Streptococcus non-lactolyticus GX-2 and application of complex microbial inoculant thereof in peanut vine silage

Abstract

The invention relates to the technical field of microorganisms, in particular to application of streptococcus non-lactolyticus GX-2 and a complex microbial inoculant thereof in peanut vine silage, and the strain GX-2 is suitable for surviving in the stomach and has an antibacterial effect on staphylococcus aureus, escherichia coli, pseudomonas fluorescens and listeria monocytogenes; the streptococcus non-lactolyticus GX-7 and the streptococcus non-lactolyticus GX-2 are prepared into a complex microbial inoculant, and then the complex microbial inoculant is inoculated into the peanut vines, so that the synergistic fermentation effect can be achieved at the mass ratio of 1: (1-3); after the gestational buffalo is fed with the silage prepared from the complex microbial inoculant, the silage is found to be capable of effectively increasing the contents of total milk solids and non-fat milk solids in the colostrum of the buffalo and relieving the diarrhea of the buffalo, and is safe and good.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, and in particular to application of non-galactolytic Streptococcus GX-2 and a composite bacterial agent thereof in peanut seedling silage. Background Art

[0002] Peanuts are a major oilseed cash crop in my country. Harvesting peanuts produces a large number of peanut vines, making the development and utilization of peanut vine resources of great significance. Peanut vines contain a variety of nutrients, including crude protein, minerals, crude fat, and vitamins. They are rich in crude protein, neutral detergent fiber, and acid detergent fiber. Compared to corn stalks, peanut vines offer advantages such as improved palatability and a softer texture that facilitates digestion, making them a high-quality animal roughage resource. Research has shown that using peanut vines in animal production can reduce breeding costs.

[0003] There are also many existing technologies about the field of peanut silage, and some lactic acid bacteria and Bacillus are often used to ferment them. However, we found in the actual fermentation process that for peanut silage substrates, not all strains have good fermentation ability for peanut silage. In order to improve the fermentation ability for peanut silage, we need to screen the strains. We generally prefer strains that can effectively maintain dry matter content, increase protein content, and reduce fiber content as indicators for evaluating fermentation ability. Of course, in addition to fermentation ability, resistance to pathogens is also indispensable. Improving the strain's resistance to pathogens will greatly reduce the incidence of livestock and have a good disease prevention effect.

[0004] In order to effectively develop higher-quality silage, we need to conduct extensive screening and verification of microorganisms, develop microorganisms suitable for the fermentation of peanut vine substrates, produce peanut vine silage, and verify the feasibility of this feed in feeding animals. Summary of the Invention

[0005] In view of the above, it is necessary to screen suitable microorganisms for peanut vine substrates, develop microorganisms that can effectively ferment peanut vines and have certain antibacterial ability against pathogens, provide theoretical support for the production of peanut vine silage, and preliminarily verify the feasibility of peanut vine silage in feeding animals.

[0006] To achieve the above objectives, the present invention screened out a new strain: Streptococcus alactolyticus strain GX-2, which is classified as Streptococcus alactolyticus GX-2, and its Chinese classification name is Streptococcus alactolyticus GX-2, and its preservation number is GDMCC NO: 65508; the strain is deposited in the Guangdong Provincial Microbiological Culture Collection Center, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou City, and the preservation date is November 19, 2024.

[0007] The present invention also includes a composite bacterial agent comprising the non-lactolyticus Streptococcus alactolyticus strain GX-2.

[0008] Furthermore, the composite bacterial agent also includes non-lactose-lytic Streptococcus alactolyticus strain GX-7; the non-lactose-lytic Streptococcus alactolyticus strain GX-7, its classification name is: Streptococcus alactolyticus GX-7, its Chinese classification name is: non-lactose-lytic Streptococcus GX-7, and its preservation number is GDMCC NO: 65509; the strain is deposited in the Guangdong Provincial Microbiological Culture Collection Center, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou City, and the preservation date is November 19, 2024.

[0009] Furthermore, the composite bacterial agent is prepared by mixing non-lactose-lytic Streptococcus alactolyticus strain GX-7 and non-lactose-lytic Streptococcus alactolyticus strain GX-2 in a volume ratio of 1:1-3.

