Schizochytrium powder for reducing methane emission from dairy cows and preparation method thereof

Abstract

The invention relates to the field of feed technology, and specifically discloses a Schizochytrium powder for reducing methane emission of dairy cows and a preparation method thereof, as well as a double-layer microalgae whole-cell Schizochytrium powder or a microalgae whole-cell Schizochytrium powder with an inner core of Schizochytrium and an outer double-layer coating structure obtained by the method. Methanogens in the rumen can reduce carbon dioxide to CH4 using hydrogen. The feed formula of the invention adopts a multi-layer core-coating structure, adds lysozyme in the outermost coating of Schizochytrium particles, adds 4-hydroxy-3-methoxybenzoic acid, D-alloisoleucine and D-2-aminobutyric acid in the middle coating to inhibit the growth of Methanobacterium brevis and Methanobacterium, adjusts the flora structure, promotes the metabolism of the flora in the rumen to move to the propionic acid path, reduces the amount of acetic acid and the ratio of acetic acid to propionic acid, promotes digestion, increases the VFA fermentation yield and the amount of propionic acid, thereby reducing methane emission and promoting the absorption of various nutrients of Schizochytrium without affecting the fermentation effect of the flora. Long-term use can significantly increase the content of nutrients such as DHA in milk.

Description

Technical Field

[0001] The invention relates to the technical field of animal husbandry, and in particular to Schizochytrium powder for reducing methane emission of dairy cows and a preparation method thereof. Background Art

[0002] With the acceleration of industrialization and the continuous growth of population, global methane emissions have shown a continuous upward trend, posing a serious threat to the earth's ecological environment and human health. As a potent greenhouse gas, the increase in methane emissions will intensify global warming, leading to frequent extreme weather events and causing irreversible damage to the ecosystem and human society.

[0003] Microorganisms in the rumen of ruminants are deeply involved in digestion. Studies have shown that the main methanogenic bacteria are Methanobrevibacter and Methanomicrobium. These two types of bacteria are the dominant genera of methanogens in the rumen, accounting for approximately 62% and 15% of the total number of methanogens, respectively (Janssen and Kirs, 2008). The methanogenic pathway of Methanobrevibacter is hydrogenotrophic, and it uses hydrogen, carbon dioxide and formate produced by bacteria and fungi as substrates to produce methane.

[0004] As for the propionate pathway, "Emerson EL, Weimer P J. Fermentation of model hemicelluloses by Prevotella strains and Butyrivibrio fibrisolvens in pure culture and in ruminal enrichment" proposed that there are functional differences between different Prevotella, but most of these Prevotella produce propionic acid or succinic acid. The increase in the abundance of Prevotella can significantly promote the increase in propionic acid content, convert more pyruvate into propionic acid, and then reduce the amount of acetic acid to reduce methane production. The sugar produced by the fermentation of fiber substances is fermented into acetic acid, propionic acid, butyric acid and volatile fatty acids VFA under the action of rumen microorganisms.

[0005] The feed raw materials eaten by ruminants will be consumed by fungi, bacteria and protozoa in the rumen and eventually turned into VFA, NH3, CO2, CH4 and H2. Among them, the VFA (volatile fatty acids) obtained by bacterial fermentation will serve as the main energy source for ruminants and will eventually be digested and absorbed by the rumen.

[0006] Animal husbandry is an important source of methane emissions, accounting for 42.9% of the entire agriculture, and the methane produced in ruminant production accounts for the vast majority of animal husbandry, mainly because ruminants degrade carbohydrates through rumen fermentation. Different strains of bacteria have different pathways for producing acid and hydrogen. The acetic acid, propionic acid, and butyric acid fermentation pathways all provide the body with the required energy and nutrients, while the acetic acid pathway produces methane in the process, which not only aggravates the greenhouse effect, but also reduces feed utilization. Therefore, choosing a reasonable measure to reduce ruminant methane emissions is a problem that needs to be solved in animal husbandry. Summary of the invention

