, and gonads, hepatopancreas and muscle are the main edible parts of river crabs. Only river crabs with well-developed gonads have high edible and economic value.

[0003] Currently, the main mode of river crab culture is mixed breeding of females and males, which has many drawbacks: 1. Male crabs have strong foraging ability, while female crabs have weak foraging ability, resulting in smaller female crabs; 2. Female and male individuals molt asynchronously, resulting in soft-shell crabs being easily killed by their peers during molting or after molting, leading to reduced survival rate; 3. Due to the different times of gonadal maturation or near-maturation of females and males, the market time of female crabs is usually from October to November each year, and the market time of male crabs is usually from November to December each year. When mixed breeding of females and males, the non-market gender needs to be removed manually, which is not conducive to fishing operations. Compared with the traditional mixed breeding mode of females and males, separate breeding of females and males has the advantages of high survival rate, large size, high yield, precise feeding and management of female and male crabs, etc. Therefore, separate breeding of female and male river crabs has attracted widespread attention in the industry and has been applied on a large scale, and the trend is increasing. Although separate breeding of female and male river crabs has a large application area, there is no special feed for male or female crabs on the market, and the same feed is usually fed to female and male crabs, such as: fresh fish, hard granular feed and expanded feed, etc.

[0004] The nutritional requirements of female and male river crab individuals are quite different at the sub-adult stage and the gonad development stage of adult crabs. When female and male river crabs are mixed and fed with the same feed, it may lead to overnutrition or undernutrition of female or male crabs. Insufficient intake of nutrients such as protein and fat will affect the growth, molting and gonad of river crabs. Excessive intake of nutrients will not only increase the metabolic burden of river crabs, reduce the immunity and quality of river crabs, but also increase the feed cost and pollute the breeding environment. Since river crabs need to undergo reproductive molting and rapid gonad development during the late breeding period (from the sub-adult stage to the stage of gonad development close to maturity), this stage is usually referred to as the fattening stage in breeding production. The feed fed at this stage is called fattening feed. Therefore, it is necessary to develop special fattening feed for female crabs and special fattening feed for male crabs to achieve precise nutrition and scientific feeding, so as to promote the reproductive molting of sub-adults, improve the weight gain rate and accelerate the gonad development of adult crabs.

[0005] Icy fresh miscellaneous fish is a traditional feed commonly used in the fattening stage of river crabs at present, but it has problems such as unstable quality, unbalanced nutrition, carrying pathogenic bacteria, easy to pollute water quality, high feed conversion ratio, inconvenient feeding, etc., which is an important reason restricting the sustainable development of river crab breeding industry. In actual river crab breeding production, since icy fresh fish has better food attraction and faster feeding speed than hard granular feed and ordinary expanded feed, breeders will still prefer to choose icy fresh fish as one of the fattening feeds. Compared with hard granular feed and ordinary expanded feed, soft granular feed has the advantages of short high-temperature time in the production process, retaining most of the nutrients in the raw materials, high water content, good palatability, strong food attraction, easy to swallow and fast digestion and absorption. In addition, scientific feeding of feed is also very important. Since the feeding behavior, nutritional requirements and physiological metabolism of river crabs may be different at different growth stages, reproductive molting and gonad development stages, therefore, the feeding time, feeding amount and feeding frequency of river crabs will affect the use effect of compound feed and the cost of feed. SUMMARY

[0006] The present application aims to solve the problems of lack of special feed for female and male crabs, poor food attraction of feed, slow gonad development of river crabs fed with traditional feed during the process of separate breeding of female and male adult crabs. Through the development of soft granular fattening feed for female and male sub-adults and the use method, the feeding rate, weight gain rate and health status of female and male crabs are improved, the advance and synchronous molting of sub-adults are promoted, the survival rate after mature molting and gonad development maturity are improved, the early marketing of river crabs is promoted, and the feed cost and breeding pollution are reduced.

[0007] The present application determines the main nutritional parameters of the soft granular feed for female and male individuals according to the nutritional requirements of female and male individuals of Eriocheir sinensis at the sub-adult stage and the gonad development stage of adult crab, combines the water stability and food attraction of soft granular feed, and the nutritional components of the soft granular fattening feed for female sub-adult crabs are as follows: the water content is 25-30%, the protein content is 29-31%, the total fat content is 11-12%, the vitamin E content is 0.14-0.15%, the total carotenoid content is 40-60 mg / Kg, and the total energy level is 15-17 KJ / g; the nutritional components of the soft granular fattening feed for male sub-adult crabs are as follows: the water content is 25-30%, the protein content is 33-36%, the total fat content is 6.5-8.5%, the total carotenoid content is 10-20 mg / Kg, and the total energy level is 13-15 KJ / g; and the female crabs and male crabs are separated and raised from the sub-adult stage to the stage of gonad development close to maturity.

[0008] Further, the nutritional components of the soft granular fattening feed for female sub-adult crabs are as follows: the water content is 25-26%, the protein content is 30-31%, the total fat content is 11-11.5%, the vitamin E content is 0.15%, the total carotenoid content is 50-60 mg / Kg, and the total energy level is 15.5-17 KJ / g; and the nutritional components of the soft granular fattening feed for male sub-adult crabs are as follows: the water content is 25-26%, the protein content is 35-36%, the total fat content is 7.5-8%, the total carotenoid content is 15-20 mg / Kg, and the total energy level is 13.5-15 KJ / g.

