Preparation method of yak rumen fluid fermented feed

Abstract

The invention provides a preparation method of a yak rumen fluid fermented feed. The method comprises the following steps: selecting rumen fluid suitable for high-concentrate barn feeding daily ration yaks; putting the rumen fluid into a fermentation container filled with feed, and uniformly stirring to form a rumen fluid and feed mixture; and adjusting the pH value of the rumen fluid feed mixture to 6.9-7.3 by using water, adjusting the temperature of the rumen fluid feed mixture to 38.5-39.5 DEG C, adjusting the ratio of water to feed to 1: 1-1.4: 1, and performing post-fermentation for 12-48 hours to obtain the yak rumen fluid fermented feed. According to the yak rumen fluid fermented feed disclosed by the invention, by promoting an L-threonine metabolic pathway, inhibition of excessive tryptophan on growth is slowed down, and the feed intake is increased. The feed also can enhance the metabolic capability of yaks, generate keratinous sulfuric acid and hyaluronic acid, and protect the body. By using the feed, the average and total weight gain of yaks can be remarkably improved, the feed-to-weight ratio is reduced, and the breeding economic benefit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cattle feed, and particularly relates to a preparation method of a fermented feed from yak rumen fluid. Background Art

[0002] The Qinghai-Tibet Plateau region has its unique climate characteristics. The average altitude of this region exceeds 3000 meters. Except for the valleys in the southeast of the plateau, the annual average temperature is generally lower than 5 degrees Celsius. Due to the low annual temperature, the season division in the Qinghai-Tibet Plateau is mainly based on the "cold season" and the "warm season". Although the temperature is relatively high from June to September, the average temperature in the remaining months is mostly lower than 0 degrees Celsius.

[0003] Therefore, the seasonal change in the Qinghai-Tibet Plateau is mainly manifested as the alternation of the cold season and the warm season. In recent years, the phenomenon of sudden temperature changes during the alternation of the cold and warm seasons has occurred frequently, especially the emergence of extreme climate events is more common. The main ruminants raised in this region are yaks and Tibetan sheep, and their feeding methods are mainly grazing.

[0004] In order to improve the production performance of yaks, supplementary feeding of concentrate has become a main means. However, the rising feed price has imposed certain restrictions on the application of supplementary feeding. Under the double impact of the continuous increase in feed prices and the meat price affected by the international market, the breeding industry is facing severe challenges. Therefore, there is an urgent need to find a feed substitute with low cost and high feeding efficiency. During the feeding process of ruminants, although the amount of roughage used is large, the main roughage used in China is mostly straw with low nutritional value. Summary of the Invention

[0005] The present invention aims to at least solve the technical problem of high cost existing in the prior art, and particularly innovatively provides a preparation method of a fermented feed from yak rumen fluid.

[0006] In order to achieve the above object of the present invention, the present invention provides a preparation method of a fermented feed from yak rumen fluid, and the method includes:

[0007] S1. Select the rumen fluid of yaks that have adapted to high-concentrate stall feeding diets;

[0008] S2. Put the rumen fluid into a fermentation container filled with feed, and stir evenly to form a rumen fluid-feed mixture, and the weight ratio of the rumen fluid in the rumen fluid-feed mixture is 10%-50%;

[0009] S3. Use dilute hydrochloric acid and sodium hydroxide solution to adjust the pH value of the rumen fluid-feed mixture to 6.9-7.3, adjust the temperature of the rumen fluid-feed mixture to 38.5°C-39.5°C, adjust the water-feed ratio to 1:1-1.4:1, and then ferment for 12 to 48 hours to obtain the fermented feed from yak rumen fluid.

[0010] As an alternative embodiment of the present invention, optionally, in step S2, the feed includes concentrate feed and roughage. The concentrate feed is fermented through steps S2 to S3 to obtain rumen fluid fermented concentrate feed, and the roughage is fermented through steps S2 to S3 to obtain rumen fluid fermented roughage.