[0007] In view of the technical problems existing in the prior art, the first aspect of the present invention provides a method for preparing Schizochytrium powder for reducing methane emissions from dairy cows, comprising the steps of:

[0008] S1: dewatering the fermentation liquid of Schizochytrium to obtain microalgae cell mud, and spraying powder to obtain the microalgae whole-cell Schizochytrium powder core;

[0009] S2: 4-Hydroxy-3-methoxybenzoic acid, D-alloisoleucine and D-2-aminobutyric acid are added to fatty acid ester A, mixed, and then the whole-cell Schizochytrium powder of microalgae in the above step S1 is added, and cold spraying is performed to obtain the double-layer whole-cell Schizochytrium powder of microalgae.

[0010] In some specific embodiments of the first aspect of the present invention, the step S3 is also included:

[0011] S3: Fatty acid ester B is mixed with lysozyme, and then the double-layer microalgae whole-cell Schizochytrium powder of step S2 is added, and a second cold spray is performed to form a microalgae whole-cell Schizochytrium powder with an inner core of Schizochytrium and an outer double-layer coating structure.

[0012] Fatty acid ester A and fatty acid ester B may be the same fatty acid ester or different fatty acid esters. In some specific embodiments, the types of fatty acid esters are enumerated.

[0013] KR1020180044051A mentions a feed composition for ruminants, which is used to reduce methane gas in the rumen of ruminants. The feed composition contains lysozyme as an active ingredient, but lysozyme bacteria act on Methanobacterium and Methanobacterium, and also act on Prevotella. As a broad-spectrum antibacterial ingredient, while reducing methane, it also inhibits other propionic acid and butyric acid-producing bacteria in the rumen, so it also has a negative impact on the production of ATP. Therefore, the release of lysozyme bacteria needs to be combined with other compounds. After inhibiting Methanobacterium and Methanobacterium, it is combined with the effects of D-2-aminobutyric acid, D-alloisoleucine and 4-hydroxy-3-methoxybenzoic acid to improve the distribution of bacterial species, reduce the conversion of pyruvate to acetic acid, reduce the amount of synthetic methane substrate, and thus reduce methane emissions. At the same time, it increases VFA production to avoid a decrease in milk production and milk fat content.

[0014] In some specific embodiments of the first aspect of the present invention, the Schizochytrium fermentation broth in step S1 is further added with auxiliary materials, and the auxiliary materials include one or more of vitamin A, vitamin E, tea polyphenols, choline chloride, sodium carbonate, yeast protein powder, and potassium sulfate.

[0015] In some specific embodiments of the first aspect of the present invention, in step S1, the amount of vitamin A, vitamin E or tea polyphenols added per 1 kg of dry weight of whole-cell schizochytrium microalgae powder is 8-12 g, in some embodiments 12 g, in some embodiments 11 g, in some embodiments 10 g, in some embodiments 9 g, and in some embodiments 8 g.

[0016] In some specific embodiments of the first aspect of the present invention, in step S1, 28 to 32 g of choline chloride, sodium carbonate or yeast protein powder is added per 1 kg of dry weight of whole-cell schizochytrium microalgae powder, in some embodiments, 28 g, in some embodiments, 29 g, in some embodiments, 30 g, in some embodiments, 31 g, and in some embodiments, 32 g.

[0017] In some specific embodiments of the first aspect of the present invention, the amount of 4-hydroxy-3-methoxybenzoic acid fed in step S2 is 15-19 wt % based on the mass of the fatty acid ester in step S2, in some embodiments it is 15 wt %, in some embodiments it is 16 wt %, in some embodiments it is 17 wt %, in some embodiments it is 18 wt %, and in some embodiments it is 19 wt %.

[0018] In some specific embodiments of the first aspect of the present invention, the amount of D-alloleucine fed in step S2 is 25-29 wt% based on the mass of the fatty acid ester in step S2, 25 wt% in some embodiments, 26 wt% in some embodiments, 27 wt% in some embodiments, 28 wt% in some embodiments, and 29 wt% in some embodiments.

