Yeast fat and its preparation method and application in poultry farming

Abstract

The present invention relates to the field of poultry farming technology, and more particularly to yeast fat, its preparation method, and its use in poultry farming. Yeast fat, a feed additive prepared using yeast fat, has been shown to improve the stability of vitamins, particularly protecting fat-soluble vitamins from the effects of light, oxygen, and humidity. Compared to vegetable oils, it can extend their shelf life, exhibiting superior stability under high-temperature or humid conditions. Furthermore, yeast fat can promote poultry growth and egg production.

Description

Technical Field

[0001] The present invention relates to the technical field of poultry breeding, and in particular to a method for preparing yeast fat and its application in poultry breeding. Background Art

[0002] Poultry farming holds a crucial position in the agricultural sector and is a key industry in meeting human demand for poultry meat and eggs. Poultry farming primarily refers to the artificial breeding and management of various poultry species, including chickens, ducks, geese, turkeys, pigeons, and quail. Through long-term selection, breeding, and domestication, these birds have adapted to artificial breeding environments and provide humans with a rich source of animal protein, such as poultry meat and eggs.

[0003] Poultry used for meat production, such as broiler breeds (e.g., white-feathered broilers), require an adequate supply of nutrients during their growth to support the rapid development of muscle tissue. Egg-laying poultry, such as laying hens, have specific nutritional requirements. They must not only meet their own maintenance needs but also provide raw materials for continued egg production. Furthermore, in poultry farming, fat-soluble vitamins play an important role in both broiler and egg-laying poultry. For example, vitamin A promotes growth in broiler poultry, enhances vision, and protects the reproductive health and egg quality of egg-laying poultry. Vitamin D assists in the absorption and utilization of calcium and phosphorus, aiding in bone development in broiler poultry and eggshell formation in egg-laying poultry. Vitamin E has antioxidant properties, enhancing the immunity and reproductive performance of poultry.

[0004] It can be seen that fat-soluble vitamins have an important impact on poultry farming. However, most fat-soluble vitamins are compounds that are extremely sensitive to light, heat and oxygen, and are easily oxidized and decomposed in the air, resulting in a significant reduction in their activity and efficacy. Therefore, in the production process of vitamin products in the prior art, auxiliary materials such as vegetable oils are usually added to embed the vitamins to protect the vitamins and reduce degradation. However, this technology is not only limited in production and unstable in quality in the production of vitamin products, but also has poor stability, resulting in low potency and reduced bioavailability during use. Therefore, it is urgent to find a new type of fat to replace vegetable oil and that can play a good role in poultry farming. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide yeast fat and a preparation method thereof and application in poultry farming.

[0006] The present invention provides a yeast fat, wherein the crude fat content is more than 70%, the proportion of fatty acid glycerides with 16 carbon atoms or less is greater than 30%, and the proportion of unsaturated fatty acids is greater than 70%.

[0007] In a specific embodiment, the percentage of single fatty acids in the yeast fat to the total fatty acids is as follows: fatty acids with less than 14 carbon atoms 0.003% to 0.033%, myristic acid 0.162% to 0.198%, pentadecanoic acid 0.054% to 0.066%, pentadecenoic acid 2.331% to 2.849%, palmitic acid 12.420% to 15.180%, palmitoleic acid 23.184% to 28.333%, heptadecanoic acid 0.090% to 0.110%, heptadecanoic acid 0.108% to 0.13 2%, stearic acid 4.347%~5.013%, oleic acid 38.264%~43.216%, linoleic acid 6.174%~7.446%, linolenic acid 4.572%~5.016%, arachidic acid 0.008%~0.010%, arachidonic acid 0.009%~0.011%, arachidienoic acid 0.081%~0.100%, behenic acid 0.009%~0.011%, erucic acid 0.018%~0.022% and lignoic acid 0.189%~0.231%.

