A yeast culture from rhodotorula mucilaginosa and its preparation method and application

Abstract

The application provides a torulopsis pullulans-derived yeast culture and a preparation method and application thereof, and belongs to the technical field of sheep breeding and breeding. The preparation method comprises the following steps: fermenting torulopsis pullulans CICC 31192 in a fermentation medium to obtain a torulopsis pullulans-derived yeast culture; the fermentation medium comprises 15-25 g of soybean meal, 0.15-0.25 g of peptone, 0.005-0.02 g of potassium dihydrogen phosphate and 0.006-0.01 g of magnesium sulfate. Research finds that the torulopsis pullulans-derived yeast culture has antioxidant capacity on sheep liver, promotes lipid metabolism, improves the fatty acid composition of sheep liver, reduces the risk of inflammation, and improves the immunity of sheep, so as to promote the healthy growth of sheep. The torulopsis pullulans-derived yeast culture provides a safe and effective sheep production promoter, feed additive or medicine for the breeding industry.

Description

Technical Field

[0001] This invention belongs to the field of sheep breeding and raising technology, and in particular relates to a yeast culture derived from Rhodotorula glutinis, its preparation method and application. Background Technology

[0002] Sheep are the most common domesticated animals, with plump bodies, dense wool, short heads, and white coats. They are now raised worldwide, are timid yet docile, easily domesticated, and provide humans with meat and fur. In sheep farming, it's common to see a few sheep that appear to eat normally, but show significantly slower growth and thinness compared to their peers; some even die from emaciation. Furthermore, lambs experience various stress responses during weaning, often exhibiting weakened immunity and susceptibility to multiple pathogens, leading to the widespread clinical use of antibiotics for prevention. However, while antibiotics kill pathogens, they can also cause drug residues, bacterial resistance, and intestinal flora imbalance, seriously impacting the healthy development of animal husbandry and endangering public health. An increasing number of countries are banning the use of antibiotics as animal growth promoters, making the search for a safe and effective feed additive an urgent need for the livestock industry. Summary of the Invention

[0003] Therefore, the purpose of this invention is to provide a Rhodotorula glutinis yeast culture, its preparation method and application, which has the effects of anti-oxidative damage to the liver, promoting lipid metabolism, improving fatty acid composition, reducing inflammation and improving immunity.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing a Rhodotorula glutinis yeast culture, comprising the following steps:

[0006] Rhodotorula mucilaginosa CICC 31192 was fermented in a fermentation medium to obtain a Rhodotorula mucilaginosa yeast culture.

[0007] The fermentation medium comprises 15-25g of soybean meal, 0.15-0.25g of peptone, 0.005-0.02g of potassium dihydrogen phosphate, and 0.006-0.01g of magnesium sulfate.

[0008] Preferably, the fermentation temperature is 28–32°C and the fermentation time is 45–50 h.

[0009] This invention provides a yeast culture of Rhodotorula glutinis prepared by the above preparation method.

[0010] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that promote sheep growth.

[0011] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that combat liver oxidative damage.

[0012] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that lower blood lipids in sheep.

[0013] Preferably, the Rhodotorula glutinis-derived yeast culture can reduce triglycerides.

[0014] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that enhance sheep immunity.

[0015] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products for treating inflammation.

[0016] This invention provides a promoter, feed additive, or drug for the healthy growth of sheep, wherein the promoter, feed additive, or drug includes the above-mentioned Rhodotorula glutinis-derived yeast culture.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention provides a Rhodotorula glutinis yeast culture, its preparation method, and its applications. Studies have found that this Rhodotorula glutinis yeast culture has antioxidant capacity in sheep liver, promotes lipid metabolism, improves the fatty acid composition of sheep liver, reduces the risk of inflammation, and enhances the immunity of sheep, thereby promoting healthy sheep growth. The Rhodotorula glutinis yeast culture of this invention provides the livestock industry with a safe and effective promoter, feed additive, or drug for sheep production. Detailed Implementation

[0019] This invention provides a method for preparing a Rhodotorula glutinis yeast culture, comprising the following steps:

[0020] Rhodotorula mucilaginosa CICC 31192 was fermented in a fermentation medium to obtain a Rhodotorula mucilaginosa yeast culture.