[0011] As an alternative embodiment of the present invention, optionally, the rumen fluid fermented concentrate feed includes wheat hay accounting for 10%-30% by weight, alfalfa hay accounting for 10%-30% by weight, yak concentrate supplement accounting for 40%-70% by weight, and rumen fluid fermented concentrate feed accounting for 5%-10% by weight.

[0012] As an alternative embodiment of the present invention, optionally, the fermentation temperature of the rumen fluid fermented concentrate feed is 39.0°C, the pH value is 7.1, the water-to-feed ratio is 1.4:1, and the fermentation time is 24 hours.

[0013] As an alternative embodiment of the present invention, optionally, the rumen fluid fermented roughage includes wheat hay accounting for 14%-17% by weight, alfalfa hay accounting for 14%-17% by weight, yak concentrate supplement accounting for 63%-67% by weight, and rumen fluid fermented roughage accounting for 3%-4% by weight.

[0014] As an alternative embodiment of the present invention, optionally, the fermentation temperature of the rumen fluid fermented roughage is 39.0°C, the pH value is 6.9, the water-to-feed ratio is 1:1, and the fermentation time is 24 hours.

[0015] As an alternative embodiment of the present invention, optionally, the yak concentrate supplement includes corn, wheat, wheat bran, rapeseed meal, soybean meal, palm oil powder, calcium hydrogen phosphate, sodium chloride, and premix.

[0016] As an alternative embodiment of the present invention, optionally, the weight ratio of rumen fluid in the rumen fluid feed mixture is 25%.

[0017] As an alternative embodiment of the present invention, optionally, the bacteria in the rumen fluid fermented roughage include: Firmicutes at 41.52±9.21%, Bacteroidetes at 52.70±8.87%, Proteobacteria at 1.41±0.12%; Cyanobacteria at 0.14±0.06%, Euryarchaeota at 0.58±0.06%, Spirochaetes at 0.93±0.10%, Patellibacteria at 0.79±0.09%, Actinobacteria at 0.47±0.04%, Fibrobacteres at 0.43±0.04%, and Desulfobacterota at 0.30±0.02%.

[0018] As an alternative embodiment of the present invention, optionally, the flora in the fermented concentrate feed of rumen fluid includes: Firmicutes at 57.82±12.79%, Bacteroidetes at 31.72±5.10%, Proteobacteria at 3.97±0.18%, Cyanobacteria at 1.23±0.05%, Euryarchaeota at 2.32±0.26%, Spirochaetes at 0.55±0.08%, Patellibacteria at 0.49±0.03%, Actinobacteria at 0.39±0.04%, Fibrobacteres at 0.25±0.02%, Desulfobacterota at 0.26±0.03%.

[0019] Advantages of the present invention: The fermented feed of yak rumen fluid of the present invention can promote the fermentation of sugars and ammonia substances to generate the L-threonine metabolic pathway, and slow down the growth inhibition caused by the excess of tryptophan and the like. It promotes the metabolism of tryptophan into kynurenic acid, and at the same time promotes the synthesis of serotonin from tryptophan to promote the feeding of yaks. Combining with vitamin D to promote bone formation, and further promoting the growth of yaks. The fermented feed of yak rumen fluid promotes the metabolism of glutamine, galactose, glucuronic acid and fructose 6-phosphate in yaks to generate keratan sulfate and hyaluronic acid to protect the yak body. The fermented feed of yak rumen fluid significantly increases the average weight gain and total weight gain. Feeding the fermented feed of rumen fluid can also reduce the feed-to-weight ratio and improve the economic benefits of breeding.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0022] Figure 1 is a flowchart of a preparation method of a fermented feed of yak rumen fluid of the present invention;

[0023] Figure 2 is an experimental flowchart of a preparation method of a fermented feed of yak rumen fluid of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

[0025] As Figure 1 and 2 shown, a preparation method of a fermented feed of yak rumen fluid, the method includes:

[0026] S1. Select the rumen fluid of yaks that have adapted to high-concentrate stall feeding diets.