[0008] More specifically, the percentage of single fatty acids in the yeast fat to the total fatty acids is as follows: fatty acids with less than 14 carbon atoms 0.033%, myristic acid 0.162%, pentadecanoic acid 0.054%, pentadecenoic acid 2.849%, palmitic acid 12.420%, palmitoleic acid 23.184%, heptadecanoic acid 0.090%, heptadecenoic acid 0.132%, stearic acid 5.013%, oleic acid 43.216%, linoleic acid 7.446%, linolenic acid 5.016%, arachidic acid 0.010%, arachidonoenoic acid 0.011%, arachidienoic acid 0.100%, behenic acid 0.011%, erucic acid 0.022% and lignoic acid 0.231%.

[0009] Alternatively, the percentage of single fatty acids in the yeast fat to the total fatty acids is as follows: 0.003% of fatty acids with less than 14 carbon atoms, 0.198% of myristic acid, 0.066% of pentadecanoic acid, 2.331% of pentadecenoic acid, 15.180% of palmitic acid, 28.333% of palmitoleic acid, 0.110% of heptadecanoic acid, 0.108% of heptadecenoic acid, 4.347% of stearic acid, 38.264% of oleic acid, 6.174% of linolenic acid, 4.572% of linolenic acid, 0.008% of arachidic acid, 0.009% of arachidonoenoic acid, 0.081% of arachidic acid, 0.009% of behenic acid, 0.018% of erucic acid, and 0.189% of lignoic acid.

[0010] Testing has shown that the yeast fat provided by the present invention has a high content of unsaturated fatty acids. This high content of unsaturated fatty acids gives the yeast fat excellent physiological activity. Therefore, this yeast fat has broad application prospects. As a feasible example, in the food industry, it can be used to develop more nutritious and healthy foods. In the pharmaceutical field, as mentioned above, yeast fat has the potential to become a key raw material or excipient for new drugs. In the field of health care products, it can be used as an active ingredient to regulate blood lipids and protect cardiovascular health. In the feed industry, it can be used to prepare higher-quality animal feed and promote healthy animal growth.

[0011] The present invention also provides a method for preparing the yeast fat as described above, which comprises:

[0012] After the yeast is enzymatically hydrolyzed by protease, the heavy phase is enzymatically hydrolyzed by mannanase, and then the heavy phase is extracted with ethanol, and the light phase is centrifuged to obtain yeast fat.

[0013] In the present invention, the raw material for preparing the yeast fat is yeast, for example, the yeast is Saccharomyces cerevisiae, Pichia pastoris, Candida, Rhodotorula or Yarrowia lipolytica. In the present invention, Saccharomyces cerevisiae is preferred.

[0014] In the preparation method of the present invention, the dry matter content of the yeast is 15% to 20%.

[0015] In the preparation method of the present invention, the conditions for the enzymatic hydrolysis of the protease include 50-60° C. and enzymatic hydrolysis for 5-15 hours.

[0016] In the preparation method of the present invention, the conditions for the enzymatic hydrolysis of the mannanase include 50-60° C. and enzymatic hydrolysis for 5-15 hours;

[0017] In the preparation method of the present invention, in the ethanol extraction step, the volume fraction of ethanol is 90% to 100%, the extraction temperature is 70 to 90° C., and the extraction time is 3 to 5 hours.

[0018] In a specific embodiment, the method for preparing yeast fat comprises the following steps:

[0019] (1) Yeast was taken to control the dry matter content to 15%~20%, protease was added, the enzymatic hydrolysis temperature was 50~55℃, the enzymatic hydrolysis time was 5~10h, and centrifugation was performed after enzymatic hydrolysis to obtain the heavy phase;

[0020] (2) The heavy phase obtained in step (1) is prepared to have a dry matter content of 10% to 15%, mannanase is added, the enzymatic hydrolysis temperature is 55 to 60°C, the enzymatic hydrolysis time is 10 to 15 hours, centrifugation is performed after enzymatic hydrolysis, the heavy phase is taken, and spray drying is performed to obtain a solid;

[0021] (3) The dried solid obtained in step (2) is added with ethanol for extraction, wherein the ethanol concentration is 90% to 100%, the extraction temperature is 70 to 90°C, and the extraction time is 3 to 5 hours. After extraction, the mixture is centrifuged and the light phase is concentrated to obtain yeast fat.

