JP5515062B2 - Lactic acid bacteria producing novel bacteriocin and method for producing silage-fermented TMR feed using the same - Google Patents

Description

The present invention relates to a lactic acid strain having an excellent bacteriocin-producing ability (an excellent inhibitory action against the growth of harmful microorganisms in fermented feed) and a property suitable for producing a high-quality fermented feed.
In addition, the present invention provides a microorganism preparation for producing a fermented feed comprising the above strain; a fermented feed that can be stored for a long time and has a high quality, characterized by adding the strain (specifically, silage, fermentation A method for producing TMR feed).

In Japan, more than 70% of roughage production such as pasture and forage crops is prepared and processed into silage.
However, some silage prepared depending on the “natural fermentation” of forage crops and pastures has a low lactic acid content and many inferior butyric acid type and acetic acid type, and its palatability and food intake are excellent. Not a thing. In addition, in the process of silage preparation and storage, there are many cases in which rolls are discarded due to generation of mold and poor quality fermentation.
In addition, “fermented TMR feed” requires high-quality feed preparation technology (fermentation technology) that makes effective use of low and unused feed resources from the perspective of building a resource recycling society and reducing environmental impact. Has been.

In addition, research on silage preparation so far includes maintaining anaerobic conditions such as old shredding and compaction, adjustment of moisture in material grass to which beet pulp is added, replenishment of material sugar content to which molasses is added, etc. The preparation technology has been spread worldwide.
In recent years, lactic acid bacteria preparations and fiber-degrading enzyme cellulases as fermentation starters have been applied to the field of silage preparation, and the effect of improving the silage fermentation quality by them has gradually been widely recognized.
By using a lactic acid bacteria preparation as a fermentation starter for silage fermentation, an effect of improving the silage fermentation quality is recognized (see Non-Patent Documents 1 to 3, Patent Documents 1 and 2). These lactic acid bacteria have a mechanism that lowers the pH by lactic acid produced in silage fermentation, partially suppresses spoilage bacteria, and preserves silage.
However, in silage fermentation, spore butyric acid bacteria and Bacillus, which are causative bacteria that degrade the quality of fermented feed, are resistant to acid, so lactic acid produced by lactic acid bacteria alone can improve the quality of silage and fermented TMR feed. A sufficient effect could not be demonstrated.

JP 2006-42647 A JP 2007-82468 A

The role and quality improvement of silage lactic acid bacteria. Yoshimi Tsuji (2001.12) Journal of Japanese Society of Grassland Science 47 (5): 527-533. Yimin Yang (2007.3.31) Preparation of silage with probiotic function. New livestock technology-near future edition-. p70-71. Yoshimi Tsuji (2006.3.1) Utilization of microorganisms in silage preparation. Livestock research 60 (3): 369-375.

An object of the present invention is to solve the above-mentioned problems and to provide a technique for producing a fermented feed (silage, fermented TMR feed) of high quality that can be stored for a long period of time using microorganisms.
Moreover, this invention aims at providing the manufacturing technology of the fermented feed which leads to reduction of a discard rate and cost reduction.

In the silage fermentation process, the present inventor significantly suppresses the growth of harmful microorganisms (microorganisms that promote the decay of fermented feed, microorganisms that cause deterioration in the quality of fermented feed, pathogenic microorganisms, etc.) and is useful for improving quality. We thought that the long-term storage property and quality of the fermented feed could be improved by promoting the growth of rice.
And this inventor paid attention to utilizing 'the lactic acid bacteria excellent in the growth inhibitory action of harmful microorganisms'.

(1) First, lactic acid bacteria having a broad antibacterial spectrum were screened against harmful microorganisms in the fermented feed. And we analyzed bacteriocin to produce, physiological biochemical properties and so on. As a result, the inventors have found a lactic acid strain having the ability to produce as many as three types of bacteriocin (excellent inhibitory action against the growth of harmful microorganisms) and having properties suitable for producing a high-quality fermented feed. One of the three types of bacteriocin was found to be a completely new molecular species with no report of homologous peptides.
(2) By adding this lactic acid strain to fermented feed materials (especially feed crops and grasses that are silage materials, fermented TMR feed materials) and silage fermentation, the growth of harmful microorganisms in the fermented feed is suppressed, It has been found that lactic acid bacteria (the lactic acid bacterial strain) can be greatly proliferated. And it was shown that the obtained fermented feed is a high-quality fermented feed that can be stored for a long time.
The present invention has been completed based on these findings.

