CN107624503B

CN107624503B - Shrimp feed additive and application thereof

Info

Publication number: CN107624503B
Application number: CN201711066845.0A
Authority: CN
Inventors: 张秋胜; 徐丙莲; 程显好; 潘佳佳; 李田招
Original assignee: Ludong University
Current assignee: Ludong University
Priority date: 2017-11-03
Filing date: 2017-11-03
Publication date: 2022-04-26
Anticipated expiration: 2037-11-03
Also published as: CN107624503A

Abstract

The invention discloses a shrimp feed additive and application thereof, and is characterized in that the additive is obtained by drying and crushing residues obtained by culturing cordyceps militaris sporocarp in cordyceps militaris culture medium. The cordyceps militaris culture medium is prepared by mixing liquid A and solid B: the liquid component A is as follows: 1000 ml of water, 10.0-15.0 g of cane sugar and KH₂PO₄0.3～0.5 g，MgSO₄0.3-0.5 g, vitamin B complex 4 tablets and vitamin C1 tablets. The composition of the solid B is as follows: 50% of wheat grains, 15% of rapeseed meal, 24% of peanut meal, 1% of dry silkworm pupa powder and 10% of rice bran; the weight ratio of the liquid A to the solid B is 2-3: 1. sealing, sterilizing and cooling the cordyceps militaris culture medium; then inoculating cordyceps militaris strains, wherein the density of the strains is 10-20 pellets/mL, and the volume ratio of the strains to the culture medium is 1: 50, inoculating, and during culture, performing dark culture and then performing light culture; obtaining cordyceps militaris sporocarp and residue. The residue contained crude polysaccharide up to 27.43%. Naturally airing or drying the residue, and crushing the residue to 80-mesh granularity to obtain the shrimp feed additive. The shrimp feed additive is beneficial to digestion and absorption of shrimps, has a fragrant smell of , is applied to improving the weight gain rate and the survival rate of the shrimps, and has an obvious effect. The addition amount of the shrimp feed additive in the shrimp feed is 10-15%.

Description

Shrimp feed additive and application thereof

Technical Field

The invention relates to the field of shrimp feed additive production, in particular to a culture medium formula for producing a shrimp feed additive and application of residues obtained after producing cordyceps militaris sporocarp in the shrimp feed additive.

Background

Scarlet caterpiller fungus (scarlet caterpiller fungus)Cordyceps militaris) Cordyceps militaris is also known as Cordyceps militaris, and belongs to Ascomycotina, Clavicipitaceae, and Cordyceps of fungi. The cordyceps militaris sporocarp has similar medicinal and nourishing effects with the cordyceps sinensis, and the cordycepin content in the cordyceps militaris is dozens of times higher than that of the traditional cordyceps sinensis, so that the cordyceps militaris sporocarp is a rare medicinal fungus. Cordyceps militaris contains abundant proteins, amino acids and more than 30 trace elements required by human body, and contains special physiological active ingredients such as cordycepin and cordycepic acid, and has anti-tumor effect. Modern medicine and pharmacology researches prove that the nutrient substances in the cordyceps militaris have the effects of nourishing lung and kidney, stopping bleeding and reducing phlegm, expanding trachea, calming, resisting bacteria, reducing blood pressure, resisting oxidation, protecting liver, enhancing immunity and the like. In 2009 the Ministry of health has approved cordyceps militaris as a new resource food. In the aspect of artificial culture medium of cordyceps militaris, there are many patents, such as application number: 201310462899.4A Cordyceps militaris culture medium and its application are provided, the culture medium is rice and pupa worm powder; as another example, application No.: 201510397546.X, a culture medium for culturing Cordyceps militaris and its preparation method, the culture medium is cereals and dried pupa bombycis; no cordyceps militaris produced by using rapeseed meal and peanut meal as auxiliary materials is found.

The artificial culture of cordyceps militaris by using rice, silkworm chrysalis meal and the like is a new technology developed in recent years, and culture medium residues overgrowing with mycelia are discarded as waste materials after fruiting bodies are harvested, so that serious resource waste and environmental pollution are caused. Cordyceps sinensis dregs (EFR) are culture medium residues left after harvest of Edible fungus sporocarp in the process of cultivating Cordyceps sinensis Edible Fungi. The production amount of edible and medicinal fungus dregs in China is also surprising, the fungus dregs are very difficult to degrade in natural environment, mould and pests are easy to breed, the environment is damaged, and waste gas generated by combustion pollutes the environment. Therefore, not only is precious biological resources wasted, but also significant environmental problems are caused, so that reasonable development and utilization are necessary, and the recycling of the mushroom dregs is realized. The patent is developed aiming at the cordyceps residues as feed resources.