[0010] Furthermore, the composite bacterial agent is prepared by mixing non-lactose-lytic Streptococcus alactolyticus strain GX-7 and non-lactose-lytic Streptococcus alactolyticus strain GX-2 in a volume ratio of 1:3.

[0011] The present invention also includes the use of the non-lactolytic Streptococcus alactolyticus strain GX-2 or the composite bacterial agent in preparing peanut seedling silage.

[0012] The present invention also includes the use of the non-lactolytic Streptococcus alactolyticus strain GX-2 in producing bile salt-resistant and / or animal diarrhea-relieving drugs.

[0013] The present invention also includes the use of the non-lactolytic Streptococcus alactolyticus strain GX-2 in an antibacterial agent, wherein the antibacterial agent inhibits pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas fluorescens and / or Listeria monocytogenes.

[0014] The present invention also includes silage containing the non-galactolytic Streptococcus alactolyticus strain GX-2 or the composite bacterial agent according to claim 2, characterized in that the silage is prepared by inoculating the non-galactolytic Streptococcus alactolyticus strain GX-2 or the composite bacterial agent into peanut seedlings at an inoculum rate of 5% by mass and silaging for 35 days.

[0015] The present invention also includes the use of the silage in increasing the content of total milk solids and / or milk non-fat solids in buffalo colostrum.

[0016] The present invention also includes a method for feeding pregnant female buffaloes with the silage, which comprises: mixing 20%-30% by mass of the silage with 70%-80% by mass of a basic diet and then feeding the mixture to the pregnant female buffaloes, wherein the basic diet is a whole-plant corn silage basic feed.

[0017] The present invention has the following beneficial effects: the strain GX-2 of the present invention was isolated from healthy pig feces by a research team. Testing has shown that the strain is suitable for survival in the stomach and has an antibacterial effect on Staphylococcus aureus, Escherichia coli, Pseudomonas fluorescens and Listeria monocytogenes; the strain has good fermentation ability on peanut vines, and non-lactolytic Streptococcus GX-7 and non-lactolytic Streptococcus GX-2 are prepared into a composite bacterial agent and then inoculated into peanut vines to achieve a synergistic fermentation effect at a mass ratio of 1:1-3. After feeding silage prepared from the composite bacterial agent to pregnant buffaloes, it was found that the feed can effectively increase the total milk solids and milk non-fat solids content in the buffalo's colostrum, alleviate diarrhea in the buffaloes, and is a safe and good silage.

[0018] Biomaterial deposit information

[0019] The strain information deposited in this application is: Streptococcus alactolyticus strain GX-7, its classification name is: Streptococcus alactolyticus GX-7, its Chinese classification name is: Streptococcus alactolyticus GX-7, and its preservation number is GDMCC NO: 65509; the strain is deposited in Guangdong Provincial Microbiological Culture Collection Center, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou City, and the preservation date is November 19, 2024.

[0020] The strain information deposited in this application is: Streptococcus alactolyticus strain GX-2, its classification name is: Streptococcus alactolyticus GX-2, its Chinese classification name is: Streptococcus alactolyticus GX-2, and the preservation number is GDMCC NO: 65508; the strain is deposited in Guangdong Provincial Microbiological Culture Collection Center, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, and the preservation date is November 19, 2024. DETAILED DESCRIPTION

[0021] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0022] Any feature disclosed in this specification (including any accompanying claims and abstract), unless otherwise stated, is merely one example of a series of equivalent or similar features.

[0023] Example 1

[0024] This example is about the isolation and identification of strains.

