Application of Bifidobacterium animalis subspecies lactis ZYhyy-003 in products for improving pet immune function

Abstract

The present invention provides an application of animal Bifidobacterium lactis subspecies ZYhyy‑003 in a product for improving the immune function of pets, belonging to the technical field of microorganisms. The present invention first proposes animal Bifidobacterium lactis subspecies ZYhyy‑003 (CGMCC No. 31553) Bifidobacterium animalum subsp.lactis ) is a new use in the preparation of products to enhance the immune function of pets. The animal Bifidobacterium lactis subsp. ZYhyy‑003 postbiotic preparation can increase the weight of pets, improve skin condition, increase the content of anti-inflammatory factors and immunoglobulins in pet serum, and reduce the content of pro-inflammatory factors and C-reactive protein in pet serum. It has the characteristics of high safety and stability, easy storage and production, long shelf life and a wide range of application scenarios. It can be used as the preferred additive for products related to enhancing the immune function of pets.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to application of animal Bifidobacterium lactis subspecies ZYhyy-003 in products for improving the immune function of pets. Background Art

[0002] The immune system is the core of the body's defense mechanism. It not only protects the body from bacteria, viruses and other pathogens, but also removes damaged cells, monitors abnormal cells and maintains the body's stability. The balance of this complex network is essential for health. It also participates in inflammatory responses and regulates other physiological processes, and is a key system for maintaining vitality.

[0003] Bifidobacterium is an important beneficial bacteria in the intestine, and is involved in physiological processes such as immunity and digestion. Compared with other bifidobacteria, animal bifidobacterium lactis has good acid resistance, bile salt resistance and oxygen resistance, and has good survival ability in the gastrointestinal tract, playing a key role in enhancing immunity. Bifidobacteria can increase the activity of immune cells, balance the expression of inflammatory cytokines, enhance SIgA production, increase NK cell tumor killing activity and PMN phagocytosis, thereby improving immunity.

[0004] Postbiotics have shown significant advantages with their excellent safety and stability, convenient storage and longer shelf life, and avoidance of the risk of drug-resistant gene transfer caused by live bacteria, and have gradually become an emerging alternative antibiotic product with broad market prospects. By adding postbiotics to pet food, the immune-enhancing effect of postbiotics can be utilized to enhance the host's immune capacity. In particular, after many postbiotics enter the animal's body, they can promote the formation of antimicrobial peptides in the body, thereby further enhancing the host's resistance to a variety of pathogenic microorganisms. At the same time, through the effective regulation of the body's immune function, the host's resistance to pathogens is enhanced. In the whole process, postbiotics not only play a role in promoting cell proliferation and differentiation, but can also further regulate the normal secretion of cytokines, thereby maintaining the body's immune balance.

[0005] In the prior art, postbiotic products have attracted attention due to their immunity-boosting properties. However, existing products are insufficient in preventing viral infections and boosting immunity, and the product preparation process is complex, making it difficult to mass produce. Summary of the invention

[0006] In view of the problems existing in the prior art, the object of the present invention is to provide an application of animal Bifidobacterium lactis subspecies ZYhyy-003 in a product for improving the immune function of pets. The postbiotic preparation prepared from animal Bifidobacterium lactis subspecies ZYhyy-003 can effectively improve immunity, has clear components and functions, and can be produced on an industrial scale.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] The present invention provides a collection number of CGMCC No. 31553 of animal Bifidobacterium lactis subspecies ZYhyy-003 ( Bifidobacterium animalis subsp.lactis ) A new use in the preparation of products for enhancing the immune function of pets, characterized in that animal Bifidobacterium lactis subspecies ZYhyy-003 was deposited in the General Microbiological Center of the China Culture Collection Administration on August 5, 2024, and the deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing.

[0009] Furthermore, the Bifidobacterium animalis subspecies lactis ZYhyy-003 is prepared into a Bifidobacterium animalis subspecies lactis postbiotic preparation.

[0010] Furthermore, the postbiotic preparation is prepared by uniformly mixing postbiotic powder of animal Bifidobacterium lactis subspecies ZYhyy-003 and glucose, and the postbiotic powder is prepared by inactivating, concentrating and freeze-drying the bacterial liquid of animal Bifidobacterium lactis subspecies ZYhyy-003.

