Pregnant sow feed capable of increasing birth weight of piglets and improving placenta inflammation of sows

Abstract

The invention discloses a pregnant sow feed for increasing birth weight of piglets and improving placenta inflammation of sows, and relates to the technical field of biology. The pregnant sow feed comprises a lysozyme oligomer and a basic ration. The pregnant sow feed for increasing birth weight of piglets and improving placenta inflammation of sows provided by the invention is used for dynamically feeding sows in the pregnancy stage, meets the nutrition and energy requirements of the sows from the late pregnancy stage to delivery, and is fed for several times two days before delivery, so that the dystocia condition of the sows can be relieved, the stillbirth rate can be effectively reduced, and the survival rate of the sows is increased. The lysozyme content in colostrum and serum is increased, the anti-inflammatory factor expression of placenta is obviously promoted, the birth weight of piglets is obviously increased, the stillbirth rate is reduced, and the reproductive performance of sows is improved.

Description

Technical Field

[0001] The present invention relates to the field of biotechnology, and particularly to a diet for pregnant sows that can increase the birth weight of piglets and improve placental inflammation in sows. Background Art

[0002] Although modern genetic breeding techniques and precise nutritional regulation have significantly increased the litter size of sows, this has been accompanied by a significant decline in the development indicators of newborn piglets. Data shows that the increase in litter size is significantly negatively correlated with parameters such as reduced birth weight, decreased within-litter weight uniformity, and increased weak piglet rate, highlighting the contradictory phenomenon between reproductive performance and offspring viability under intensive production models.

[0003] During pregnancy, sows are fed restrictedly to control their body condition. However, pregnant sows are prone to severe nutritional deficiencies, resulting in insufficient nutrients being taken in by the maternal fetus through the placenta, leading to a decrease in piglet birth weight and affecting the reproductive performance of sows. Sows are often subjected to various stresses during late pregnancy and lactation, which can trigger inflammatory responses and metabolic disorders, leading to placental inflammation in sows and ultimately affecting fetal development.

[0004] In order to increase the litter size of sows while also increasing the birth weight of piglets, thereby improving pig farming efficiency, adding appropriate nutritional regulators to the pregnancy diet of sows is an ideal choice. However, different types and levels of nutritional regulators in the diet have different effects on the reproductive performance of sows. Therefore, screening and determining the appropriate level of dietary nutritional regulators is of great practical significance for increasing the birth weight of piglets, reducing placental efficiency, and improving reproductive performance. Summary of the Invention

[0005] The object of the present invention is to provide a diet for pregnant sows that can increase the birth weight of piglets and improve placental inflammation in sows to solve the problems existing in the above-mentioned prior art. This diet for pregnant sows can relieve the dystocia situation of sows, effectively reduce the stillbirth rate, increase the lysozyme content in colostrum and serum, significantly promote the expression of anti-inflammatory factors in the placenta, significantly increase the birth weight of piglets, reduce the stillbirth rate, and improve the reproductive performance of sows.

[0006] To achieve the above object, the present invention provides the following solution:

[0007] The present invention provides a diet for pregnant sows that can increase the birth weight of piglets and improve placental inflammation in sows, comprising lysozyme oligomers and a basal diet.

[0008] Further, the mass ratio of the lysozyme oligomers to the basal diet is 0.1:99.9.

[0009] Furthermore, the basal diet includes corn, wheat bran, soybean hulls, soybean meal, salt, limestone, monocalcium phosphate, soybean oil, choline, sodium bicarbonate, premix, and phytase.

[0010] Furthermore, by mass, the basal diet includes 54.06 parts of corn, 18.00 parts of wheat bran, 7.40 parts of soybean hulls, 16.00 parts of soybean meal, 0.40 part of salt, 0.93 part of limestone, 1.00 part of monocalcium phosphate, 1.50 parts of soybean oil, 0.10 part of choline, 0.25 part of sodium bicarbonate, 0.25 part of premix, and 0.01 part of phytase.