[0027] It should be noted that in step S1, select yaks that have adapted to high-concentrate stall feeding diets, and select 21 three-year-old healthy male yaks with similar body weights (186.5 ± 15.7) kg. Collect rumen fluid from the 21 yaks at 8:30 in the morning. Then place the collected rumen fluid in a thermos flask for insulation and seal it, and immediately send it to the laboratory for rumen fluid fermentation inoculation. One hour before the rumen fluid arrives at the laboratory, heat the pre-weighed feed and water to 38.5°C - 39.5°C for insulation. The roughage is cut into pieces in advance, and the concentrate feed is in powder form.

[0028] S2. Put the rumen fluid into a fermentation container containing feed and stir evenly to form a rumen fluid-feed mixture, and the weight ratio of rumen fluid in the rumen fluid-feed mixture is 10% - 50%.

[0029] It should be noted that in step S2, in this embodiment, the selected weight ratio of rumen fluid is 25%. During the stirring process, use a stirrer to stir to ensure that the rumen fluid and the feed are fully mixed.

[0030] S3. Use dilute hydrochloric acid and sodium hydroxide solution to adjust the pH value of the rumen fluid-feed mixture to 6.9 - 7.3, adjust the temperature of the rumen fluid-feed mixture to 38.5°C - 39.5°C, and adjust the water-to-feed ratio to 1:1 - 1.4:1, and then ferment for 12 to 48 hours to obtain fermented yak rumen fluid feed.

[0031] It should be noted that in step S3, in this embodiment, the pH value of the rumen fluid-feed mixture is adjusted by dilute hydrochloric acid and sodium hydroxide solution.

[0032] Table 1 Grouping of Fermented Feed Parameters

[0033]

[0034]

[0035] It can be proved by the above verification table that the volatile acid content of the G4 group of fermented roughage by rumen fluid (39.0°C, pH 6.9, water-to-feed ratio 1.4:1) is the highest after 24 hours of fermentation. Therefore, the fermentation parameters of the G4 group of fermented roughage by rumen fluid are the best among other groups at 24 hours in this experiment. The volatile acid content of the G12 group of fermented concentrate feed by rumen fluid (39.0°C, pH 7.1, water-to-feed ratio 1:1) is the highest after 24 hours of fermentation. Therefore, the fermentation parameters of the G12 group of fermented concentrate feed by rumen fluid are the best among other groups at 24 hours in this experiment.

[0036] In this embodiment, the rumen fluid of yaks that have adapted to high-concentrate housed diets is collected, and then 25% of the yak rumen fluid is added to the concentrate and roughage. By controlling different fermentation temperature gradients, pH gradients, water-to-feed ratios, and fermentation time gradients, the effects of four parameters on the fermentation of yak concentrate supplements and roughage (wheat straw) are verified through in-depth research. By analyzing the results of volatile fatty acids produced during the fermentation of yak rumen fluid-fermented feed, the optimal fermentation parameters for rumen fluid-fermented roughage are determined as: temperature 39.0 °C, pH 6.9, water-to-feed ratio 1:1, and fermentation time 24 hours. By analyzing the results of volatile fatty acids produced during the fermentation of yak rumen fluid-fermented feed, the optimal fermentation parameters for rumen fluid-fermented concentrate are: temperature 39.0 °C, pH 7.1, water-to-feed ratio 1.4:1, and fermentation time 24 hours.

[0037] By collecting yak rumen fluid as a fermenting agent, pre-fermenting yak concentrate and roughage, determining the optimal fermentation parameters, and conducting feeding verification experiments, it is proven that fermented feed can not only improve the nutritional value of feed but also enhance animal production performance. The average daily gain of rumen fluid-fermented roughage increased by 18.64% compared to the control group. During the entire formal test period, the average weight gain of the rumen fluid-fermented roughage group was 6.55 kg higher than that of the control group, the total weight gain increased by 18.56%, and the average daily gain increased by 0.11 kg / d on average; the average weight gain of rumen fluid-fermented concentrate increased by 35.61% compared to the control group, and during the entire formal test period, it was 12.57 kg higher than that of the control group on average. Feeding yak rumen fluid-fermented feed significantly increased the total weight gain of yaks, and the average daily gain increased by 0.21 kg / d on average. Feeding yak rumen fluid-fermented feed can also reduce the feed-to-weight ratio and improve the economic benefits of farming.