[0021] The fermentation medium comprises 15-25g of soybean meal, 0.15-0.25g of peptone, 0.005-0.02g of potassium dihydrogen phosphate, and 0.006-0.01g of magnesium sulfate. The water content of the fermentation medium is 50wt%-60wt%.

[0022] In this invention, *Rhodotorula mucilaginosa* CICC 31192 is fermented in a fermentation medium to obtain a *Rhodotorula mucilaginosa* yeast culture. During fermentation, the inoculum size of the *Rhodotorula mucilaginosa* is 4-6%, more preferably 4.5-5.5%, and even more preferably 5%. The inoculum size refers to the ratio of the volume of the seed culture to the volume of the culture medium after inoculation. As a preferred embodiment, the fermentation medium comprises 20g of soybean meal, 0.2g of peptone, 0.01g of potassium dihydrogen phosphate, and 0.008g of magnesium sulfate. The initial pH of the fermentation medium is 5-7, more preferably 5.5-6.5, and even more preferably 6. The *Rhodotorula mucilaginosa* is a *Rhodotorula mucilaginosa* seed culture. The preparation of the seed culture includes inoculating *Rhodotorula mucilaginosa* onto PDA medium to obtain a cultured *Rhodotorula mucilaginosa* strain, and then inoculating the cultured *Rhodotorula mucilaginosa* strain onto YPD seed medium to obtain the *Rhodotorula mucilaginosa* seed culture. This invention does not have special requirements for the inoculation amount of the seed culture; a loopful of bacterial cells is picked up and placed in the seed culture medium for conventional culture. The fermentation temperature is preferably 28–32°C, more preferably 29–31°C, and even more preferably 30°C; the fermentation time is preferably 45–50 h, more preferably 46–49 h, and even more preferably 48 h. The Rhodotorula glutinis strain of this invention, after being cultured in the above fermentation medium, produces a Rhodotorula glutinis-derived yeast culture that exhibits antioxidant capacity in sheep liver, promotes lipid metabolism, improves the fatty acid composition of sheep liver, reduces the risk of inflammation, and enhances the immunity of sheep, thereby promoting healthy growth in sheep.

[0023] This invention provides a yeast culture of Rhodotorula glutinis prepared by the above preparation method.

[0024] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that promote sheep growth.

[0025] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that combat liver oxidative damage.

[0026] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that lower blood lipids in sheep.

[0027] In this invention, the Rhodotorula glutinis-derived yeast culture can reduce triglycerides.

[0028] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products that enhance sheep immunity.

[0029] This invention provides an application of the above-mentioned Rhodotorula glutinis-derived yeast culture in the preparation of products for treating inflammation.

[0030] In this invention, the product includes accelerators, feed additives, or drugs.

[0031] This invention provides a promoter, feed additive, or drug for the healthy growth of sheep, wherein the promoter, feed additive, or drug includes the above-mentioned Rhodotorula glutinis-derived yeast culture.

[0032] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0033] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] In the following examples, the PDA culture medium was obtained by sterilizing 200g of potato, 20g of glucose, 20g of agar and 1L of water at 115°C for 20min.

[0035] The YPD seed culture medium is prepared by mixing 20g glucose, 10g peptone, 10g yeast extract and 1000mL water, and then sterilizing at 115℃ for 20min.

[0036] The fermentation medium was prepared by adding 20g soybean meal, 0.2g peptone, 0.01g potassium dihydrogen phosphate, and 0.008g magnesium sulfate to water to make the water content of the fermentation medium 60wt% and the initial pH 6.0, and then sterilizing at 115℃ for 20min.

[0037] All animal-related trials were evaluated and approved by the Animal Welfare and Ethics Committee of Inner Mongolia Agricultural University (NND2022110).

[0038] The sheep were purchased from Inner Mongolia Fuchuan Technology Co., Ltd., and the basic daily ration was purchased from Inner Mongolia Fuchuan Feed Co., Ltd.

[0039] Data Analysis: All data were analyzed using IBM SPSS Statistics 21.0 (SPSS Inc., Chicago, IL, USA) software. One-way ANOVA was performed, and Duncan's method was used for post-hoc comparisons. Tabular data are presented as mean and standard error of the mean (SEM), while image data are presented as mean ± standard deviation (SD). P < 0.05 was defined as statistically significant, and 0.05 ≤ P < 0.1 was defined as a trend. GraphPad Prism 9.5 (GraphPad Software, Boston, USA) was used for plotting.