[0009] The present application also provides the component formula of the soft granular fattening feed for female and male individuals of Eriocheir sinensis satisfying the above-mentioned nutritional component parameters, and the soft granular fattening feed for female sub-adult crabs contains the following components in parts by weight: steam fish meal 18-25%, soybean meal 15-25%, fermented soybean meal 10-15%, peanut meal 5-10%, rapeseed meal 5-10%, chicken meal 3-6%, Antarctic krill meal 2-5%, yeast paste 2-5%, high-gluten flour 15-20%, rice bran 3-8%, choline chloride 0.3-0.8%, compound vitamin 0.3-0.8%, vitamin E 0.08%, compound mineral 0.8-1.2%, calcium dihydrogen phosphate 1-3%, sodium humate 0.4-0.6%, sodium diacetate 0.2%, Dunaliella salina powder 0.2-0.3%, soybean phospholipid oil 2-3%, soybean oil 2-4%, and refined fish oil 2-4%. The soft granular fattening feed for male crab sub-adults contains the following components by weight: steam fish meal 22-30%, soybean meal 10-15%, fermented soybean meal 10-15%, peanut meal 5-10%, rapeseed meal 5-10%, chicken meal 6-10%, Antarctic krill meal 3-5%, blood meal 1.8-3.5%, yeast paste 2-5%, high-gluten flour 13-18%, rice bran 3-8%, choline chloride 0.3-0.8%, compound vitamin 0.3-0.8%, compound mineral 0.8-1.2%, calcium dihydrogen phosphate 1-3%, sodium humate 0.4-0.6%, sodium diacetate 0.2%, Haematococcus pluvialis powder 0.05-0.1%, soybean phospholipid oil 1-2%, and soybean oil 1-2%.

[0010] Further, the soft granular fattening feed for female crab sub-adults contains the following components by weight: steam fish meal 19-22%, soybean meal 18-21%, fermented soybean meal 11-12%, peanut meal 5-7%, rapeseed meal 5-7%, chicken meal 3-4%, Antarctic krill meal 2-4%, yeast paste 2-3%, high-gluten flour 15-17%, rice bran 3-5%, choline chloride 0.3-0.6%, compound vitamin 0.3-0.6%, vitamin E 0.08%, compound mineral 0.8-1%, calcium dihydrogen phosphate 1-2%, sodium humate 0.4-0.5%, sodium diacetate 0.2%, Haematococcus pluvialis powder 0.2-0.25%, soybean phospholipid oil 2-2.5%, soybean oil 3.5-4%, and refined fish oil 3.5-4%; The soft granular fattening feed for male crab sub-adults contains the following components by weight: steam fish meal 28-30%, soybean meal 10-12%, fermented soybean meal 10-12%, peanut meal 5-7%, rapeseed meal 5-7%, chicken meal 6-8%, Antarctic krill meal 3-4%, blood meal 3-3.5%, yeast paste 2-3%, high-gluten flour 13.5-14%, rice bran 3-4%, choline chloride 0.3-0.4%, compound vitamin 0.4-0.5%, compound mineral 0.8-1%, calcium dihydrogen phosphate 1-2%, sodium humate 0.4-0.5%, sodium diacetate 0.2%, Haematococcus pluvialis powder 0.06-0.08%, soybean phospholipid oil 1.5-2%, and soybean oil 1.5-2%.

[0011] Further, the soft granular fattening feed for female crab sub-adults contains the following components by weight: steam fish meal 20%, soybean meal 20%, fermented soybean meal 11%, peanut meal 5%, rapeseed meal 5%, chicken meal 3%, Antarctic krill meal 2%, yeast paste 2%, high-gluten flour 15.1%, rice bran 3%, choline chloride 0.3%, compound vitamin 0.4%, vitamin E 0.08%, compound mineral 0.8%, calcium dihydrogen phosphate 1.5%, sodium humate 0.4%, sodium diacetate 0.2%, Haematococcus pluvialis powder 0.22%, soybean phospholipid oil 2%, refined fish oil 4%, and soybean oil 4%; The soft granular fattening feed for male crab sub-adults contains the following components in parts by weight: steam fish meal 30%, soybean meal 10%, fermented soybean meal 11.5%, peanut meal 5%, rapeseed meal 5%, chicken meal 6%, Antarctic krill meal 3%, blood meal 3.5%, yeast paste 2%, high-gluten flour 13.83%, rice bran 3%, choline chloride 0.3%, compound vitamins 0.4%, compound minerals 0.8%, calcium dihydrogen phosphate 1.5%, sodium humate 0.4%, sodium diacetate 0.2%, haematococcus pluvialis powder 0.07%, soybean phospholipid oil 1.5%, and soybean oil 2%.

[0012] The application also provides a soft granular fattening feed for female crab sub-adults, which is prepared from the component formula of the soft granular fattening feed for female crab sub-adults provided in the application, contains the formula components of the soft granular fattening feed for female crab sub-adults provided in the application, and meets the nutritional parameters of the soft granular fattening feed for female crab sub-adults provided in the application.

[0013] Further, the soft granular fattening feed for female crab sub-adults has a particle size of 3±0.5mm and a length of 4.5±0.5mm.

[0014] Further, the soft granular fattening feed for female crab sub-adults has a particle size of 3±0.5mm and a length of 4.5±0.5mm.

[0015] Further, the soft granular fattening feed for female crab sub-adults has a particle size of 3±0.5mm and a length of 4.5±0.5mm.

[0016] The application also provides a soft granular fattening feed for male crab sub-adults, which is prepared from the component formula of the soft granular fattening feed for male crab sub-adults provided in the application, contains the formula components of the soft granular fattening feed for male crab sub-adults provided in the application, and meets the nutritional parameters of the soft granular fattening feed for male crab sub-adults provided in the application.

[0017] Further, the soft granular fattening feed for male crab sub-adults has a particle size of 3±0.5mm and a length of 4.5±0.5mm.

[0018] Further, the soft granular fattening feed for male crab sub-adults has a particle size of 3±0.5mm and a length of 4.5±0.5mm.

[0019] Further, the soft granular fattening feed for male crab sub-adults has a particle size of 3±0.5mm and a length of 4.5±0.5mm.