[0011] Furthermore, the preparation of the animal Bifidobacterium lactis subspecies ZYhyy-003 bacterial liquid comprises the following steps:

[0012] (1) Take out the frozen Bifidobacterium animalis subsp. lactis ZYhyy-003 from the -80°C refrigerator, quickly thaw it in a 37°C water bath, inoculate the strain into 5 mL of liquid MRS medium, and culture it anaerobically at 37°C for 24 to 48 hours until the bacterial solution becomes turbid;

[0013] (2) The turbid bacterial solution obtained in step (1) is inoculated on an MRS solid culture medium for activation, the activated bacteria are inoculated in a primary culture medium, and a seed solution is obtained through primary culture; the seed solution is inoculated in a secondary culture medium, and a bacterial solution is obtained through secondary culture;

[0014] (3) Centrifuge the bacterial solution at 4°C, 3000-5000 rpm for 15 min, collect the cells, wash with sterile saline, and resuspend to obtain a suspension. Adjust the concentration of the suspension to greater than 1×10 9 CFU / mL, that is, the bacterial liquid of animal Bifidobacterium lactis subspecies ZYhyy-003 was obtained.

[0015] Furthermore, in step (1), the strain inoculation amount is 0.02-0.04%.

[0016] Furthermore, in step (2), the primary culture medium and the secondary culture medium are both MRS liquid culture medium.

[0017] Furthermore, in step (2), the inoculation amount of the seed liquid inoculated into the secondary culture medium is 1% to 2%.

[0018] Furthermore, in step (2), the primary culture condition is culturing at 36-38°C for 24-48 h; the secondary culture condition is culturing at 36-38°C for 24-48 h.

[0019] Furthermore, the sterilization conditions are as follows: sterilization at 121°C for more than 30 min, applying the inactivated bacterial solution on an MRS plate, and placing it at 37°C for anaerobic culture for more than 48 h to ensure that no bacterial colonies grow.

[0020] Furthermore, the pet includes a cat, a dog, a rabbit, a piglet, a mouse, a mink, a golden bear, a chinchilla, a guinea pig or a meerkat.

[0021] Furthermore, the product is one or more of the following:

[0022] (1) The product can increase the weight of pets;

[0023] (2) The product can improve the skin condition of the pet;

[0024] (3) The product can increase the content of anti-inflammatory factors in pet serum;

[0025] (4) The product can increase the immunoglobulin content in pet serum;

[0026] (5) The product can reduce the level of pro-inflammatory factors in pet serum;

[0027] (6) The product can reduce the level of C-reactive protein in pet serum.

[0028] Strain deposit information:

[0029] Bifidobacterium animalis subsp. lactis ZYhyy-003, depository institution: General Microbiology Center of China Microbiological Culture Collection Administration (CGMCC); address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101; deposit date: August 5, 2024; deposit number CGMCC No. 31553; classification name: Bifidobacterium animalis subsp. lactis Bifidobacterium animalis subsp. lactis .

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention first proposes the animal Bifidobacterium lactis subspecies ZYhyy-003 (with a deposit number of CGMCC No. 31553) Bifidobacterium animalis subsp.lactis) A new use in the preparation of products for improving the immune function of pets; experimental results show that the animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic preparation described in the present application is superior to the currently developed and marketed postbiotic solid preparation for improving immune function made from Lactobacillus acidophilus. Specifically, taking the animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic preparation can increase the weight of pets, improve skin condition, increase the content of anti-inflammatory factors and immunoglobulins in pet serum, and reduce the content of pro-inflammatory factors and C-reactive protein in pet serum. It has the characteristics of high safety and stability, easy storage and production, long shelf life and a wide range of application scenarios, and can be used as a preferred additive for products related to improving the immune function of pets;

[0032] 2. The animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic preparation provided by the present invention is prepared by inactivating, concentrating and freeze-drying the bacterial liquid of animal Bifidobacterium lactis subspecies ZYhyy-003. The probiotics are inactive and long-term use will not affect the intestinal microecological balance of pets, nor cause immune imbalance or allergic reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0034] Figure 1 The growth of the animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic solid preparation described in Example 2 on the MRS plate is shown;