[0019] In some specific embodiments of the first aspect of the present invention, the amount of D-2-aminobutyric acid fed in step S2 is 25-29 wt% based on the mass of the fatty acid ester in step S2, 26 wt% in some embodiments, 27 wt% in some embodiments, 28 wt% in some embodiments, and 29 wt% in some embodiments.

[0020] In some specific embodiments of the first aspect of the present invention, the fatty acid A in step S2 is selected from one or a mixture of palm fat powder, stearic acid, sorbitan monostearate, monolaurin, monoglyceride, paraffin, beeswax, sucrose fatty acid ester, polyglycerol fatty acid ester, and hydrogenated vegetable oil.

[0021] In some specific embodiments of the first aspect of the present invention, the feed mass of lysozyme lysozyme bacteria in step S3 is 0.6-2.0wt% in terms of fatty acid ester B, in some embodiments, 0.7wt%, in some embodiments, 0.8wt%, in some embodiments, 0.9wt%, in some embodiments, 1.0wt%, in some embodiments, 1.2wt%, in some embodiments, 1.4wt%, in some embodiments, 1.6wt%, in some embodiments, 1.8wt%, and in some embodiments, 2.0wt%.

[0022] In some specific embodiments of the first aspect of the present invention, the fatty acid ester B in step S3 is selected from one or a mixture of palm fat powder, stearic acid, sorbitan monostearate, monolaurin, monoglyceride, paraffin, beeswax, sucrose fatty acid ester, polyglycerol fatty acid ester, and hydrogenated vegetable oil.

[0023] In some specific embodiments of the first aspect of the present invention, the mass ratio of the fatty acid ester A mixture of step S2 to the microalgae whole-cell schizochytrium powder core of step S1 is 1:(7-9), in some embodiments 1:7, in some embodiments 1:8, and in some embodiments 1:9.

[0024] In some specific embodiments of the first aspect of the present invention, the mass ratio of the double-layer microalgae whole-cell schizochytrium powder to the fatty acid ester B mixture in step S2 is 1:(6-9), in some embodiments 1:6, in some embodiments 1:7, in some embodiments 1:8, and in some embodiments 1:9.

[0025] The second aspect of the present invention proposes a Schizochytrium powder for reducing methane emissions from dairy cows, which is prepared by the method described in the first aspect. The Schizochytrium powder is a double-layer microalgae whole-cell Schizochytrium powder (a single-layer microalgae whole-cell Schizochytrium powder with an inner core and an outer double-layer coating structure), or the Schizochytrium powder is a microalgae whole-cell Schizochytrium powder with an inner core and an outer double-layer coating structure.

[0026] The third aspect of the present invention provides a feed comprising the Schizochytrium powder for reducing methane emission of dairy cows as described in the second aspect.

[0027] In the present invention, D-alloisoleucine (CAS: 1509-35-9), D-2-aminobutyric acid (CAS: 2623-91-8), lysozyme (CAS: 12650-88-3), VFA (volatile organic acid), 4-hydroxy-3-methoxybenzoic acid (CAS: 121-34-6);

[0028] The fatty acid esters A and B in the present invention are both fatty acid esters. The fatty acid esters in the present invention refer to one or more of palm fat powder, stearic acid, sorbitan monostearate, monolaurin, monoglyceride, paraffin, beeswax, sucrose fatty acid ester, polyglycerol fatty acid ester, and hydrogenated vegetable oil, which are mixed and stirred evenly.

[0029] The composition of each basic diet

[0030]

[0031]

[0032] Reference: Conventional nutrients in fermentation substrates refer to Zhang Liying. Feed analysis and feed quality detection technology 4th edition, Beijing: China Agricultural University Press, 2016.

[0033] Methane determination: Gas chromatograph (Shimadzu 2014C) with TCD thermal conductivity cell is used to determine the concentration of CH4 in the gas sample. The standard gas concentration (L / L) of CH4 is 5%, 1%, 0.5% and 0.1%.

[0034] VFA (volatile fatty acid) analysis: determined by gas chromatography; standard T / NAIA 0005-2020.