[0020] This invention also provides a method for using a special soft pellet feed for sub-adult female crabs under separate male and female rearing conditions. The method for using the special soft pellet feed for sub-adult female crabs includes: after the fourth molt of the female crabs, continuously feeding them with the special soft pellet feed for sub-adult female crabs provided by this invention until more than 80% of the adult crabs have completed their reproductive molt, for a continuous feeding period of 30±5 days, and then continuing feeding until the ovarian index is ≥5%, and continuing feeding for another 40±5 days; when the average daily water temperature in the rearing area is 24-30℃, the total daily feeding amount is 2-4% of the total weight of the female crabs (preferably 2-4%). 3%), fed twice a day, around 7:00 AM (6:30-7:30 AM), mainly feeding in deep water, with the morning feeding amount being 30-40% of the total daily feeding amount, and around 5:00 PM (5:30-6:30 PM), mainly feeding in shallow water, with the afternoon feeding amount being 60-70% of the total daily feeding amount; when the average daily water temperature in the breeding area is below 24℃, the total daily feeding amount is 0.5-2% of the total weight of the female crabs, fed 0.5-1 times a day, around 5:00 PM (5:30-6:30 PM), mainly feeding in shallow water.

[0021] The method of using the special soft pellet fattening feed for sub-adult male crabs includes: after the fourth molt of male crabs, continuously feed them with the special soft pellet feed for sub-adult female crabs provided by the present invention until more than 80% of the adult crabs have completed their reproductive molt. The continuous feeding period is 30±5 days, and then continue feeding until the gonad index is ≥2%, and continue feeding for another 45±5 days. When the average daily water temperature in the rearing area is 24-30℃, the total daily feed amount is 2-3% of the total weight of the female crabs, and feeding is done twice a day, around 7:00 AM. (6:30-7:30) Feeding is mainly done in deep water areas, with the morning feeding amount being 30-40% of the total daily feeding amount. Around 17:00 in the afternoon (17:30-18:30), feeding is mainly done in shallow water areas, with the afternoon feeding amount being 60-70% of the total daily feeding amount. When the average daily water temperature in the breeding area is below 24℃, the total daily feeding amount is 0.5-2% of the total weight of the female crabs, and feeding is done 0.5-1 times a day. Around 17:00 in the afternoon (17:30-18:30), feeding is mainly done in shallow water areas.

[0022] Based on research into the separate male and female rearing techniques, nutritional physiology, and feeding behavior of river crabs, this invention develops specialized soft pellet feeds for female and male crabs, suitable for monoculture of female and male crabs in ponds, respectively. Through repeated research and verification, the main nutritional parameters, feed formula, processing technology, and application methods of the feeds were determined. By scientifically feeding male and female sub-adult river crabs after their fourth molt, the survival rate, weight gain rate, feeding rate, and gonadal development after reproductive molting were improved, significantly increasing the farming efficiency. The main innovations of this invention are fourfold: I. According to the feeding behavior of river crab, compared with traditional feed, the moisture content in the feed of female and male crabs is increased, the feed palatability is improved, the feeding response time is shortened, and the feeding amount of river crab is increased.

[0023] II. According to the nutritional requirements of female crab sub-adults and adult crabs in different stages of gonad development, and the environmental conditions of pond culture, the fat content, energy level and astaxanthin content in the feed of female crabs are increased, which can improve the weight gain rate and survival rate of sub-adult reproductive molting, and promote fat accumulation in the hepatopancreas, so that female crabs can molt for reproduction 10-15 days earlier, thereby achieving the purpose of early marketing. III. According to the nutritional requirements of male crab sub-adults and gonad development, and the environmental conditions of pond culture, the protein content and arginine content in the feed of male crabs are increased, and the fat and carotenoid content is reduced. The sub-adult male crab fattening feed not only improves the palatability and increases the feeding amount, but also can promote the male crab to complete the reproductive molting 10-15 days earlier, thereby achieving early marketing.

[0024] IV. By scientifically feeding river crab sub-adults, the starting time, ending time, feeding time, feeding amount and daily feeding frequency are different, which can not only improve the molting synchrony, weight gain rate and survival rate, but also improve the utilization rate of feed by river crabs, reduce the pollution of aquaculture, and improve the economic benefits of river crab culture. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The dissolution rate of compound feed with different water content during water soaking is compared.

[0026] Figure 2 The effect of compound feed with different water content on the feeding behavior time of female and male sub-adult river crabs is shown. (a) Male crab feeding behavior, the horizontal coordinate from left to right is the feeding behavior: search, positioning, exploration, feeding, feeding response, (b) female crab feeding behavior, the horizontal coordinate from left to right is the feeding behavior: search, positioning, exploration, feeding, feeding response.

[0027] Figure 3 The effect of compound feed with different water content on the feeding rate of female and male sub-adult river crabs is shown. (a) Male crab feeding rate, (b) female crab feeding rate.

[0028] Figure 4 The regression analysis chart of the effect of different protein levels in soft pellet feed on the survival rate and growth indicators of male crabs during fattening period is shown. (a) Male crab survival rate, (b) male crab final body weight, (c) male crab weight gain rate, (d) male crab specific growth rate.

[0029] Figure 5Regression analysis graphs of the effects of different protein levels in soft pellet feeds on the survival rate and growth indicators of female crabs during the fattening period. (a) Survival rate of female crabs, (b) final body weight of female crabs, (c) weight gain rate of female crabs, (d) specific growth rate of female crabs.

[0030] Figure 6 Regression analysis graphs of the effects of different fat levels in soft pellet feeds on the weight gain rate of male crabs and the malondialdehyde content of hepatopancreas. (a) Weight gain rate of male crabs, (b) malondialdehyde content of hepatopancreas of male crabs.

[0031] Figure 7 Regression analysis graphs of the effects of different fat levels in soft pellet feeds on the ovary index of female crabs and the malondialdehyde content of hemolymph. (a) Ovary index of female crabs, (b) malondialdehyde content of hemolymph of female crabs.

[0032] Figure 8 Comparison of the appearance of soft pellet feeds with and without the addition of a mildew inhibitor after storage. A is a photograph of the deteriorated soft pellet feed without the addition of a mildew inhibitor, and B is a photograph of the soft pellet feed with the addition of a mildew inhibitor.

[0033] Figure 9 Effects of different feeds on the reproductive molting rate (A) and gonadal index (B) of female crab sub-adults.