[0035] Figure 2 The weight changes of cats in each group described in Example 3 are shown;

[0036] Figure 3 The skin condition scores of each group of cats described in Example 3 are shown;

[0037] Figure 4 The content of anti-inflammatory factors in the serum of each group of cats described in Example 3 is shown;

[0038] Figure 5 The contents of pro-inflammatory factors in the serum of each group of cats described in Example 3 are shown;

[0039] Figure 6 The immunoglobulin content in the serum of each group of cats described in Example 3 is shown. DETAILED DESCRIPTION

[0040] The examples are provided to better illustrate the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art may make non-essential improvements and adjustments to the implementation scheme according to the above invention content, which still fall within the protection scope of the present invention.

[0041] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0042] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention in detail, and are not used to limit the present invention.

[0043] Example 1: Isolation and identification of bacterial species

[0044] 1. Source of the strain: feces of healthy pet cats in catteries and animal stray rescue stations in Yancheng District, Luohe City, Henan Province. The strain was screened and isolated from feces of healthy pet cats collected in large quantities during the period from July 1, 2023 to August 1, 2023.

[0045] 2. Screening and purification of strains

[0046] (1) Sampling: Use sterile tweezers to collect 10 g of fecal sample on a clean bench and set aside.

[0047] (2) Sample preparation:

[0048] ① Take 90 mL of sterilized saline (0.85%) and place it in a sterile conical flask, then add the sample from step (1), shake and set aside;

[0049] ② Perform gradient dilution of the dilution solution in step ①, diluting 10 -1 , 10 -2 , 10 -3 , 10 -4 and 10 -5 , numbered 1, 2, 3, 4 and 5, for use.

[0050] (3) Prepare MRS solid medium: dissolve 20.00 g of glucose, 10.00 g of peptone, 5.00 g of yeast extract, 10.00 g of beef extract, 1.00 g of Tween 80, 5.00 g of sodium acetate, 0.58 g of magnesium sulfate, 0.25 g of manganese sulfate, and 2.00 g of potassium dihydrogen phosphate in 1 L of deionized water. Add 17 g of agar and sterilize at 121°C for 15 min.

[0051] (4) Cultivation: 10 -1 , 10 -2 , 10 -3 , 10 -4 and 10-5 The solution was spread on MRS solid medium plates using a spreading rod and cultured at 37°C for 48 h.

[0052] (5) Purification of strains: Select milky white raised colonies of different shapes and sizes for isolation and purification, and select a single colony to streak three zones on an MRS solid culture medium plate. After streaking, culture the plate at 37°C under anaerobic conditions for 48 h. Repeat the above operation for a total of three streakings to purify the pure strain.

[0053] 3. Strain Identification

[0054] The strain was cultured anaerobically at 37°C on MRS solid medium plates for 48 h, and a single colony was picked for PCR. The primers were 16S rRNA universal primers 27F and 1492R, and the PCR reaction conditions were: 95°C pre-denaturation for 3 min; 95°C denaturation for 15 s, 60°C annealing for 15 s, 72°C extension for 90 s, 35 cycles; 72°C final extension for 5 min. The obtained 16S rRNA was subjected to BLAST analysis with the sequences of known strains on the GenBank website, and the identification result was: animal Bifidobacterium lactis subsp. Bifidobacterium animalis subsp. lactis ).

[0055] The identified strain was named Bifidobacterium animalis subsp. lactis ZYhyy-003, and the strain was sent to the General Microbiological Center of China Microbiological Culture Collection Administration for preservation. The preservation information is as follows;

[0056] Bifidobacterium animalis subsp. lactis ZYhyy-003, depository institution: General Microbiology Center of China Microbiological Culture Collection Administration (CGMCC); address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing; deposit date: August 5, 2024; deposit number CGMCC No. 31553; classification name: Bifidobacterium animalis subsp. lactis Bifidobacterium animalis subsp.lactis .