[0035] Chromatographic column: Agilent DB-WAX capillary column (30mx0.32mmx0.25um); initial column temperature 65℃, increased to 190℃ at a rate of 12.5℃ / min; inlet temperature: 230℃; detector temperature: 290℃; carrier gas is high-purity nitrogen; constant pressure: 100KPa; air flow rate: 400mL / min; hydrogen flow rate: 40mL / min; tail gas flow rate: 30mL / min; split injection mode, split ratio is 25:1; injection volume: 1ul.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The Schizochytrium powder used in this scheme has good antioxidant capacity to prevent the oxidation of unsaturated fatty acids in vivo and in vitro, thereby achieving the effects of reducing methane, increasing VFA, and increasing DHA absorption. Methanogens in the rumen can use hydrogen to reduce carbon dioxide to CH4. The feed formula of the present invention adopts a multi-layer core-coated structure, which combines the chemical substances regulating the flora with the structure of the multi-layer core-coated DHA particles. Only one feed needs to be added to achieve better regulation of the flora and promotion of VFA, DHA absorption and reduction of methane, which is convenient for feeding.

[0038] Adding lysozyme to the outermost layer of Schizochytrium granules, and adding 4-hydroxy-3-methoxybenzoic acid, D-alloisoleucine and D-2-aminobutyric acid to the middle layer can inhibit the growth of Methanobacterium brevis and Methanobacterium, adjust the flora structure, promote the metabolism of rumen flora to the propionic acid pathway, reduce the amount of acetate and the acetic acid / propionic acid ratio, promote digestion, increase VFA fermentation production and propionic acid, and thus enhance the absorption of various nutrients of Schizochytrium. Long-term use can significantly increase the content of nutrients such as DHA in milk. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention shows the process in which sugar produced by fermentation of fiber materials in the prior art is fermented to produce acetic acid, propionic acid, butyric acid and volatile fatty acids (VFA) under the action of rumen microorganisms; DETAILED DESCRIPTION

[0040] The present invention is applicable to ruminants such as dairy cows and dairy goats, and dairy cows are taken as an example for illustration.

[0041] Example 1

[0042] A method for preparing a Schizochytrium powder additive for reducing methane generation in dairy cows, comprising the following steps:

[0043] Step 1: Add vitamin A, vitamin E and tea polyphenols (the amount of each is 1wt%, based on the dry weight of whole-cell schizochytrium powder of microalgae), choline chloride, sodium carbonate, yeast protein powder (the amount of each is 1wt%, based on the dry weight of whole-cell schizochytrium powder of microalgae), potassium sulfate (15g / L, based on the volume of schizochytrium fermentation liquid) to 71g / L schizochytrium fermentation liquid, control 90% of water to obtain wet material, vacuum evaporate to obtain microalgae cell mud, compound, mix, stir and emulsify, and then obtain whole-cell schizochytrium powder of microalgae through homogenization and powder spraying.

[0044] Step 2: Add 4-hydroxy-3-methoxybenzoic acid (17 wt%, based on monolaurin), D-alloisoleucine and D-2-aminobutyric acid (27 wt%, based on monolaurin) into monolaurin, stir evenly to obtain a monolaurin mixture, and mix 10 parts of the monolaurin mixture with 70 parts of the microalgae whole-cell schizochytrium powder prepared in the above step 1, and cold spray to obtain double-layer microalgae whole-cell schizochytrium powder particles.

[0045] Step 3: palm fat powder and lysozyme (1.2wt%, based on the mass of palm fat powder) are stirred evenly to obtain a palm fat powder mixture, 60 parts of double-layer microalgae whole-cell schizochytrium powder are mixed with 10 parts of the palm fat powder mixture, and microalgae whole-cell schizochytrium powder particles are obtained by secondary cold spraying to form microalgae whole-cell schizochytrium powder particles with an inner core of schizochytrium and an outer double-layer coating structure.