After the fruit body is harvested, the dry weight of the waste culture medium residue in each bottle is about 40g, the cordycepin contained in the culture medium residue is about 0.5%, the total sugar content is about 21.93%, the protein content is about 10%, the cordyceps polysaccharide content is about 12.86%, and in addition, the culture medium residue also contains effective components such as alkaloid, terpenoid, sterol, glycoside, phenol, enzyme, vitamin, SOD and the like, so that the culture medium residue still has great utilization value. Cordycepin has antibacterial, antitumor, antiviral, and oxygen free radical antagonizing effects, has high medicinal value and wide pharmacological action, and is a kind of physiologically active substance with great importance in the pharmaceutical industry. If the compound feed is applied to a feed formula, various nutrient components in the medium residue can be fully utilized, the feed cost can be reduced, and the effect of changing waste into valuable is achieved.

Compared with the raw material used for preparing the original edible fungus culture medium, the fungus residue has the advantages that the nutritional components are changed, the nutritional value is obviously improved, the crude fiber is degraded, the content is greatly reduced, and correspondingly, the relative proportion of protein is increased, so the fungus residue is also called as fungus chaff protein. The residue is transformed by the edible fungi, so that the effective nutrient content is increased, and if the residue is used in the feed industry, the digestion utilization rate is greatly improved and the palatability is improved due to the degradation of the residue on crude fibers.

With the improvement of living standard of people, the demand and quality requirements of people on aquatic products are also improved. On one hand, most of the existing prawn feeds are mainly focused on the production speed of prawns and the yield of fishes, but neglect the improvement of the quality of the prawns. On the other hand, the proportion of corn, wheat, bean pulp and the like in the traditional feed formula is higher, the feed cost is higher and higher along with the increasing rising of the price of grains, and the economic benefit of the aquaculture industry is seriously influenced.

Shrimps have high nutritional value, contain various proteins, have soft meat quality, are easy to digest, are rich in rich mineral substances (calcium, phosphorus and iron), and are popular with consumers. China is the second and fourth major export countries of world shrimp products, and prawns are one of the main shrimp products, and the small fluctuation of the yield and quality of the prawns can have great influence on the aquatic product trade. The market price of the prawns is high, but the prawns are susceptible to shrimp diseases and have high breeding risks, and if the prawns are ill or even die in the breeding process, the quantity and the quality of the prawns can be greatly reduced.

The quality of the shrimp feed is a key factor influencing the water area ecosystem, the disease resistance of the shrimps and the quality. Taking the prawns as an example, the cost of the feed for the prawns accounts for 30-40% of the cost of the prawns for breeding, and is the maximum cost item expenditure in the process of breeding the prawns (Yuan, international trade structure and competitiveness research of Chinese shrimp products [ D ]. Qingdao: China oceanic university, 2009), so that the feed for the prawns becomes one of the important factors for determining the economic benefit of the prawn breeding. The application of adding polysaccharide, immunopotentiator and the like in compound feed for prawns is common, and the application number is as follows: 200710022923.7 Cordyceps sinensis feed additive for activating and enhancing immunity and its preparation method are provided. The patent utilizes cordyceps militaris and cordyceps sinensis strains to ferment corn, soybean meal and the like, and the fermented product is used as an animal feed additive. As another example, patent application No.: 97107712.6A feed additive containing Cordyceps fungi for meat animals is prepared from starch. None of the above patents mention the use of wheat grain and peanut meal to produce cordyceps militaris fruit bodies and the use of the residue thereof in fishery feeds. Therefore, through retrieval, no cordyceps militaris is produced by using wheat and peanut meal as culture mediums, no cordyceps militaris residue is used as a shrimp feed additive, and no related patent and literature report of the application of the feed additive in prawns is found.

Disclosure of Invention

The invention aims to provide a culture medium formula for producing a shrimp feed additive, a feed additive taking residues of a cordyceps militaris culture medium as a raw material and a preparation method thereof, which can solve the problems of high cost, poor disease resistance and the like of the conventional prawn feed and reduce the economic burden of fishermen.