[0034] Figure 10 Effects of different feeds on the reproductive molting rate (A) and gonadal index (B) of male crab sub-adults. DETAILED DESCRIPTION

[0035] Based on the in-depth study of the nutritional requirements and metabolism of female and male crab sub-adults during the sub-adult to adult stage, according to the nutritional requirements, feeding behavior, reproductive molting, gonadal development, body health and physiological metabolism of female and male crab sub-adults, and in combination with the water stability and palatability of soft pellet feeds, the main nutritional parameters in the soft pellet fattening feeds for female and male crabs are determined as follows: the water content in the soft pellet fattening feed for female crab sub-adults is 25-30% ( Figure 1 , Figure 2 , Figure 3 ), the protein content is 29-31% ( Figure 5 ), the total fat content is about 11% ( Figure 7 ), and the total energy level is 15-17 KJ / g; the water content in the soft pellet fattening feed for male crab sub-adults is 25-30% ( Figure 1 , Figure 2 , Figure 3 ), the protein content is 33-36% ( Figure 4 ), the total fat content is 6.5-8.5% ( Figure 6 ), and the total energy level is 13-15 KJ / g.

[0036] According to the nutritional parameters and feed raw material characteristics required by the female and male special soft granular fattening feed, the composition of each raw material in the female crab sub-adult special soft granular fattening feed formula is determined: steam fish meal 18-25%, soybean meal 15-25%, fermented soybean meal 10-15%, peanut meal 5-10%, rapeseed meal 5-10%, chicken meal 3-6%, Antarctic krill meal 2-5%, yeast paste 2-5%, high gluten flour 15-20%, rice bran 3-8%, choline chloride 0.3-0.8%, compound vitamin 0.3-0.8%, vitamin E 0.08%, compound mineral 0.8-1.2%, calcium dihydrogen phosphate 1-3%, sodium humate 0.4-0.6%, sodium diacetate 0.2% (antifungal agent), haematococcus pluvialis powder (astaxanthin content is about 3%) 0.2-0.3%, soybean phospholipid oil 2-3%, soybean oil 2-4%, refined fish oil 2-4%; The weight composition of each component in the male crab sub-adult special soft granular fattening feed formula is: steam fish meal 22-30%, soybean meal 10-15%, fermented soybean meal 10-15%, peanut meal 5-10%, rapeseed meal 5-10%, chicken meal 6-10%, Antarctic krill meal 3-5%, blood meal 1.8-3.5%, yeast paste 2-5%, high gluten flour 13-18%, rice bran 3-8%, choline chloride 0.3-0.8%, compound vitamin 0.3-0.8%, compound mineral 0.8-1.2%, calcium dihydrogen phosphate 1-3%, sodium humate 0.4-0.6%, sodium diacetate 0.2% (antifungal agent), haematococcus pluvialis powder (astaxanthin content is about 3%) 0.05-0.1%, soybean phospholipid oil 1-2%, soybean oil 1-2%.

[0037] According to the differences between female and male river crab sub-adults and adults in terms of nutritional requirements, feeding behavior, gonadal development, body health and physiological metabolism, the present application develops and sets the nutritional parameters of female and male crab fattening feed. The female special feed increases the content of total fat, carotenoids and vitamin E in the fattening feed, and reduces the protein content. The male special feed increases the content of protein and arginine, and appropriately reduces the content of fat and carotenoids. This not only realizes precise nutrition for female and male crabs, but also improves the survival rate and weight gain rate of fattening, reduces the feed conversion ratio and feed cost. Through the nutritional regulation in the feed, the antioxidant, immune performance and nutritional quality of female and male sub-adult river crabs are improved, thereby improving the survival rate and final breeding benefit.

[0038] The application provides a formula of soft granular fattening feed for female and male crabs, and a processing and packaging method of the fattening feed: various raw materials are granulated into sinkable expanded soft granular feed through the processes of impurity removal, coarse crushing, batching, primary mixing, ultrafine crushing, secondary mixing, conditioning, granulation and drying, the steam addition amount is controlled during conditioning so that the moisture content of the final expanded soft granular feed is maintained at about 25-30%, the foraging property is improved, and if the moisture content is too high, the excess moisture needs to be removed by drying process, and finally the soft granular feed is packaged by vacuumizing in a breathing bag (the negative pressure in the bag reaches 0.1 Mpa), and can be stored at room temperature. The particle size of the soft granular fattening feed for female sub-adult crabs is about 3 mm, and the length is about 4.5 mm; the particle size of the soft granular fattening feed for male sub-adult crabs is about 4 mm, and the length is about 6 mm. The soft granular fattening feed for female and male crabs is required to be soaked in water (under the condition of water temperature of 20℃) for 2 hours, and the dissolution rate is less than 15%, and the soft granular feed is still not disintegrated after being soaked in water for 3 hours under the water temperature of 20℃.

[0039] The fattening feed is made into soft granular feed with a moisture content of 25-30% in the application, the foraging property of the feed is improved, the feeding time is shortened, and the feeding amount of the river crab is increased; meanwhile, high gluten flour is used to increase the elasticity and adhesion of the feed, so as to reduce the dissolution rate of the fattening feed in water.

[0040] The application provides the scientific use method of the soft granular fattening feed for female and male crabs, the sub-adult fattening feed can be used after the fourth molting of the crabs in pond culture; the use time of the female crab single breeding pond is usually in late July, the fattening feeding time is usually not less than 70 days, and the feed can be stopped to be used until October; the use time of the male crab single breeding pond is usually in early August, the fattening feeding time is usually not less than 75 days, and the feed can be stopped to be used until the end of October. The daily feeding amount is 2-4% of the total weight of the river crabs (the pond water temperature is 25-30℃), the feeding is carried out twice a day, the morning feeding amount accounts for 30-40% of the whole day, and the feeding time is about 7:00 in the morning, and the feeding is mainly carried out in the deep water area; the afternoon feeding amount accounts for 60-70% of the whole day, and the feeding time is about 17:00 in the afternoon, and the feeding is mainly carried out in the shallow water area. The scientific feeding method of the soft granular fattening feed for female and male crabs provided in the application promotes the sub-adult crabs to molt for reproduction 10-15 days earlier, realizes the early molting and synchronous molting of the sub-adult crabs, and improves the survival rate and gonad development after mature molting, which lays a foundation for early marketing; meanwhile, the feeding workload of the crabs in the later period of culture is reduced, and the labor cost is reduced.