[0040] Example 1

[0041] Preparation of Rhodotorula glutinis-derived yeast culture:

[0042] (1) Rhodotorula mucilaginosa CICC 31192 was inoculated onto PDA medium and cultured at 30°C. After the strain grew, it was inoculated again onto YPD seed medium and cultured at a constant temperature of 30°C and a shaker at 180 r / min for 24 h to obtain Rhodotorula mucilaginosa seed liquid. The present invention does not have strict requirements on the inoculation amount of the seed culture. One loopful of cells can be picked up with an inoculation loop and cultured in seed medium in a conventional manner.

[0043] (2) The seed culture of Rhodotorula glutinis was inoculated into the fermentation medium at a rate of 5%, and fermented at a constant temperature of 30°C for 48 hours to obtain the yeast culture of Rhodotorula glutinis (named RYC).

[0044] Example 2

[0045] Application of the Rhodotorula glutinis culture (RYC) prepared in Example 1

[0046] Twenty-four three-month-old Dorper rams, weighing 36±4 kg, were randomly divided into four groups of six rams each: CON group (fed a basal diet); L group (fed a basal diet + 10 g / d RYC); M group (fed a basal diet + 20 g / d RYC); and H group (fed a basal diet + 40 g / d RYC). The experiment lasted 90 days, including a 15-day pre-trial period and a 75-day main trial period. During the experiment, all rams were fed twice daily at 8:00 AM and 6:00 PM, with free access to water. During the pre-trial period, all rams were fed only the basal diet. During the main trial period, each ram was given a corresponding amount of RYC before their regular feeding at 8:00 AM each day. On the last day of the main trial period, blood was drawn from all rams before feeding, and serum was separated. The rams were fasted and deprived of water that evening. The following day, five rams from each group were randomly selected for slaughter and sampling.

[0047] Blood was collected from the jugular vein of sheep using disposable vacuum blood collection tubes. After standing at room temperature for 40 minutes, the blood was centrifuged at 3000 rpm for 10 minutes. The serum was then collected and stored at -20°C for later use. Liver samples were collected immediately after slaughter and flash-frozen in liquid nitrogen, then transferred to a -80°C freezer for later use.

[0048] (1) Liver antioxidant capacity

[0049] 0.2g of liver sample was added to 1.8mL of physiological saline to prepare a 1:9 liver homogenate. The homogenate was then centrifuged at 3000g, 4℃, for 10min. The supernatant was collected for later use. T-AOC, CAT, GPx, MDA, SOD, and protein quantification were performed using commercially available kits (purchased from Nanjing Jiancheng Biotechnology Institute) according to the instructions.

[0050] SOD, GPx, and CAT are three enzymes that play important roles in the antioxidant system. SOD can eliminate superoxide anion free radicals to protect cell membranes; GPx and CAT can scavenge H2O2, thereby protecting cell membranes from damage.

[0051] As shown in Table 1, compared with CON, the SOD activity in the liver of group H was significantly increased (P<0.05); the GPx activities in groups L, M, and H were all significantly increased (P<0.05), while there was no significant difference among the three experimental groups; compared with CON, the MDA content in groups L, M, and H was significantly decreased (P<0.05), while there was no significant difference among the three experimental groups. There were no significant differences in liver CAT activity and T-AOC among the groups. This indicates that RYC can enhance the antioxidant enzyme system capacity of sheep liver in response to ROS attack and reduce oxidative damage to the liver.

[0052] Table 1. Effects of RYC on antioxidant indices in sheep liver

[0053] SOD(U / mgprot) <![CDATA[196.97 b ]]> <![CDATA[205.09 b ]]> <![CDATA[196.26 b ]]> <![CDATA[223.31 a ]]> 3.745 0.007 CAT(U / mgprot) 36.47 41.79 40.27 37.94 1.086 0.361 GPx(U / mgprot) <![CDATA[10.45 b ]]> <![CDATA[14.62 a ]]> <![CDATA[13.23 a ]]> <![CDATA[13.74 a ]]> 0.573 0.024 T-AOC(μmol / gprot) 72.48 71.50 74.26 73.79 1.311 0.911 MDA(nmol / mgprot) <![CDATA[1.26 a ]]> <![CDATA[0.74 b ]]> <![CDATA[0.78 b ]]> <![CDATA[0.88 b ]]> 0.062 0.022

[0054] (2) Serum lipid metabolism

[0055] The levels of glucose (GLU), total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) were determined according to the instructions of a commercially available kit (purchased from Nanjing Jiancheng Bioengineering Institute). Free fatty acids (FFA) were determined using an ELISA method (purchased from Baoman Biotechnology Co., Ltd.).