[0025] 1. Strain Screening and Isolation: Fresh feces from healthy pigs was collected. 10g of fresh feces was placed in 90mL of sterile saline and shaken in a 250mL Erlenmeyer flask for 20 minutes. 100μL of each appropriately diluted bacterial solution was spread onto Ca-MRS (CaCO3: 2g / L) plates and incubated in a 37°C incubator for 24 hours. Morphological characteristics of the bacteria were recorded. Colonies with distinct morphology and color were streaked and purified three times. A single colony was selected and placed on a clean glass slide. One to two drops of 3% hydrogen peroxide solution were added and allowed to stand for observation. A positive result was identified if a large number of bubbles formed within half a minute; a negative result was identified if no bubbles formed. The isolated and purified single colony was Gram-stained and its color and morphology were observed under a microscope. Lactic acid bacteria are Gram-positive and should appear purple after Gram staining. The single colony screened was inoculated into MRS liquid medium and incubated at 37°C for 18-2 hours. Add the bacteria and glycerol into an EP tube, mix well (the final concentration of glycerol is 15%), and store in a -20°C refrigerator for later use.

[0026] 2. Morphological and molecular identification of the screened GX-2 and GX-7 strains:

[0027] ① The GX-2 strain was inoculated on MRS plate culture medium and cultured for 24 hours. The colonies were round and 0.4 mm in size. The colonies were flesh-colored, transparent and matte. The colonies were round and convex, with a smooth surface and neat edges. Microscopic examination showed that the bacteria were oblate and clustered. After molecular identification, the strain was finally classified and named Streptococcus alactolyticus.

[0028] ② The GX-7 strain was inoculated on MRS plate culture medium and cultured for 24 hours. The colonies were round and 0.9 mm in size. The colonies were white, opaque, smooth, round, convex, and had neat edges. Microscopic examination showed that the bacteria were spherical, single or in pairs, and not curved. After molecular identification, the strain was finally classified and named Streptococcus alactolyticus.

[0029] Example 2

[0030] This example is a test on the acid resistance, bile salt resistance and artificial gastrointestinal fluid resistance of strains GX-2 and GX-7.

[0031] 1. Acid and bile salt resistance test:

[0032] MRS liquid culture medium was prepared and adjusted to pH 2.0, 3.0, and 4.0 with 1 mol / L hydrochloric acid. A 2% inoculum was inoculated into each of the liquid culture media at different pH values. A medium without hydrochloric acid was used as a control. After incubation at 37°C for 3 hours, viable bacteria were counted. The survival rate was calculated as (viable bacteria count at 3 hours / viable bacteria count at 0 hours) × 100%. Simultaneously, a 2% inoculum was inoculated into liquid culture media containing different bile salt concentrations (0.3% and 0.5%). After incubation at 37°C for 4 hours, viable bacteria were counted. The survival rate was calculated as (viable bacteria count at 4 hours / viable bacteria count at 0 hours) × 100%. The results are shown in Table 1.

[0033] 2. Artificial gastrointestinal fluid experiment:

[0034] Artificial gastric fluid formula: 3.1g / L NaCl, 1.1g / L KCl, 0.15g / L CaCl2·2H2O, 0.6g / L NaHCO3, adjusted to pH 3.0, sterilized at 121°C for 20 minutes, and pepsin (10g / L) added in a clean hood. Artificial intestinal fluid formula: Weigh 6.8g KH2PO4 and dissolve it in 500mL of water. Adjust the pH of the mixture to 6.8 with 0.1M NaOH. Dissolve 1.0g of trypsin in water. Mix the two solutions and dilute to 1000mL with water to obtain artificial intestinal fluid. Inoculate the artificial gastric fluid at a 2% inoculum level. MRS medium without other ingredients is used as a control. After incubation at 37°C for 3 hours, count the viable bacteria. Survival rate = (number of viable cells at 3 hours / number of viable cells at 0 hours) × 100%. Similarly, when 2% of the inoculum was inoculated into artificial intestinal fluid and cultured for 4 hours, the survival rate = (number of viable cells at 4 hours / number of viable cells at 0 hours) × 100%. The results are shown in Table 1.