[0038] As an alternative embodiment of the present invention, optionally, in step S2, the feed includes concentrate and roughage. The concentrate is fermented through steps S2 to S3 to obtain rumen fluid-fermented concentrate, and the roughage is fermented through steps S2 to S3 to obtain rumen fluid-fermented roughage.

[0039] As an alternative embodiment of the present invention, optionally, the rumen fluid-fermented concentrate includes wheat hay with a weight ratio of 10% - 30%, alfalfa hay with a weight ratio of 10% - 30%, yak concentrate supplement with a weight ratio of 40% - 70%, and rumen fluid-fermented concentrate with a weight ratio of 5% - 10%.

[0040] As an alternative embodiment of the present invention, optionally, the fermentation temperature of the rumen fluid-fermented concentrate is 39.0 °C, the pH value is 7.1, the water-to-feed ratio is 1.4:1, and the fermentation time is 24 hours.

[0041] As an alternative embodiment of the present invention, optionally, the rumen fluid-fermented roughage comprises wheat hay accounting for 14%-17% by weight, alfalfa hay accounting for 14%-17% by weight, yak concentrate supplement accounting for 63%-67% by weight, and rumen fluid-fermented roughage material accounting for 3%-4% by weight.

[0042] As an alternative embodiment of the present invention, optionally, the fermentation temperature of the rumen fluid-fermented roughage is 39.0 °C, the pH value is 6.9, the water-to-feed ratio is 1:1, and the fermentation time is 24 hours.

[0043] As an alternative embodiment of the present invention, optionally, the yak concentrate supplement comprises corn, wheat, wheat bran, rapeseed meal, soybean meal, palm oil powder, calcium hydrogen phosphate, sodium chloride, and premix.

[0044] As an alternative embodiment of the present invention, optionally, the weight percentage of rumen fluid in the rumen fluid feed mixture is 25%.

[0045] As an alternative embodiment of the present invention, optionally, the flora in the rumen fluid-fermented roughage comprises: Firmicutes accounting for 41.52±9.21%, Bacteroidetes accounting for 52.70±8.87%, Proteobacteria accounting for 1.41±0.12%; Cyanobacteria accounting for 0.14±0.06%, Euryarchaeota accounting for 0.58±0.06%, Spirochaetes accounting for 0.93±0.10%, Patellibacteria accounting for 0.79±0.09%, Actinobacteria accounting for 0.47±0.04%, Fibrobacteres accounting for 0.43±0.04%, and Desulfobacterota accounting for 0.30±0.02%.

[0046] As an alternative embodiment of the present invention, optionally, the flora in the rumen fluid-fermented concentrate feed comprises: Firmicutes accounting for 57.82±12.79%, Bacteroidetes accounting for 31.72±5.10%, Proteobacteria accounting for 3.97±0.18%, Cyanobacteria accounting for 1.23±0.05%, Euryarchaeota accounting for 2.32±0.26%, Spirochaetes accounting for 0.55±0.08%, Patellibacteria accounting for 0.49±0.03%, Actinobacteria accounting for 0.39±0.04%, Fibrobacteres accounting for 0.25±0.02%, and Desulfobacterota accounting for 0.26±0.03%.