The formula for producing the cordyceps militaris culture medium is formed by mixing liquid A, solid B and the like: the liquid A comprises the following components: adding sucrose 10.0-15.0 g and KH into 1000 ml tap water₂PO₄ 0.3~0.5 g，MgSO₄0.3-0.5 g, vitamin B complex tablets and vitamin C1 tablets; the composition of the solid part of B is as follows: 50% of wheat grains, 15% of rapeseed meal, 24% of peanut meal, 1% of dry silkworm pupa powder and 10% of rice bran; the liquid-solid ratio of the liquid A to the solid B is 2-3: 1; mixing, placing into culture flask, sealing, sterilizing, and cooling. Wherein the sterilization conditions are as follows: sterilizing at 121 ℃ and 1.1Mpa for 30-45 min. The cordyceps militaris culture medium provided by the invention can be used for culturing cordyceps militaris (shown in figure 1).

The method for culturing the cordyceps militaris by using the cordyceps militaris culture medium comprises the steps of inoculation, culture, harvesting, drying and the like. The method comprises the following specific steps: inoculation is carried out first. Inoculating Cordyceps militaris strain into the Cordyceps militaris culture medium, wherein the Cordyceps militaris strain isCordyceps militaris(L.) Link, No. 3.4655, from China General Microbiological Culture Collection Center (CGMCC). The inoculation bacteria are liquid strains, the density of the cordyceps militaris strains is 10-20 pellets/ml, and the volume ratio of the cordyceps militaris culture medium to the cordyceps militaris strains is 50: 1; then, the culture is carried out. Culturing for 5-6 days at 25 deg.C and humidity of 80-87% in dark until Cordyceps militaris mycelia overgrow the surface of Cordyceps militaris culture medium; and (3) illumination culture adopted on days 6-25: in 12 hours in the daytime, the fluorescent lamp is used for illumination, the temperature is 22-25 ℃, the humidity is 80-85%, and the illumination intensity is controlled to be 150-200 Lx; closing light at 12 hours at night, wherein the temperature is 20-23 ℃, and the humidity is 80-83%; ventilating for 30 min each time in the morning and evening for 2 times a day; and (3) illumination culture adopted on the 26 th-45 th day: illuminating by natural light and a fluorescent lamp for 12 hours in the day at the temperature of 22-25 ℃ and the humidity of 80 percent, and controlling the total illumination intensity at 1100 Lx; closing light at 12 hours at night, wherein the temperature is 20 ℃ and the humidity is 75-85%; ventilating for 30 min each time in the morning and evening for 2 times a day; the light sources used for culturing are all scattered light, and the culture bottle is rotated in the culturing process to ensure that the illumination is uniform; the yield is increased by 20 percent compared with the yield of the cordyceps militaris sporocarp cultured by using the culture medium and the culture method in the prior art; the content of adenosine in each 1g of cordyceps militaris sporocarp is 15-20 mg, the content of cordycepin is 7.5-8.0 mg, and the content of polysaccharide is 25-3 mg, which are obviously higher than that of cordyceps militaris cultured by adopting the prior art method. And finally harvesting and drying: taking out the mature cordyceps militaris sporocarp in the culture bottle after the culture in the step, and drying by solar irradiation or hot air circulation; putting the harvested cordyceps militaris residues in a stainless steel plate of 80 meshes, uniformly spreading, and drying by hot air circulation at 40-45 ℃ until the water content is controlled below 10%.

The invention takes wheat grains and peanut meal as main raw materials, rice bran as auxiliary materials, a little dry silkworm pupa powder, vitamins and the like as nutrient components to prepare a cordyceps militaris culture medium, finally determines the optimal formula of the culture medium through a gradient experiment, and then adopts a special three-stage culture expanding mode: dark culture, then different illumination culture modes at different time periods, and light source adoption scattered light, in the culture process, regularly rotating a culture bottle or a culture basin to make the illumination uniform, namely, by determining an optimal cordyceps militaris culture medium formula and optimizing a culture scheme on the whole, the cordyceps militaris sporocarp obtained by strictly culturing according to the method is detected, and the detection results show that: the yield is increased by 20 percent compared with the yield of the cordyceps militaris sporocarp cultured by using the culture medium and the culture method in the prior art; the content of adenosine in each 1.0 g of cordyceps militaris fruiting body is 15-20 mg, the content of cordycepin is 7.5-8.0 mg, and the content of polysaccharide is 25-3 mg, which is obviously higher than that of cordyceps militaris cultured by the prior art method.

The cordyceps militaris residue obtained by the method is applied to shrimp feeds.

