CN108065037A - Microbial fermentation prepares the method and functional feed of functional feed - Google Patents

Abstract

The present invention relates to the methods and functional feed that a kind of microbial fermentation prepares functional feed, belong to field of fermentation engineering.Preparation method includes：Microorganism fungus kind is fermented in fluid nutrient medium for the first time after 36 48h, be then seeded in solid medium second of 100 140h of fermentation.Microorganism fungus kind is the microorganism with production DHA abilities.This method is simple, take solid-liquid fermentation combined process, pass through the content and protein content of DHA in the effective control function feed of fermentation period, it is of low cost, low energy consumption, equipment damage is small, without waste water discarded object generate, the treatment and finishing section that ferments is simple, solves the problems, such as that fermentation thalli is directly granulated difficulty.Functional feed in the present invention contains abundant DHA and protein, and nutritive value is high, can improve the production performance of animal and the quality of animal product.

Description

Method for preparing functional feed by microbial fermentation and functional feed

technical field

The invention relates to the field of fermentation engineering, and in particular to a method for preparing functional feed by microbial fermentation and the functional feed.

Background technique

Docosahexaenoic acid (DHA) is a long-chain polyunsaturated fatty acid with important physiological functions, which can promote brain and vision development and improve intelligence, so it is widely added to infant milk powder. In addition, DHA has physiological functions such as preventing and treating cardiovascular diseases, preventing senile dementia, and inhibiting cell cancer, so it is widely used in the food industry.

Studies have found that Schizochytrium can accumulate a large amount of DHA, and the DHA content in algal oil is higher than that of other microalgae. In addition, there are many other microbial strains that can be used to produce DHA. However, most of these microorganisms use pure liquid fermentation. During the fermentation process, continuous aeration and stirring are required to ensure dissolved oxygen, and the water content of liquid fermentation is as high as 80%. The energy consumption of drying treatment is high, and the DHA produced by liquid fermentation is polyunsaturated. Fatty acids are easily oxidized and require further embedding.

Therefore, it is necessary to improve the method for producing DHA by microorganisms in the prior art.

Contents of the invention

The first object of the present invention is to provide a method for preparing functional feed by microbial fermentation. The method is simple, adopts a solid-liquid fermentation combination process, and effectively controls the content of DHA and protein in the functional feed through the fermentation cycle, and is low in cost and energy-efficient. Low consumption, little equipment damage, no waste water and waste, simple post-fermentation treatment section, which solves the problem of difficult direct granulation of fermentation cells.

The second object of the present invention is to provide a functional feed, which is rich in DHA and protein, has high nutritional value, and can improve the production performance of animals and the quality of animal products.

The present invention solves its technical problem and adopts the following technical solutions to realize:

The invention proposes a method for preparing functional feed by microbial fermentation, which comprises the following steps: first fermenting microbial strains in liquid medium for 36-48 hours, and then inoculating them into solid medium for second fermentation for 100-140 hours.

The microbial strain is a microorganism capable of producing DHA.

Preferably, the microbial strain includes any one of Schizochytrium, Thraustochytrium, Dinoflagellate and yeast.

The components of the liquid medium include glucose, sodium glutamate, yeast extract and inorganic salts.

The components of solid medium include protein substances, inorganic salts and vitamins.

The present invention also proposes a functional feed, which can be prepared by the above preparation method.

The beneficial effects of the method for preparing functional feed and the functional feed by microbial fermentation in a preferred embodiment of the present invention are:

By first using liquid fermentation to give Schizochytrium a better growth environment, when the concentration of the bacteria is high, carry out aseptic concentration and enrichment and transfer to a solid medium to continue fermentation, which can make the fermentation process unnecessary Continuous aeration and stirring avoid the problems of complicated operation and high energy consumption cost caused by the pure liquid fermentation used in the conventional fermentation process. Protein substances are mainly used as nitrogen sources for Schizochytrium, and the selected protein substances are rich in protein, and the source of raw materials is relatively easy and the cost is low.

The functional feed obtained by the above method is rich in DHA and protein, has high nutritional value, can increase the nutritional value of animal diets, improve the production performance of animals and the quality of animal products.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

The method for preparing functional feed through microbial fermentation and the functional feed according to the embodiments of the present invention will be described in detail below.