[0022] Furthermore, the present invention provides the use of yeast fat in improving poultry breeding effects.

[0023] The yeast fat described in the present invention is extracted from yeast, and its preparation mainly comprises: (1) taking yeast to control the dry matter content to 15% to 20%, adding protease, enzymatically hydrolyzing and centrifuging to obtain a heavy phase;

[0024] (2) The heavy phase obtained in step (1) is prepared into an emulsion with a dry matter content of 10% to 15%, mannanase is added, and after enzymatic hydrolysis, centrifugation is performed, and the heavy phase is taken and spray-dried to obtain a solid;

[0025] (3) The dried solid obtained in step (2) is added with ethanol for extraction, and after extraction, the mixture is centrifuged and the light phase is concentrated to obtain yeast fat.

[0026] The present invention has found in experiments that yeast fat can replace vegetable oil in encapsulating fat-soluble vitamins, improving the stability of the vitamins and achieving a superior effect compared to vegetable oil. Furthermore, yeast fat can improve the growth performance of poultry, particularly increasing the growth of poultry meat and promoting egg production.

[0027] In the present invention, the poultry includes, but is not limited to, chickens, ducks, geese, turkeys, pigeons, or quails. The poultry may be meat poultry or laying poultry, which is not limited in the present invention. In embodiments of the present invention, improving poultry farming efficiency includes: promoting the growth of meat poultry, reducing the feed-to-meat ratio of meat poultry, increasing the egg production rate of laying poultry, and / or reducing the feed-to-egg ratio of laying poultry.

[0028] In some specific embodiments, the poultry is a chicken, for example, a broiler chicken or a laying hen.

[0029] As a feasibility case, the broiler breed is selected from white-feathered broilers, yellow-feathered broilers, 817 mixed chickens, Gushi chickens, three-yellow chickens, black-bone chickens, reed chickens, Lushi chickens, bantam chickens, Arbor Acres broilers, Avian broilers, Digao broilers, Nandan Yao chickens, Beijing oily chickens, Taoyuan chickens or Changting River frogs.

[0030] As a feasibility case, the laying hen breed is selected from white-shelled laying hens, brown-shelled laying hens, pink-shelled laying hens, green-shelled laying hens, white single-comb Leghorn chickens, Luodao red chickens, Dawufen No. 1, Hailan brown laying hens, Hailan white w36, Roman pink laying hens, Roman brown laying hens, Jingbai 938 laying hens or Nongda No. 3.

[0031] The present invention also provides a feed additive, the preparation raw materials of which include yeast fat, fat-soluble vitamins and yeast cell walls.

[0032] In some embodiments, the fat-soluble vitamin in the feed additive is vitamin D2, vitamin D3 or vitamin A.

[0033] In some embodiments, the mass ratio of the yeast fat, fat-soluble vitamins and yeast cell wall is 1: (5-10): (5-200).

[0034] Furthermore, the present invention also provides a method for preparing the feed additive, which comprises:

[0035] mixing yeast fat and fat-soluble vitamins to obtain yeast fat containing vitamins;

[0036] adding ethanol to the vitamin-containing yeast fat and stirring, and then adding yeast cell walls and mixing to obtain a mixture;

[0037] The mixture is subjected to rotary evaporation and then dried to obtain the feed additive.

[0038] In the embodiments of the present invention, after yeast fat and fat-soluble vitamins are mixed, the mass fraction of the fat-soluble vitamins is 0.1% to 15%. Taking vitamin D2 as an example, VD2 is dissolved in yeast fat to a mass fraction of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 2.0%, 3.0%, 5.0%, 7.0%, 10.0%, 11%, 12%, 13%, 14%, or 15%. In a specific embodiment, VD2 is dissolved in yeast fat to a mass fraction of 0.8%.