The shrimp feed additive of the invention is an ecological environment-friendly green biological additive. The ecological environment-friendly green biological additive provided by the invention can obviously enhance the disease resistance of the prawns, improve the living rate of the young prawns and the adult prawns in the growth process by 7-9%, and has obvious effect. The growth speed of the prawns is obviously increased, and in 56-day contrast culture, the weight gain rate of the prawns added with the cordyceps militaris mushroom dregs is increased by 4.5-6.0% under the condition that the feed feeding amount is not increased and the feed amount is the same (figure 2).

The effects of the present invention are further clarified by comparative tests as follows.

First, experimental conditions and comparative experimental groups.

The experimental seawater is underground seawater, and is subjected to sedimentation aeration, continuous aeration in the pond and still water culture. The ammonia nitrogen, nitrite, hydrogen sulfide, pH value and dissolved oxygen value of the experimental water are all in the normal range. The water temperature is 27 ℃, and the salinity is 28 thousandths.

The experimental farm is an industrial cultivation greenhouse, each cement pond is (1.5 multiplied by 1.5) and 3 cubic meters, and the two groups of the cement ponds are divided into 4 cement ponds. 200 shrimp larvae with the average weight of 4 grams are stocked in each of 8 cement ponds. Feeding common prawn feed to a control group; the experimental group feeds prawn feed with 10-15% of cordyceps militaris residue. Feeding twice a day.

And secondly, tracking measurement and experimental results.

1. And (3) calculating the survival rate: and respectively recording the death number in the two groups of parallel experiment pools every day, and obtaining the average amount after the calculation is finished.

2. Measuring the weight of the prawns: the weight of the fish is measured by an electronic scale in 5 fish ponds (20 fish in each group) randomly in two groups of parallel test ponds once every 14 days, and finally the weight is summed and averaged.

3. The follow-up measurement time was 56 days.

4. The results of the experiments are set forth below in the tabular form.

Table 1 two parallel experiments compare survival.

	Average survival Rate (%)	Remarks for note
			Control group	86	Mean value of
Experimental group	95	Mean value of

Table 2 comparison of two parallel experiments to body weight (unit: g).

	14	28	42	56	Remarks for note
						Control group	4.8	7.3	10.2	15.2	Mean value of
Experimental group	5.6	8.7	13.7	18.6	Mean value of

And thirdly, an experimental conclusion.

Through strict and serious experiments, the environment-friendly green biological additive has obvious effects on improving the survival rate, the growth speed and the like in the application of the prawn culture technology. The observation shows that the prawn body color of the experimental group is bright, the prawn body is strong, the swimming is fast and powerful, and the disease resistance is enhanced. During the feeding period, the bait coefficient of the prawns in the experimental group is reduced, the disease resistance is good, the growth is fast, the breeding cost is reduced, and the manpower and material resources are saved. The additive of the present invention is a biological product, so that it has no pollution to prawn growth and retains the original rich nutrients and delicious taste of prawn. Meanwhile, the residue after the cordyceps militaris culture medium is used as a shrimp feed additive, so that the recycling of resources is realized, the production cost of the feed is reduced, and the problem of environmental pollution caused by the discarded cordyceps militaris culture medium residue is solved. It should be noted that, based on the above design, even if some insubstantial modifications or colorings are made on the present invention to solve the same technical problems, the essence of the technical solution adopted is still the same as the present invention, and therefore, the technical solution should be within the scope of the present invention.

Compared with the prior art, the technology of the invention has the following advantages.

1. The rapeseed dregs contain more toxic and harmful substances, and the application of the rapeseed dregs in the daily ration of animals is greatly limited. Such as isothiocyanate, thiocyanate, oxazolidinethione, nitrile, sinapine, tannin, phytic acid, etc. Not only influences the palatability of the daily ration and influences the utilization of other nutrient substances, but also can cause the goiter of animals and inhibit the growth of the animals. Through high-temperature high-humidity sterilization treatment in the production process of cordyceps militaris sporocarp, growth of cordyceps militaris mycelia and other processes, harmful substances are greatly degraded, the protein content is improved to a certain extent in the growth process of cordyceps militaris, and the palatability of animals is improved.

2. The leftovers of the cordyceps culture medium still have residual incompletely converted wheat, and simultaneously have a large amount of cordyceps mycelia, wherein the mycelia contain a large amount of proteins and a plurality of amino acids which are not utilized. By implementing the invention, the feed can be directly absorbed and utilized by animals, and has comprehensive nutrition, good palatability and low cost.