The embodiment of the present invention provides a method for preparing functional feed by microbial fermentation, for example, may include the following steps: first fermenting the microbial strain in a liquid medium, and then inoculating it into a solid medium for second fermentation. By first using liquid fermentation to give Schizochytrium a better growth environment, when the bacterial concentration is high, carry out aseptic concentration and enrichment and transfer to a solid medium to continue fermentation. Therefore, there is no need for continuous aeration and stirring during the fermentation process, thereby avoiding the problems of complicated operation and high energy consumption cost caused by the pure liquid fermentation adopted in the conventional fermentation process.

The above-mentioned microbial strains are microorganisms capable of producing DHA, as an alternative, for example, any one of Schizochytrium, Thraustochytrium, Dinoflagellates and yeasts. As an option, the components of the above-mentioned liquid medium may include, for example, glucose, inorganic salts, sodium glutamate and/or yeast extract. Wherein, the mass percentages of glucose, sodium glutamate, yeast extract and inorganic salts in the liquid medium can be, for example, 5-7wt%, 2-4wt%, 0.8-1wt% and 3-5wt%, preferably 6wt% %, 3wt%, 0.9wt% and 4wt%.

Preferably, the inorganic salts may include, for example, 0.5-0.7wt% phosphate, 0.7-0.9wt% sulfate, 1.5-2.5wt% sodium salt, 0.02-0.04wt% calcium chloride and the like. Preferably, the inorganic salts include 0.6 wt% potassium dihydrogen phosphate, 0.8 wt% magnesium sulfate, 2 wt% sodium chloride, 0.03 wt% calcium chloride and 0.44 wt% sodium sulfate.

As an option, the components of the above-mentioned solid medium may include, for example, protein substances, inorganic salts and vitamins. Preferably, protein substances may include corn, wheat, soybean and their derivatives and processing by-products. In the embodiment of the present invention, corn starch and corn steep liquor powder may be used as examples, and wheat may be wheat bran as an example. , Soybeans can take soybean cake flour as an example. These protein substances are mainly used as nitrogen sources for Schizochytrium, and they are rich in protein. In addition, such protein substances can better increase the porosity between the medium, so that there are certain pores between the various material components, so as to improve the effect of oxygen and mass transfer during the cultivation process.

In addition, the protein substance may also include at least one of xylose residue, spirulina powder and feather meal, which are relatively easy to source and have low cost.

Preferably, the solid medium may contain cornstarch, wheat bran, soybean cake powder, corn steep liquor dry powder with a mass ratio of 10-14:38-42:8-12:8-12:3-5:3-5 , inorganic salts and vitamins. More preferably, the mass ratio of corn starch, wheat bran, soybean cake powder, dry corn steep liquor powder, inorganic salt and vitamin is 12:40:10:10:4:4.

Wherein, the types of inorganic salts can refer to the liquid culture medium, vitamins can include, for example, 0.8-1.2wt% thiamine, 0.2-0.4wt% calcium pantothenate, 0.004-0.008wt% biotin and 0.01-0.02wt% Cyanocobalamin. Preferably, the vitamins include 1.0 wt% thiamine, 0.3 wt% calcium pantothenate, 0.006 wt% biotin and 0.015 wt% cyanocobalamin.

In order to provide a good growth and fermentation environment for Schizochytrium in the solid medium, the embodiment of the present invention also adds water with a mass ratio of 10-14:18-22 to cornstarch in the solid medium to obtain fluffy The vegetative growth environment, avoid the solid medium is too dry and hard. Before inoculating Schizochytrium, the components of the mixed solid medium can also be cooked at 95-100°C for 10-20min, so that the granular components in the solid medium can be evenly dispersed, which is more conducive to different cultures in the medium. Location of Schizochytrium growth. Sterilize at high temperature for at least 20 minutes after cooking.

The Schizochytrium is inoculated in the liquid medium, and fermented for the first time at 26-30° C. for 36-48 hours.

Preferably, the temperature for the first fermentation is 27-29°C, more preferably 28°C. Specifically, the temperature of the first fermentation may be 26°C, 26.5°C, 27°C, 27.5°C, 28°C, 28.5°C, 29°C, 29.5°C and 30°C.

Preferably, the time for the first fermentation is 40-44h, more preferably, 42h. Specifically, the time for the first fermentation can be 36h, 38h, 40h, 42h, 44h, 46h and 48h.