[0011] Furthermore, the premix includes the following components: vitamin A, niacinamide, vitamin D3, vitamin E, riboflavin B2, vitamin B 12 , biotin, pantothenic acid, folic acid, L - ascorbic acid, vitamin K3, iron, zinc, copper, manganese, iodine, selenium, and cobalt.

[0012] Furthermore, in the diet for pregnant sows, the contents of the components in the premix are as follows: vitamin A 5000 IU / kg, niacinamide 10 mg / kg, vitamin D3 500 IU / kg, vitamin E 15 mg / kg, riboflavin B2 5 mg / kg, vitamin B 12 0.01 mg / kg, biotin 0.24 mg / kg, pantothenic acid 4 mg / kg, folic acid 1.12 mg / kg, L - ascorbic acid 50 mg / kg, vitamin K3 1.2 mg / kg, iron 154 mg / kg, zinc 100 mg / kg, copper 22 mg / kg, manganese 50 mg / kg, iodine 0.56 mg / kg, selenium 0.5 mg / kg, cobalt 0.56 mg / kg.

[0013] The present invention also provides the application of the above - mentioned lysozyme oligomer in the preparation of a feed additive for increasing the birth weight of piglets and improving placental inflammation in sows.

[0014] The present invention also provides a feed additive for increasing the birth weight of piglets and improving placental inflammation in sows, and the active ingredient includes the above - mentioned lysozyme oligomer.

[0015] The present invention also provides the application of the above - mentioned lysozyme oligomer in the preparation of a diet for pregnant sows for increasing the birth weight of piglets and improving placental inflammation in sows.

[0016] The present invention also provides the application of the above - mentioned feed additive in the preparation of a diet for pregnant sows for increasing the birth weight of piglets and improving placental inflammation in sows.

[0017] The present invention discloses the following technical effects:

[0018] The research of the present invention finds that adding lysozyme oligomers to the diet is an ideal nutritional regulation method for pregnant sows. By analyzing the content of immune factors in the colostrum and serum of sows treated with lysozyme oligomers and the mRNA expression levels of inflammatory factors and angiogenesis factors in the placenta, the results show that after treatment with lysozyme oligomers, the neonatal weight of piglets, placental efficiency, the content of immune factors in colostrum and serum, and the expression level of anti-inflammatory factors in the placenta all increase. This indicates that lysozyme oligomers are a potential antibiotic alternative product and can be used as a nutritional regulator in the feed for pregnant sows, thereby preparing a diet for pregnant sows that can increase the neonatal weight of piglets and improve placental inflammation.

[0019] Using the diet for pregnant sows provided by the present invention to dynamically feed sows during the pregnancy stage meets the nutritional and energy requirements of sows from late pregnancy to parturition. Implementing divided feeding two days before parturition can relieve the dystocia situation of sows, effectively reduce the stillbirth rate, increase the lysozyme content in colostrum and serum, significantly promote the expression of anti-inflammatory factors in the placenta, significantly increase the neonatal weight of piglets, reduce the stillbirth rate, and improve the reproductive performance of sows. Brief Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 It is the scoring chart of the tear stains and rust stains of sows in each experimental group; among them, A and B are the representative pictures and scoring statistical charts of the tear stains of sows before and after the experiment respectively; C and D are the representative pictures and scoring statistical charts of the rust stains of sows before and after the experiment respectively; all data are expressed as mean ± standard deviation, ****P<0.0001;

[0022] Figure 2 It is the detection result of the content of short-chain fatty acids in the feces of sows in each experimental group; among them, A is the acetic acid content; B is the propionic acid content; C is the isobutyric acid content; D is the butyric acid content; E is the isovaleric acid content; F is the valeric acid content; G is the total short-chain fatty acid content; H is the total content of branched-chain fatty acids; I is the total content of volatile fatty acids (VFA); SCFAs: short-chain fatty acids, the sum of acetic acid, propionic acid, butyric acid and valeric acid; BSCFA: branched-chain short-chain fatty acids, isobutyric acid and isovaleric acid; total VFAs: SCFAs + BSCFAs; LYZ: lysozyme oligomers; CON: control group; all data are expressed as mean ± standard deviation, *P<0.05, **P<0.01;