3. The invention can realize the production of the cordyceps militaris, namely small-scale production and moderate large-scale production. Meanwhile, while continuously providing the cordyceps militaris, also provides raw materials for producing animal feed additives, so that multiple purposes are achieved; the invention realizes the high-efficiency full-utilization of resources, can produce edible cordyceps militaris for people and also can produce the feed additive for prawns by using leftovers of agricultural and sideline products as raw materials, realizes the cyclic utilization of resources, protects the environment and improves the economic benefit.

4. The production method adopted by the invention has the advantages of low raw material cost, simple equipment and operation, realization of large-scale production, contribution to comprehensive utilization of cordyceps militaris and waste recycling. The whole production process has mild conditions and no toxic and harmful substances are taken, so that the safety of the produced cordyceps militaris can be met, the biological activity of cordyceps militaris residues can be maintained to the maximum extent, and the safety of the prawn feed is improved.

5. The invention has simple production process, stable procedure, easy control and high success rate, has less repeated production investment, small occupied area and no three-waste problem, is suitable for enterprises, and the product of the invention not only has food for people, but also has functional feed additive, namely shrimp feed additive.

Drawings

FIG. 1 shows the method for obtaining Cordyceps militaris in growth.

FIG. 2 shows the growth potential of prawn.

The figure a shows that prawns fed with the cordyceps militaris residue feed additive produced by the method are fed with food.

The graph b shows the prawns fed the same amount of a commercial feed additive.

Panel c is a prawn ingesting a control feed.

Detailed Description

The present invention will be described in further detail with reference to the following examples, but is not limited thereto.

Example 1: preparing a cordyceps militaris culture medium.

The formula of the cordyceps militaris culture medium is formed by mixing a liquid A and a solid B: the liquid A comprises the following components: adding 10.0-15.0 g of sucrose and KH into 1000 ml of tap water₂PO₄ 0.3～0.5 g，MgSO₄0.3-0.5 g, vitamin B complex tablets and vitamin C1 tablets. The composition of the solid part of B is as follows: 50% of wheat grains, 15% of rapeseed meal, 24% of peanut meal, 1% of dry silkworm pupa powder and 10% of rice bran; the liquid-solid ratio of the liquid A to the solid B is 2-3: 1; mixing, placing into culture flask, sealing, sterilizing, and cooling. Wherein the sterilization conditions are as follows: sterilizing at 121 ℃ and 1.1MPa for 50-60 min. The cordyceps militaris culture medium provided by the invention can be used for culturing cordyceps militaris.

Example 2: and (5) culturing cordyceps militaris.

The cordyceps militaris culture medium prepared by the embodiment is used for culturing cordyceps militaris, and comprises the steps of inoculation, culture, harvesting, drying and the like. The method specifically comprises the following steps: inoculation is carried out first. Inoculating Cordyceps militaris strains into a culture bottle of the Cordyceps militaris culture medium prepared in the example 1 in a super clean bench, wherein the Cordyceps militaris strains are Cordyceps militaris (L.) Link, liquid strains, the density of the Cordyceps militaris strains is 3-5 pellets/mL, and each culture bottle contains 1mL of Cordyceps militaris strains; and then culturing: culturing for 5-6 days at 25 deg.C and humidity of 80-87% in dark until Cordyceps militaris mycelia overgrow the surface of Cordyceps militaris culture medium; and (3) illumination culture adopted on days 6-25: in 12 hours in the daytime, the fluorescent lamp is used for illumination, the temperature is 22-25 ℃, the humidity is 80-85%, and the illumination intensity is controlled to be 150-200 Lx; closing light at 12 hours at night, wherein the temperature is 20-23 ℃, and the humidity is 80-83%; ventilating for 30 min each time in the morning and evening for 2 times a day; and (3) illumination culture adopted on the 26 th-45 th day: illuminating by natural light and a fluorescent lamp for 12 hours in the day at the temperature of 22-25 ℃ and the humidity of 80 percent, and controlling the total illumination intensity at 1100 Lx; closing light at 12 hours at night, wherein the temperature is 20 ℃ and the humidity is 75-85%; ventilating for 30 min each time in the morning and evening for 2 times a day; the light sources used in the culture in the step are all scattered light, and the culture bottle is turned regularly in the culture process to ensure uniform illumination; and (3) harvesting and culturing again: taking out mature cordyceps militaris sporocarp in a culture bottle after culture; and finally, drying: putting the harvested cordyceps militaris sporocarp in a stainless steel tray filled with gauze, uniformly spreading, and drying by hot air circulation at the temperature of 30-37 ℃ until the water content is controlled to be below 10%.