That is, the present invention according to claim 1 is a lactic acid strain “Enterococcus faecium” having Enterocin L50A, Enterocin L50B and Enterocin IT production ability, acid resistance, and excellent lactic acid fermentation ability. NAS62 it relates to the strain (NITE P-781) ".
The present invention according to claim 2 relates to the strain according to claim 1, wherein the strain has an excellent inhibitory action against the growth of harmful microorganisms in the fermented feed.
This invention which concerns on Claim 3 is related with the manufacturing method of fermented feed characterized by adding the strain of Claim 1 or 2 to the raw material for fermented feed.
This invention which concerns on Claim 4 is related with the manufacturing method of the fermented feed of Claim 3 whose said raw material for fermented feed is a raw material for silage or a raw material for fermented TMR feed.
The present invention according to claim 5 relates to a microbial preparation for producing fermented feed comprising the strain according to claim 1 or 2 .

The present invention makes it possible to provide a microorganism that has an excellent inhibitory effect on the growth of harmful microorganisms and that is suitable for producing a high-quality fermented feed. Further, it is possible to provide a microorganism preparation for producing a fermented feed containing the microorganism.
As a result, the present invention makes it possible to produce a fermented feed in which harmful microorganisms (microorganisms that promote the decay of fermented feed, microorganisms that cause deterioration in the quality of fermented feed, pathogenic microorganisms, etc.) are reduced and lactic acid bacteria have grown. . And, it is possible to produce a fermented feed (silage, fermented TMR feed) that can be stored for a long period of time and is of good quality (low pH, high lactic acid content, low ammonia nitrogen content). To do.
In addition, the present invention makes it possible to produce a fermented feed that is highly feedable and safe for livestock.

Thus, the present invention makes it possible to provide a fermented feed production technique that leads to a reduction in the disposal rate and cost reduction.
The present invention also makes it possible to provide a polypeptide (bacteriocin) having antibacterial properties.

1 is a photographic image diagram of a NAS62 strain isolated in Example 1. FIG. It is a figure in Example 1 which shows the separation result of the bacteriocin by the chromatography. FIG. 3 shows amino acid sequences and modifying groups of three types of bacteriocin in Example 1.

The present invention relates to a lactic acid strain having an excellent bacteriocin-producing ability (an excellent inhibitory action against the growth of harmful microorganisms in fermented feed) and a property suitable for producing a high-quality fermented feed.
In addition, the present invention provides a microorganism preparation for producing a fermented feed comprising the above strain; a fermented feed that can be stored for a long time and has a high quality, characterized by adding the strain (specifically, silage, fermentation A method for producing TMR feed).

<New lactic acid strain>
The novel lactic acid strain in the present invention has an excellent bacteriocin-producing ability (an excellent inhibitory action against the growth of harmful microorganisms in fermented feed) and is suitable for the production of high-quality fermented feed , Has.
Examples of such strains include “Enterococcus faecium NAS62 strain (NITE P-781)”.

As a feature of the mycological property of the NAS62 strain, first, “excellent bacteriocin-producing ability” can be mentioned.
Here, the superior bacteriocin-producing ability is specifically the ability to simultaneously produce three types of bacteriocins, Enterocin L50B, Enterocin L50A, and Enterocin IT.
The NAS62 strain has “an excellent growth inhibitory action against harmful microorganisms in the fermented feed” by the produced bacteriocin.
Here, harmful microorganisms are aerobic bacteria such as Escherichia coli, which are 'microorganisms that promote the decay of fermented feed', fungi such as yeast and fungi; 'causative microorganisms that degrade the quality of fermented feed' Bacillus, butyric acid bacteria, etc .; Salmonella, etc., which is a “livestock pathogenic microorganism”.

Three types of bacteriocins, Enterocin L50B, Enterocin L50A, and Enterocin IT, are polypeptide substances having excellent antibacterial activity.
In particular, Enterocin L50B and L50A exhibit antibacterial activity against many microorganisms in the fermented feed and have a broad antibacterial spectrum. Enterocin IT shows strong antibacterial activity against Enterococcus faecium and related ones, but shows little antibacterial activity against other bacteria and has a narrow antibacterial spectrum.
Specifically, Enterocin L50B is a polypeptide in which the N-terminus of the amino acid sequence shown in SEQ ID NO: 1 is modified with a formyl group. Enterocin L50A is a polypeptide in which the N-terminus of the amino acid sequence shown in SEQ ID NO: 2 is modified with a formyl group. Enterocin IT is a polypeptide having the amino acid sequence shown in SEQ ID NO: 3. Enterocin IT is a completely new bacteriocin because there is no polypeptide having homology.
In addition, these bacteriocins may have various modifying groups such as formyl group, phosphate group, methyl group, acetyl group as long as they have the same antibacterial spectrum (specifically, the same antibacterial spectrum as in Table 2). Such as those having a glycoside bond, those modified with a glycoside bond, and amino acid sequences having no more than several substitutions, additions, deletions in the amino acid sequence of the above SEQ ID NO. Can be treated with seeds.