[0056] As shown in Table 2, compared with CON, TC in groups L and M was significantly reduced (P<0.05), while there was no significant difference between groups L and M; compared with CON, LDL-C in groups L, M, and H was significantly reduced (P<0.05), but there was no significant difference among the three experimental groups; compared with CON, TG content in groups M and H was significantly reduced (P<0.05), while there was no significant difference between groups M and H. There were no significant differences in GLU and FFA content among the groups. This indicates that RYC can simultaneously reduce TC and LDL-C content in sheep serum, and also shows a trend towards reducing serum FFA content, suggesting that RYC has a regulatory effect on sheep lipid metabolism.

[0057] Serum GLU levels reflect blood glucose levels, which are considered relevant to health. Ruminants primarily obtain GLU through endogenous synthesis, especially gluconeogenesis. Therefore, GLU levels can, to some extent, reflect the energy intake and health status of livestock over a period of time. The results showed no significant difference in GLU levels among the groups, indirectly proving that no differences in energy intake were observed among the sheep groups in this study; the experimental results were only related to the effect of RYC supplementation.

[0058] Table 2. Effects of RYC on serum lipid metabolism parameters in sheep.

[0059] GLU(mmol / L) 3.41 3.20 3.34 3.34 0.076 0.841 TC(mmol / L) <![CDATA[3.06 a ]]> <![CDATA[2.46 b ]]> <![CDATA[2.47 b ]]> <![CDATA[2.66 ab ]]> 0.095 0.040 TG(mmol / L) <![CDATA[0.34 a ]]> <![CDATA[0.31 ab ]]> <![CDATA[0.22 c ]]> <![CDATA[0.25 bc ]]> 0.011 0.014 LDL-C(mmol / L) <![CDATA[0.37 a ]]> <![CDATA[0.22 b ]]> <![CDATA[0.25 b ]]> <![CDATA[0.26 b ]]> 0.017 0.013 FFA(mmol / L) 0.57 0.56 0.56 0.53 0.005 0.056

[0060] (3) Liver fatty acid content

[0061] Weigh 0.6g of liver, grind it into powder with liquid nitrogen, add 0.7mL of 10mol / L KOH and 5.3mL of methanol, mix well, and heat in a 55℃ water bath for 1.5h, shaking occasionally to mix. Cool to room temperature, add 0.58mL of 12mol / L H2SO4, mix again, and heat in a 55℃ water bath for 1.5h, shaking occasionally to mix. Cool to room temperature, add 3mL of n-hexane, vortex for 5min, centrifuge at 1500g for 5min, and take 1mL of the supernatant. Filter through a 0.22μm organic filter membrane into a sample vial for analysis. The fatty acid content was determined using a 6890N gas chromatograph (Agilent). The instrument conditions and procedures were as described by Zhao Cun (Zhao Cun. Study on the regulatory network of flavor precursors of Ujumqin mutton [D]. Inner Mongolia Agricultural University, 2022).

[0062] Table 3 shows that, compared with CON, the liver C16:0 content in group M was significantly decreased (P<0.05), while the C18:2n6C and C20:1 contents were significantly increased (P<0.05); the C22:2n6 content in group H was significantly increased (P<0.05); the C18:3n6 content in group H showed an increasing trend (P=0.05); and the ΣPUFA content in group M was significantly increased (P<0.05). There were no significant differences in the contents of other fatty acids.

[0063] Fatty acids in animals mainly come from exogenous daily diet and endogenous de novo synthesis. The main product of de novo synthesis is C16:0. Compared with CON, the C16:0 content in the liver of sheep in group M was significantly lower, while the C18:0 content showed an increasing trend. C18:0 can be converted from C16:0. This indicates that daily supplementation with 20g RYC can significantly reduce the C16:0 content in the liver, and may promote the conversion of C16:0 to C18:0 in the liver. The C20:1 content in group M was significantly higher than that in CON, while the C18:1 content showed a decreasing trend, indicating that daily supplementation with 20g RYC can promote the conversion of C18:1 to C20:1 in sheep liver.