The material obtained after the first fermentation is centrifuged and concentrated, the concentrated bacteria are collected and transferred to a solid medium, and the second fermentation is carried out at 26-30° C. for 100-140 hours.

Preferably, the temperature of the second fermentation is also 27-29°C, more preferably, 28°C. Specifically, the temperature of the second fermentation can also be 26°C, 26.5°C, 27°C, 27.5°C, 28°C, 28.5°C, 29°C, 29.5°C and 30°C.

Preferably, the time for the second fermentation is 110-130h, more preferably, 120h. Specifically, the time for the first fermentation can be 110h, 115h, 120h, 125h, 130h, 135h and 140h.

Alternatively, the inoculum amount of the bacteria in the solid medium may be, for example, 10-30 wt%, preferably 15-25 wt%, more preferably 20 wt% of the solid medium. Inoculation according to the above-mentioned preferred inoculation amount can make the solid medium and the bacteria reach the best balance, and avoid the situation that too much or too little nutrients required for the fermentation of the bacteria will lead to poor fermentation effects and fermentation products.

Preferably, during the second fermentation process, the solid medium is turned every 10-14 hours, and each turn can last for 5-10 minutes, for example. Specifically, each turning can be carried out in the following manner: in the aseptic operation room, use a sterile shovel and a sterile coating rod to stir the medium, first use a sterile shovel to shovel the medium, and then use a The stick is evenly coated and turned back and forth for 2-3 rounds for a total of 5-10 minutes. It should be noted that sterility is guaranteed during the turning process.

By turning the solid medium during the second fermentation, not only can the medium be prevented from agglomerating, but also the bacteria and nutrients can be fully contacted to achieve a fluffy environment, that is, the solid medium contains a certain amount of nutrients. Air and water form an environment suitable for the growth and reproduction of Schizochytrium, which is composed of solid, liquid and gas, and is conducive to dissolved oxygen.

Further, in the embodiment of the present invention, sterile water is added to the solid medium during the turning process. Optionally, the supplementary amount of sterile water is 5-10wt% of the solid medium, for example, it can be 5wt%, 6wt% , 7wt%, 8wt%, 9wt% and 10wt%. Preferably, the amount of water replenishment is different in different fermentation stages. Because the early stage of fermentation is short, the amount of water replenishment can be relatively small, and the middle and late stage of fermentation is long and the water evaporates a lot, so the amount of water replenishment can be relatively increased in this fermentation stage. By supplementing sterile water during the turning process, on the one hand, it can help prevent the agglomeration of the medium, and on the other hand, it can facilitate water as a mass transfer medium for solid fermentation, so that the three states of solid, liquid, and gas can reach phase equilibrium during fermentation. In order to obtain a good fermentation environment, the Schizochytrium can grow better.

Both the culture medium and the bacteria obtained by the above method have the viscosity and surface state that meet the requirements of the granulation process, thus solving the difficulty in the treatment of the fermentation waste liquid and the low degree of dryness in the prior art that only exist in the bacteria obtained by pure liquid fermentation , Difficulty in granulation and the inability to recycle the bacteria, and at the same time, it also supplements high-protein nutrients.

In view of this, in industrial production, the solid medium obtained from the second fermentation in the fermentation method provided by the embodiments of the present invention and the bacteria can be directly dried, pulverized and granulated to obtain DHA-rich and high-protein functional products.

Drying and crushing can be carried out in a microwave dryer, until the material to be dried has no obvious moisture and is in the form of dry powder. Preferably, the drying power during the drying process is not lower than 5kw, the drying temperature is 90-110°C, and the drying time is 0.5-2h. The granulation index can be in accordance with the general index of feed.

It has been determined that the functional product prepared by the above preparation method has the following characteristics: the DHA content is 8wt%-30wt%, the protein content is 30wt%-80wt%, and the crude fiber content is less than 10wt%. Preferably, the above functional product has a DHA content of 10wt%-20wt%, a protein content of 40wt%-60wt%, and a crude fiber content of less than 5wt%.

Further, the above-mentioned functional product has a particle size of 0.8-6mm, a moisture content of no more than 10wt%, and a carbon-to-nitrogen ratio of (15-30):1.