In addition, as a mycological property of the NAS62 strain, “property suitable for production of high-quality fermented feed” can be mentioned, and specifically, it has “acid resistance” and “excellent lactic acid fermentation ability”. is there. In addition, NAS62 strain | stump | stock points out the growth ability on anaerobic conditions, and since fermentation of a normal fermented feed is performed on anaerobic conditions, it is an essential property.
Here, "acid resistance" excellent lactic acid fermentation ability "is an essential property for producing a high-quality fermented feed (low pH and containing a large amount of lactic acid and organic acid). Moreover, as an excellent lactic acid fermentation ability, it has an efficient homofermentation type lactic acid fermentation ability and an L-type lactic acid production ability with high metabolism.

In addition, even strains other than the NAS62 strain were separately separated if they were “lactic acid bacteria belonging to Enterococcus faecium” having the same properties in terms of mycological properties as described above. Even a strain can be used as the strain of the present invention.
In particular, those having the same base sequence as 16S rDNA described in SEQ ID NO: 4 in the sequence listing can be used.

  As a method for separating the strain, a diluted solution of a separation source such as fermented feed material or fermented feed (specifically, grass or feed crop silage) is applied to an agar medium, and the strain is separated and cultured under anaerobic conditions. Then, selection can be made by examining the antibacterial spectrum, physiological and biochemical properties, etc. of the culture solution.

<Method for producing fermented feed>
In the present invention, it is essential to add the novel lactic acid strain to the fermented feed material.
As a method of addition, it is desirable that the addition is carried out so as not to be biased in the raw material and preferably uniform. For example, it can be carried out by a method in which the strain is dissolved (suspended or mixed) in water, a culture solution or the like and sprayed, or a method of mixing and stirring.
The amount of the strain to be added may be 10 ⁶ to 10 ¹⁰ bacteria level, preferably 10 ⁷ to 10 ⁹ bacteria level (specifically, about 10 ⁸ bacteria level) with respect to 1 kg of the raw material. desirable.
The strain is preferably added before the start of silage fermentation, but may be added at an intermediate stage of silage fermentation.
In addition to the novel lactic acid strain, other useful microorganisms (for example, microorganisms having an action of reducing nitrate and nitrite, probiotic microorganisms having an intestinal action of livestock, etc.) may be added.

  Examples of fermented feed materials that can be used in the present invention include silage raw grass and feed crops (eg, Italian ryegrass, Sudan grass, orchard, alfalfa, sorghum, corn, sorghum, etc.), fermented TMR feed materials (eg, concentrated) Feed, hay, beet pulp, vitamin / mineral preparations, raw materials mixed with crop by-products, food by-products, etc.).

As said fermentation, it can carry out on the conditions similar to normal silage fermentation. For example, when “silage” is prepared, it can be fermented by leaving it to stand for 30 days or more at an outside air temperature (about 10 to 30 ° C.) under anaerobic conditions. Specifically, it can be performed by a normal method using a silo, a roll bale silage method, a flexible container back method, and the like.
In addition, when preparing “fermented TMR feed”, it is fermented by preparing a moisture content of about 40 to 70% and leaving it at an outside temperature (about 10 to 30 ° C.) for 15 days or more under anaerobic conditions. be able to. Specifically, it can be performed by a flexible container back method, a roll bale method, or the like.

<Properties of fermented feed>
In the silage fermentation process, the added novel lactic acid strain grows in the feed and produces three types of bacteriocin. Therefore, the fermented feed obtained through the above fermentation process is one in which the harmful microorganisms (microorganisms that promote the decay of fermented feed, microorganisms that cause deterioration in the quality of fermented feed, pathogenic microorganisms, etc.) are greatly reduced. . Moreover, the number of lactic acid bacteria (the added strain) is greatly increased.
As a result, the lactic acid content in the fermented feed is increased and the pH is lowered. In addition, since spoilage microorganisms are suppressed, the decomposition of organic matter is suppressed.