[0023] Figure 3Detection results of the contents of immune factors and lysozyme in the colostrum and serum of sows in each experimental group; among them, A - F are the levels of IgA, IgG, IgM, TNF-α, IL-10, and lysozyme in the colostrum of sows; G - L are the levels of IgA, IgG, IgM, TNF-α, IL-10, and lysozyme in the serum of sows; the data are expressed as mean ± standard deviation; LYZ: lysozyme oligomer; IgA: immunoglobulin A; IgG: immunoglobulin G; IgM: immunoglobulin M; TNF-α: tumor necrosis factor-α; IL-10: interleukin 10; CON: control group; *P < 0.05; **P < 0.01; ****P < 0.0001;

[0024] Figure 4 Detection results of the expression of genes related to placental angiogenesis and placental inflammation in sows in each experimental group; among them, A is the mRNA expression level of the placental angiogenesis marker CD31 in sows; B is the mRNA expression level of VEGF-A in the placenta of sows; C is the mRNA expression level of the pro-inflammatory factor TNF-α in the placenta of sows; D is the mRNA expression level of the anti-inflammatory factor IL-10 in the placenta of sows; the data are expressed as mean ± standard deviation; LYZ: lysozyme oligomer; CD31: platelet endothelial cell adhesion molecule-1; VEGF-A: vascular endothelial growth factor A; TNF-α: tumor necrosis factor-α; IL-10: interleukin 10; CON: control group; *P < 0.05; **P < 0.01; ****P < 0.0001. Detailed implementation manners

[0025] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0026] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0027] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0028] Without departing from the scope or spirit of this invention, various modifications and variations can be made to the specific embodiments of the specification of this invention, which will be obvious to those skilled in the art. Other embodiments obtained from the specification of this invention will be obvious to those skilled in the art. The specification and examples of this invention are merely exemplary.

[0029] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0030] Example 1

[0031] I. Experimental methods

[0032] (I) Experimental grouping

[0033] Two hundred 2-4 parity growing crossbred sows with similar body conditions and good health were randomly divided into two groups, with 100 replicates in each group and 1 sow in each replicate. During the period from 85 days of pregnancy to entering the farrowing house, they were fed a basal diet (control group) and a diet containing 0.1% lysozyme oligomer (purchased from Shanghai Aikuiying Biotechnology Co., Ltd.) (lysozyme oligomer group) respectively, as shown in Table 1 specifically. Ensure that the energy and crude protein nutritional levels of the diet are consistent. The experimental period is from 85 days of pregnancy to 21 days after weaning.

[0034] Feeding method for pregnant sows:

[0035] From 85 to 100 days of pregnancy, the daily feed intake per sow is 2.5 - 3.0 kg;

[0036] From 100 days of pregnancy to 3 days before parturition, the daily feed intake per sow is 3.5 kg;

[0037] From 2 days before parturition to parturition, the daily feed intake per sow is 2.5 kg, and it is fed twice.

[0038] Table 1 is the feed formula and nutrient composition table of the pregnant sow diet

[0039]

[0040]

[0041] Note: 1. The premix in each kilogram of the pregnancy diet includes the following components: vitamin A 5000 IU / kg, niacinamide 10 mg / kg, vitamin D3 500 IU / kg, vitamin E 15 mg / kg, riboflavin B2 5 mg / kg, vitamin B 12 0.01 mg / kg, biotin 0.24 mg / kg, pantothenic acid 4 mg / kg, folic acid 1.12 mg / kg, L-ascorbic acid 50 mg / kg, vitamin K3 1.2 mg / kg, iron (inorganic iron) 154 mg / kg, zinc 100 mg / kg, copper 22 mg / kg, manganese 50 mg / kg, iodine 0.56 mg / kg, selenium 0.5 mg / kg, cobalt 0.56 mg / kg.