[0047] Example 1

[0048] Effects of Rumen Fluid-Fermented Roughage Material on Growth Performance, Serum Biochemical Indexes, and Rumen Flora of Yaks

[0049] Twenty 3-year-old male yaks with similar body weights (132.73±15.33 kg) were selected and evenly divided into two groups (10 yaks in each group). The two groups of yaks were fed diets with a concentrate-to-forage ratio of 65:35 (CG group) and 10% rumen fluid-fermented roughage (FRG group). All yaks were uniformly numbered, allowed to drink water freely throughout the day, and fed twice with TMR diet at 8:00 and 17:00 every day during the experimental period. The experimental period was 75 days, the pre-feeding period was 15 days, and the formal period was 60 days;

[0050] About 1000 g of feed was weighed from the experimental diet by the quartering method, dried in an oven at 65 °C until constant weight, and the air-dried sample was weighed again and then ground to 1 mm by a grinder for routine feed detection. The detection items included crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium (Ca), and phosphorus (P);

[0051] On the 60th day of the formal experiment, 150 ml of rumen fluid samples were collected using a gastric tube sampler before morning feeding. After the rumen fluid samples were filtered through four layers of gauze, the rumen pH was immediately measured with a bench-top pH meter. The remaining rumen fluid samples were aliquoted into four 15-ml centrifuge tubes and one 50-ml centrifuge tube. The 15-ml samples were immediately frozen in liquid nitrogen and stored at -80 °C at room temperature for later use. The 50-ml sample was placed in a foam box with dry ice and then stored in a -20 °C refrigerator for later use. One of the 50-ml samples was used to measure volatile fatty acids, ammonia nitrogen, and MCP, and the 15-ml samples were used for rumen fluid microbiomics and metabolomics determination;

[0052] Before the start and at the end of the experimental period, the yaks were driven into the restraining rack on an empty stomach, and they passed through the restraining rack in turn. The body weights of the experimental yaks were recorded, and the average daily gain (ADG) and total weight gain (TWG) were calculated. The amount of feed fed and the remaining feed amount were recorded every day, and the dry matter intake (DMI) was calculated; The average daily gain of the rumen fluid-fermented roughage group increased by 18.64% compared with the control group. During the entire formal experimental period, the average weight gain of the rumen fluid-fermented roughage group was 6.55 kg higher than that of the control group, and the total weight gain increased by 18.56%. The rumen fluid-fermented roughage group significantly reduced the feed-to-weight ratio compared with the control group (p<0.05)

[0053] Table 2 Effect of rumen fluid-fermented roughage on the growth performance of yaks

[0054]

[0055] Feeding yaks with 10% rumen fluid-fermented roughage increased the average daily gain of yaks compared with the control group, and significantly reduced the feed-to-gain ratio. The concentration of alanine aminotransferase in the serum increased significantly, and the concentrations of total serum protein and total cholesterol decreased significantly. The concentration of ammonia nitrogen and acetic acid in the rumen fluid decreased significantly, and the concentration of microbial protein, isovaleric acid and valeric acid in the yak rumen increased significantly. And it improved the rumen microbial diversity, significantly reduced the relative abundances of Firmicutes, Cyanobacteria, Patellibacteria, Oscillospira, Eubacterium and Chryseobacterium, and significantly increased the relative abundances of Bacteroidetes, Spirochaetes, Fibrobacteres and Succinivibrio. At the same time, it significantly increased the bile secretion pathway and the concentrations of metabolites such as deoxycholic acid, chenodeoxycholic acid, glycocholic acid and glycochenodeoxycholic acid. It promoted the synthesis of bile acids, and thus promoted the growth of yaks.

[0056] Table 3 Effect of rumen fluid-fermented crude material on yak rumen microorganisms at genus level

[0057]

[0058] Example 2

[0059] Effect of rumen fluid-fermented concentrate on growth performance, serum biochemical indexes, rumen flora structure and metabolites of yaks

[0060] Twenty three-year-old healthy male yaks with similar body weights (134.4 ± 14.7) kg were selected from the grazing pasture and randomly divided into 2 groups (10 yaks in each group). The diet of the control group was: 17.5% wheat hay + 17.5% alfalfa hay + 65% yak concentrate supplement, and the diet of the rumen fluid-fermented concentrate group (FCG) was: 17.5% wheat hay + 17.5%