  Therefore, the fermented feed (silage, fermented TMR feed) produced according to the present invention can be 'long-term storage' and 'good quality' (low pH, high lactic acid content, low ammonia nitrogen content) It is.

<Microbial preparation>
In the present invention, it can be provided in the form of a microorganism preparation containing the novel lactic acid strain.
Examples of the form of the microbial preparation include a powdered form obtained by freeze-drying the above-mentioned novel lactic acid strain, a solid form mixed with an excipient, a form filled in a capsule, a liquid ampoule form, and the like. it can. Preferably, the form of a lyophilized formulation is suitable.
Moreover, in this invention, in addition to the said novel lactic acid strain, it can also be set as the form of the agent formed by mixing other useful strains mentioned above separately.

As a usage form of the agent, it can be added directly to the raw material, but it is preferable to use it by dissolving (suspending or mixing) it in water or a culture solution.
The amount of the microorganism preparation of the present invention used is 10 ⁶ to 10 ¹⁰ bacteria level, preferably 10 ⁷ to 10 ⁹ bacteria level (specifically, about 10 ⁸ bacteria level) with respect to 1 kg of the raw material, It is desirable to add at.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, the technical scope of this invention is not limited by these.
<Example 1> Isolation and identification of NAS62 strain (1) Separation of strain Lactic acid strain having an excellent inhibitory effect on the growth of harmful microorganisms in fermented feed from silage, food residue, fermentation liquid and pig / cow gut Separation.
First, 10 g of each sample was collected in a plastic bag for stomacher (Hiryu KN208, manufactured by Asahi Kasei Co., Ltd.), 90 ml of sterilized physiological saline was added to make a 10-fold diluted solution, and this solution was further added to 10 ^8. Dilute to double.
Apply these diluted solutions to Lactobacilli MRS agar medium (DIFCO Laboratories, Detroit, USA), normal agar medium (Nissui Pharmaceutical Co., Ltd., Japan) and GYP white agar medium (Ozaki et al., Lactobacillus Experiment Manual, 1992). Then, an isolated strain was obtained by culturing at 37 ° C. for 2 days under anaerobic conditions using an anaerobic culture apparatus.
Each isolated strain obtained was screened for bacteriocin-producing lactic acid bacteria by the Spot-on-lawn method. Specifically, the culture solution of each isolate was dropped and cultured on indicator bacteria Lactococcus lactis RO50 and Enterococcus faecium WHE81, and lactic acid strains excellent in the growth inhibitory action of these indicator bacteria were selected.
As a result, among the above separation sources, 'NAS62 strain', which is a lactic acid strain having excellent antibacterial activity, was selected from Italian ryegrass silage.

(2) Mycological properties Table 1 shows the results of examining the mycological properties, physiological and biochemical properties, etc. of the strains isolated from the above culture. Moreover, the microscope picture of the isolate | separated strain is shown in FIG.

As FIG. 1 shows, the NAS62 strain was shown to be Streptococcus of the genus Enterococcus. As shown in Table 1, they were catalase-negative, homofermentative lactic acid cocci that produce L (+) lactic acid, and homofermentative lactic acid bacteria that produce L (+) lactic acid. Moreover, it was able to grow to pH4.5 and was shown to have acid resistance.
From these results, it was shown that the NAS62 strain is a lactic acid strain having “properties suitable for the production of high-quality fermented feed” (anaerobic, acid-resistant, and excellent lactic acid producing ability).

(3) Bacteriocin production ability Next, in order to examine the bacteriocin production ability in the NAS62 strain in detail, bacteriocin was purified from the culture supernatant showing antibacterial activity as described above.
First, the NAS62 strain was inoculated into 1 L of MRS liquid medium and cultured at 37 ° C. for 15 hours. The supernatant was collected by rotary centrifugation at 4,000 rpm and filtered through a 0.45 μm filter. The filtrate was adjusted to pH 6 with NaOH and applied to a cation exchange resin (SP-Sepharose HP; length 100-mm, inner diameter 26-mm [Amersham Biosciences, Orsay, France]), and concentration gradient with 0-1M NaCl. To obtain two active fractions α and β.
One of these fractions α was applied to C8 reverse phase HPLC, washed with a solution containing 35% acetonitrile and 0.1% trifluoroacetic acid, and then eluted with a water-acetonitrile gradient. As a result, since the peak shown in FIG. 2A was obtained, the major peaks Peak 1 and 2 were separated and purified by performing the same HPLC. The result of peak 1 is shown in FIG. 2B, and the result of peak 2 is shown in FIG. 2C.
The other fraction β was applied to C8 reverse phase HPLC, washed with a solution containing 20% acetonitrile and 0.1% trifluoroacetic acid, and then eluted with a concentration gradient of water-acetonitrile. As a result, peak 3 which is a major peak shown in FIG. 2D was obtained.
From these facts, it was revealed that three types of polypeptides indicated by peaks 1 to 3 exist in the culture supernatant.