[0039] In the embodiment of the present invention, the mass-volume ratio of the yeast fat containing vitamins to ethanol is 1 g: (1-30) mL; for example, the mass-volume ratio of the yeast fat containing vitamins to ethanol is 1 g: (15-25) mL. As a feasibility example, the mass-volume ratio of the yeast fat containing vitamins to ethanol is 1g:1mL, 1g:2mL, 1g:3mL, 1g:4mL, 1g:5mL, 1g:6mL, 1g:7mL, 1g:8mL, 1g:9mL, 1g:10mL, 1g:11mL, 1g:12mL, 1g:13mL, 1g:14mL, 1g:15mL, 1g:16mL, 1g:17mL, 1g:18mL, 1g:19mL, 1g:20mL, 1g:21mL, 1g:22mL, 1g:23mL, 1g:24mL, 1g:25mL, 1g:26mL, 1g:27mL, 1g:28mL, 1g:29mL, and 1g:30mL. In a specific embodiment, the mass-volume ratio of the yeast fat containing vitamins to ethanol is 1g:20mL.

[0040] In an embodiment of the present invention, after adding ethanol, stirring is carried out at 20-60°C for 10-60 minutes; for example, the stirring temperature is 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C; and the stirring time is 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes or 60 minutes.

[0041] In an embodiment of the present invention, the mass ratio of the yeast fat to the yeast cell wall is 1:(1-20). For example, the mass ratio of the yeast fat to the yeast cell wall is 1:(8-12). As a feasible example, the mass ratio of the yeast fat to the yeast cell wall is 1:8, 1:9, 1:10, or 1:12. In a specific embodiment, the mass ratio of the yeast fat to the yeast cell wall is 1:9.

[0042] In an embodiment of the present invention, after adding the yeast cell walls, stirring is carried out at 20-60°C for 10-60 min; for example, the stirring temperature is 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C; and the stirring time is 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min.

[0043] In an embodiment of the present invention, the temperature of the rotary evaporation is 45-55°C, for example, the temperature is 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C, 53°C, 54°C or 55°C.

[0044] In an embodiment of the present invention, the drying conditions include: drying at 40°C to 60°C for 2 to 5 hours. For example, the drying temperature is 40°C, 45°C, 50°C, 55°C, or 60°C. The drying time is 2 hours, 3 hours, 4 hours, or 5 hours.

[0045] The preparation method of the feed additive provided by the present invention is very simple. In the prepared product, yeast fat and yeast cell walls jointly embed vitamins, thereby effectively protecting the vitamins from the influence of light, oxygen, humidity, etc., and can better extend its shelf life compared with vegetable oil, especially showing better stability under high temperature or humid conditions.

[0046] Furthermore, the present invention also provides a poultry feed, which comprises a basic diet and the feed additive as described above, or the feed additive prepared by the preparation method as described above.

[0047] In the present invention, the basic diet comprises: corn, soybean oil, soybean meal, wheat bran, calcium carbonate, calcium dihydrogen phosphate, methionine, lysine, salt, choline chloride and premix;

[0048] or including corn, soybean meal, wheat bran, soybean oil, monocalcium phosphate, rock flour, lysine, methionine, salt, baking soda, choline chloride, and premixes;

[0049] The premix comprises FeSO4·H2O, CuSO4·5H2O, MnSO4·H2O, ZnSO4·H2O, yeast selenium, vitamin A, vitamin E, vitamin K2, vitamin B1, vitamin B2, vitamin B6, vitamin B12, niacin, pantothenic acid, folic acid and vitamin H;

[0050] Alternatively, the premix comprises: FeSO4·H2O, CuSO4·5H2O, MnSO4·H2O, ZnSO4·H2O and yeast selenium.

[0051] In the present invention, the feed additive accounts for 0.10% of the feed mass (based on the VD2 content of 5000U / kg in the total feed).