[0035] Table 1 Acid and bile salt resistance test results of strains GX-2 and GX-7

[0036]

[0037] As shown in Table 1, under the conditions of pH 2-4, the lower the pH, the lower the survival rate of the strains. When the pH reached 2, the survival rate of the two strains was only 8%. This shows that under the condition of pH 2, the two strains basically cannot survive. From the perspective of significance, there is no significant difference in the survival rate of the two strains (p>0.05); in the bile salt test, as the bile salt concentration increases, the survival rate of the two strains will decrease. Under the condition of 0.3% bile salt concentration, the survival rate of strain GX-7 is significantly higher than that of strain GX-2 (p<0.05). Under the condition of 0.5% bile salt concentration, the survival rate of strain GX-7 is extremely significantly higher than that of strain GX-2 (p<0.001). From the perspective of survival rate, the survival rate of GX-7 was higher than that of GX-2, indicating that strain GX-7 has better bile salt tolerance than strain GX-2. From the results of artificial gastric fluid treatment, the survival rate of GX-7 was significantly lower than that of GX-2 (p<0.05), indicating that strain GX-2 is more suitable for survival in the stomach than strain GX-7. From the results of artificial intestinal fluid treatment, the survival rate of GX-7 was extremely significantly higher than that of GX-2 (p<0.001), indicating that strain GX-7 is more suitable for survival in the intestine than strain GX-2.

[0038] Example 3

[0039] This example is a bacteriostasis experiment of strain GX-2.

[0040] Six indicator bacteria (Staphylococcus aureus, Escherichia coli, Pseudomonas fluorescens, Listeria monocytogenes, Salmonella Choleraesuis, and Shigella flexneri) were activated and cultured for later use. The antibacterial activity of strain GX-2 against these six indicator bacteria was determined using the punch agar diffusion method. The diameters of the clearing zones (inhibition zone diameter = measured diameter minus well diameter) were measured. The results are shown in Table 2.

[0041] Table 2 Antibacterial effect of strain GX-2 on common pathogens

[0042]

[0043] Note: “—” in the table indicates no inhibitory effect, different lowercase letters indicate significant differences in the same column of data (p<0.05), and the same letters indicate no significant differences in the same column (p>0.05). The same applies to the following tables.

[0044] As shown in Table 2, strain GX-2 has an antibacterial effect on Staphylococcus aureus, Escherichia coli, Pseudomonas fluorescens and Listeria monocytogenes, but has no antibacterial effect on Salmonella Choleraesuis and Shigella flexneri. From the inhibition zone, the inhibition zone of Staphylococcus aureus is significantly higher than that of other pathogens (p < 0.05), and the inhibition zone of Escherichia coli is significantly lower than that of Staphylococcus aureus and higher than that of Listeria monocytogenes. monocytogenes and Pseudomonas fluorescens (p<0.05), the inhibition zones of Listeria monocytogenes and Pseudomonas fluorescens were not significantly different (p>0.05), and were significantly lower than those of other bacteria; this indicated that strain GX-2 had the best antibacterial effect against Staphylococcus aureus, followed by Escherichia coli, and then Listeria monocytogenes and Pseudomonas fluorescens.

[0045] Example 4

[0046] This example shows the fermentation effects of different screened bacterial agents on peanut silage.

[0047] 1. Experimental design: This study adopted a completely randomized experimental design, with three groups and three replicates in each group: a control group without any bacterial agent (CK group), a group with non-galactolytic Streptococcus GX-7 (GX-7), and a group with non-galactolytic Streptococcus GX-2 (GX-2).

[0048] Experimental method: crush the sterilized peanut vines and adjust the water content to about 40% with distilled water, and inoculate them at a mass percentage of 5% (the effective viable bacteria count is 10 7 -10 8cfu / g) The corresponding inoculum was inoculated into the sterilized peanut vines, mixed and placed in 250 mL silage bottles for ensiling. Each bottle contained 200 g of sample, which was sealed with sealing film and fermented in the dark for 35 days. The nutritional components and fermentation parameters after fermentation were tested. The indicators of nutrient component determination included dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF) and acid detergent fiber (ADF) content, and the results are shown in Table 3; the indicators of fermentation parameter determination included lactic acid, acetic acid and ammonia nitrogen, and the results are shown in Table 4.

[0049] Table 3 Effects of different microbial agents on the nutritional components of peanut silage

[0050]

[0051] As shown in Table 3, after the peanut vines were fermented by strain GX-2, the contents of crude fiber (CF), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were significantly lower than those in the control group CK (p<0.05); the crude protein (CP) content was significantly increased compared with the control group CK (p<0.05), and the dry matter (DM) content was not significantly different from that in the control group CK (p>0.05).

