Kluyveromyces lactis FRI and novel application of lysate thereof

Abstract

The invention belongs to the technical field of biology, and discloses kluyveromyces lactis FRI and application of lysate thereof in preparation of weaned piglet feed additives or application of lysate thereof in preparation of weaned piglet feeds, and the preservation number of the kluyveromyces lactis FRI is CGMCC No.30910; the preservation date is June 24, 2024, the classification name is Kluyveromyces lactis, the preservation unit is China General Microbiological Culture Collection Center, and the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing. Kluyveromyces lactis and lysate thereof are added into the feed, so that the growth performance of weaned piglets can be improved, and the diarrhea rate can be reduced.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, and more specifically to a novel use of Kluyveromyces lactis FRI and its lysate products. Background Technology

[0002] The applicant filed an earlier application, publication number CN120536262A, entitled "Kluyveromyces lactis FRI and its uses" (hereinafter referred to as the earlier application). In that patent application, the applicant screened and obtained a strain of Kluyveromyces lactis FRI, which has a unique lignin-degrading enzyme (laccase) gene; based on its strong adaptability to sinapic acid, one of the raw materials in the lignin synthesis process, it can decompose lignin.

[0003] The application of Kluyveromyces lactis in feed can be seen in the following patent application:

[0004] US Patent Application No. 4083960A, which relates to a method for preventing diarrhea in piglets and calves, mentions that an effective amount of β-galactosidase is administered orally to the pig or calf during at least a portion of the lactation or weaning period, and wherein the β-galactosidase is stable in the stomach of the pig or calf; the β-galactosidase is derived from Kluyveromyces lactis.

[0005] In the course of this study, the applicant discovered some differences in application from the aforementioned technologies, and thus filed this application. Summary of the Invention

[0006] One of the objectives of this invention is to provide a novel function of Kluyveromyces lactis FRI in the preparation of feed for weaned piglets, which can improve growth performance and diarrhea rate in weaned piglet feed.

[0007] Simultaneous studies on the lysate products of this strain have also shown some effectiveness.

[0008] Another objective of this invention is to provide the application of Kluyveromyces lactis FRI in the preparation of feed additives for weaned piglets or in the preparation of feed for weaned piglets, wherein the Kluyveromyces lactis FRI has the accession number CGMCC No. 30910; accession date June 24, 2024; classification name: Kluyveromyces lactis; depository institution: China General Microbiological Culture Collection Center; depository address: No. 3, No. 1 Courtyard, Beichen West Road, Chaoyang District, Beijing.

[0009] Information on related strains of Kluyveromyces lactis FRI, such as ITS, can be found in previous applications.

[0010] In the above applications, the weaned piglet feed additives and weaned piglet feeds refer to weaned piglet feed additives and weaned piglet feeds that have the function of promoting the growth performance of weaned piglets and / or reducing the diarrhea rate.

[0011] Furthermore, this invention also discloses the application of the lysate of Kluyveromyces lactis FRI in the preparation of feed additives for weaned piglets or in the preparation of feed for weaned piglets. The Kluyveromyces lactis FRI has the accession number CGMCC No. 30910; accession date June 24, 2024; classification name: Kluyveromyces lactis; depository institution: China General Microbiological Culture Collection Center; depository address: No. 3, No. 1 Courtyard, Beichen West Road, Chaoyang District, Beijing.

[0012] In the above applications, the weaned piglet feed additives and weaned piglet feeds refer to weaned piglet feed additives and weaned piglet feeds that have the function of promoting the growth performance of weaned piglets and / or reducing the diarrhea rate.

[0013] Finally, the present invention also discloses a weaned piglet feed containing the above-mentioned Kluyveromyces lactis FRI or Kluyveromyces lactis FRI lysate.

[0014] In the above-mentioned weaned piglet feed, the weaned piglet feed contains 0.1~1wt% of Kluyveromyces lactis FRI or the lysate of Kluyveromyces lactis FRI.

[0015] In the above-mentioned weaned piglet feed, the weaned piglet feed contains 0.3~0.7wt% of Kluyveromyces lactis FRI or the lysate of Kluyveromyces lactis FRI.