[0042] 2. Feed nutrient composition determination: Select no less than 1000 g of representative original samples. Quarter the samples down to 250 g, dry them at 60 °C, grind them finely with a plant sample grinder, and pass them through 40-mesh and 18-mesh test sieves. Seal them in sample bags and store them in a cool place for future determination.

[0043] 3. Analyze and determine the contents of crude protein (CP), crude ash (Ash), dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the feed samples. The method refers to "Feed Analysis and Feed Quality Detection Technology" (3rd edition).

[0044] (2) Measurement indicators

[0045] Measure the body weight and backfat of sows on the 85th, 110th day of pregnancy, the day of parturition, and the day of weaning. Score the sow's tear stains and rust stains before and after the experiment. Collect sow feces on the 110th day of pregnancy to measure the short-chain fatty acid content. Record the number of live-born piglets, dead piglets, and mummified piglets and the placental weight on the day of parturition to analyze the reproductive performance of sows, and collect sow serum and colostrum to measure the lysozyme content and immune factors, and collect some placental tissues to analyze the relative content of placental inflammatory factors.

[0046] (3) Sample collection and test methods

[0047] (1) Scoring of lacrimal and rust spots: Before the experiment (85 days of pregnancy) and after the experiment (21 days of lactation), all sows were scored for periorbital lacrimal staining and body surface iron spot deposition. Briefly, the lacrimal spot score was graded on a scale of 0 to 5: 0 (no staining), 1 (barely detectable staining confined to the eyelids), 2 (obvious staining covering ≤50% of the eye area), 3 (obvious staining covering 50%-100% of the eye area), 4 (severe staining ≥100% of the eye area, no submandibular extension), 5 (severe staining extending below the oral line); we used a scale of 0 to 3 to score the rust spots, where 0 (no deposition in the facial, dorsal or hip areas), 1 (deposition in one area), 2 (deposition in two areas), 3 (deposition in all three areas).

[0048] (2) Collection of sow feces: Fresh fecal samples of sows were obtained by rectal massage. After collection, the surface layer was removed to eliminate contamination, and the samples were immediately stored at -20 °C pending analysis.

[0049] Determination of short-chain fatty acid content: The frozen fecal specimens were equilibrated on ice, thawed under control, and then homogenized with 0.5 mL of ultrapure water per 10 mg aliquot. The following experimental steps were carried out using the method of "Yang et al., 2021", and all steps were carried out on ice. Finally, gas-liquid chromatography was used to analyze the short-chain fatty acid content.

[0050] (3) Collection of sow parturition blood: Fasting blood of sows during parturition was collected by ear vein puncture, centrifuged at 3000 rpm at 4 °C for 10 min, plasma was separated, aliquoted and stored at -20 °C for chemical analysis. Colostrum collection started after the birth of the first piglet. Three mammary glands (front, middle and rear mammary glands) were selected for sampling, about 25 mL was taken from each sow and placed in a 50 mL sterile centrifuge tube, and stored at -20 °C until analysis.

[0051] Quantitative determination of the concentrations of immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), tumor necrosis factor-α (TNF-α), interleukin 10 (IL-10) and lysozyme in sow serum and colostrum was performed using hypersensitive porcine IgA, IgG, IgM, TNF-α, IL-10 and LYZ enzyme-linked immunosorbent assay kits (Jiangsu Meimian Industry Co., Ltd.). The detection was carried out strictly according to the manufacturer's standardized protocol, including precoating of 96-well plates and 450 nm spectrophotometric measurement with wavelength correction.