[0052] Furthermore, the present invention also provides a method for raising poultry, which comprises feeding the poultry feed as described above, or feeding the feed additive as described above, or feeding the feed additive prepared by the preparation method as described above.

[0053] In the present invention, the feeding animals are poultry, specifically broilers or laying hens. The size of broilers starting to be fed is 1-day-old Cobb white broilers, and the size of laying hens starting to be fed is 57-week-old Hy-Line Brown commercial laying hens.

[0054] The present invention utilizes yeast fat to prepare a feed additive, which has been found to improve the stability of vitamins, particularly protecting fat-soluble vitamins from the effects of light, oxygen, and humidity. This significantly extends their shelf life compared to vegetable oils, and exhibits superior stability under high-temperature or humid conditions. Furthermore, yeast fat can promote growth and egg production in poultry. DETAILED DESCRIPTION

[0055] The present invention provides yeast fat, its preparation method, and its application in poultry farming. Those skilled in the art can refer to the contents herein and appropriately modify the process parameters to achieve the desired results. It is particularly important to note that all similar substitutions and modifications obvious to those skilled in the art are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments. It is obvious that those skilled in the art can modify or appropriately alter and combine the methods and applications herein to implement and apply the technology of the present invention without departing from the content, spirit, and scope of the present invention.

[0056] The test materials used in this invention are all common commercial products and can be purchased on the market. The sources of ingredients and equipment models used in the preparation process are shown in Tables 1 and 2 below:

[0057] Table 1 Sources of ingredients

[0058]

[0059] Table 2 Device information

[0060]

[0061] The present invention will be further described below in conjunction with the embodiments:

[0062] Example 1 Preparation of yeast fat

[0063] 1.1 Direct yeast extraction

[0064] Weigh 3 kg of fresh yeast, add 7 kg of 90% ethanol, extract and reflux at 80 ° C for 4 hours, obtain fat extract after solid-liquid separation, and finally concentrate under reduced pressure at 50 ° C and recover the solvent to obtain solids, and analyze the crude fat content of the solids.

[0065] 1.2 Yeast Extraction after Protease Hydrolysis

[0066] Weigh 3 kg of fresh yeast and add water to prepare 20 kg of yeast milk with a dry matter of 15%. Add papain according to 0.5‰ of the total mass of the material, control the pH at 5.0-6.0 and perform enzymatic hydrolysis for 5 hours at a temperature of 50-55°C. After enzymatic hydrolysis, centrifuge and wash with an equal volume of process water. Collect the heavy phase, add 7 kg of 90% ethanol to the heavy phase, extract and reflux at 80°C for 4 hours, obtain fat extract after solid-liquid separation, and finally concentrate under reduced pressure at 50°C and recover the solvent to obtain solids, which are then tested and analyzed for crude fat content.

[0067] 1.3 Yeast Extraction after Enzymatic Hydrolysis with Protease and Mannanase

[0068] Weigh 3 kg of fresh yeast, add water to prepare 20 kg of yeast milk, dry matter 15%, add papain according to 0.5‰ of the total mass of the material, control the pH 5.0-6.0 for enzymatic hydrolysis for 5 hours, the temperature is 50-55°C, centrifuge after enzymatic hydrolysis, add an equal volume of process water for washing, collect the heavy phase for detection of dry matter 12%, add mannanase according to 1‰ of the total mass of the material for enzymatic hydrolysis for 10 hours, the temperature is 55-60°C, centrifuge after enzymatic hydrolysis, take the heavy phase for spray drying to obtain a solid, add 7 kg of 90% ethanol to the solid, extract and reflux at 80°C for 4 hours, obtain a fat extract after solid-liquid separation, and finally concentrate under reduced pressure at 50°C and recover the solvent to obtain a solid, and analyze the crude fat content of the solid.