[0046] Example 2

[0047] A method for preparing a Schizochytrium powder additive for reducing methane generation in dairy cows, comprising the following steps:

[0048] Step 1: Add vitamin A, vitamin E and tea polyphenols (the amount of each is 1wt%, based on the dry weight of whole-cell schizochytrium powder of microalgae), choline chloride, sodium carbonate, yeast protein powder (the amount of each is 1wt%, based on the dry weight of whole-cell schizochytrium powder of microalgae), potassium sulfate (15g / L, based on the volume of schizochytrium fermentation liquid) to 71g / L schizochytrium fermentation liquid, control 90% of water to obtain wet material, vacuum evaporate to obtain microalgae cell mud, compound, mix, stir and emulsify, and then obtain whole-cell schizochytrium powder of microalgae through homogenization and powder spraying.

[0049] Step 2: Add 4-hydroxy-3-methoxybenzoic acid (17 wt%, based on monolaurin), D-alloisoleucine and D-2-aminobutyric acid (27 wt%, based on monolaurin) into monolaurin, stir evenly to obtain a monolaurin mixture, and mix 10 parts of the monolaurin mixture with 70 parts of the microalgae whole-cell schizochytrium powder obtained in the previous step, and cold spray to obtain double-layer microalgae whole-cell schizochytrium powder particles.

[0050] Step 3: 60 parts of double-layer microalgae whole-cell Schizochytrium powder are mixed with 10 parts of palm fat powder mixture, and then cold-sprayed twice to obtain microalgae whole-cell Schizochytrium powder particles, thereby forming microalgae whole-cell Schizochytrium powder particles with an inner core of Schizochytrium and an outer double-layer coating structure.

[0051] Comparative Example 1

[0052] The difference between Comparative Example 1 and Example 1 is that D-alloisoleucine, D-2-aminobutyric acid and 4-hydroxy-3-methoxybenzoic acid are not added in step 2.

[0053] Comparative Example 2

[0054] The difference between Comparative Example 2 and Example 1 is that D-alloisoleucine is not added in step 2.

[0055] Comparative Example 3

[0056] The difference between Comparative Example 3 and Example 1 is that in step 2, 4-hydroxy-3-methoxybenzoic acid is not added.

[0057] Comparative Example 4

[0058] The difference between Comparative Example 4 and Example 1 is that 4-hydroxy-3-methoxybenzoic acid, D-alloisoleucine and D-2-aminobutyric acid are not added in step 2 and lysozyme is not added in step 3.

[0059] Embodiment 3:

[0060] The algae powder particles prepared in Examples 1 to 2 and Comparative Examples 1 to 4 were used as additives for fermentation tests such as methane, gas production and VFA. The specific method is as follows:

[0061] Three Holstein lactating dairy cows in good health, with a body weight of 720±20kg, similar milk production and feed intake, and installed with permanent rumen fistulas were selected.

[0062] Rumen fluid collection

[0063] Before morning feeding, the chyme in the rumen of each Holstein lactating dairy cow was collected and filtered through 4 layers of gauze to obtain the rumen fluid. The collected rumen fluid was mixed evenly and placed in a thermos cup preheated at 39°C and filled with carbon dioxide, and then brought back to the laboratory.

[0064] Preparation of rumen fermentation liquid

[0065] According to the method of Menke et al., trace element solution A, buffer solution B, buffer solution C, Na2S reduction solution and resazurin indicator solution were prepared. Rumen buffer solution was prepared by 400 mL of distilled water, 0.1 mL of A solution, 200 mL of B solution, 200 mL of C solution, 1 mL of resazurin solution and 40 mL of reducing agent solution. Rumen fluid and rumen buffer solution were mixed at a ratio of 1:2 (volume) to prepare mixed artificial rumen culture medium. During this process, carbon dioxide was continuously introduced to maintain an anaerobic environment.

[0066] In vitro fermentation

[0067] Each 1000g basal feed was added with 10g of the compounded Schizochytrium powder of Examples 1-2 and Comparative Examples 1-4, mixed well, and 0.5g was accurately weighed as a fermentation substrate and placed in a preheated glass syringe coated with vaseline, and 30ml of artificial rumen culture medium was added to each syringe. Finally, the air was exhausted, the sealing film was sealed, the initial scale value was recorded, and the mixture was placed in a 39°C constant temperature shaking water bath for timed culture, and 3 replicates were set for each treatment in each batch of experiments.