[0041] The soft granular fattening feed for female and male crabs provided in the application prolongs the shelf life of the soft granular fattening feed to more than 30 days through the addition of a mildew inhibitor (sodium diacetate) in the feed formula, high-temperature and high-pressure sterilization in the processing process and vacuum negative pressure packaging measures.

[0042] The soft granular fattening feed for male and female crabs provided by the application can replace the ice fresh miscellaneous fish, snails and corns, etc. widely used in the current river crab breeding, so as to improve the utilization rate of the feed by the river crab and reduce the pollution of the bait feeding to the water quality of the pond.

[0043] The soft granular fattening feed for male and female crabs provided by the application is suitable for feed enterprises, river crab breeding enterprises and breeding farmers, and is beneficial to early marketing of the river crab in the pond and reduction of the bait cost. The application has the advantages of convenient application and good practical use effect, and has high practical value.

[0044] The basic principle, main features and advantages of the application are shown and described above. It should be understood by the person skilled in the art that the application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principle of the application. Various changes and improvements can be made to the application without departing from the spirit and scope of the application, and all the changes and improvements fall within the scope of the application. The scope of protection of the application is defined by the appended claims and their equivalents.

[0045] In order to make the above-mentioned objects, features and advantages of the application more obvious and easy to understand, the technical solutions of the application are described below in connection with examples. Obviously, the described examples are only part of the examples of the application, not all the examples. Based on the examples in the application, all other examples obtained by the person skilled in the art without creative labor fall within the scope of protection of the application.

[0046] Example 1: Preparation of soft granular fattening feed for female sub-adult river crab and comparison of fattening effects (I) Determination of nutritional parameters and feed formula of the soft granular fattening feed for female crab It is determined by the application that the main nutritional parameters of the feed for the female sub-adult river crab in the fattening stage (gonadal development stage) are: water content of about 25%, crude protein content of 30%, total fat content of 11%, vitamin E content of 0.15%, total carotenoid content of 50 mg / kg, and total energy of 15.90 KJ / g; and the feed is composed of the following raw materials in weight: steam fish meal 20%, soybean meal 20%, fermented soybean meal 11%, peanut meal 5%, rapeseed meal 5%, chicken meal 3%, Antarctic krill meal 2%, yeast paste 2%, high gluten flour 15.1%, rice bran 3%, choline chloride 0.3%, compound vitamin 0.4%, vitamin E 0.08%, compound mineral 0.8%, calcium dihydrogen phosphate 1.5%, sodium humate 0.4%, sodium diacetate 0.2%, Haematococcus pluvialis powder 0.22%, soybean phospholipid oil 2%, refined fish oil 4%, and soybean oil 4%.

[0047] (II) Processing, packaging and storage of the soft granular fattening feed for female crab Various feed raw materials are processed by impurity removal, coarse crushing, batching, primary mixing, ultrafine grinding (all raw materials pass through an 80-mesh screen), secondary mixing, conditioning, and granulation processes to produce sinking soft granular expanded feed. During the batching process, an antifungal agent, sodium diacetate, is added. During conditioning, the amount of steam added is precisely controlled to maintain the moisture content of the expanded soft granular feed at 25-30% after it is ejected and cooled, thereby improving the attractiveness of the feed. If the moisture content of the feed is higher than 30%, a drying process is used to remove excess moisture. The sub-adult female crab fattening feed has a particle size of about 3 mm and a length of about 4.5 mm. Finally, the feed is packaged in a vacuum using a breathing bag (the negative pressure in the bag reaches 0.1 MPa), which can be stored at room temperature or in a freezer at a temperature below -10 degrees Celsius.

[0048] (Three) Sources of commercial fattening feed for ice-fresh fish and river crab Commercially available ice-fresh fish (control feed 1) and commercial river crab fattening feed (control feed 2) are used as control feeds to evaluate the fattening effect of the female sub-adult river crab-specific soft granular fattening feed. The commercially available ice-fresh fish is purchased from the ice fish freezer at Dongling Sluice in Rizhao, and is mainly small yellow croaker. The commercial river crab fattening feed is purchased from a feed sales store in Chongming Fort, and the main nutritional components are: moisture 9.3%, crude protein 40.2%, fat 8%, and ash 9.2%.

[0049] (Four) Sources of river crabs and fattening culture conditions Female sub-adult crabs with intact appendages and good vitality are selected for the breeding experiment. The initial body weight of the female crabs is (86.75 ± 2.12) g, and they are soaked in a 30 mg / L povidone iodine solution for 30 minutes before being released into the pond. The fattening culture experiment is conducted in an outdoor pond (length x width x depth = 15 m x 8 m x 1.2 m), and three independent net enclosures (mesh size 0.85 mm x 0.85 mm) with the same area (length x width x height = 7.3 m x 3.8 m x 1.2 m) are arranged in each pond. To prevent the crabs from mixing, escaping, and enemy organisms from entering, a 30 cm double-layer smooth plastic plate is sewn along the top of the net enclosure, and the bottom is wrapped with bricks and buried 40 cm underground. Before the experiment, bleaching powder (effective chlorine content 30%) is used to disinfect the entire pond by pouring water. After 10 days of disinfection, water is added to the pond to a depth of 1.2 m, and the water is then disinfected with 1200 kg / hm 2 After 10 days of disinfection, water is added to the pond to a depth of 1.2 m, and the water is then disinfected with 1200 kg / hm

[0050] (Five) Feeding method of female sub-adult-specific soft granular fattening feed After the fourth molting of the pond monoculture female crab (usually in the middle and late July in the Yangtze River Basin), the fattening feed is continuously fed for more than 30 days, so as to promote the rapid molting of the river crab sub-adult, improve the survival rate and the weight gain rate, and lay a foundation for the fattening (gonadal development) of the river crab; more than 80% of the adult crabs complete the reproductive molting and continue to feed for about 40 days (usually in the late September to early October in the Yangtze River Basin), and the average ovary index of the female crabs is usually ≥5%, so as to be caught and marketed.