[0057] Example 2: Preparation of animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic solid preparation

[0058] In this example, animal Bifidobacterium lactis subspecies ZYhyy-003 was used to prepare a postbiotic solid preparation, and the specific method was as follows:

[0059] (1) Prepare MRS liquid medium: dissolve 20.00 g of glucose, 10.00 g of peptone, 5.00 g of yeast extract, 10.00 g of beef extract, 1.00 g of Tween 80, 5.00 g of sodium acetate, 0.58 g of magnesium sulfate, 0.25 g of manganese sulfate, and 2.00 g of potassium dihydrogen phosphate in 1 L of deionized water and sterilize at 121°C for 15 min.

[0060] (2) Animal Bifidobacterium lactis subsp. ZYhyy-003 was activated on MRS solid medium, and the activated bacteria were inoculated into MRS liquid medium, and cultured at 37°C for 48 h to obtain seed solution; the seed solution was inoculated into MRS liquid medium at an inoculum rate of 1%, and cultured at 37°C for 48 h to obtain bacterial solution; after centrifuging the bacterial solution, the bacteria were collected, washed with sterile saline, and resuspended to obtain a suspension; the concentration of the suspension was adjusted to obtain 1.0×10 10 CFU / mL of bacterial suspension.

[0061] (3) The bacterial suspension was sterilized at 121°C for 30 min, and the inactivated bacterial suspension was spread on an MRS plate and incubated at 37°C for more than 48 hours. The sterilized bacterial suspension was freeze-dried to obtain postbiotic powder; according to the number of live bacteria in the bacterial suspension, the postbiotic powder was mixed with glucose (purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) to prepare a plate containing 2.0×10-100 cells of animal Bifidobacterium lactis subsp. ZYhyy-003. 10 CFU / g of postbiotic solid preparation.

[0062] The postbiotic solid preparation was taken and coated on an MRS plate in the same manner as above, and then placed at 37°C for anaerobically culture for more than 48 hours.

[0063] The results are as follows Figure 1 As shown, there are a large number of live bacteria in the non-sterile bacterial suspension after coating, while no live bacteria are detected in the sterilized bacterial suspension and postbiotic solid preparation.

[0064] Example 3: Effect of animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation on the immune function of pet cats

[0065] In order to explore the effect of the animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation described in Example 2 on the immune function of pets, this example takes pet cats as an example and conducts the following animal experiments:

[0066] (1) Experimental groups

[0067] In this experiment, 16 pet cats from Zhongyuan Food Laboratory were randomly divided into 4 groups, 4 cats in each group, namely positive control group, negative control group, experimental group 1 and experimental group 2. The specific treatments are as follows:

[0068] Positive control group: A commercially available solid preparation of postbiotics with immune-enhancing properties (Lactobacillus acidophilus ( lactobacillus acidophilus ) Postbiotics) were dissolved in 10 mL of sterile saline and administered orally once a day.

[0069] Negative control group: 10 mL of sterile saline was administered once a day.

[0070] Experimental group 1: The animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation prepared in Example 2 was dissolved in 10 mL of sterile saline and then orally administered at a dose of 250 mg / kg body weight, once a day.

[0071] Experimental group 2: The animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation prepared in Example 2 was dissolved in 10 mL of sterile saline and then orally administered at a dose of 500 mg / kg body weight, once a day.

[0072] All cats were vaccinated and dewormed before the experiment. The experimental environment had a 12-hour day and night cycle, the temperature was controlled at 18-26°C, and the relative humidity was 40%-70%. The cattery was cleaned of feces and disinfected twice a day. Each cat was fed twice a day, 40 grams of basic feed each time. The feed was a baked staple food that met the nutritional standards of the Association of American Feed Control Officials (AAFCO, 2023) and the National Research Council (NRC, 2006). Free drinking water was provided. The week before the experiment was the adaptation period, and the following 28 days were the formal experimental period. After the experiment, the cats' blood was collected for evaluation.

[0073] All data were statistically analyzed using GraphPad Prism 10.1.2. The significance level is: * indicates p <0.05, ** indicates p < 0.01, *** indicates p < 0.001, **** indicates p < 0.0001.