[0016] It should be noted that, in this field, the acquisition of bacterial lysate products is generally divided into two methods: hydrolysis and enzymatic hydrolysis, both of which ultimately yield a mixture of the bacterial cell wall and contents. In production, both of the above methods are applicable to this invention. In the relevant experiments of this invention, the hydrolysis method was used to obtain the lysate products of Kluyveromyces lactis FRI.

[0017] Beneficial effects

[0018] Adding Kluyveromyces lactis and its lysate to feed can improve the growth performance of weaned piglets and reduce the diarrhea rate. Furthermore, based on the results of this experiment, the optimal addition amount of Kluyveromyces lactis powder (live bacteria) is 0.5 wt%, and the optimal addition amount of Kluyveromyces lactis lysate is 1 wt%. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0020] Figure 1 Figure 1 shows the effect of Kluyveromyces lactis FRI on the levels of pro-inflammatory cytokines and immunoglobulins in the plasma of weaned piglets; (A) shows the plasma levels of IL-6, TNF-α and IgA on day 14 of the experiment; (B) shows the plasma levels of IL-6, TNF-α and IgA on day 28 of the experiment.

[0021] Figure 2 Figures show the effects of Kluyveromyces lactis FRI hydrolysate on the levels of pro-inflammatory cytokines and immunoglobulins in the plasma of weaned piglets; (A) plasma levels of IL-6, TNF-α, and IgA on day 14 of the experiment; (B) plasma levels of IL-6, TNF-α, and IgA on day 28 of the experiment. Detailed Implementation

[0022] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0023] Example 1

[0024] β-galactosidase activity assay

[0025] Kluyveromyces lactis (FRI) was cultured in malt extract medium under the following conditions: temperature 30℃, shaker speed 150 rpm, pH = 7.0, culture volume 50 mL, inoculum size 2%, with three replicates per group. β-galactosidase levels were determined using culture medium collected during the logarithmic growth phase (6 hours of culture).

[0026] Test subjects: blank group (CON) is the culture medium without Kluyveromyces lactis FRI, Kluyveromyces lactis FRI culture medium (S1), and Kluyveromyces lactis FRI lysate (S2).

[0027] Assay method: The β-galactosidase activity assay kit from Beijing Box Biotechnology Co., Ltd. was used. The assay method is as described in the kit's instruction manual.

[0028] ① Preheat the spectrophotometer / ELISA reader for at least 30 minutes, adjust the wavelength to 400 nm, and zero the instrument with distilled water.

[0029] ② Add the reagents shown in Table 1 below to a 96-well plate or centrifuge tube in sequence;

[0030] Table 1 Reagent List

[0031] Absorbance measurement: Measure the absorbance at 400 nm and record it as Ameasurement, Acontrol, Astandard, and Ablank; calculate ΔAmeasurement = Ameasurement - Acontrol, ΔAstandard = Astandard - Ablank.

[0032] Note: Each test group should have a control group, and the blank group only needs to be tested 1-2 times.

[0033] Establishment of the standard curve: Plot the standard curve with 300, 200, 100, 50, 25, and 12.5 nmol / mL as the abscissa (x) and the corresponding ΔA standard as the ordinate (y). The standard equation is y = kx + b. Substitute the ΔA measurement into the formula to obtain x (nmol / mL).

[0034] Unit definition: One unit of enzyme activity is defined as 1 nmol of p-nitrophenol generated per hour per mL of liquid sample.

[0035] β-galactosidase β-GAL (U / mL) = (x*Vtotal) / (Vsample*T).

[0036] Notes: Vsample: Volume of crude enzyme solution added to the reaction system, 0.01 mL; Vsample total: Total volume of crude enzyme solution, 1 mL; Vreaction total: Total volume of the reaction system, 0.07 mL; T: Reaction time, 0.5 h.

[0037] The results of β-galactosidase activity assay are shown in Table 2.

[0038] Table 2 Results of β-galactosidase activity assay

[0039] project CON S1 (live yeast) S2 (yeast lysate) β-galactosidase activity Not detected Not detected Not detected

[0040] The test results showed that no β-galactosidase activity was detected in either T1 or T2 samples, indicating that Kluyveromyces lactis FRI does not have β-galactosidase activity.