[0069] 1.4 Upgrading the extraction process after yeast hydrolysis with protease and mannanase

[0070] Weigh 3 kg of fresh yeast, add water to prepare 15 kg of yeast milk, dry matter 20%, add papain according to 1.5‰ of the total mass of the material, control the pH 5.0-6.0 for enzymatic hydrolysis for 10 hours, the temperature is 50-55°C, centrifuge after enzymatic hydrolysis, add an equal volume of process water for washing, collect the heavy phase for detection of dry matter 14%, add mannanase according to 3‰ of the total mass of the material for enzymatic hydrolysis for 15 hours, the temperature is 55-60°C, centrifuge after enzymatic hydrolysis, take the heavy phase for spray drying to obtain a solid, add 7 kg of 90% ethanol to the solid, extract and reflux at 80°C for 4 hours, obtain a fat extract after solid-liquid separation, and finally concentrate under reduced pressure at 50°C and recover the solvent to obtain a solid, and analyze the crude fat content of the solid.

[0071] 1.5 Detection of crude fat and fatty acids

[0072] The crude fat content was determined in accordance with GB / T 6433-2006.

[0073] Fatty acids were detected using the following assay:

[0074] Chromatographic system: An Agilent gas chromatography system (Agilent7820, Agilent Technologies, USA) and a CP-Sil88 (100m×0.25mm×0.25µm, Agilent, USA) gas chromatography column were used. The injection volume was 1µL, the split ratio was 10:1, the carrier gas was high-purity helium, the flow rate was 1.0mL / min, and the initial temperature of the column oven was 100°C for 5.0min, then programmed to 240°C at 4°C / min and maintained for 15min.

[0075] Mass spectrometry system: An Aiglent quadrupole mass spectrometer (Agilent 5977, Agilent Technologies, USA) was used, employing an electron impact ionization (EI) source. Analytes were detected in single-channel scanning (SIM) mode. Mass spectrometry analysis conditions were as follows: inlet temperature 260°C, quadrupole temperature 150°C, single-channel scanning (SIM) mode, and mass scan range (m / z): 30–550.

[0076] Test results:

[0077] In Examples 1.1 and 1.2, the crude fat content in the solids was detected to be 31.2% and 47.6%, respectively. Since the fat content did not meet the expected requirement of more than 70%, fatty acid content detection and application testing were not performed.

[0078] The yeast fat obtained in Example 1.3 had a crude fat content of 76.11%. The proportion of single fatty acids to total fatty acids is shown in Table 3, of which glycerides with 16 carbon atoms or less accounted for 38.70%, and unsaturated fatty acids accounted for 81.98%.

[0079] The yeast fat obtained in Example 1.4 had a crude fat content of 93.00%. The proportion of single fatty acids to total fatty acids is shown in Table 3, of which glycerides with 16 carbon atoms or less accounted for 46.11%, and unsaturated fatty acids accounted for 79.89%.

[0080] Table 3

[0081]

[0082] Example 2

[0083] Weigh 1.25 g of VD2, add 10 g of yeast fat (prepared in 1.3 of Example 1) and 200 mL of ethanol and stir to dissolve thoroughly, then add 90 g of yeast cell walls, weigh 1.25 g of VD2, add 200 mL of ethanol and stir to dissolve thoroughly, after sufficient dissolution, add 100 g of yeast cell walls, weigh 1.25 g of VD2, add 10 g of vegetable oil and 200 mL of ethanol and stir to dissolve thoroughly, then add 90 g of yeast cell walls, stir the three separately and transfer to a rotary evaporator, evaporate under reduced pressure at 50°C to recover the solvent until the material is dispersed. When it has good fluidity, take it out and disperse it on a plate, dry it for 2 h, and obtain VD2 + yeast fat + cell walls, VD2 + cell walls, and VD2 + vegetable oil + cell walls samples, respectively. An accelerated stability experiment was conducted to compare the stability. The loss rate of VD2+yeast fat+cell wall was 6.29% in 7 days and 8.79% in 14 days. The loss rate of VD2+cell wall was 14.36% in 7 days and 19.38% in 14 days. The loss rate of VD2+vegetable oil+cell wall was 7.04% in 7 days and 9.86% in 14 days.