Optionally, the functional feed in the embodiments of the present invention may be the above-mentioned functional product directly, or may be obtained by mixing the above-mentioned functional product with common feed.

Specifically, the above-mentioned functional feed can be animal feed or marine feed for application in animal or marine farming. Applying the above-mentioned animal feed or marine product feed to the cultivation of animals or marine products can increase the dietary nutritional value of animals or marine products, improve the production performance and product quality of animals or marine products.

The characteristics and performance of the present invention will be described in further detail below in conjunction with the examples.

Example 1

The Schizochytrium was inoculated in the liquid medium, and fermented for the first time at 26° C. for 48 hours, and then centrifuged and concentrated to collect the concentrated bacteria. Add water to the solid medium, cook at 95°C for 20 minutes, and sterilize for 20 minutes. According to the inoculation amount of 10wt%, the concentrated bacteria were transferred to the solid medium, and the second fermentation was carried out at 26° C. for 140 h. The culture medium and bacteria obtained from the second fermentation were dried and pulverized in a microwave dryer with a drying power of 5kw and a drying temperature of 90°C for 2 hours, and then granulated to obtain a functional feed.

In the second fermentation, the solid medium is stirred every 10 hours, and each stirring can last for 5 minutes, for example. During the turning process, add sterilized water to the solid medium according to 5wt% of the solid medium.

Wherein, liquid medium contains 5wt%, 2wt%, 0.8wt% and 3wt% glucose, sodium glutamate, yeast extract and inorganic salt, and inorganic salt contains the potassium dihydrogen phosphate of 0.5wt%, the sulfuric acid of 0.7wt% Magnesium, 1.5 wt% sodium chloride, 0.02 wt% calcium chloride and 0.40 wt% sodium sulfate.

The solid medium contains corn, wheat, soybean, dry powder of corn steep liquor, inorganic salts and vitamins in a mass ratio of 10:38:8:8:3:3. Inorganic salts are the same as those used for the liquid medium. The vitamin contains 0.8 wt% thiamine, 0.2 wt% calcium pantothenate, 0.004 wt% biotin and 0.01 wt% cyanocobalamin. The mass ratio of the water added to the solid medium before cooking to the cornstarch contained is 10:18.

Example 2

The Schizochytrium was inoculated in the liquid medium, and fermented for the first time at 30° C. for 36 hours, then centrifuged and concentrated, and the concentrated bacteria were collected. Add water to the solid medium, cook at 100°C for 10 minutes, and sterilize for 30 minutes. According to the inoculum amount of 30wt%, the concentrated bacteria were transferred to the solid medium, and the second fermentation was carried out at 30° C. for 100 h. The culture medium and cells obtained from the second fermentation were dried and pulverized in a microwave dryer with a drying power of 10kw and a drying temperature of 110°C for 0.5h, and then granulated to obtain a functional product. The above functional product is mixed with common feed to obtain functional feed.

In the second fermentation, the solid medium is stirred once every 14 hours, and each stirring can last for 10 minutes, for example. During the turning process, sterilized water was added to the solid medium at 10 wt% of the solid medium.

Wherein, liquid medium contains 7wt%, 4wt%, 1wt% and 5wt% glucose, sodium glutamate, yeast extract and inorganic salt, and inorganic salt contains the potassium dihydrogen phosphate of 0.7wt%, the magnesium sulfate of 0.9wt% , 2.5wt% sodium chloride, 0.04wt% calcium chloride and 0.48wt% sodium sulfate.

The solid medium contains corn starch, wheat bran, soybean cake powder, corn steep liquor dry powder, inorganic salts and vitamins in a mass ratio of 14:42:12:12:5:5. Inorganic salts are the same as those used for the liquid medium. The vitamin contains 1.2 wt% thiamine, 0.4 wt% calcium pantothenate, 0.008 wt% biotin and 0.02 wt% cyanocobalamin. The mass ratio of the water added to the solid medium before cooking to the cornstarch contained is 14:22.