[0052] After strain GX-7 fermented peanut vines, the crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF) dry matter (DM) and crude protein (CP) contents were not significantly different from those of the control group CK (p>0.05); this indicates that for peanut vine substrates, strain GX-2 has the most significant crude fiber degradation effect and protein enhancement effect, indicating that strain GX-2 has the best fermentation effect on peanut vine substrates.

[0053] Table 4 Results of different microbial agents on the fermentation parameters of peanut silage

[0054]

[0055] As shown in Table 4, after the peanut vines were fermented with strain GX-7, the lactic acid content was significantly increased compared with the control CK (p<0.05), the acetic acid content was significantly decreased compared with the control CK (p<0.05), and the ammonia nitrogen content was not significantly different from that of the control CK (p>0.05).

[0056] After peanut vines were fermented with strain GX-2, the lactic acid content was significantly increased compared with the control CK (p<0.05), and the ammonia nitrogen content and acetic acid content were significantly decreased compared with the control CK (p<0.05).

[0057] Combining the nutritional components and parameters of silage, after using strain GX-2 to ferment peanut vines, the ammonia nitrogen content of the feed was significantly reduced, and the fermentation effect was better than that of strain GX-7. Strain GX-7 had a certain fermentation effect on peanut vines, and the lactic acid content would increase, but the overall fermentation effect was not as good as that of strain GX-2.

[0058] Example 5

[0059] This example shows the fermentation effect of the composite microbial agent on peanut seedlings.

[0060] According to the experimental results of Example 4, we found that: the fermentation of strain GX-2 can reduce the dry matter loss of peanut vines, reduce the crude fiber, neutral detergent fiber, and acid detergent fiber levels of silage peanut vines, increase the crude protein content, increase the lactic acid content, and reduce NH3 / TN; the fermentation of strain GX-7 can reduce the dry matter loss of peanut vines and increase the lactic acid content. In order to increase the diversity of strains and study the effect of the composite microbial agent on the quality of peanut vine silage, the research team considered preparing a composite microbial agent with strains GX-7 and GX-2 according to the mass ratio of Table 5, and then inoculating it with peanut vines at a mass percentage of 5% (the effective viable bacteria count is 10 7 -10 8 cfu / g) peanut silage was prepared according to the method of Example 4. The optimal experimental group was selected based on the crude protein (CP), crude fiber (CF), lactic acid (LA), and ammonia nitrogen (NH3 / TN) contents as optimization indicators, as shown in Tables 5 and 6.

[0061] Table 5 Mass ratio of each strain of composite bacterial agent

[0062]

[0063] Table 6 Experimental results of composite microbial agents

[0064]

[0065] As can be seen from Table 6, from the perspective of crude protein (CP), compared with Table 3 of Example 4, the crude protein content of the T3, T4 and T5 experimental groups was higher than that of the GX-2 fermentation group (16.36%), and the crude protein content of T1 and T2 was lower than that of the GX-2 fermentation group (16.36%); from the perspective of the groups, the crude protein (CP) content of the T5 experimental group was significantly higher than that of the T1, T2 and T4 groups (p<0.05), and higher than that of T3, but the difference was not significant (p>0.05).

[0066] From the perspective of crude fiber (CF), compared with Table 3 of Example 4, the crude fiber (CF) content of the experimental groups T3, T4 and T5 was lower than that of the GX-2 fermentation group (20.38%), and the crude fiber (CF) content of T1 and T2 was higher than that of the GX-2 fermentation group (20.38%); from the perspective of between groups, the crude fiber (CF) content of the experimental groups T3, T4 and T5 was not significantly different (p>0.05), and the crude fiber (CF) content of T1 and T2 was not significantly different (p>0.05).

[0067] From the perspective of lactic acid (LA) content, compared with Table 3 of Example 4, the lactic acid content of the T3, T4, and T5 experimental groups was higher than that of the GX-2 fermentation group (3.04%), and the lactic acid content of T1 and T2 was basically consistent with that of the GX-2 fermentation group (3.04%). From the perspective of the groups, the lactic acid content of the T5 experimental group was significantly higher than that of the T4 and T3 experimental groups (p<0.05), while the difference between the T2 and T1 experimental groups was not significant (p>0.05), and was the lowest among the experimental groups.