[0041] The above results indicate that the superior effects of this invention in subsequent aquaculture experiments are not related to β-galactosidase.

[0042] Example 2

[0043] Experimental Design

[0044] This experiment employed a single-factor randomized experimental design to explore the effects of different amounts of Kluyveromycin FRI supplementation on the growth performance and diarrhea rate of weaned piglets and to investigate its mechanism of action.

[0045] Ninety 28-day-old weaned piglets (average weight approximately 7.5 kg) were selected and divided into five treatment groups according to weight, with six replicates (pens) per treatment group and three piglets per pen. The CT group served as the control group, fed a corn-soybean meal basal diet; the T1 group received an additional 0.5% yeast powder on top of the basal diet; the T2 group received an additional 1% yeast powder on top of the basal diet; the T3 group received an additional 0.5% yeast hydrolysate on top of the basal diet; and the T4 group received an additional 1% yeast hydrolysate on top of the basal diet. The protein and metabolizable energy of each group were balanced by adjusting the amounts of soybean meal and corn, ensuring that the protein, amino acid, and metabolizable energy of each treatment group were consistent with the control diet (Table 3). Piglets had free access to feed and water during the experiment, which lasted for 28 days.

[0046] Table 3. Dietary composition during the trial period (basal feeding, %)

[0047] raw material control group Group T1 Group T2 Group T3 Group T4 corn 35.81 35.61 35.41 35.51 35.31 Soybean meal, 43% crude protein 16.80 16.50 16.20 16.60 16.30 <![CDATA[Kluyveromyces lactis FRI bacterial powder 1 > - 0.50 1.00 - - <![CDATA[Kluyveromyces lactis FRI hydrolyzate 2 > - - - 0.50 1.00 puffed corn 15.00 15.00 15.00 15.00 15.00 puffed soybeans 13.50 13.50 13.50 13.50 13.50 Fish meal 3.00 3.00 3.00 3.00 3.00 whey powder 10.00 10.00 10.00 10.00 10.00 Soybean oil 1.00 1.00 1.00 1.00 1.00 calcium dihydrogen phosphate 0.70 0.70 0.70 0.70 0.70 stone powder 1.00 1.00 1.00 1.00 1.00 salt 0.40 0.40 0.40 0.40 0.40 Choline chloride 60% 0.05 0.05 0.05 0.05 0.05 Lysine 1.15 1.15 1.15 1.15 1.15 Methionine 0.09 0.09 0.09 0.09 0.09 threonine 0.26 0.26 0.26 0.26 0.26 Tryptophan 0.02 0.02 0.02 0.02 0.02 10000 phytase 0.02 0.02 0.02 0.02 0.02 Zinc oxide 0.20 0.20 0.20 0.20 0.20 1% premix 1.00 1.00 1.00 1.00 1.00 total 100.00 100.00 100.00 100.00 100.00

[0048] Note: 1 The viable count of Kluyveromyces lactis FRI was 8.25 × 10⁻⁶. 10 CFU / g;

[0049] 2 The preparation method of Kluyveromyces lactis FRI hydrolysate is as follows: Kluyveromyces lactis FRI bacterial culture is concentrated to a dry weight fraction of 10-12%. The initial pH value is measured using a pH meter and adjusted to 5.0 (using phosphate buffer or dilute acid / alkali solution). 0.3% (w / w) of yeast cell wall-breaking enzyme A (complex protease A) is added to the culture, and enzymatic hydrolysis is carried out at 45℃ for 3 hours. This enzyme mainly breaks down protein-polysaccharide complexes in the cell wall by specifically hydrolyzing protein bonds, thus initially opening the cell structure. After enzymatic hydrolysis, the pH is measured and adjusted to 9.0 (using sodium hydroxide solution). Subsequently, 0.1% (w / w) of yeast cell wall-breaking enzyme B (cellulase B) is added, and enzymatic hydrolysis is carried out at 55℃ for 3 hours. This enzyme can efficiently degrade β-glucan and cellulose, further cleaving the cell wall and releasing intracellular active components. After enzymatic hydrolysis, moisture is removed using spray drying technology to finally obtain the Kluyveromyces lactis FRI hydrolysate product.