[0051] The feeding amount of the female crab is usually related to the water temperature and the body weight of the river crab, the daily average water temperature in the pond is 24-30℃, the daily feeding amount is usually about 2-3% of the total weight of the river crab, the feeding is carried out twice a day, the feeding amount in the morning accounts for 30-40% of the whole day, the feeding time is about 7:00 in the morning, and the feeding is mainly carried out in the deep water area; the feeding amount in the afternoon accounts for 60-70% of the whole day, the feeding time is about 18:00 in the afternoon, and the feeding is mainly carried out in the shallow water area; when the daily average water temperature in the pond is lower than 24 degrees, the daily feeding amount is usually about 0.5-2% of the total weight of the river crab, the feeding is carried out 0.5-1 times a day, and the feeding time is about 17:00 in the afternoon. 3 hours after the feeding, the remaining bait in each enclosure is checked, and the feeding weight and the approximate remaining proportion of each enclosure are recorded, the feeding amount of the next day is adjusted according to the water temperature and the remaining bait, the breeding experiment officially starts on July 20, and ends on September 30, and the breeding experiment lasts for 70 days in total.

[0052] (Six) Evaluation index of the fattening effect of the female crab During the breeding experiment, the change of the reproductive molting rate of the river crab is monitored, the survival number, the body weight, the yield and the feed coefficient of the river crab are counted after the experiment, 3 river crabs are randomly taken out from each experimental net enclosure for dissection, the gonadal index is counted, the liver and pancreas are taken out for dissection, and the blood lymph is extracted and stored in a-40 degree refrigerator for detecting the antioxidant and immune enzyme activity.

[0053] (Seven) Effect comparison In example 1 of the present application, the female sub-adult river crabs are fed with the female crab soft granular fattening feed, the fresh-frozen fish and the commercial fattening feed respectively for 70 days. As shown in Table 1, compared with the commercial river crab feed on the market, the female crab soft granular fattening feed of the present application can significantly improve the survival rate, the final body weight and the weight gain rate, increase the final breeding yield and reduce the feed coefficient. Compared with the fresh-frozen fish group, the final growth and breeding performance index of the female crabs in the example 1 group are also slightly better than those of the fresh-frozen fish group, and the feed coefficient is significantly reduced.

[0054] Table 1 Influence of feeding different baits on the fattening effect of female sub-adult river crabs As Figure 9As shown, the soft granular fattening feed for female crabs of the present application can significantly promote the reproductive molting of sub-adult river crabs in the early stage, and the reproductive molting time is about 15 days earlier, and the final gonadal index is significantly higher than that of the commercial feed for river crabs. And compared with the ice fresh fish group, there is no significant difference in the reproductive molting and gonadal development of female crabs, which shows that the soft granular fattening feed for female crabs of the present application can realize early marketing of river crabs, and can improve the gonadal index of sub-adult female crabs, and the fattening effect is better than that of the common commercial feed for river crabs on the market, and can replace ice fresh fish.

[0055] As shown in Table 2, the soft granular fattening feed for female crabs can significantly improve the acid phosphatase activity in the hepatopancreas and blood lymph of female crabs, and at the same time, it can improve the glutathione peroxidase activity in the hepatopancreas, and reduce the content of malondialdehyde (lipid peroxidation product) in the hepatopancreas and blood lymph. This shows that the soft granular fattening feed for female crabs can significantly improve the antioxidant and immune performance of female crabs.

[0056] Table 2 Effect of different feeds on the antioxidant and immune indexes of female sub-adults Example 2 Preparation of soft granular fattening feed for male sub-adult river crabs and comparison of fattening effects (I) Nutritional parameters and feed formula of the soft granular fattening feed for male crabs According to the research of the inventor, the main nutritional parameters of the feed for feeding male sub-adult river crabs in the fattening stage (gonadal development stage) are: water content of about 25%, protein content of 35%, total fat content of 7.5%, total carotenoid content of 15 mg / kg feed, and total energy of 13.62 KJ / g; composed of the following raw materials by weight: steam fish meal 30%, soybean meal 10%, fermented soybean meal 11.5%, peanut meal 5%, rapeseed meal 5%, chicken meal 6%, Antarctic krill meal 3%, blood meal 3.5%, yeast paste 2%, high gluten flour 13.83%, rice bran 3%, choline chloride 0.3%, compound vitamin 0.4%, compound mineral 0.8%, calcium dihydrogen phosphate 1.5%, sodium humate 0.4%, sodium diacetate 0.2%, Dunaliella salina powder 0.07%, soybean phospholipid oil 1.5%, and soybean oil 2%.

[0057] (II) Processing, packaging and storage of the soft granular fattening feed for male crabs The same as example 1.

[0058] (III) Sources of ice fresh fish and commercial fattening feed for river crabs The same as example 1.

[0059] (IV) Sources of river crabs and fattening culture conditions The male sub-adults with intact appendages and better vitality were selected for the breeding experiment. The average initial weight of the male crabs was (97.75 ± 1.67) g, and the male crabs were soaked in 30 mg / L povidone iodine solution for 30 min before being released into the pond.

[0060] (V) Feeding method of the soft granular fattening feed for male sub-adults After the fourth molting of the single male crabs in the pond (usually in early October in the Yangtze River Basin), the soft granular fattening feed was continuously fed for more than 30 days, which could promote the rapid molting of the sub-adults, improve the survival rate and weight gain rate, and lay the foundation for the fattening (gonadal development) of the crabs. More than 80% of the mature crabs completed the reproductive molting and were continuously fed for about 45 days (usually in late October in the Yangtze River Basin), at which time the average gonadal index of the male crabs was usually greater than or equal to 2%, and the male crabs could be caught and marketed. The daily feeding amount and feeding time were referred to example 1. The breeding experiment officially started on August 1 and ended on October 20, with a total duration of 80 days.