[0061] alfalfa hay + 58.5% yak concentrate supplement + 6.5% rumen fluid-fermented concentrate. The experimental period was 75 days, the pre-feeding period was 15 days, and the formal period was 60 days;

[0062] About 1000 g of feed was weighed from the experimental diet by the quartering method, dried in an oven at 65 °C to constant weight, and the air-dried sample was weighed again and then ground to 1 mm by a grinder for routine feed detection. The detection items included crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium (Ca) and phosphorus (P);

[0063] On the 60th day of the formal experiment, 150 ml of rumen fluid samples were collected using a gastric tube sampler before morning feeding. After filtering the rumen fluid samples through four layers of gauze, the rumen pH was immediately measured using a bench-top pH meter. The remaining rumen fluid samples were aliquoted into four 15-ml centrifuge tubes and one 50-ml centrifuge tube. Immediately, the 15-ml samples were frozen in liquid nitrogen and stored at -80 °C at room temperature for later use. The 50-ml sample was placed in a foam box filled with dry ice and then stored in a -20 °C refrigerator for later use. One of the 50-ml samples was used to measure volatile fatty acids, ammonia nitrogen, and MCP, and the 15-ml samples were used for rumen fluid microbiomics and metabolomics assays;

[0064] Before the start and at the end of the experimental period, the yaks were driven into the restraining rack on an empty stomach and made to pass through the restraining rack in turn. The weights of the experimental yaks were recorded, and the average daily gain (ADG) and total weight gain (TWG) were calculated. The daily feed intake and remaining feed amount were recorded every day, and the dry matter intake (DMI) was calculated; The average weight gain of the rumen fluid-fermented concentrate increased by 35.61% compared with the control group, and the average weight gain was 12.57 kg more than that of the control group during the entire formal experimental period. Feeding the rumen fluid-fermented feed significantly increased the total weight gain of the yaks (p < 0.05), the average daily gain increased by 0.21 kg / d on average, and the feed-to-weight ratio was significantly reduced (p < 0.05).

[0065] Table 4 Effect of rumen fluid-fermented concentrates on the growth performance of yaks

[0066]

[0067] Feeding yaks with 10% rumen fluid fermented concentrate increased the average daily gain of yaks compared with the control group, and significantly reduced the feed-to-gain ratio. The concentration of alanine aminotransferase in serum increased significantly. The concentration of ammonia nitrogen and acetic acid in rumen fluid decreased significantly, while the concentration of microbial protein, propionic acid, butyric acid and valeric acid in yak rumen increased significantly. Moreover, the rumen microbial diversity was improved, the relative abundances of Patellibacteraceae, Eubacterium, Eubacterium and Chryseobacterium were significantly reduced, while the relative abundances of Cyanobacteria, NK4A214, Methylobacterium and Clostridium were significantly increased. Feeding rumen fluid fermented concentrate promoted the fermentation of sugars and ammonia substances to generate the L-threonine metabolic pathway, and alleviated the growth inhibition caused by the excess of tryptophan and other substances. It promoted the metabolism of tryptophan to kynurenic acid, and at the same time promoted the synthesis of serotonin from tryptophan to promote the feeding of yaks, combined with vitamin D to promote bone formation, and thus promoted the growth of yaks. On the other hand, it promoted the metabolic pathway of tryptophan to generate nicotinamide, accelerated the metabolism, anti-inflammatory and antioxidant effects of yaks, and thus promoted the health of yaks. Feeding rumen fluid fermented concentrate promoted the metabolism of glutamine, galactose, glucuronic acid and fructose 6-phosphate in yaks to generate chondroitin sulfate and hyaluronic acid to protect the yak body.