[0074] This study strictly complies with international animal use guidelines and the Regulations on the Administration of Laboratory Animals in China, and has been approved by the Animal Experiment Ethics Committee of China Agricultural University (approval number: AW11104202-5-2). All experiments were conducted under the premise of minimizing animal suffering.

[0075] (2) Weight changes

[0076] The cats in the negative control group, positive control group, experimental group 1 and experimental group 2 were weighed on days 0, 7, 14, 21 and 28 of feeding, and the weight changes were recorded.

[0077] like Figure 2 As shown, as the number of feeding days increases, the weight of each group of cats gradually increases, among which the weight of experimental group 2 is higher than that of the other groups, and the weight of the negative control group is the lowest. This shows that taking the animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic solid preparation described in Example 2 can effectively increase the weight of cats.

[0078] (3) Skin condition score

[0079] The scoring criteria for pet cat skin condition are shown in Table 1.

[0080]

[0081] After 28 days of feeding, the cats' skin was scored and the results were as follows: Figure 3 The skin condition scores of cats in experimental groups 1 and 2 were higher than those in the positive control group and the negative control group, and the data of experimental group 2 were significantly higher than those of the negative control group ( p <0.01). This indicates that taking the animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation described in Example 2 can effectively improve the skin condition of cats and make the skin more moisturized and shiny.

[0082] (4) Determination of anti-inflammatory factor content in serum

[0083] After 28 days of feeding, 2 ml of blood was obtained from the forelimb vein of each cat, placed in a sterile centrifuge tube and allowed to stand for 30 min. The blood was then centrifuged at 3500 r / min at 4°C for 10 min, and the supernatant was collected and stored at -80°C. The serum immune factor indicators were subsequently determined. The specific determination method was determined according to the instructions of the ELISA kit (Shanghai ELISA Biotechnology Co., Ltd.).

[0084] like Figure 4 As shown, the anti-inflammatory factor IL-10 in the serum of cats in experimental groups 1 and 2 was higher than that in the negative control group and the positive control group, and the IL-10 content in experimental group 2 was significantly higher than that in the negative control group ( p < 0.01); the IL-4 content in experimental group 1 was significantly higher than that in the negative control group ( p < 0.01), the IL-4 content in experimental group 2 was significantly higher than that in the negative control group ( p <0.001) and the positive control group ( p< 0.0001). This indicates that the animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation described in Example 2 helps to increase the content of anti-inflammatory factors in cat serum, inhibit inflammatory response, and thus control inflammation and regulate the degree of immune response.

[0085] (5) Determination of pro-inflammatory factors in serum

[0086] like Figure 5 As shown, the IL-1β content in experimental group 2 was lower than that in the positive control group, negative control group and experimental group 1, and there was a significant difference between the negative control group and experimental group 1 ( p < 0.05). Although there was no significant difference in IL-1β content between experimental group 1 and the negative control group and the positive control group, both showed a downward trend; the IL-6 content of experimental group 1 and experimental group 2 was significantly lower than that of the negative control group ( p < 0.01). Compared with the negative control group, the TNF-α content in experimental group 1 decreased significantly ( p < 0.05), the TNF-α content in experimental group 2 was significantly lower than that in the negative control group ( p < 0.05) and the positive control group ( p < 0.001). The IFN-γ content showed a gradual downward trend in the negative control group, the positive control group, the experimental group 1 and the experimental group 2. This indicates that the animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation described in Example 2 helps to reduce the content of pro-inflammatory factors in cat serum, inhibits the activation of the immune system, and thus regulates inflammation treatment.

[0087] (6) Determination of immunoglobulin content in serum

[0088] Figure 6 The results show the effect of taking the animal Bifidobacterium lactis subsp. ZYhyy-003 postbiotic solid preparation described in Example 2 on the immunoglobulin in cat serum. The IgG content in the experimental group 2 was significantly higher than that in the negative control group ( p < 0.05) and the positive control group ( p < 0.01), indicating that a high dose of animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic solid preparation can effectively increase the IgG content in serum. The IgA and IgM contents in serum showed a gradual downward trend in the negative control group, the positive control group, experimental group 1 and experimental group 2. It shows that the animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic solid preparation described in Example 2 helps to increase the IgG, IgA and IgM contents in cat serum, and plays an important role in antiviral, antibacterial, antitoxin and mucosal immunity.