The cautions of Cordyceps militaris in culture.

A. The light irradiation needs scattered light but not direct light, the Cordyceps grows with directional light, the bottle in the place with uniform light irradiation needs to be turned to make the light irradiation uniform, and the fruiting body grows upwards.

B. The temperature and humidity should be strictly controlled during the cultivation process, so the temperature should be strictly controlled. Under the condition that no temperature control equipment is arranged in a workshop at present, the temperature of the culture room is controlled by ground water spraying, the water is sprayed for 3 times in a day generally, but the temperature is changed according to the temperature condition of the day, the temperature is increased more, the temperature of the culture room exceeds 25 ℃, and the temperature of an air conditioner is required to be reduced.

C. Ventilating the culture chamber once or twice every day, wherein the time is selected to be 20-30 minutes each time when the temperature is relatively low in the morning and evening.

D. The bottle polluted after inoculation needs to be taken out in time, the culture medium in the bottle is poured out and sterilized again, and then the bottle is inoculated again, so that the polluted bottle cannot be placed in a culture room for culture, and the whole culture room is polluted by mixed bacteria.

The cordyceps militaris cultured by the method can be harvested for two seasons in one year under natural conditions; if under the factory condition, the annual production can be realized. By utilizing the patent technology, the yield of the cordyceps militaris is improved by 20%.

Example 3: a feed formula using Cordyceps militaris culture medium residue as raw material and its preparation method are provided.

The invention discloses a prawn feed, which solves the problems that the existing feed is high in cost and the quality of prawns cannot be well improved. The prawn feed additive of the invention is prepared from cordyceps militaris culture medium mushroom dreg powder, cordyceps militaris mycelium powder, unused rapeseed meal, peanut meal, rice bran, a vitamin mixture, trace elements and the like. The components of the invention utilize the production waste of the solid culture medium residue left after the cordyceps militaris sporocarp is picked, the production waste is fully recycled, and the production cost of the feed is greatly reduced.

Example 4: influence of Cordyceps militaris culture medium residue on feeding and growth of prawn.

In 2013, 4 side-by-side shrimp ponds with the area of 2 mu are selected in a muzeping horse-breeding island in the tobacco station city of Shandong province, and random tests are respectively carried out, and the results are as follows.

Table 3 influence of cordyceps militaris residues on feeding and growth of prawns.

Group of	1 control	2 Cordyceps militaris residue dry powder (5%)	3 Cordyceps militaris residue dry powder (10%)	4 Cordyceps militaris residue dry powder (20%)
					Weight gain (%)	74.35±2.3	78.0±1.7	83.13±1.9	70.45±3.5
Survival rate (%)	87.14±1.5	88.25±1.0	95.17±3.2	78.34±2.3

Note: different english letters in the upper corners of the same column indicate significant differences (P < 0.05).

From the table 3, it can be seen that when 5%, 10% and 20% of cordyceps militaris residue dry powder is added to the feed to replace peanut meal, the weight gain rate of the prawns (P is less than 0.05) can be affected, so that the purposes of reducing cost and changing waste into valuable are achieved; but the weight gain rate of the prawns by adding 5 percent and 10 percent of cordyceps militaris residue dry powder is positive. The weight gain rate and the survival rate of the prawn by 20 percent or more of the cordyceps militaris residue dry powder are negative. Therefore, the addition of 10-15% can obviously improve the survival rate of the prawns and has higher economic benefit (P is less than 0.05).

Claims

1. The shrimp feed additive is characterized in that the additive is obtained by drying and crushing residues obtained after cordyceps militaris sporocarp is cultured by a cordyceps militaris culture medium, wherein the cordyceps militaris culture medium is prepared from a liquid A and a solid B according to a weight ratio of the liquid to the solid of 2-3: 1, wherein the component of the liquid A is as follows: adding 10.0-15.0 g of sucrose and KH into 1000 ml of tap water₂PO₄ 0.3～0.5 g，MgSO₄0.3-0.5 g, vitamin B complex tablets and vitamin C1 tablets; the composition of the solid part of B is as follows: 50% of wheat grains, 15% of rapeseed meal, 24% of peanut meal, 1% of dry silkworm pupa powder and 10% of rice bran.

2. The shrimp feed additive as claimed in claim 1, wherein the shrimp feed additive is used for increasing the weight gain and survival rate of shrimps.

3. The shrimp feed additive according to claim 2, wherein the amount of the shrimp feed additive added to the shrimp feed is 10 to 15%.