[0068] From the perspective of ammonia nitrogen (NH3 / TN) content, compared with Table 3 of Example 4, the NH3 / TN content of the T3, T4 and T5 experimental groups was significantly lower than that of the GX-2 fermentation group (2.05%), and the NH3 / TN content of the T1 and T2 experimental groups was higher than that of the GX-2 fermentation group (2.05%); from the perspective of between groups, the NH3 / TN content of the T1 and T2 experimental groups was not significantly different (p>0.05), and the NH3 / TN content of T3, T4 and T5 was not significantly different (p>0.05) and was significantly lower than that of the T1 and T2 experimental groups (p<0.05).

[0069] The above results show that the ratio of T3, T4 and T5 composite strains can significantly synergistically improve the fermentation effect of peanut seedlings, while the ratio of T1 and T2 composite strains cannot synergistically increase the fermentation effect of peanut seedlings. Therefore, the mass ratio of the composite microbial agent is selected: strain GX-7: strain GX-2 = 1:1-3. Compared with the T3, T4 and T5 experimental groups, the fermentation effect of the T5 experimental group is slightly better. The optimal mass ratio of the composite microbial agent is selected: strain GX-7: strain GX-2 = 1:3.

[0070] Example 6

[0071] This embodiment is to experiment with peanut silage on dairy buffaloes, specifically as follows:

[0072] Fifty pregnant buffaloes in good condition and of similar gestational age were selected and divided into five groups for feeding. They were fed peanut silage starting 60 days before the expected birth date. The specific feeding method was: 50% of the daily feed intake was fed at 9:00 and 16:00 every day. The feed fed to each group was as follows:

[0073] CK: The basic diet is whole-plant corn silage-based feed.

[0074] Control 1: 20% by mass of peanut vine silage without fungicide + 80% by mass of whole-plant corn silage basic feed.

[0075] Control 2: 30% by mass of peanut vine silage without fungicide + 70% by mass of whole-plant corn silage basic feed.

[0076] Experiment 1: 20% by mass of peanut seedling silage containing microbial agent (microbial agent was added according to the T5 experimental group of Example 5) + 80% by mass of whole-plant corn silage basic feed.

[0077] Experiment 2: 30% by mass of peanut seedling silage containing microbial agent (the microbial agent was added according to the T5 experimental group of Example 5) + 70% by mass of whole-plant corn silage basic feed; the number of diarrhea cases in buffaloes during the experimental period was recorded: 1 occurrence of diarrhea was recorded as 1, and 2 occurrences of diarrhea were recorded as 2.

[0078] Colostrum sample collection: Within 24 hours of buffalo delivery, 30 mL of mixed milk sample was collected by hand expression and stored in a -20°C refrigerator for testing. The colostrum was tested for milk fat, milk protein, lactose, milk non-fat solids, and total milk solids content, as shown in Table 7.

[0079] Table 7 Effect of peanut silage on buffalo colostrum composition

[0080]

[0081] As shown in Table 7, there was no significant difference in the milk fat and lactose content in the colostrum of each experimental group (p>0.05), indicating that peanut silage had little effect on the milk fat and lactose content in colostrum.

[0082] In terms of milk protein content, Experiment 2>Experiment 1>CK, but the difference in milk protein content among Experiment 1, Experiment 2 and CK groups was not significant, but was significantly higher than Control 1 and Control 2 (p<0.05), indicating that for milk protein, the improvement effect of Experiment 1 and Experiment 2 was not obvious.

[0083] From the perspective of milk non-fat solids, the milk non-fat solids content of Experiment 1 and Experiment 2 was higher than that of the control CK group, among which the difference between Experiment 2 and CK was significant (p<0.05), and the milk non-fat solids content increased with the increase of the addition amount of peanut vine silage containing bacterial agents. The milk non-fat solids content of Control 1 and Control 2 was lower than that of the control CK group, and the milk non-fat solids content decreased with the increase of the addition amount of peanut vine silage without bacterial agents.