[0061] (VI) Evaluation index of the fattening effect of the male crabs The same as example 1.

[0062] (VII) Effect comparison As shown in Table 3, the soft granular fattening feed for male crabs of the present application can significantly improve the final body weight and weight gain rate compared with the commercial feed for river crabs on the market. Compared with the ice fresh fish group, the survival rate and yield of the male crabs in the soft granular fattening feed group for male crabs are slightly better than those in the ice fresh fish feeding group, and the feed conversion ratio is also significantly reduced.

[0063] Table 3 Growth and breeding performance data of male sub-adults fed with different feeds As shown in Table 3, the soft granular fattening feed for male crabs of the present application can significantly improve the final body weight and weight gain rate compared with the commercial feed for river crabs on the market. Compared with the ice fresh fish group, the survival rate and yield of the male crabs in the soft granular fattening feed group for male crabs are slightly better than those in the ice fresh fish feeding group, and the feed conversion ratio is also significantly reduced. Figure 10 As shown in Table 3, the soft granular fattening feed for male crabs of the present application can significantly improve the final body weight and weight gain rate compared with the commercial feed for river crabs on the market. Compared with the ice fresh fish group, the survival rate and yield of the male crabs in the soft granular fattening feed group for male crabs are slightly better than those in the ice fresh fish feeding group, and the feed conversion ratio is also significantly reduced.

[0064] As shown in Table 4, the soft granular fattening feed for male crabs can significantly improve the glutathione peroxidase and acid phosphatase activities in the hepatopancreas and the acid phosphatase activity in the blood lymph of the male crabs, and reduce the content of malondialdehyde (lipid peroxidation product) in the hepatopancreas compared with the commercial feed for river crabs and ice fresh fish. This indicates that the soft granular fattening feed for male crabs can significantly improve the antioxidant and immune performance of the male crabs.

[0065] Table 4 Effects of different feeds on the indexes of oxidation resistance and immunity of male sub-adults From the above examples, it can be seen that the female and male sub-adult river crab special soft granular fattening feed of the present application is superior to ice-fresh frozen fish and conventional puffing fattening feed of river crab, has the advantages of accurate nutrition, stable quality, convenient feeding, good food attraction and palatability, etc., and can not only improve the survival, weight gain and reduce the feed coefficient of female and male crabs, but also improve the health status of river crabs, promote reproductive molting and gonadal development, promote early marketing, and has a broad application prospect.

[0066] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A formula for a soft pellet feed specifically for sub-adult female crabs under separate male and female rearing conditions, characterized in that the soft pellet fattening feed for sub-adult female crabs contains the following components in parts by weight: 18-25% steamed fish meal, 15-25% soybean meal, 10-15% fermented soybean meal, 5-10% peanut meal, 5-10% rapeseed meal, 3-6% chicken meal, 2-5% Antarctic krill meal, 2-5% yeast extract, 15-20% high-gluten flour, 3-8% rice bran, 0.3-0.8% choline chloride, 0.3-0.8% compound vitamins, 0.08% vitamin E, 0.8-1.2% compound minerals, 1-3% calcium dihydrogen phosphate, 0.4-0.6% sodium humate, 0.2% sodium diacetate, 0.2-0.3% Haematococcus pluvialis powder, 2-3% soybean lecithin oil, 2-4% soybean oil, and 2-4% refined fish oil; This soft pellet fattening feed for sub-adult male crabs contains the following components by weight: 22-30% steamed fishmeal, 10-15% soybean meal, 10-15% fermented soybean meal, 5-10% peanut meal, 5-10% rapeseed meal, 6-10% chicken meal, 3-5% Antarctic krill meal, and blood meal. 1.8-3.5%, yeast paste 2-5%, high-gluten flour 13-18%, rice bran 3-8%, choline chloride 0.3-0.8%, compound vitamins 0.3-0.8%, compound minerals 0.8-1.2%, calcium dihydrogen phosphate 1-3%, sodium humate 0.4-0.6%, sodium diacetate 0.2%, Haematococcus pluvialis powder 0.05-0.1%, soybean lecithin oil 1-2%, soybean oil 1-2%.

2. The formulation according to claim 1, characterized in that, The special soft pellet fattening feed for sub-adult female crabs contains the following components by weight: steamed fish meal 19-22%, soybean meal 18-21%, fermented soybean meal 11-12%, peanut meal 5-7%, rapeseed meal 5-7%, chicken meal 3-4%, Antarctic krill meal 2-4%, yeast extract 2-3%, high-gluten flour 15-17%, rice bran 3-5%, choline chloride 0.3-0.6%, compound vitamins 0.3-0.6%, vitamin E 0.08%, compound minerals 0.8-1%, calcium dihydrogen phosphate 1-2%, sodium humate 0.4-0.5%, sodium diacetate 0.2%, Haematococcus pluvialis powder 0.2-0.25%, soybean lecithin oil 2-2.5%, soybean oil 3.5-4%, and refined fish oil 3.5-4%. The special soft pellet fattening feed for sub-adult male crabs contains the following components by weight: 28-30% steamed fish meal, 10-12% soybean meal, 10-12% fermented soybean meal, 5-7% peanut meal, 5-7% rapeseed meal, 6-8% chicken meal, 3-4% Antarctic krill meal, 3-3.5% blood meal, 2-3% yeast extract, 13.5-14% high-gluten flour, 3-4% rice bran, 0.3-0.4% choline chloride, 0.4-0.5% compound vitamins, 0.8-1% compound minerals, 1-2% calcium dihydrogen phosphate, 0.4-0.5% sodium humate, 0.2% sodium diacetate, 0.06-0.08% Haematococcus pluvialis powder, 1.5-2% soybean lecithin oil, and 1.5-2% soybean oil.