[0050] Test index determination and methods

[0051] Growth performance

[0052] Each piglet was weighed on days 0, 14, and 28 of the experiment. Feed consumption was recorded on days 14 and 28. Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio F:G (ADFI / ADG) were calculated based on the above data. Mortality rate and medication administration were recorded throughout the experiment.

[0053] Stool score

[0054] During the 0-28 day experiment, each piglet was observed for diarrhea at 2 pm every day. The condition of the feces was scored according to the standards in the table below. A score of ≥3 was considered the onset of diarrhea symptoms. The diagnosis was also made in combination with the piglet's mental state, the condition of the feces in the pen, and the condition of the anus (whether there was fecal contamination or redness at the anus). The number of piglets with diarrhea and the duration of diarrhea were recorded (Table 4).

[0055] Table 4. Stool Scoring Criteria

[0056] diarrhea severity Appearance score Normal (dry stool) Normal, cylindrical 1 Normal (soft stool) Soft and tangible 2 Mild diarrhea viscous, shapeless, high moisture content 3 Severe diarrhea Liquid, unformed, watery, thin feces 4

[0057] Plasma antioxidant and immune indicators

[0058] On days 14 and 28 of the experiment, blood samples were collected from the anterior vena cava in blood collection tubes containing a procoagulant. The supernatant was collected by centrifugation to obtain plasma samples. Pro-inflammatory cytokines, interleukin (IL)-6 and tumor necrosis factor (TNF)-α, and immunoglobulin (Ig) A were measured in the plasma samples. All these indicators were measured using kits purchased from Shanghai Enzyme-Linked Biotechnology Co., Ltd., and the measurement methods followed the kit instructions.

[0059] Statistical analysis

[0060] The experimental data will be statistically analyzed using the GLM program in SAS 9.4 (SAS Institute, 2008). Each column will serve as the statistical unit for production performance. The Tukey LSD test will be used for multiple comparisons between groups, with a p-value less than or equal to 0.05 indicating a significant difference between groups.

[0061] The experimental results are shown in Tables 5 and 6.

[0062] Table 5 Growth performance of weaned piglets

[0063] Note: CT, control group fed with basal diet; T1, basal diet supplemented with 0.5% Kluyveromyces lactis; T2, basal diet supplemented with 1% Kluyveromyces lactis; T3, basal diet supplemented with 0.5% Kluyveromyces lactis hydrolysate; T4, basal diet supplemented with 1% Kluyveromyces lactis hydrolysate. a,b,c Different letters represent significant differences (p < 0.05).

[0064] Table 6. Diarrhea rate in weaned piglets (%)

[0065] Note: CT, control group fed with basal diet; T1, basal diet supplemented with 0.5% Kluyveromyces lactis; T2, basal diet supplemented with 1% Kluyveromyces lactis; T3, basal diet supplemented with 0.5% Kluyveromyces lactis hydrolysate; T4, basal diet supplemented with 1% Kluyveromyces lactis hydrolysate.

[0066] a,b Different letters represent significant differences (p < 0.05).

[0067] Figure 1 Effects of Kluyveromyces lactis FRI on the levels of pro-inflammatory cytokines and immunoglobulins in the plasma of weaned piglets. (A) Plasma levels of IL-6, TNF-α, and IgA on day 14 of the experiment; (B) Plasma levels of IL-6, TNF-α, and IgA on day 28 of the experiment.

[0068] Figure 2 Effects of Kluyveromyces lactis FRI hydrolysate on the levels of pro-inflammatory cytokines and immunoglobulins in the plasma of weaned piglets. (A) Plasma levels of IL-6, TNF-α, and IgA on day 14 of the experiment; (B) Plasma levels of IL-6, TNF-α, and IgA on day 28 of the experiment.

[0069] Results analysis:

[0070] WeightBW

[0071] BW0 (initial body weight): The initial body weight values ​​of each treatment group were similar (P = 0.994), indicating that there was no significant difference in initial body weight among the groups and the initial conditions of the experiment were balanced.

