Application of bacillus subtilis QST713 in improving production performance and reproduction traits of Xiaoshan chicken

Abstract

The invention discloses application of bacillus subtilis QST713 in improving the production performance and reproduction traits of Xiaoshan chickens. The production performance of the Xiaoshan chickens is improved by any one or more than two of the following steps: (1) reducing the feed-egg ratio of the Xiaoshan chickens; (2) the egg weight of Xiaoshan chicken is increased; (3) the egg protein height of Xiaoshan chicken is increased; (4) increasing any one or more of total protein, globulin and albumin in serum of the Xiaoshan chicken; (5) reducing any one or more of cholesterol, triglyceride, glutamic oxalacetic transaminase, glutamic-pyruvic transaminase and low-density lipoprotein in serum of the Xiaoshan chicken; and (6) increasing any one or more of immune globulin A, immune globulin G and immune globulin M in the serum of the Xiaoshan chicken. By adding the bacillus subtilis QST713 strain, the feed-egg ratio of the Xiaoshan chicken can be remarkably reduced, the egg quality and serum biochemical indexes of the Xiaoshan chicken can be effectively improved, the immune function is enhanced, and the ovarian gene expression of the Xiaoshan chicken is influenced.

Description

Technical Field

[0001] The invention relates to the application of Bacillus subtilis QST713, and in particular to the application of Bacillus subtilis QST713 in improving the production performance and reproductive traits of Xiaoshan chicken. Background Art

[0002] Xiaoshan chicken is a local breed for both meat and eggs. It is large, has good meat quality, grows fast in the early stage, has a high slaughter rate, and produces a lot of eggs. It is favored by consumers. Feed-egg ratio and egg quality are important indicators for measuring the production performance of laying hens. The production performance of laying hens directly affects the economic benefits of the breeding industry. Therefore, it is necessary to study how to improve the production performance of Xiaoshan chickens.

[0003] Bacillus subtilis has many functions, such as inhibiting pathogenic bacteria, improving immune function, and participating in digestion and absorption. In the experiment of Xu et al., 6.0×10 5 CFU / g and 9.0×10 5 CFU / g Bacillus subtilis, the results showed that Bacillus subtilis had no significant effect on the feed-to-egg ratio of Xuefeng black-bone chickens (Effects of Bacillus subtilis C-3102 on production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders [J]. Journal of Animal Physiology and Animal Nutrition, 2019, 103 (1): 182-190). In the study of Zhao Jiani et al., a 4-week experiment of adding Bacillus subtilis PB6 to late-laying Hy-Line brown laying hens was conducted. The results showed that its egg production rate was significantly improved, and the feed-to-egg ratio and broken soft egg rate were effectively reduced (Effects of Bacillus subtilis PB6 preparation on production performance, egg quality, antioxidant capacity and intestinal flora of late-laying laying hens [J]. China Animal Husbandry Journal, 2024, 60 (06): 298-302). The research on the effect of Bacillus subtilis on feed-egg ratio varies depending on the Bacillus subtilis dosage, animal age, animal breed and feed composition.

[0004] It has been reported that Bacillus subtilis QST713 can synthesize lipopeptide antimicrobial peptides and protein antimicrobial substances, which can reduce the production of inflammatory factors by adjusting the permeability of the mucosal barrier, secrete a variety of digestive enzymes and maintain the healthy balance of intestinal microecology (Modulatory Effects of Bacillus subtilis on the Performance, Morphology, Cecal Microbiota and Gut Barrier Function of Laying Hens. [J]. Animals, 2021 (6), 11: 1523). However, it is still unknown whether Bacillus subtilis QST713 can be effectively used in Xiaoshan chicken production.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] The invention aims to provide an application of Bacillus subtilis QST713 in improving the production performance and reproductive traits of Xiaoshan chickens. Adding the Bacillus subtilis QST713 strain can significantly reduce the feed-egg ratio of Xiaoshan chickens, effectively improve the quality of Xiaoshan eggs and serum biochemical indicators, enhance the immune function, and affect the ovarian gene expression of Xiaoshan chickens.

[0007] In order to achieve the above object, the present invention provides the use of Bacillus subtilis QST713 in improving the production performance and reproductive traits of Xiaoshan chicken.