3. The formulation according to claim 1, characterized in that, The special soft pellet fattening feed for sub-adult female crabs contains the following components by weight: 20% steamed fish meal, 20% soybean meal, 11% fermented soybean meal, 5% peanut meal, 5% rapeseed meal, 3% chicken meal, 2% Antarctic krill meal, 2% yeast extract, 15.1% high-gluten flour, 3% rice bran, 0.3% choline chloride, 0.4% compound vitamins, 0.08% vitamin E, 0.8% compound minerals, 1.5% calcium dihydrogen phosphate, 0.4% sodium humate, 0.2% sodium diacetate, 0.22% Haematococcus pluvialis powder, 2% soybean lecithin oil, 4% refined fish oil, and 4% soybean oil. This soft pellet fattening feed for sub-adult male crabs contains the following components by weight: 30% steamed fishmeal, 10% soybean meal, 11.5% fermented soybean meal, 5% peanut meal, 5% rapeseed meal, 6% chicken meal, 3% Antarctic krill meal, 3.5% blood meal, 2% yeast extract, 13.83% high-gluten flour, 3% rice bran, 0.3% choline chloride, 0.4% compound vitamins, 0.8% compound minerals, 1.5% calcium dihydrogen phosphate, 0.4% sodium humate, 0.2% sodium diacetate, and Haematococcus pluvialis powder. 0.07%, soybean lecithin oil 1.5%, soybean oil 2%.

4. The formulation according to any one of claims 1-3, characterized in that, The nutritional components of the formula for soft pellet fattening feed for sub-adult female crabs include: protein content 29-31%, total fat content 11-12%, vitamin E content 0.14-0.15%, total carotenoid content 40-60 mg / Kg, and total energy level 15-17 KJ / g; The nutritional components of the formula for soft pellet fattening feed for sub-adult male crabs include: protein content 33-36%, total fat content 6.5-8.5%, total carotenoid content 10-20 mg / Kg, and total energy level 13-15 KJ / g.

5. The formulation according to claim 4, characterized in that, When preparing soft pellet fattening feed, the moisture content of the soft pellet fattening feed for sub-adult female crabs is 25-30%, and the moisture content of the soft pellet fattening feed for sub-adult male crabs is 25-30%.

6. A soft pellet feed specifically for sub-adult crabs under separate male and female rearing conditions, characterized in that, The soft pellet fattening feed for sub-adult female crabs contains the formulation components of the soft pellet fattening feed for sub-adult female crabs as described in any one of claims 1-3, and contains the moisture and nutrients contained in the formulation of the soft pellet fattening feed for sub-adult female crabs as described in claim 4 or 5. The special soft pellet fattening feed for sub-adult male crabs contains the formulation components of the special soft pellet fattening feed for sub-adult male crabs as described in any one of claims 1-3, and contains the moisture and nutrients contained in the formulation of the special soft pellet fattening feed for sub-adult male crabs as described in claim 4 or 5.

7. The soft pellet feed specifically for sub-adult crabs under separate male and female rearing conditions as described in claim 6, characterized in that, At 20℃, the solubility loss rate of the special soft pellet fattening feed for female sub-adult crabs and the special soft pellet fattening feed for male sub-adult crabs after soaking in water for 2 hours is less than 15%, and they do not disintegrate after soaking in water for 3 hours.

8. The soft pellet feed specifically for sub-adult crabs under separate male and female rearing conditions as described in claim 6, characterized in that, The particle size of the soft pellet fattening feed for sub-adult female crabs is 3±0.5mm and the length is 4.5±0.5mm; the particle size of the soft pellet fattening feed for sub-adult male crabs is 4±0.5mm and the length is 6±0.5mm.

9. A method for using a special soft pellet feed for sub-adult crabs under separate male and female rearing conditions, characterized in that, The method of using the special soft pellet fattening feed for sub-adult female crabs includes: after the fourth molt of the female crabs, continuously feeding them with the special soft pellet fattening feed for sub-adult female crabs prepared according to the formula of any one of claims 1-5 or the special soft pellet fattening feed for sub-adult female crabs according to any one of claims 6-8 until more than 80% of the adult crabs have completed the reproductive molt, and then continuing to feed them until the ovarian index is ≥5%; The method of using the special soft pellet fattening feed for male sub-adult crabs includes: after the fourth molt of male crabs, using the formula of the special soft pellet fattening feed for male sub-adult crabs as described in any one of claims 1-5 or the special soft pellet feed for male sub-adult crabs as described in any one of claims 6-8, continuously feeding until more than 80% of the adult crabs have completed reproductive molting, and then continuing to feed until the gonad index is ≥2%.

10. The method of use according to claim 9, characterized in that, The method of using soft pellet fattening feed for sub-adult female crabs includes: When the average daily water temperature in the rearing area is 24-30℃, the total daily feed amount is 2-4% of the total weight of the female crabs, fed twice a day. Around 7:00 AM, feeding is mainly done in deep water areas, with the morning feed amount being 30-40% of the total daily feed amount. Around 5:00 PM, feeding is mainly done in shallow water areas, with the afternoon feed amount being 60-70% of the total daily feed amount. When the average daily water temperature in the rearing area is below 24℃, the total daily feed amount is 0.5-2% of the total weight of the female crabs, fed 0.5-1 times a day, with the afternoon feed amount being mainly done in shallow water areas around 5:00 PM. The method of using soft pellet fattening feed for sub-adult male crabs includes: When the average daily water temperature in the rearing area is 24-30℃, the total daily feeding amount is 2-4% of the total weight of the female crabs, and feeding is done twice a day. Around 7:00 AM, feeding is mainly done in the deep water area, with the morning feeding amount being 30-40% of the total daily feeding amount. Around 5:00 PM, feeding is mainly done in the shallow water area, with the afternoon feeding amount being 60-70% of the total daily feeding amount. When the average daily water temperature in the rearing area is below 24℃, the total daily feeding amount is 0.5-2% of the total weight of the female crabs, and feeding is done 0.5-1 times a day, with feeding being mainly done in the shallow water area around 5:00 PM.

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