[0084] Table 4

[0085]

[0086] Example 3: Application in broiler farming

[0087] 162 one-day-old Cobb white broiler chickens were used as experimental animals. The experiment was divided into three treatment groups, each with six replicates and nine birds per replicate. The experimental period was six weeks, and the experimental diets were mixed every two weeks. The groups are shown in Table 5. The broiler diets without VD2 yeast cell walls served as control group 1, VD2 vegetable oil yeast cell walls served as control group 2, and VD2 yeast fat cell walls served as the experimental group (prepared in Section 1.3 of Example 1). The results showed that the addition of yeast fat to the compound product significantly improved broiler growth.

[0088] Table 5 Experimental groups

[0089]

[0090] The composition of the basal diet is shown in Table 6, wherein the premix comprises FeSO4·H2O 14.524%, CuSO4·5H2O 3.733%, MnSO4·H2O 33.080%, ZnSO4·H2O 26.920%, 2000 ppm yeast selenium 13.140%, vitamin A 800000 IU 0.002%, vitamin E 2.389%, vitamin K2 0.299%, vitamin B10.299%, vitamin B2 0.478%, vitamin B6 0.478%, vitamin B12 0.003%, niacin 3.584%, pantothenic acid (B5) 0.956%, folic acid 0.108% and vitamins 0.009%.

[0091] Table 6 Composition of basal diet for broiler chickens (%)

[0092]

[0093] The feeding period was 6 weeks. Feed was delivered at 20:00 in the evening of the first, third, and sixth weeks of the experiment, but the chickens were allowed to drink water freely. At 8:00 the next morning, body weight was measured for each replicate and the feed-to-meat ratio was calculated:

[0094] The formula for calculating the feed-to-meat ratio is:

[0095] Feed-to-meat ratio = total feed consumption / total weight gain.

[0096] The results are shown in Table 7:

[0097] Table 7 Growth effect of broiler chickens

[0098]

[0099] The above results show that encapsulating vitamin D2 with yeast fat can more effectively improve the stability of the vitamin and promote the growth of broiler chickens. Compared with vegetable oil, yeast fat has a more significant effect on promoting broiler growth.

[0100] Example 4: Application in laying hen farming

[0101] The experimental animals were 162 57-week-old Hy-Line Brown commercial laying hens. The experiment was divided into three treatment groups, each with six replicates and nine hens per replicate. The experimental period was six weeks, and the experimental diets were mixed every two weeks. The laying hen diets were not supplemented with VD2 yeast cell walls (Control 1), VD2 vegetable oil yeast cell walls (Control 2), and VD2 yeast fat cell walls (prepared in 1.3 of Example 1) in laying hen farming applications. The results showed that the addition of yeast fat in the compound product significantly improved the growth of laying hens.

[0102] Table 8 Experimental groups

[0103]

[0104] The composition of the basal diet is shown in Table 9, wherein the premix comprises 15.189% FeSO4·H2O, 4.084% CuSO4·5H2O, 36.194% MnSO4·H2O, 29.454% ZnSO4·H2O, and 14.377% 2000 ppm yeast selenium.

[0105] Table 9 Basic diet formula for laying hens

[0106]

[0107] The feeding cycle is six weeks. The egg production rate is counted and the feed-to-egg ratio is calculated:

[0108] Egg production rate = total egg production / total number of chickens × 100%

[0109] Feed-to-egg ratio = amount of feed consumed / total egg production

[0110] The results are shown in Table 10:

[0111] Table 10 Egg production rate and feed-to-egg ratio of laying hens

[0112]

[0113] Note: Different letters in the same column indicate significant differences, p>0.05.

[0114] The results above demonstrate that encapsulating vitamin D2 with yeast fat can increase egg production and reduce feed-to-egg ratio in laying hens. Compared to vegetable oil, yeast fat exhibits a significantly greater effect in increasing egg production and / or feed-to-egg ratio.