Example 3

The Schizochytrium was inoculated in the liquid medium, and fermented for the first time at 27° C. for 44 hours, and then concentrated by centrifugation, and the concentrated bacteria were collected. Add water to the solid medium, cook at 98°C for 15 minutes, and sterilize for 30 minutes. According to the inoculum amount of 15wt%, the concentrated bacteria were transferred to the solid medium, and the second fermentation was carried out at 27° C. for 130 h. The culture medium and cells obtained from the second fermentation were dried and pulverized in a microwave dryer with a drying power of 12kw and a drying temperature of 100°C for 1 hour, and then granulated to obtain a functional product. The above functional product is mixed with common feed to obtain functional feed.

In the second fermentation, the solid medium is stirred once every 12 hours, and each stirring can last for 7.5 minutes, for example. During the shaking process, sterilized water was added to the solid medium at 7 wt% of the solid medium.

Among them, the liquid medium contains 6wt%, 3wt%, 0.9wt% and 4wt% of glucose, sodium glutamate, yeast extract and inorganic salts, and the inorganic salts contain 0.6wt% potassium dihydrogen phosphate, 0.8%wt% Magnesium sulfate, 2wt% sodium chloride, 0.03wt% calcium chloride and 0.44wt% sodium sulfate.

The solid medium contains corn starch, wheat bran, soybean cake powder, corn steep liquor dry powder, inorganic salts and vitamins in a mass ratio of 12:40:10:10:4:4. Inorganic salts are the same as those used for the liquid medium. The vitamin contains 1.0 wt% thiamine, 0.3 wt% calcium pantothenate, 0.006 wt% biotin and 0.015 wt% cyanocobalamin. The mass ratio of the water added to the solid medium before cooking to the cornstarch contained is 12:20.

Example 4

The Schizochytrium was inoculated in the liquid medium, and fermented for the first time at 29° C. for 40 hours, then centrifuged and concentrated, and the concentrated bacteria were collected. Add water to the solid medium, cook at 98°C for 15 minutes, and sterilize for 30 minutes. According to the inoculation amount of 25 wt%, the concentrated bacteria were transferred to the solid medium, and the second fermentation was carried out at 29° C. for 110 h. The culture medium and cells obtained from the second fermentation were dried and pulverized in a microwave dryer with a drying power of 15kw and a drying temperature of 105°C for 1 hour, and then granulated to obtain a functional product. The above functional product is mixed with common feed to obtain functional feed.

In the second fermentation, the solid medium is stirred once every 12 hours, and each stirring can last for 7.5 minutes, for example. During the turning process, sterilized water was added to the solid medium according to 8wt% of the solid medium.

Among them, the liquid medium contains 6wt%, 3wt%, 0.9wt% and 4wt% of glucose, sodium glutamate, yeast extract and inorganic salts, and the inorganic salts contain 0.6wt% potassium dihydrogen phosphate, 0.8%wt% Magnesium sulfate, 2wt% sodium chloride, 0.03wt% calcium chloride and 0.44wt% sodium sulfate.

The solid medium contains corn starch, wheat bran, soybean cake powder, corn steep liquor dry powder, inorganic salts and vitamins in a mass ratio of 12:40:10:10:4:4. Inorganic salts are the same as those used for the liquid medium. The vitamin contains 1.0 wt% thiamine, 0.3 wt% calcium pantothenate, 0.006 wt% biotin and 0.015 wt% cyanocobalamin. The mass ratio of the water added to the solid medium before cooking to the cornstarch contained is 12:20.

Example 5

The Schizochytrium was inoculated in the liquid medium, and fermented for the first time at 28° C. for 42 hours, then centrifuged and concentrated, and the concentrated bacteria were collected. Add water to the solid medium, cook at 98°C for 15 minutes, and sterilize for 30 minutes. According to the inoculum amount of 20wt%, the concentrated bacteria were transferred to the solid medium, and the second fermentation was carried out at 28° C. for 120 h. The culture medium and cells obtained from the second fermentation were dried and pulverized in a microwave dryer with a drying power of 8kw and a drying temperature of 95°C for 1.5h, and then granulated to obtain a functional product. The above functional product is mixed with common feed to obtain functional feed.

In the second fermentation, the solid medium is stirred once every 12 hours, and each stirring can last for 7.5 minutes, for example. During the turning process, 7.5 wt% of the solid medium was supplemented with sterilized water to the solid medium.