[0008] Preferably, the method for improving the production performance of Xiaoshan chicken is selected from any one or more of the following:

[0009] (1) Reduce the feed-to-egg ratio of Xiaoshan chickens;

[0010] (2) Increase the egg weight of Xiaoshan chickens;

[0011] (3) Increase the egg protein level of Xiaoshan chickens;

[0012] (4) increasing any one or more of the total protein, globulin, and albumin in the serum of Xiaoshan chickens;

[0013] (5) reducing any one or more of the following in the serum cholesterol, triglyceride, aspartate aminotransferase, alanine aminotransferase, and low-density lipoprotein of Xiaoshan chickens;

[0014] (6) increasing any one or more of immunoglobulin A, immunoglobulin G, and immunoglobulin M in the serum of Xiaoshan chicken;

[0015] (7) Reducing any one of the following: tumor necrosis factor, interleukin-1β, and interleukin-6 in the serum of Xiaoshan chickens.

[0016] Preferably, the addition amount of the Bacillus subtilis QST713 in the basal diet is 100-400 mg / kg.

[0017] Preferably, when the addition amount of the Bacillus subtilis QST713 in the basic diet is 200 mg / kg, improving the production performance of Xiaoshan chicken is further selected from: improving any one or more of the eggshell strength and Haugh unit of Xiaoshan chicken eggs.

[0018] Preferably, when the addition amount of the Bacillus subtilis QST713 in the basal diet is 100-200 mg / kg, the expression level of AMN in the chicken ovary is upregulated.

[0019] Preferably, when the addition amount of the Bacillus subtilis QST713 in the basal diet is 100 mg / kg, the expression level of STAR in the chicken ovary is up-regulated and / or the expression level of PERP1 is down-regulated.

[0020] Preferably, when the addition amount of the Bacillus subtilis QST713 in the basal diet is 400 mg / kg, the expression level of THBS4 in the chicken ovary is upregulated.

[0021] Preferably, the Xiaoshan chicken is selected from 387-day-old Xiaoshan hens.

[0022] The application of the Bacillus subtilis QST713 of the present invention in improving the production performance and reproductive traits of Xiaoshan chicken has the following advantages:

[0023] The present invention can significantly reduce the feed-to-egg ratio, effectively improve egg quality and serum biochemical indicators, enhance immune function, and affect ovarian gene expression of Xiaoshan chickens by adding Bacillus subtilis QST713 strain to the feed of 55-week-old Xiaoshan chickens. Considering aspects such as breeding production and feed cost, adding 200 mg / kg of Bacillus subtilis QST713 strain to the basic diet has a relatively better comprehensive effect. Therefore, Bacillus subtilis QST713 strain is expected to be used as an antibiotic substitute for Xiaoshan chickens, providing a theoretical basis for green antibiotic-free breeding of Xiaoshan chickens. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 These are the results of the effect of adding Bacillus subtilis QST713 strain to the diet on the feed-to-egg ratio of Xiaoshan chickens in Experimental Example 1 of the present invention.

[0025] Figure 2 The volcano plots of differentially expressed genes in each comparison group in Experimental Example 2 of the present invention; (A) CvsL comparison group; (B) CvsM comparison group; (C) CvsH comparison group. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that if the specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased from the market.

[0028] In the present invention, all features defined in the form of numerical ranges or percentage ranges, such as values, quantities, contents and concentrations, are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0029] The features mentioned in the present invention can be combined arbitrarily, as long as there is no contradiction in the combination of these features, all possible combinations should be considered as the scope of this specification. Each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equal or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equal or similar features.

[0030] The test materials used in the following experimental examples are as follows:

[0031] 1) Bacillus subtilis QST713 strain (content ≥1×10 10 CFU / g): purchased from Elan Animal Health Co., Ltd.;

[0032] 2) The experimental animals were 387-day-old Xiaoshan hens, provided by the Xiaoshan Chicken Breed Resource Farm and raised in three-layer fully stepped chicken cages.