The isolated and purified product obtained by fractionating each peak 1 to 3 was analyzed by nanoLC-MS / MS and the molecular weight was measured. Moreover, N terminal sequence was performed using the peptide sequencer (473A microsequencer, Applied Biosystems), and the amino acid sequence was determined.
The results are shown in FIG. In FIG. 3, “Formyl-” represents a formyl group-modified amino acid.
As a result, what peak 1 shows is a polypeptide having the molecular weight of 5206 Da, SEQ ID NO: 1 and the amino acid sequence shown in FIG. 3 (1), and having the modifying group shown in FIG. 3 (1). Indicated. And it became clear from the similarity of the amino acid sequence that it is 'Enterocin 50B' in NAS62 strain.
Moreover, what peak 2 shows is a polypeptide having the molecular weight of 5218 Da, SEQ ID NO: 2 and the amino acid sequence shown in FIG. 3 (2), and having the modifying group shown in FIG. 3 (2). It was. And it became clear from the similarity of the amino acid sequence that it is 'Enterocin 50A' in NAS62 strain.
Furthermore, what peak 3 shows was a polypeptide having a molecular weight of 6390 Da, SEQ ID NO: 3 and the amino acid sequence shown in FIG. 3 (3). Since this amino acid sequence revealed that it was a completely new bacteriocin, it was named 'Enterocin IT'.
In FIG. 2, the minor peaks indicated by 1 ′ and 2 ′ were polypeptides containing sites where oxidative deamination of Enterocin 50B and Enterocin 50A, respectively.

(4) Antibacterial spectrum The antibacterial spectrum was investigated about three types of said bacteriocin obtained.
For Bacillus, lactic acid bacteria, Listeria, Staphylococcus aureus, Escherichia coli, Salmonella, psychromycetes, and green-concentrated bacteria present in the fermented feed, 50 μL of each indicator bacterial suspension shown in Table 2 and 10 μL of purified bacteriocin ( About 1 μg) was injected into a 96-well microplate and cultured at 30 ° C. or 37 ° C., which is the indicated growth temperature of each indicator bacterium, for 24 hours.
Further, as a control, those without bacteriocin were cultured in the same manner.
Then, the absorbance at 600 nm was continuously measured using a microplate reader, and the value when the difference from the control reached the maximum during the culture period was defined as a value representing antibacterial activity. The results are shown in Table 2.

As a result, Enterocin L50B and L50A exhibit antibacterial activity for all of the above-mentioned bacteria belonging to Bacillus, lactic acid bacteria, Listeria, Staphylococcus aureus, Escherichia coli, Salmonella, spirits, and green-concentrated fungi, which are abundant in fermented feed. It was shown to have a broad antimicrobial spectrum.
On the other hand, Enterocin IT showed strong antibacterial activity against Enterococcus faecium and its related ones, but showed little antibacterial activity against other fungi and a narrow antibacterial spectrum.

  From these facts, the NAS62 strain has the ability to produce Enterocin L50B, Enterocin L50A, Enterocin IT (excellent bacteriocin production ability), and is a harmful microorganism in fermented feed that promotes spoilage (such as Escherichia coli). Aerobic bacteria), microorganisms that cause deterioration in the quality of fermented feed (such as Bacillus) and pathogenic microorganisms (such as Salmonella).

(5) Molecular phylogenetic analysis The selected NAS62 strain was subjected to molecular phylogenetic analysis by determining the entire region base sequence of the 16S rRNA gene. The determined base sequence of 16S rDNA is shown in the Sequence Listing (SEQ ID NO: 4).

As a result of molecular phylogenetic analysis, the molecular phylogenetic position of the NAS62 strain was in the cluster of the genus Enteorococcus, and showed the closest phylogenetic relationship with the reference strain with Enterococcus faecium. Furthermore, it was identified as Enterococcus faecium by the result of DNA-DNA homology test.
Although this strain has the most related strain relationship with the reference strain, it was different in the ability to produce bacteriocin from the reference strain in terms of sugar fermentation characteristics. Therefore, the present inventors determined that this strain was a novel strain and named it “Enterococcus faecium NAS62”. This strain has been deposited with the Patent Organism Depositary, National Institute of Technology and Evaluation, and the deposit number is “NITE P-781”.