Among them, the liquid medium contains 6wt%, 3wt%, 0.9wt% and 4wt% of glucose, sodium glutamate, yeast extract and inorganic salts, and the inorganic salts contain 0.6wt% potassium dihydrogen phosphate, 0.8%wt% Magnesium sulfate, 2wt% sodium chloride, 0.03wt% calcium chloride and 0.44wt% sodium sulfate.

The solid medium contains corn starch, wheat bran, soybean cake powder, corn steep liquor dry powder, inorganic salts and vitamins in a mass ratio of 12:40:10:10:4:4. Inorganic salts are the same as those used for the liquid medium. The vitamin contains 1.0 wt% thiamine, 0.3 wt% calcium pantothenate, 0.006 wt% biotin and 0.015 wt% cyanocobalamin. The mass ratio of the water added to the solid medium before cooking to the cornstarch contained is 12:20.

Example 6

The difference between this example and Example 5 is that the microbial strain used is Thraustochytrium.

Example 7

The difference between this example and example 5 is that the microbial strain used is dinoflagellates.

Example 8

The difference between this embodiment and embodiment 5 is that the microbial strain used is yeast.

Example 9

The difference between this embodiment and embodiment 5 is that the protein substances in the solid medium also contain xylose residue. The mass ratio of xylose residue to corn starch is 4-6:10-14.

Example 10

The difference between this example and Example 5 is that the protein substances in the solid medium also contain xylose residue and spirulina powder. The mass ratio of xylose residue, spirulina powder and corn starch is 2-3:1-2:10-14.

Example 11

The difference between this example and Example 5 is that the protein substances in the solid medium also contain xylose residue, spirulina powder and feather meal. The mass ratio of xylose residue, spirulina powder, feather powder and corn starch is 1-2:1-2:1-2:10-14.

Example 12

This embodiment provides an animal feed, which contains the functional feed obtained in the above-mentioned Examples 1-11.

Example 13

This embodiment provides a marine feed, which contains the functional feed obtained in the above-mentioned Examples 1-11.

Example 14

This embodiment provides an infant milk powder, which contains the functional feed obtained in the above-mentioned Examples 1-11.

Test example 1

Repeat the implementation of the above-mentioned Examples 2-11 to obtain enough functional feed. Taking Example 5-8 as an example, control group 1-4 is set, and control group 1-4 corresponds to embodiment 5-8 respectively, and the difference between control group and embodiment is that control group adopts existing pure liquid fermentation method (referring to patent CN104312929B), the content of DHA and protein in the functional feed of comparative example 5-8 and matched group 1-4 gained (accounting for the weight percent of functional feed with DHA/protein), its result is as shown in table 1 and table 2 Show.

Table 1 DHA and protein content (%)

Table 2 DHA and protein content (%)

Combining Table 1 and Table 2, it can be seen that the functional feed obtained from Examples 5-8 has significantly higher DHA and protein contents than the functional feed obtained from Control Group 1-4. It shows that the preparation method (combined solid-liquid fermentation process) provided by the embodiment of the present invention can ferment and produce more DHA and protein than the pure liquid fermentation process of the prior art.

And, the DHA and protein content of the functional feed obtained in Example 5 are higher than those in Examples 6-8, illustrating that the present invention is especially suitable for Schizochytrium, Thraustochytrium, Dinoflagellates and yeasts. in Schizochytrium.

Test example 2

Taking the functional feeds of Example 5 and Control Group 1 in Test Example 1 as examples, their feed characteristics are compared as shown in Table 3.

Table 3 Feed characteristics

As can be seen from Table 3, the functional feed prepared by the preparation method (solid-liquid fermentation combined process) provided by the embodiment of the present invention has better feed characteristics than the pure liquid fermentation process of the prior art, and effectively solves the current problem. The problem of difficult granulation in the technical field.

In addition, in the same way, Example 6-8 was compared with the control group 2-3, and the results also showed that the combined solid-liquid fermentation process can obtain feed additives with better characteristics than the pure liquid fermentation process, and there is no difficulty in granulation The problem.

Note: the DHA content range of the functional feed obtained in the above Examples 5-8 is 8wt%-30wt%, the protein content range is 30wt%-80wt%, the crude fiber content is not more than 10wt%, and the particle size range is 0.8-6mm. The moisture content is not more than 10wt%, and the carbon-nitrogen ratio range is (15-30):1.