[0033] Experimental Example 1 Experimental Design of the Effect of Bacillus subtilis QST713 Strain on Xiaoshan Chicken

[0034] A single-factor experimental design was used to randomly divide 384 Xiaoshan chickens with similar production performance and good health into 4 groups (8 replicates in each group and 12 chickens in each replicate).

[0035] The 4 groups designed are as follows:

[0036] Control group; Basic diet;

[0037] BSL group: basal diet + 100 mg / kg Bacillus subtilis QST713 strain;

[0038] BSM group: basic diet + 200 mg / kg Bacillus subtilis QST713 strain;

[0039] BSH group: basic diet + 400 mg / kg Bacillus subtilis QST713 strain.

[0040] The pre-experiment lasted for 1 week and the experimental period was 8 weeks.

[0041] The basic diet formula was formulated in accordance with the "NRC (1994) Laying Hen Nutrient Standards". The detailed basic diet composition and nutritional levels are shown in Table 1. During the entire trial, all experimental chickens were caged and kept under the same feeding and management conditions, including free access to food and water, and 16 hours of light per day. During the trial, daily feed consumption, mortality and culling, egg production, and temperature and humidity in the house were recorded.

[0042] Table 1 Basic diet composition and nutritional level (calculated by dry matter)

[0043]

[0044] Note: 1: Each kg of premix contains: Vitamin A 8000IU, Vitamin B24.5 mg, Vitamin B52 mg, Vitamin B60.2 mg, Vitamin B 12 0.02 mg, vitamin D3 2800 IU, vitamin E 23 IU, vitamin K 32.6 mg, biotin 0.0075 mg, folic acid 0.05 mg, calcium pantothenate 15 mg, niacin 30.5 mg, sodium chloride 37.5 mg, copper (CuSO4·5H2O) 17.5 mg, iron (FeSO4·7H2O) 60 mg, manganese (MnSO4·H2O) 65 mg, zinc (ZnO) 70 mg, iodine (KI) 0.75 mg and selenium (Na2SeO3) 0.2 mg. 2: Nutrient content is calculated.

[0045] Experimental Example 2 Measurement Index

[0046] The production performance, serum indices and immune performance were measured, and the ovarian transcriptome was sequenced. The experimental data were statistically analyzed using SPSS27.0 software. The significance of the differences was tested using one-way analysis of variance (ANOVA), and the least significant difference (LSD) method was used for multiple comparisons. The results were presented as "mean ± standard deviation", and P < 0.05 was set as the basis for judging the significance of the difference.

[0047] The experimental process and results of each measurement are as follows:

[0048] 1. Production performance

[0049] The feed intake, egg production and egg weight of each replicate chicken were recorded every day. After the experiment, the feed-egg ratio was calculated using the following formula:

[0050] Feed-egg ratio (g / g) = feed intake / egg weight

[0051] At the end of the experiment, 5 eggs were randomly selected from each replicate for egg quality measurement. The eggshell thickness measuring instrument, eggshell strength analyzer and SONOVA egg quality automatic analyzer were used to test the eggshell thickness, eggshell strength, Haugh unit, albumen height, yolk color and egg weight, and the vernier caliper was used to measure the longitudinal and transverse diameters of the eggs to calculate the egg shape index.

[0052] The calculation formula of the egg shape index is as follows:

[0053] Egg shape index = longitudinal diameter / transverse diameter

[0054] like Figure 1 The figure shows the effect of adding Bacillus subtilis QST713 strain to the diet on the feed-to-egg ratio of Xiaoshan chickens in Experimental Example 2 of the present invention. As can be seen from the figure, in terms of feed-to-egg ratio, the BSL group, BSM group and BSH group were significantly lower than the control group (P﹤0.05).

[0055] As shown in Table 2, the results of the effect of adding Bacillus subtilis QST713 strain to the diet on the quality of Xiaoshan eggs in Experimental Example 2 of the present invention are shown. As shown in Table 2, compared with the control group, the egg weight of the BSL group, the BSM group and the BSH group increased significantly by 7.13%, 7.55% and 6.93% respectively (P﹤0.05); the egg shape index of the experimental group did not change significantly compared with the control group (P﹥0.05); in terms of eggshell thickness, the eggshell thickness of the BSL group was significantly reduced (P﹤0.05); in terms of eggshell strength, the eggshell strength of the BSM group was significantly improved (P﹤0.05); compared with the control group, the yolk color of the BSM group was significantly reduced (P﹤0.05), and the protein height and Haugh unit of the BSM group were significantly improved (P﹤0.05).