[0084] In terms of total milk solids, the total milk solids content of Experiments 1 and 2 was significantly higher than that of the control CK group (p<0.05), the total milk solids content of Control 2 was significantly lower than that of the control CK group (p<0.05), and there was no significant difference in the total milk solids content between Control 1 and the CK group (p>0.05). As the amount of peanut vine silage without fungicide added increased, the total milk solids content decreased.

[0085] In terms of the number of diarrhea, the number of diarrhea in Experiment 1 and Experiment 2 was 0, which was lower than that in the CK group and Control 1 and Control 2.

[0086] The results showed that peanut vine feed prepared by fermentation of composite non-lactolytic Streptococcus had a significant effect on improving the non-fat solids and total solids of buffalo milk, and had a significant effect on ruminants. In addition, it could effectively relieve diarrhea in animals.

[0087] In summary, the strain GX-2 screened by the applicant of the present invention is suitable for survival in the stomach and has an antibacterial effect on Staphylococcus aureus, Escherichia coli, Pseudomonas fluorescens, and Listeria monocytogenes; it has good fermentation ability on peanut seedlings, and a composite bacterial agent prepared by non-lactolytic Streptococcus GX-7 and non-lactolytic Streptococcus GX-2 and inoculated into peanut seedlings can achieve a synergistic fermentation effect at a mass ratio of 1:1-3. After feeding silage prepared from this composite bacterial agent to pregnant buffaloes, it was found that the feed can effectively increase the total milk solids and milk non-fat solids content in the buffalo colostrum, thereby alleviating diarrhea in the buffaloes.

[0088] The above-described embodiments merely illustrate several embodiments of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. Streptococcus alactolyticus strain GX-2, characterized in that The deposit number of the Streptococcus alactolyticus strain GX-2 is GDMCC NO:65508.

2. A composite bacterial agent comprising the Streptococcus alactolyticus strain GX-2 according to claim 1.

3. The composite bacterial agent according to claim 2, characterized in that The composite bacterial agent further comprises a non-lactose-lytic Streptococcus alactolyticus strain GX-7; the deposit number of the non-lactose-lytic Streptococcus alactolyticus strain GX-2 is GDMCC NO:65509.

4. The composite bacterial agent according to claim 3, characterized in that The composite bacterial agent is prepared by mixing non-lactose-lytic Streptococcus alactolyticus strain GX-7 and non-lactose-lytic Streptococcus alactolyticus strain GX-2 in a mass ratio of 1:1-3.

5. The composite bacterial agent according to claim 4, characterized in that The composite bacterial agent is prepared by mixing non-lactose-lytic Streptococcus alactolyticus strain GX-7 and non-lactose-lytic Streptococcus alactolyticus strain GX-2 in a mass ratio of 1:

3.

6. Use of the Streptococcus alactolyticus strain GX-2 according to claim 1 or the composite bacterial agent according to claim 2 in preparing peanut seedling silage.

7. Use of the Streptococcus alactolyticus strain GX-2 according to claim 1 in the production of bile salt-tolerant and / or diarrhea-relieving drugs.

8. Use of the Streptococcus alactolyticus strain GX-2 in the preparation of an antibacterial agent according to claim 1, characterized in that: The pathogenic bacteria inhibited by the bacteriostatic agent are Staphylococcus aureus, Escherichia coli, Pseudomonas fluorescens and / or Listeria monocytogenes.

9. Silage comprising the Streptococcus alactolyticus strain GX-2 according to claim 1 or the composite bacterial agent according to claim 2, characterized in that: The silage preparation method comprises the following steps: inoculating non-lactose Streptococcus alactolyticus strain GX-2 or a composite bacterial agent into peanut seedlings at an inoculation rate of 5% by mass and silaging for 35 days to obtain the silage.

10. A method for feeding pregnant buffaloes with the silage according to claim 9, wherein the method comprises: mixing 20%-30% by mass of the silage with 70%-80% by mass of a basal diet and feeding the mixture to the pregnant buffaloes, wherein the basal diet is a whole-plant corn silage basal diet.

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