[0064] C18:2n6C enhances the metabolic adaptability and anti-tumor immunity of CD8T cells and can be converted into C18:3n6. C22:2n6 is a PUFA with anti-inflammatory, anti-tumor, and antioxidant functions. Compared with the CON group, the M group showed a significant increase in C18:2n6C and PUFA, while the H group showed an increasing trend in C18:3n6 and a significant increase in C22:2n6, indicating that daily supplementation with 20g RYC can enhance the liver's ability to absorb C18:2n6C fatty acids.

[0065] In summary, RYC can enhance the liver's ability to absorb and synthesize PUFAs, improve the fatty acid composition of sheep liver, and reduce the risk of inflammation.

[0066] Table 3. Effects of RYC on fatty acid composition of sheep liver (percentage of total fatty acids, %)

[0067]

[0068]

[0069] ΣSFA=C8:0+C10:0+C12:0+C14:0+C15:0+C16:0+C17:0+C18:0;

[0070] ΣMUFA=C14:1+C16:1+C17:1+C18:1C+C20:1;

[0071] ΣPUFA=C18:2n6C+C18:3n3+C18:3n6+C20:3n3+C20:3n6+C22:2n6+C22:6n3.

[0072] (4) Liver immune cytokines

[0073] 0.1g of liver sample was added to 0.9mL of physiological saline to prepare a 1:9 liver homogenate. The homogenate was then centrifuged at 3000g, 4℃, for 10min, and the supernatant was collected. The levels of IL-1β, IL-6, IL-10, TNF-α, and IFN-γ in the homogenate were determined using an ELISA kit (purchased from Baoman Biotechnology Co., Ltd.) according to the manufacturer's instructions. Protein quantification was performed using a protein quantification kit (purchased from Nanjing Jiancheng Biotechnology Research Institute).

[0074] Liver RNA extraction and real-time quantitative PCR

[0075] 0.05g of liver was added to 1mL of RNAisoPlus (Takara), and total RNA was extracted according to the instructions. The concentration was determined using Implen P330 (Implen). cDNA was extracted using ABioderiti96 (Thermo Fisher Scientific) and stored at -20℃. β-actin was used as an internal control gene, and qPCR experiments (from Aikerui Biotechnology Co., Ltd.) were performed using a LightCycler 480Ⅱ Instrument (Roche) to detect the expression levels of antioxidant, lipid metabolism, and immune-related mRNAs. Results were expressed as a percentage of the total RNA. -ΔΔct Calculation. Primer design began by consulting relevant mRNA sequences at the National Center for Biotechnology Information (NCBI), using the Primer-BLAST function, and then sending the sequences to Beijing BGI Genomics Co., Ltd. for synthesis. Specific primer information is shown in Table 4.

[0076] Table 4 Primer Information

[0077]

[0078]

[0079]

[0080] To further investigate the mechanism by which RYC affects lipid metabolism in sheep liver, the mRNA expression levels of several key enzymes and proteins related to this process were measured. Lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) are two enzymes involved in lipid degradation, playing a role in catalyzing the degradation of triglycerides.

[0081] Table 5 shows that, compared with CON, the expression levels of HSL gene were significantly upregulated in groups M and H (P<0.05), and the expression level of FABP1 gene was significantly downregulated (P<0.05), with no significant difference between groups M and H; compared with CON, the expression level of LPL gene was significantly upregulated in group M (P<0.05). The expression levels of other genes did not change significantly.

[0082] The results in Table 5 show that the expression levels of LPL and HSL mRNA in group M were significantly upregulated compared to those in group CON. This indicates that the daily addition of 20g RYC increases the expression of LPL and HSL mRNA in sheep, thereby increasing the activity of LPL and HSL enzymes, catalyzing the degradation of triglycerides, and reducing serum triglyceride levels.

[0083] Fatty acid binding protein 1 (FABP1) is a protein that can specifically bind to long-chain fatty acids in the cell membrane and participate in fatty acid transport. The results in Table 5 show that the expression levels of FABP1 mRNA in the CON, L and M groups were significantly lower than those in the CON group, indicating that RYC can reduce the levels of TG and TC in sheep serum by downregulating the expression of FABP1 mRNA in sheep liver.