[0072] BW14 (body weight after 14 days of treatment): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (increased by 13.5%), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, there were no significant changes in either the low-dose yeast hydrolysate T3 group or the high-dose yeast hydrolysate T4 group.

[0073] BW28 (body weight after 28 days of treatment): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (increased by 16.7%), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, there were no significant changes in either the low-dose yeast hydrolysate T3 group or the high-dose yeast hydrolysate T4 group.

[0074] Average daily weight gain (ADG)

[0075] ADG (treatment period 1–14 days): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (44.4% increase), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, the high-dose yeast hydrolysate T4 group was significantly higher than the control group (P < 0.05) (38.3% increase), while the low-dose yeast hydrolysate T3 group showed no significant change.

[0076] ADG (treatment period 15-28 days): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (increased by 38.5%), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, the low-dose yeast hydrolysate T3 group was significantly higher than the control group (P < 0.05) (increased by 25.4%), while the high-dose yeast hydrolysate T4 group showed no significant change.

[0077] Throughout the entire ADG period (treatment period 1-28 days): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (68.5% increase), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, the low-dose yeast hydrolysate T3 group (48.4% increase) and the high-dose yeast hydrolysate T4 group (44.7% increase) were both significantly higher than the control group CT (P < 0.05).

[0078] Average Daily Feed Intake (ADFI)

[0079] ADFI (treatment period 1-14 days): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (increased by 28.3%), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, the high-dose yeast hydrolysate T4 group was significantly higher than the control group (P < 0.05) (increased by 18.5%), while the low-dose yeast hydrolysate T3 group showed no significant change.

[0080] ADFI (treatment period 15-28 days): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (increased by 29.7%), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, there were no significant changes in either the low-dose yeast hydrolysate T3 group or the high-dose yeast hydrolysate T4 group.

[0081] Throughout the entire experimental period (treatment period 1-14 days): For the yeast group, the low-dose yeast T1 group was significantly higher than the control group CT (P < 0.05) (increased by 34.8%), while the high-dose yeast T2 group showed no significant change; for yeast hydrolysate, the low-dose yeast hydrolysate T3 group was significantly higher than the control group (P < 0.05) (increased by 23.4%), while the high-dose yeast hydrolysate T4 group showed no significant change.

[0082] Material weight ratio (F / G)

[0083] Material weight ratio (F / G): There were no significant differences between groups at each stage of the experiment.

[0084] Piglet diarrhea rate

[0085] Diarrhea rate: As shown in Table 4, the diarrhea rates of the T1, T2, T3 and T4 groups were significantly lower than those of the CT group during the 1-14 days of the experiment (P<0.001) (average reduction of 33.3%).

[0086] During the 15-28 day trial, the diarrhea rates in groups T1, T2, T3, and T4 were significantly lower than those in group CT (P < 0.001) (mean reduction of 54.3%).

[0087] During the entire trial period of 1–28 days, the diarrhea rate in groups T1, T2, T3, and T4 decreased by an average of 39.4%.

[0088] Body's immunity

[0089] from Figure 1 The results showed that adding 0.5% Kluyveromyces lactis FRI to the feed effectively improved the health of weaned piglets. Specifically, it reduced inflammatory response: On days 14 and 28 of the experiment, the concentration of IL-6 (an indicator of inflammation level) in the plasma of piglets in the experimental group decreased significantly. The decrease in IL-6 level indicates that this yeast can effectively alleviate the intestinal inflammatory response caused by weaning stress.

[0090] Enhancing Immunity: On day 14 of the experiment, the level of IgA (an antibody reflecting immune function) in the plasma of piglets in the experimental group increased significantly. The increased IgA level indicates that this yeast can enhance the body's immune defense capabilities.

[0091] In summary, the 0.5% Kluyveromyces lactis FRI feed additive provides dual protection for weaned piglets by reducing inflammatory factor levels and increasing immune antibody content: on the one hand, it reduces inflammatory response, and on the other hand, it enhances immunity, thus ensuring the healthy growth of weaned piglets.