[0056] Table 2 Effect of Bacillus subtilis QST713 strain on the quality of eggs in Xiaoshan

[0057]

[0058]

[0059] Note: Data in the same row with different lowercase letters indicate significant differences (P﹤0.05), and the same letters indicate insignificant differences (P﹥0.05), the same below.

[0060] After the Bacillus subtilis QST713 strain is added to the basic diet of Xiaoshan chickens in the present invention, the feed-egg ratio thereof is significantly reduced. This may be because the Bacillus subtilis QST713 strain promotes the secretion of a variety of digestive enzymes such as amylase, cellulase, protease and lipase. These digestive enzymes can decompose complex nutrients into small molecules that are easier to absorb, thereby improving the digestion and absorption efficiency of nutrients and reducing feed consumption.

[0061] The invention adds the Bacillus subtilis QST713 strain to the basic diet of Xiaoshan chickens, which can significantly improve the protein height, Haugh unit, eggshell strength, eggshell thickness and egg weight. The reason may be that the Bacillus subtilis QST713 strain can improve the digestion and absorption rate of nutrients of laying hens to increase the protein content in eggs; it can maintain the homeostasis of intestinal microbial communities, synthesize antibacterial substances, ensure their nutritional status and health status, and improve their egg quality.

[0062] 2. Determination of serum indicators

[0063] After the experiment, one chicken was randomly selected from each replicate, and 5 ml of blood was collected from the wing vein after fasting for 12 hours. The blood sample was centrifuged at 2500r / min for 15 minutes, and the serum sample was stored at -20℃ for subsequent determination of serum indicators. The levels of serum total protein (TP), albumin (ALB), globulin (GLB), total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were detected using Mindray BS-420 fully automatic biochemical analyzer.

[0064] As shown in Table 3, the results of the effect of adding Bacillus subtilis QST713 strain to the diet on the serum biochemical indicators of Xiaoshan chickens in Experimental Example 2 of the present invention are shown. As shown in Table 3, compared with the control group, the total protein (TP) and globulin (GLB) of the experimental group were significantly increased (P﹤0.05). In terms of albumin (ALB), the BSL group was significantly increased compared with the control group (P﹤0.05), and the BSM group and BSH group had an increasing trend but no significant change (P﹥0.05). Compared with the control group, the levels of cholesterol (TC), triglyceride (TG), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the experimental group all showed a downward trend but no significant change (P﹥0.05). In terms of low-density lipoprotein (LDL), the BSL group was significantly reduced compared with the control group (P﹤0.05), and the BSM group and BSH group had a decreasing trend but no significant difference (P﹥0.05).

[0065] Table 3 Effects of Bacillus subtilis QST713 strain on serum biochemical parameters of Xiaoshan chicken

[0066]

[0067] The contents of serum albumin (ALB), globulin (GLB) and total protein (TP) in the Bacillus subtilis QST713 strain group of the present invention are significantly higher than those in the control group. This may be because the level of total protein (TP) in serum is positively correlated with protein metabolic activity, and Bacillus subtilis can produce a variety of digestive enzymes, which promotes the absorption and utilization of protein; the metabolites of Bacillus subtilis have the ability to stimulate the host immune system, thereby increasing the levels of serum albumin and globulin.

[0068] The cholesterol (TC) and triglyceride (TG) levels of the Bacillus subtilis QST713 strain group of the present invention showed a downward trend, but did not reach a significant level.

[0069] The Bacillus subtilis QST713 strain of the present invention significantly reduced the low-density lipoprotein cholesterol (LDL) content in serum and increased the high-density lipoprotein cholesterol (HDL) level, but did not reach a significant level. The difference between the Bacillus subtilis QST713 strain group of the present invention and the control group did not reach a significant level, but the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) tended to decrease, indicating that Bacillus subtilis would not adversely affect the liver function of laying hens.