[0084] Table 5. Effects of RYC on the expression levels of lipid metabolism-related genes in sheep liver.

[0085] PPARA 1 1.28 1.35 1.20 0.103 0.666 FASN 1 1.72 2.07 2.63 0.262 0.164 HSL <![CDATA[1 b ]]> <![CDATA[1.51 ab ]]> <![CDATA[1.73 a ]]> <![CDATA[1.96 a ]]> 0.131 0.041 LPL <![CDATA[1 b ]]> <![CDATA[1.07 b ]]> <![CDATA[1.66 a ]]> <![CDATA[0.88 b ]]> 0.109 0.046 ACC 1 1.66 1.58 1.47 0.141 0.361 CPT1β 1 1.24 1.11 1.43 0.105 0.544 SREBP1 1 1.40 1.02 0.93 0.105 0.472 SCD 1 0.89 1.20 1.05 0.185 0.954 FABP1 <![CDATA[1 a ]]> <![CDATA[0.52 b ]]> <![CDATA[0.39 b ]]> <![CDATA[1.05 a ]]> 0.092 0.008

[0086] The results in Table 6 show that, compared with CON, the levels of TNF-α and IFN-γ in the liver of sheep in group M were significantly decreased (P<0.05), while the other indicators had no significant effect.

[0087] Table 6. Effects of RYC on sheep liver immune factors

[0088]

[0089]

[0090] Table 7 shows that, compared with CON, the expression level of TNF-α gene in the liver of group M was significantly downregulated (P<0.05); the expression level of IFN-γ gene in both groups L and M was significantly downregulated (P<0.05), with no significant difference between the two groups; compared with CON, the expression level of TLR4 gene in groups L, M, and H was significantly downregulated (P<0.05), with no significant difference among the three experimental groups. Other indicators had no significant effect. This indicates that RYC can reduce the level of pro-inflammatory factors in sheep liver, alleviate the inflammatory response in sheep, and is beneficial to sheep health.

[0091] Table 7. Effects of RYC on the expression levels of immune-related genes in sheep liver.

[0092] IL-1β 1 0.92 0.88 1.17 0.053 0.234 IL-6 1 0.89 1.30 1.19 0.108 0.595 IL-10 1 0.61 0.66 0.70 0.067 0.155 TNF-α <![CDATA[1 a ]]> <![CDATA[0.92 a ]]> <![CDATA[0.69 b ]]> <![CDATA[0.94 a ]]> 0.037 0.004 IFN-γ <![CDATA[1 a ]]> <![CDATA[0.59 b ]]> <![CDATA[0.56 b ]]> <![CDATA[0.88 a ]]> 0.087 0.012 TLR4 <![CDATA[1 a ]]> <![CDATA[0.58 b ]]> <![CDATA[0.65 b ]]> <![CDATA[0.74 b ]]> 0.046 0.002

[0093] In summary, RYC can enhance the antioxidant capacity of sheep liver by upregulating the expression of Nrf2 and related antioxidant enzyme mRNA, reduce blood lipid levels and improve liver fatty acid composition by regulating the expression of lipid metabolism-related genes such as HSL, LPL, and FABP1, and also has a certain beneficial effect on the immune capacity of sheep liver. The recommended dosage of RYC is 20-40g / day per sheep.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of Rhodotorula glutinis-derived yeast culture in the preparation of products that lower blood lipids in sheep, characterized in that, The method for preparing the Rhodotorula glutinis-derived yeast culture includes the following steps: Red yeast ( Rhodotorula mucilaginosa CICC 31192 was fermented in fermentation medium to obtain a yeast culture of Rhodotorula glutinis. The fermentation medium comprises 15-25g of soybean meal, 0.15-0.25g of peptone, 0.005-0.02g of potassium dihydrogen phosphate, and 0.006-0.01g of magnesium sulfate; The fermentation temperature is 28~32℃, and the fermentation time is 45~50h; The water content of the fermentation medium is 50wt%~60wt%.

2. The application according to claim 1, characterized in that, The yeast culture derived from *Rhodotorula glutinis* can lower triglycerides.

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