Test example 3

Taking Example 12 as an example, the animal feed provided by Example 12 is used to feed pigs instead of common feed. The average daily weight gain of pigs after feeding with common feed. In addition, the marine feed provided by Example 13 was used to feed silver carp instead of common feed, all the other culture conditions were unchanged, and it was cultured for 15 days. The average daily weight gain of silver carp after culture in Example 13 was compared with that of silver carp cultured with common feed. The average daily weight gain of silver carp. The results are shown in Table 4.

Table 4 Average daily weight gain

As can be seen from Table 4, adopting the animal feed or marine feed that contains the functional feed provided by the embodiments of the present invention to raise pigs or silver carp can obviously improve its average daily weight gain compared with commonly used feeds to raise pigs or silver carp. the feed utilization rate.

In summary, the method for preparing functional feed by microbial fermentation in the embodiment of the present invention is simple, adopts solid-liquid fermentation combined process, effectively controls the content of DHA and protein in functional feed through the fermentation cycle, low cost, low energy consumption, The equipment is less damaged, no waste water is produced, and the post-fermentation treatment section is simple, which solves the problem of difficult direct granulation of fermentation cells. The functional feed obtained by the above method is rich in DHA and protein, has high nutritional value, can increase the nutritional value of animal diets, improve the production performance of animals and the quality of animal products.

The embodiments described above are some, not all, embodiments of the present invention. The detailed description of the embodiments of the invention is not intended to limit the scope of the claimed invention but to represent only selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Claims (11)

1. a kind of method that microbial fermentation prepares functional feed, which is characterized in that comprise the following steps：By microorganism fungus kind Ferment 36-48h for the first time in fluid nutrient medium, is then seeded in solid medium second of fermentation 100-140h；

The microorganism fungus kind is the microorganism of the ability with production DHA；

The ingredient of the fluid nutrient medium includes glucose, inorganic salts, sodium glutamate and yeast extract；

The ingredient of the solid medium includes protein matter, inorganic salts and vitamin.

2. the method that microbial fermentation prepares functional feed according to claim 1, the microorganism fungus kind includes fragmentation Any one in chytrid, thraustochytriale, dino flagellate and saccharomycete.

3. the method that microbial fermentation prepares functional feed according to claim 1, which is characterized in that for the first time fermentation with The temperature of second of fermentation is 26-30 DEG C；

Preferably, the temperature of fermentation and second of fermentation is 27-29 DEG C for the first time；

More preferably, the temperature of fermentation and second of fermentation is 28 DEG C for the first time.

4. the method that microbial fermentation prepares functional feed according to claim 1, which is characterized in that fermented for the second time The solid medium is stirred every 10-14h once, stir lasting 5-10min every time in journey.

5. the method that microbial fermentation prepares functional feed according to claim 4, which is characterized in that during stirring to Sterile water is supplemented in the solid medium；

Preferably, the magnitude of recruitment of the sterile water is the 5-10wt% of the solid medium.

6. the method that microbial fermentation prepares functional feed according to claim 1, which is characterized in that inoculation micro- life Before object strain, by the ingredient of the mixed solid medium under conditions of 95-100 DEG C boiling 10-20min.

7. the method that microbial fermentation prepares functional feed according to claim 1, which is characterized in that inoculum concentration is described The 10-30wt% of solid medium；

Preferably, the inoculum concentration is the 15-25wt% of the solid medium；

More preferably, the inoculum concentration is the 20wt% of the solid medium.

8. the method that microbial fermentation prepares functional feed according to claim 1, which is characterized in that further include second Solid medium obtained by secondary fermentation is dried with thalline, crushes and is granulated；

Preferably, dry power is not less than 5kw, and drying temperature is 90-110 DEG C, drying time 0.5-2h.

9. a kind of functional feed, which is characterized in that the DHA content of the functional feed is 8wt%-30wt%, albumen contains It measures and is less than 10wt% for 30wt%-80wt%, crude fiber content.

10. functional feed according to claim 9, which is characterized in that the DHA content of the functional feed is 10wt%-20wt%, the protein content are 40wt%-60wt%, the crude fiber content is less than 5wt%.

11. according to any one of claim 9 or 10 functional feed, which is characterized in that the particle of the functional feed It spends for 0.8-6mm, moisture is no more than 10wt%, carbon-nitrogen ratio is (15-30)：1.