[0052] (4) Collection of sow placentas: After the neonates were born, the umbilical cords were ligated surgically, and the piglets were marked for individual placenta matching. The placental expulsion was monitored. After transecting at the base of the umbilical cord, samples were collected at 2 - 3 cm from the umbilical cord - placental junction. One normal birth weight (NBW) placenta and one low birth weight (LBW) placenta were taken from each sow. LBW ≤ mean of each litter - 2 standard deviations (SD), and NBW = the weight range of mean to mean ± 2SD of each litter. After the placentas were expelled, one representative placenta of each weight category from each sow was quickly frozen in liquid nitrogen and stored at -80°C.

[0053] mRNA expression levels of placental inflammatory factors and angiogenic factors: Total RNA was extracted from placental tissues using EZB reagent (Invitgen, Carlsad, USA). Reverse transcription was performed using PrimeScript RT Reagent Kit (EZBioscience). Finally, RT-qPCR analysis was carried out using a QuantStudio 6 Real-Time PCR system (Thermo Fisher Scientific). The thermal cycling parameters were as follows: initial denaturation at 95°C for 30 s; then 40 cycles of 95°C for 10 s (denaturation) and 60°C for 30 s (annealing / extension). Melting curve analysis verified the specificity of the reaction. Using β-actin as the reference gene, the expression of the target gene was represented as the ratio of the target gene to the reference gene.

[0054] (IV) Data processing

[0055] Two hundred sows were included in the data analysis. Each sow was considered as one replicate for statistical analysis. After the experimental data were sorted out using Excel software, a normality test was performed using the SPSS program. For data that conformed to a normal distribution, a t-test was used, and for data that did not conform to a normal distribution, a Mann-Whitney-U test was used for analysis. The stillbirth rate, weak piglet rate, and ineffective piglet rate were analyzed using a chi-square test, and the mRNA expression of the placenta was analyzed using a two-way test. The results were expressed as mean ± standard deviation. A statistically significant trend was indicated by 0.05 < P < 0.10, a significant difference was indicated by *P < 0.05, and an extremely significant difference was indicated by **P < 0.01. The graphs were completed using GraphPad Prism 9 software.

[0056] II. Experimental results

[0057] (1) Number of valid samples at each stage of sows

[0058] The number of valid samples at each stage of sows is shown in Table 2. At 110 days of gestation, 2 sows in the control group were excluded due to premature birth and dystocia. 4 sows in the lysozyme oligomer group were excluded due to dystocia or death. During lactation, invalid sample sizes were excluded due to sow death or poor milk production.

[0059] Table 2 Effective sample size of sows at each stage

[0060]

[0061] (2) Effect of adding 0.1% lysozyme oligomer to the gestation diet on the reproductive performance of sows

[0062] The detection results of the reproductive performance of sows in each experimental group are shown in Table 3. Among them, the live piglet rate, stillbirth rate, healthy piglet rate, weak piglet rate and ineffective piglet rate were analyzed by chi-square test, and the remaining data were expressed as mean ± standard deviation.

[0063] Compared with the control group, the 0.1% lysozyme oligomer treatment group increased the birth weight and live piglet rate of piglets (P<0.05), placental efficiency (P<0.01), and decreased the stillbirth rate (P<0.01), weak piglet rate and ineffective piglet rate (P<0.05).

[0064] Table 3 Effect of adding 0.1% lysozyme oligomer to the gestation diet on the reproductive performance of sows

[0065]

[0066] (3) Effect of adding 0.1% lysozyme oligomer to the gestation diet on the body weight and backfat of sows

[0067] The detection results of the body weight and backfat of sows in each experimental group are shown in Table 4. Compared with the control group, 0.1% lysozyme oligomer had no effect on the body weight and backfat of sows.

[0068] Table 4 Effect of adding 0.1% lysozyme oligomer to the gestation diet on the body weight and backfat of sows

[0069]

[0070] (4) Effect of adding 0.1% lysozyme oligomer to the gestation diet on the scores of sow tear stains and rust stains

[0071] The scores of sow tear stains and rust stains in each experimental group are shown in Figure 1 . Compared with the control group, the 0.1% lysozyme oligomer treatment group significantly reduced the scores of sow tear stains and rust stains (P<0.0001).