[0115] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a feed additive, characterized in that: It includes: mixing yeast fat and fat-soluble vitamins to obtain yeast fat containing vitamins; adding ethanol to the vitamin-containing yeast fat and stirring, and then adding yeast cell walls and mixing to obtain a mixture; The mixture is subjected to rotary evaporation and then dried to obtain the feed additive; The fat-soluble vitamin is vitamin D2, vitamin D3 or vitamin A; the crude fat content in the yeast fat is more than 70%, the fatty acid glyceride with 16 carbon atoms or less accounts for more than 30%, and the unsaturated fatty acid accounts for more than 70%.

2. The preparation method according to claim 1, characterized in that The percentage of single fatty acids in the yeast fat to the total fatty acids is: 0.003% to 0.033% of fatty acids below 14 carbon atoms, 0.162% to 0.198% of myristic acid, 0.054% to 0.066% of pentadecanoic acid, 2.331% to 2.849% of pentadecenoic acid, 12.420% to 15.180% of palmitic acid, 23.184% to 28.333% of palmitoleic acid, 0.090% to 0.110% of heptadecanoic acid, 0.108% to 0.132% of heptadecanoic acid, Stearic acid 4.347%~5.013%, oleic acid 38.264%~43.216%, linoleic acid 6.174%~7.446%, linolenic acid 4.572%~5.016%, arachidic acid 0.008%~0.010%, arachidonic acid 0.009%~0.011%, arachidienoic acid 0.081%~0.100%, behenic acid 0.009%~0.011%, erucic acid 0.018%~0.022% and lignoic acid 0.189%~0.231%.

3. The preparation method according to claim 1 or 2, characterized in that The preparation method of yeast fat comprises: hydrolyzing yeast with protease, hydrolyzing the heavy phase with mannanase, extracting the heavy phase with ethanol, and centrifuging to obtain the light phase to obtain yeast fat.

4. The preparation method according to claim 3, characterized in that The dry matter content of the yeast is 15% to 20%, The conditions for the protease hydrolysis include 50-60° C. and 5-15 hours of enzymatic hydrolysis; The conditions for the mannanase hydrolysis include 50-60° C. and 5-15 hours of enzymatic hydrolysis; In the ethanol extraction step, the volume fraction of ethanol is 90% to 100%, the extraction temperature is 70 to 90° C., and the extraction time is 3 to 5 hours.

5. The preparation method according to claim 1, characterized in that After yeast fat and fat-soluble vitamins are mixed, the mass fraction of fat-soluble vitamins is 0.1%~15%; The mass-volume ratio of yeast fat containing vitamins to ethanol is 1 g: (1-30) mL; After adding ethanol, stirring at 20-60° C. for 10-60 minutes; The mass ratio of the yeast fat to the yeast cell wall is 1: (1-20); After adding the yeast cell walls, stirring at 20-60° C. for 10-60 minutes; The drying conditions include: drying at 40° C. to 60° C. for 2 to 5 hours.

6. The preparation method according to claim 1, characterized in that The step of adding a basic diet comprises: corn, soybean oil, soybean meal, wheat bran, calcium carbonate, calcium dihydrogen phosphate, methionine, lysine, salt, choline chloride and premix; or including corn, soybean meal, wheat bran, soybean oil, monocalcium phosphate, rock flour, lysine, methionine, salt, baking soda, choline chloride, and premixes; The premix comprises FeSO4·H2O, CuSO4·5H2O, MnSO4·H2O, ZnSO4·H2O, yeast selenium, vitamin A, vitamin E, vitamin K2, vitamin B1, vitamin B2, vitamin B6, vitamin B12, niacin, pantothenic acid, folic acid and vitamin H; Alternatively, the premix comprises: FeSO4·H2O, CuSO4·5H2O, MnSO4·H2O, ZnSO4·H2O and yeast selenium.

7. The feed additive prepared by the preparation method according to any one of claims 1 to 6.

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