[0068] Table 5 Effect of rumen fluid fermented concentrate on rumen microorganisms of yaks at phylum level

[0069]

[0070] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A preparation method of a yak rumen fluid fermentation feed, characterized in that, The method includes: S1. Select the rumen fluid of yaks that have adapted to high-concentrate stall feeding diets. S2. Put the rumen fluid into a fermentation container filled with feed and stir evenly to form a rumen fluid-feed mixture, where the weight ratio of rumen fluid in the rumen fluid-feed mixture is 10%-50%. S3. Use dilute hydrochloric acid and sodium hydroxide solution to adjust the pH value of the rumen fluid-feed mixture to 6.9-7.3, adjust the temperature of the rumen fluid-feed mixture to 38.5°C-39.5°C, adjust the water-to-feed ratio to 1:1-1.4:1, and then ferment for 12 to 48 hours to obtain yak rumen fluid-fermented feed.

2. The preparation method of the fermented yak rumen fluid feed according to claim 1, characterized in that, In step S2, the feed includes concentrate feed and roughage. After fermentation through steps S2 to S3, rumen fluid-fermented concentrate feed is obtained from the concentrate feed, and rumen fluid-fermented roughage is obtained from the roughage.

3. The preparation method of the yak rumen fluid fermentation feed according to claim 2, characterized in that, The rumen fluid-fermented concentrate feed includes wheat hay accounting for 10%-30% by weight, alfalfa hay accounting for 10%-30% by weight, yak concentrate supplement accounting for 40%-70% by weight, and rumen fluid-fermented concentrate feed accounting for 5%-10% by weight.

4. The preparation method of the yak rumen fluid fermentation feed according to claim 2, characterized in that, The fermentation temperature of the rumen fluid-fermented concentrate feed is 39.0°C, the pH value is 7.1, the water-to-feed ratio is 1.4:1, and the fermentation time is 24 hours.

5. The preparation method of the yak rumen fluid fermented feed according to claim 2, wherein, The rumen fluid-fermented roughage includes wheat hay accounting for 14%-17% by weight, alfalfa hay accounting for 14%-17% by weight, yak concentrate supplement accounting for 63%-67% by weight, and rumen fluid-fermented roughage accounting for 3%-4% by weight.

6. The preparation method of the yak rumen fluid fermentation feed according to claim 2, characterized in that, The fermentation temperature of the rumen fluid-fermented roughage is 39.0°C, the pH value is 6.9, the water-to-feed ratio is 1:1, and the fermentation time is 24 hours.

7. The preparation method of the yak rumen fluid fermented feed according to claim 3 or 5, characterized in that The yak concentrate supplement includes corn, wheat, wheat bran, rapeseed meal, soybean meal, palm oil powder, calcium hydrogen phosphate, sodium chloride, and premix.

8. The preparation method of the yak rumen fluid fermentation feed according to claim 1, wherein, The weight ratio of rumen fluid in the rumen fluid-feed mixture is 25%.

9. The preparation method of the yak rumen fluid fermentation feed according to claim 2, characterized in that, The flora in the rumen fluid-fermented roughage includes: Firmicutes at 41.52±9.21%, Bacteroidetes at 52.70±8.87%, Proteobacteria at 1.41±0.12%; Cyanobacteria at 0.14±0.06%, Euryarchaeota at 0.58±0.06%, Spirochaetes at 0.93±0.10%, Patellibacteria at 0.79±0.09%, Actinobacteria at 0.47±0.04%, Fibrobacteres at 0.43±0.04%, and Desulfobacterota at 0.30±0.02%.

10. The preparation method of the yak rumen fluid fermentation feed according to claim 2, characterized in that, The flora in the rumen fluid-fermented concentrate feed includes: Firmicutes at 57.82±12.79%, Bacteroidetes at 31.72±5.10%, Proteobacteria at 3.97±0.18%, Cyanobacteria at 1.23±0.05%, Euryarchaeota at 2.32±0.26%, Spirochaetes at 0.55±0.08%, Patellibacteria at 0.49±0.03%, Actinobacteria at 0.39±0.04%, Fibrobacteres at 0.25±0.02%, and Desulfobacterota at 0.26±0.03%.

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