[0070] 3. Determination of immune performance

[0071] After the experiment, one chicken was randomly selected from each replicate, and 5 ml of blood was collected from the wing vein after fasting for 12 hours. The blood sample was centrifuged at 2500r / min for 15 minutes, and the serum sample was stored at -20°C for subsequent determination of serum indicators. The serum immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), interleukin-6 (IL-6) and interleukin-1β (IL-1β) contents were detected using Huawei Delang DR-200BS enzyme label analyzer.

[0072] As shown in Table 4, the effect of adding Bacillus subtilis QST713 strain to the diet in Experimental Example 2 of the present invention on the serum immune indexes of Xiaoshan chickens. As shown in Table 4, compared with the control group, the content of immunoglobulin A (IgA) in the experimental group was significantly increased (P﹤0.05); the content of immunoglobulin G (IgG) and immunoglobulin M (IgM) in the BSM group and the BSH group was significantly increased (P﹤0.05). Compared with the control group, the levels of tumor necrosis factor (TNFα), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in the experimental group were significantly reduced (P﹤0.05), and the addition amount of Bacillus subtilis QST713 strain decreased.

[0073] Table 4 Effects of Bacillus subtilis QST713 strain on serum immune indexes of Xiaoshan chicken

[0074]

[0075] After the Bacillus subtilis QST713 strain is added to the diet of Xiaoshan chickens, the levels of IgA, IgG and IgM in the serum of the chickens are significantly improved. This may be because Bacillus subtilis can produce metabolites with immunomodulatory effects such as short-chain fatty acids and peptidoglycan, which can directly or indirectly affect the function of B cells, thereby promoting the production of antibodies, stimulating the body's immune response, and maintaining a stable state of the immune system.

[0076] After the Bacillus subtilis QST713 strain is added to the laying hen diet, the levels of IL-1β, IL-6 and TNF-α in the laying hen serum are significantly reduced. This may be because the Bacillus subtilis QST713 strain can colonize in the intestine, maintain the balance of intestinal flora, and increase the level of anti-inflammatory cytokines, thereby reducing the production of inflammatory factors; it can enhance the integrity of the intestinal mucosal immune system, reduce the invasion of harmful substances and pathogens, and thus reduce the inflammatory response.

[0077] 4. Ovarian transcriptome sequencing

[0078] The total RNA of the ovarian tissue of the experimental laying hen was extracted by Trizol method, and the concentration and purity were detected by nanodrop-2000, and the integrity was detected by RNA-specific agarose electrophoresis to ensure that the extracted RNA could meet the standards for sequencing library construction. AMPure XP beads were used to screen cDNA of about 400 to 500 bp, PCR amplification was performed, and AMPure XP beads were used to purify the PCR product to finally complete the preparation of the library. The next-generation sequencing (NGS) technology was used to perform paired-end (PE) sequencing on these libraries based on the Illumina sequencing platform.

[0079] Sequencing data analysis is as follows:

[0080] First, data quality control was performed to filter out low-quality data. The main criteria for data filtering included: using fastp to remove sequences with adapters at the 3' end and removing reads with an average quality score lower than Q20. HISAT2 (v2.1.0) was used to construct an index of the reference genome, and paired-end Clean reads were aligned to the reference genome using HISAT2. HTSeq (v0.9.1) was used to statistically compare the Read Count value on each gene as the original expression of the gene. In order to make the gene expression levels between different genes and different samples comparable, FPKM was used to standardize the expression. DESeq (v1.38.3) software was used to perform differential expression analysis between the two comparison combinations. DESeq was used to perform differential analysis of gene expression, and the conditions for screening differentially expressed genes were: expression difference fold |log2FoldChange|>1, significant P-value<0.05.

[0081] (1) Ovarian transcriptome data analysis

[0082] As shown in Table 5, a total of 1252388886 sequences and 1230902818 high-quality sequences (clean reads) were obtained by transcriptome sequencing of the cDNA library, and the high-quality sequences accounted for 98.29% of the original sequences. The average high-quality sequence content of Q20 and Q30 was 98.69% and 96.36%, respectively, and the average GC content was 46.11%, and the base content was consistent with the theoretical distribution ratio. The average number of original bases was 7.88Gb, and the average number of high-quality bases was 7.72Gb, indicating that 97.97% of the original sequences passed the quality control standards. The above data show that the sample quality is good, and the base recognition accuracy is high during sequencing, and the content of each base is close, which is suitable for in-depth bioinformatics analysis.