[0089] (7) Determination of serum C-reactive protein level

[0090]

[0091] The effect of the animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic solid preparation described in Example 2 on the C-reactive protein content in cat serum is shown in Table 2. The experimental results show that the C-reactive protein content in the serum of experimental group 2 is 4.73, which is lower than the negative control group (8.21), the positive control group (6.97) and the experimental group 1 (5.72), and the decrease is significant compared with the negative control group. The C-reactive protein content in the serum of experimental group 1 was 5.72, which was lower than that of the negative control group and the positive control group. C-reactive protein plays a multi-faceted role in identifying pathogens, activating the complement system, enhancing phagocytosis and regulating immune responses in inflammatory responses, and is an important indicator in the diagnosis of inflammation and infection. The above results show that the animal Bifidobacterium lactis subspecies ZYhyy-003 postbiotic solid preparation described in Example 2 can effectively regulate the C-reactive protein content in cat serum.

[0092] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement scheme, a person skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. Bifidobacterium animalis subsp. lactis with a deposit number of CGMCC No. 31553 ( Bifidobacterium animalis subsp.lactis ) The use of the postbiotic preparation ZYhyy-003 in the preparation of a product for enhancing the immune function of pets, characterized in that: Bifidobacterium animalis subspecies lactis ZYhyy-003 was deposited in the General Microbiology Center of China Microbiological Culture Collection Administration on August 5, 2024, and the deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing; The postbiotic preparation is prepared by uniformly mixing postbiotic powder of animal Bifidobacterium lactis subspecies ZYhyy-003 and glucose, and the postbiotic powder is prepared by inactivating, concentrating and freeze-drying bacterial liquid of animal Bifidobacterium lactis subspecies ZYhyy-003.

2. The use according to claim 1, characterized in that The preparation of the animal Bifidobacterium lactis subspecies ZYhyy-003 bacterial liquid comprises the following steps: (1) Take out the frozen Bifidobacterium animalis subsp. lactis ZYhyy-003 from the -80°C refrigerator, quickly thaw it in a 37°C water bath, inoculate the strain into 5 mL of liquid MRS medium, and culture it anaerobically at 37°C for 24 to 48 hours until the bacterial solution becomes turbid; (2) The turbid bacterial solution obtained in step (1) is inoculated on an MRS solid culture medium for activation, the activated bacteria are inoculated in a primary culture medium, and a seed solution is obtained through primary culture; the seed solution is inoculated in a secondary culture medium, and a bacterial solution is obtained through secondary culture; (3) Centrifuge the bacterial solution at 4°C, 3000-5000 rpm for 15 min, collect the cells, wash with sterile saline, and resuspend to obtain a suspension. Adjust the concentration of the suspension to greater than 1×10 9 CFU / mL, that is, the bacterial liquid of animal Bifidobacterium lactis subspecies ZYhyy-003 was obtained.

3. The use according to claim 2, characterized in that: In step (1), the strain inoculation amount is 0.02~0.04%.

4. The use according to claim 2, characterized in that: In step (2), the primary culture medium and the secondary culture medium are both MRS liquid culture medium.

5. The use according to claim 2, characterized in that: In step (2), the inoculation amount of the seed liquid inoculated into the secondary culture medium is 1% to 2%.

6. The use according to claim 2, characterized in that In step (2), the primary culture condition is culturing at 36-38°C for 24-48 h; the secondary culture condition is culturing at 36-38°C for 24-48 h.

7. The use according to any one of claims 1 to 6, characterized in that: The pets include cats, dogs, rabbits, piglets, mice, minks, golden bears, chinchillas, guinea pigs or meerkats.

8. The use according to any one of claims 1 to 6, characterized in that: The product is one or more of the following: (1) The product can increase the weight of pets; (2) The product can improve the skin condition of the pet; (3) The product can increase the content of anti-inflammatory factors in pet serum; (4) The product can increase the immunoglobulin content in pet serum; (5) The product can reduce the level of pro-inflammatory factors in pet serum; (6) The product can reduce the level of C-reactive protein in pet serum.

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