<Example 2> Production of fermented feed and fermented quality (1) Production of feed crop silage and grass silage First, the NAS62 strain was inoculated into Lactobacilli MRS liquid medium (DIFCO Laboratories, Detroit, USA), and was subjected to 30 ° C under anaerobic conditions. And the concentration of the bacterial culture was adjusted to 1.0 × 10 ⁸ cfu / ml (1.0 × 10 ⁸ cells / ml).
Next, feed rice (variety: Hamasari) in the yellow ripening period was harvested with a feed rice-only harvesting roll baler, formed into a roll bale, and sealed using a wrap machine. Further, Timothy orchardgrass mixed sowing grass at the heading stage was harvested with a harvesting roll baler for pasture, formed into a roll bale, and sealed using a wrap machine.
At the time of forming each roll veil, 1200 ml of NAS62 strain culture solution per roll (the culture solution of the bacteria per 1 kg of the raw material) was automatically added by an automatic addition device (the fungus culture solution was injected into the addition tank) attached to the roll baler. 1 ml) was added. Then, silage fermentation was carried out by storing in the field for 90 days to produce “forage crop roll bale silage” and “grass roll bale silage”.
As a control, forage crop roll bale silage and grass roll bale silage were produced in the same manner as above except that NAS62 strain was not added.

(2) Manufacture of fermented TMR feed 1 mL of the above-mentioned NAS62 fungus culture solution is added to concentrated feed, hay, beet pulp and vitamin / mineral preparations and mixed to adjust the water content to about 60%. Was stored for 15 days to produce a fermented TMR feed.
As a control, a fermented TMR feed was produced in the same manner as described above except that the NAS62 strain was not added.

(3) Fermentation quality and microbial flora of various fermented feeds For the feed crop silage, grass silage, and fermented TMR feed obtained above, the fermentation quality and microbial flora were examined depending on whether NAS62 strain was added.
For each roll bale silage, 5 rolls are tested for each treatment section, and samples from the outer layer part to the middle part of the upper, middle and lower stages of the roll bale are sampled as analysis samples, and a total of 3 points for each roll bale for quality analysis Provided.
In addition, five fermented TMR feeds were tested for each treatment section, and the upper, middle and lower stages of the fermented TMR feed were sampled as analysis samples, and a total of three points were used for quality analysis for each fermented TMR feed. .
The results are shown in Table 3.

nd: not detected, ±: weakly positive

As a result, as Table 3 shows, by adding NAS62 strain, harmful microorganisms in the fermented feed are greatly reduced (1/13 to 1/433 for aerobic bacteria compared to the control; 1/15 to undetected; filamentous fungi were undetected).
From this, the obtained fermented feed is one that is suppressed in the growth of microorganisms that promote spoilage (E. coli, other aerobic bacteria, fungi such as mold), and is “suitable for long-term storage” It has been suggested. It was also suggested that the growth of causative microorganisms and pathogenic microorganisms that degrade the quality of fermented feed is suppressed.

It was also shown that lactic acid bacteria in the fermented feed grow significantly (53-111 times compared to the control). Considering the antibacterial spectrum of bacteriocin produced by the NAS62 strain, most of this was thought to be the growth of the NAS62 strain itself.
The fermented feed thus obtained has a high lactic acid content, a low pH, and a reduced content of various organic acids other than lactic acid and ammonia nitrogen. 'It was shown.

The present invention is expected to be widely used in the livestock field as an additive for silage and TMR fermented feed. It is also environmentally friendly and safe.
In addition, technology transfer to feed manufacturers is expected as an additive for new silage preparation (manufacturing).

  NITE P-781

Claims (5)

A lactic acid strain “Enterococcus faecium NAS62 strain (NITE P-781) ” that has the ability to produce Enterocin L50A, Enterocin L50B and Enterocin IT, and has acid resistance and excellent lactic acid fermentation ability .   The strain according to claim 1, wherein the strain has an excellent inhibitory action against growth of harmful microorganisms in the fermented feed.   A method for producing a fermented feed, comprising adding the strain according to claim 1 to a raw material for fermented feed.   The method for producing a fermented feed according to claim 3, wherein the raw material for fermented feed is a raw material for silage or a raw material for fermented TMR feed.   A microbial preparation for producing a fermented feed comprising the strain according to claim 1 or 2.