[0068] Index determination

[0069] The gas production was recorded at 3h, 6h, 9h, 12h, 24h and 48h. All the gas in the bottle was collected at 3h, 6h, 9h, 24h and 48h, injected into the gas sampling bag, and the methane production of the collected gas was determined by gas chromatograph. The methane ratio was calculated based on the gas production and CH4 production. After 48h of the in vitro fermentation test, the syringe was immersed in a water bath to terminate the fermentation, and then the culture medium was poured into a centrifuge tube, and the pH in the fermentation broth was determined using a pH meter. After the determination, the centrifuge was placed in a centrifuge, and the supernatant was taken for the determination of ammonia nitrogen and volatile fatty acids VFA. According to the phenol-sodium hypochlorite colorimetric method, the NH3-N content was calculated by colorimetry using an enzyme marker, and the content of volatile fatty acids VFA was determined by high performance gas chromatograph.

[0070] Test results

[0071] As shown in Table 1, the in vitro gas production of Example 1 was significantly lower than that of the other five groups (P<0.05). Adding the algae powder of Example 1 significantly reduced the methane emission and the proportion of methane in the total gas production at 3h, 6h, 9h, 24h and 48h (P<0.01).

[0072] Table 1 Effect of in vitro fermentation gas production of dairy cows

[0073]

[0074] Note: The numbers with different lowercase letters in the same column indicate significant differences (P<0.05), while the numbers without letters or with the same letters indicate no significant differences (P>0.05).

[0075] Table 2 shows the test data of total volatile fatty acids VFA, acetic acid, propionic acid, total butyric acid, and acetic acid / propionic acid at 48 hours.

[0076] Table 2 Content of each component in the supernatant

[0077]

[0078] Note: The numbers with different lowercase letters in the same column indicate significant differences (P<0.05), while the numbers without letters or with the same letters indicate no significant differences (P>0.05).

[0079] Example 1 Algae powder significantly increased the content of propionic acid (P<0.05), and significantly reduced the content of acetic acid and the ratio of acetic acid / propionic acid (P<0.05); the acetic acid content and the acetic acid / propionic acid ratio were significantly lower than those of the other five groups (P<0.05).

[0080] Example 4

[0081] 24 Holstein lactating cows with the same body shape, age and feed intake as those in Example 3 but without permanent rumen fistula were selected and divided into feeding groups 1 to 4, with 6 cows in each group. The test results were averaged and fed in the following manner:

[0082] According to the composition table of each basic diet, each cow was fed 150g of Example 1, Example 2, and Comparative Example 4 algae powder particles mixed with 1kg of each basic diet feed as feeding groups 1 to 3, and fed twice a day for 10 days (Example 1 corresponds to feeding group 1, Example 2 corresponds to feeding group 2, and Comparative Example 4 corresponds to feeding group 3).

[0083] According to the basic diet composition table, each cow was fed 1.15 kg of each basic diet feed (without any algae powder particles) twice a day as feeding group 4, and was fed twice a day for 10 days.

[0084] On the 11th day, under normal feeding conditions, milk production, milk fat rate, milk protein rate, milk DHA content, milk total solids content, FCM and other indicators were measured.

[0085] Milk sampling method:

[0086] The milk samples were collected with a sampler. A total of 50 mL of milk samples were collected in the ratio of morning: noon: evening = 4:3:3. After adding milk sample preservatives, they were sent to the measurement center for milk fat detection and milk DHA content analysis using near-infrared equipment. For each group of cows, the GreenFeed system was used to install infrared sensors on the cows' heads to monitor methane and carbon dioxide emissions.