[0092] from Figure 2The results showed that adding 1% Kluyveromyces lactis FRI hydrolysate to the feed had a trend of improving the health of weaned piglets: on the one hand, the level of the inflammatory factor IL-6 in the plasma of the experimental groups on days 14 and 28 showed a decreasing trend (0.05 < p < 0.10), indicating that it may help alleviate intestinal inflammation caused by weaning stress; on the other hand, the content of the immune antibody IgA in the plasma of piglets in the experimental group on day 14 was significantly increased (p < 0.05), indicating that the hydrolysate can enhance the body's immunity. Although the reduction of IL-6 did not reach statistical significance, overall, 1% Kluyveromyces lactis FRI hydrolysate showed potential application value in reducing inflammatory response and improving immunity, providing a reference direction for subsequent optimization of addition amount or combination with other additives.

[0093] in conclusion

[0094] 1. Adding Kluyveromyces lactis and its hydrolysate to feed can improve the growth performance of weaned piglets and reduce the diarrhea rate. Furthermore, based on the results of this experiment, the optimal addition level of Kluyveromyces lactis powder is 0.5%, and the optimal addition level of Kluyveromyces lactis hydrolysate is 1%.

[0095] 2. Previous studies (US4083960A) have demonstrated that β-galactosidase derived from Kluyveromyces lactis can alleviate diarrhea in piglets;

[0096] In the study of this application, it was found that Kluyveromyces lactis FRI does not have β-galactosidase activity, and the 0.5 wt% yeast group had an overwhelming advantage in both growth performance and reduced diarrhea rate, which suggests that colonization of live bacteria may be the reason for this advantage.

[0097] The embodiments presented herein are merely selected implementations based on combinations of all possible embodiments. The appended claims should not be limited to the embodiments described herein. Some numerical ranges used in the claims include sub-ranges within them, and variations within these ranges should also be covered by the appended claims.

Claims

1. Application of Kluyveromyces lactis FRI in the preparation of feed additives for weaned piglets or in the preparation of feed for weaned piglets, wherein the preservation number of Kluyveromyces lactis FRI is CGMCC No. 30910; the preservation date is June 24, 2024; the classification name is Kluyveromyces lactis; the depository unit is China General Microbiological Culture Collection Center; the depository address is No. 3, No. 1 Courtyard, Beichen West Road, Chaoyang District, Beijing.

2. The application according to claim 1, characterized in that, The aforementioned weaned piglet feed additives and weaned piglet feeds refer to weaned piglet feed additives and weaned piglet feeds that have the function of promoting the growth performance of weaned piglets and / or reducing the diarrhea rate.

3. The application of the lysate of Kluyveromyces lactis FRI in the preparation of feed additives for weaned piglets or in the preparation of feed for weaned piglets, wherein the preservation number of Kluyveromyces lactis FRI is CGMCC No. 30910; the preservation date is June 24, 2024; the classification name is Kluyveromyces lactis; the depository unit is China General Microbiological Culture Collection Center; the depository address is No. 3, No. 1, Beichen West Road, Chaoyang District, Beijing.

4. The application according to claim 3, characterized in that, The aforementioned weaned piglet feed additives and piglet feeds refer to weaned piglet feed additives and piglet feeds that have the function of promoting the growth performance of weaned piglets and / or reducing the diarrhea rate.

5. The application according to claim 3, characterized in that, The lysate of Kluyveromyces lactis FRI is a hydrolysis product of Kluyveromyces lactis FRI.

6. A weaned piglet feed, characterized in that, Contains the lysate of Kluyveromyces lactis FRI or Kluyveromyces lactis FRI as described in claim 1.

7. The weaned piglet feed according to claim 6, characterized in that, The weaned piglet feed contains 0.1-2 wt% of Kluyveromyces lactis FRI or its lysate.

8. The weaned piglet feed according to claim 7, characterized in that, The weaned piglet feed contains 0.3-0.7 wt% of Kluyveromyces lactis FRI, or 0.8-1.3 wt% of Kluyveromyces lactis FRI lysate.

9. The weaned piglet feed according to claim 6, characterized in that, The lysate of Kluyveromyces lactis FRI is a hydrolysis product of Kluyveromyces lactis FRI.

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