[0083] Table 5 Statistics of ovarian transcriptome data

[0084]

[0085]

[0086] Note: Samples C1-C6 are the control group, L1-L6 are the BSL group, M1-M6 are the BSM group, and H1-H6 are the BSH group.

[0087] (2) Screening of differentially expressed genes

[0088] like Figure 2As shown, it is a volcano map of differentially expressed genes in the comparison groups of CvsL, CvsM and CvsH in Experimental Example 2 of the present invention. In the three comparison groups of CvsL (control group vs BSL group), CvsM (control group vs BSM group) and CvsH (control group vs BSH group), there are 22, 123 and 159 differentially expressed genes, respectively, of which 8, 18 and 23 genes are up-regulated, and 14, 105 and 136 genes are down-regulated. Table 5, Table 6 and Table 7 respectively show the top 5 up-regulated and down-regulated significantly differentially expressed genes in the three comparison groups of CvsL, CvsM and CvsH.

[0089] Table 6 CvsL ovarian tissue up-regulated and down-regulated differentially expressed genes (partial)

[0090]

[0091]

[0092] Table 7 Up-regulated and down-regulated differentially expressed genes in CvsM ovarian tissue (partial)

[0093]

[0094] Table 8 CvsH ovarian tissue up-regulated and down-regulated differentially expressed genes (partial)

[0095]

[0096]

[0097] After adding Bacillus subtilis QST713 strain, the expression levels of AMN in the ovaries of the experimental chickens in the BSL group and the BSM group were upregulated, the expression level of STAR in the ovaries of the experimental chickens in the BSL group was upregulated, the expression level of PERP1 in the ovaries of the experimental chickens in the BSL group was downregulated, and the expression level of THBS4 in the ovaries of the experimental chickens in the BSH group was upregulated.

[0098] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. Application of Bacillus subtilis QST713 in improving the production performance and reproductive traits of Xiaoshan chicken.

2. The use according to claim 1, characterized in that: The method for improving the production performance of Xiaoshan chicken is selected from any one or more of the following: (1) Reduce the feed-to-egg ratio of Xiaoshan chickens; (2) Increase the egg weight of Xiaoshan chickens; (3) Increase the egg protein level of Xiaoshan chickens; (4) increasing any one or more of the total protein, globulin, and albumin in the serum of Xiaoshan chickens; (5) reducing any one or more of the following in the serum cholesterol, triglyceride, aspartate aminotransferase, alanine aminotransferase, and low-density lipoprotein of Xiaoshan chickens; (6) increasing any one or more of immunoglobulin A, immunoglobulin G, and immunoglobulin M in the serum of Xiaoshan chicken; (7) Reducing any one of the following: tumor necrosis factor, interleukin-1β, and interleukin-6 in the serum of Xiaoshan chickens.

3. The use according to claim 2, characterized in that: The addition amount of the Bacillus subtilis QST713 in the basic diet is 100-400 mg / kg.

4. The use according to claim 2, characterized in that: When the addition amount of the Bacillus subtilis QST713 in the basic diet is 200 mg / kg, improving the production performance of Xiaoshan chicken is further selected from: improving any one or more of the eggshell strength and Haugh unit of Xiaoshan chicken.

5. The use according to claim 1, characterized in that: When the addition amount of the Bacillus subtilis QST713 in the basic diet is 100-200 mg / kg, the expression amount of AMN in the chicken ovary is upregulated.

6. The use according to claim 1, characterized in that: When the addition amount of the Bacillus subtilis QST713 in the basic diet is 100 mg / kg, the expression amount of STAR in the chicken ovary is up-regulated and / or the expression amount of PERP1 is down-regulated.

7. The use according to claim 1, characterized in that: When the addition amount of the Bacillus subtilis QST713 in the basal diet is 400 mg / kg, the expression level of THBS4 in the chicken ovary is upregulated.

8. The use according to any one of claims 1 to 7, characterized in that: The Xiaoshan chicken is selected from 387-day-old Xiaoshan hens.

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