[0087] Test results

[0088] As shown in Table 3, the addition of Schizochytrium powder significantly increased the DHA content in milk, and the DHA content in feeding group 1 was significantly higher than that in the other three groups (P<0.05);

[0089] Table 3 Effects of Schizochytrium powder on production performance of dairy cows

[0090]

[0091] Note: The numbers with different lowercase letters in the same column indicate significant differences (P<0.05), while the numbers without letters or with the same letters indicate no significant differences (P>0.05).

[0092] As shown in Table 4, the emissions of methane and carbon dioxide in feeding groups 1 and 2 (P<0.05), especially feeding group 1, were significantly lower than those in the other three groups (P<0.01).

[0093] Table 4 Effect of the feed of the present invention on rumen methane and carbon dioxide emissions of dairy cows

[0094]

[0095] Note: The numbers with different lowercase letters in the same column indicate significant differences (P<0.05), while the numbers without letters or with the same letters indicate no significant differences (P>0.05).

[0096] In summary, adding lysozyme, D-alloisoleucine, D-2-aminobutyric acid and 4-hydroxy-3-methoxybenzoic acid to the diet of dairy cows can significantly reduce methane emissions and increase the DHA content in milk. Using D-alloisoleucine and D-2-aminobutyric acid as culture amino acids and 4-hydroxy-3-methoxybenzoic acid as an inhibitor can significantly change the structure and composition of the bacterial community, promote the rumen acid production biological system to approach the bacterial community that metabolizes propionic acid / butyric acid, improve the ability of the bacterial community to produce VFA, increase the DHA content, effectively reduce methane production, increase the propionic acid ratio, reduce the acetic acid / propionic acid ratio, and reduce the hydrogen accumulation caused by it.

Claims

1. A method for preparing Schizochytrium powder for reducing methane emissions from dairy cows, characterized in that: include: S1: dewatering the fermentation liquid of Schizochytrium to obtain microalgae cell mud, and then spraying powder to obtain the microalgae whole-cell Schizochytrium powder core. The fermentation liquid of Schizochytrium in step S1 is added with auxiliary materials, and the auxiliary materials include one or more of vitamin A, vitamin E, tea polyphenols, choline chloride, sodium carbonate, yeast protein powder, and potassium sulfate. The amount of vitamin A, vitamin E or tea polyphenols added is 8-12 g per 1 kg of dry weight of whole-cell schizochytrium microalgae powder, and the amount of choline chloride, sodium carbonate or yeast protein powder added in step S1 is 28-32 g per 1 kg of dry weight of whole-cell schizochytrium microalgae powder; S2: 4-hydroxy-3-methoxybenzoic acid, D-alloisoleucine and D-2-aminobutyric acid are added to monolaurin, mixed to obtain a monolaurin mixture, and then added with the whole-cell schizochytrium powder of microalgae in the above step S1, and cold sprayed to obtain a double-layer microalgae whole-cell schizochytrium powder. The mass ratio of the monolaurin mixture in step S2 to the whole-cell schizochytrium algae powder core in step S1 is 1:(7-9); S3: palm fat powder is mixed with lysozyme to obtain a palm fat powder mixture, and then the double-layer microalgae whole-cell Schizochytrium powder from step S2 is added, and a second cold spray is performed to form a microalgae whole-cell Schizochytrium powder with a core of Schizochytrium and an outer double-layer coating structure. The mass ratio of the mixture of double-layer microalgae whole-cell Schizochytrium powder and palm fat powder in step S3 is 1:(6-9), and the mass of lysozyme in step S3 is 0.6-2wt% based on palm fat powder.

2. The method for preparing Schizochytrium powder for reducing methane emission from dairy cows according to claim 1, characterized in that: The amount of 4-hydroxy-3-methoxybenzoic acid added in step S2 is 15-19wt% based on the mass of monolaurin in step S2, the amount of D-alloleucine added in step S2 is 25-27wt% based on the mass of monolaurin in step S2, and the amount of D-2-aminobutyric acid added in step S2 is 25-27wt% based on the mass of monolaurin in step S2.

3. Algae powder particles obtained by the preparation method according to claim 1.

4. A feed comprising the algal powder particles of claim 3.

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