[0072] (5) Effect of adding 0.1% lysozyme oligomer to the gestation diet on the content of short-chain fatty acids in sow feces

[0073] The detection results of the content of short-chain fatty acids in the feces of sows in each experimental group are shown in Figure 2Compared with the control group, the 0.1% lysozyme oligomer treatment group significantly increased the concentration of acetate in feces (P<0.01), and simultaneously, the contents of butyrate, valerate, total short-chain fatty acids (SCFAs) and total volatile fatty acids (VFAs) also increased (P<0.05).

[0074] (6) Effects of adding 0.1% lysozyme oligomer to the gestation diet on the contents of immune factors and lysozyme in the colostrum and serum of sows

[0075] The detection results of the contents of immune factors and lysozyme in the colostrum and serum of sows in each experimental group are shown in Figure 3 . Adding lysozyme oligomer to the diet significantly increased the concentrations of IgA, IgM and IL-10 in colostrum (P<0.01). Serum analysis showed increased levels of IgG and IL-10 (P<0.01). The concentrations of IgG in colostrum and IgM in serum in the lysozyme oligomer group were significantly higher than those in the control group (P<0.05). Compared with the control group, the 0.1% lysozyme oligomer treatment group significantly increased the content of lysozyme in colostrum (P<0.01), and there was a tendency to increase the content of lysozyme in serum (P = 0.086).

[0076] (7) Effects of adding 0.1% lysozyme oligomer to the gestation diet on the angiogenesis of sow placenta and the expression of genes related to placental inflammation

[0077] The detection results of the angiogenesis of sow placenta and the expression of genes related to placental inflammation in each experimental group are shown in Figure 4 . Compared with the control group, the 0.1% lysozyme oligomer treatment group significantly increased the placental vascular density of normal body weight (P<0.05); meanwhile, compared with the control group, the mRNA expression level of the placental anti-inflammatory factor IL-10 in the 0.1% lysozyme oligomer treatment group was significantly increased.

[0078] In summary, adding 0.1% lysozyme oligomer to the gestation diet can increase the birth weight of piglets, reduce placental inflammation and thus improve the litter performance of sows.

[0079] The above-described embodiments are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A gestation sow diet for increasing the birth weight of piglets and improving placental inflammation in sows, characterized in that, It includes lysozyme oligomers and a basal diet.

2. The gestation sow diet according to claim 1, characterized in that, The mass ratio of the lysozyme oligomers to the basal diet is 0.1:99.

9.

3. The pregnancy sow diet according to claim 1, characterized in that, The basal diet includes corn, wheat bran, soybean hulls, soybean meal, salt, limestone, dicalcium phosphate, soybean oil, choline, sodium bicarbonate, premix and phytase.

4. The pregnancy sow diet according to claim 3, characterized in that, By mass, the basal diet includes 54.06 parts of corn, 18.00 parts of wheat bran, 7.40 parts of soybean hulls, 16.00 parts of soybean meal, 0.40 parts of salt, 0.93 parts of limestone, 1.00 part of dicalcium phosphate, 1.50 parts of soybean oil, 0.10 part of choline, 0.25 part of sodium bicarbonate, 0.25 part of premix and 0.01 part of phytase.

5. The gestation sow diet according to claim 3, characterized in that, The premix comprises the following components: vitamin A, nicotinamide, vitamin D3, vitamin E, riboflavin B2, vitamin B 12 , biotin, pantothenic acid, folic acid, L-ascorbic acid, vitamin K3, iron, zinc, copper, manganese, iodine, selenium, and cobalt.

6. The gestation sow diet according to claim 5, wherein In the diet of the pregnant sows, the contents of the components in the premix are as follows: vitamin A 5000 IU / kg, nicotinamide 10 mg / kg, vitamin D3 500 IU / kg, vitamin E 15 mg / kg, riboflavin B2 5 mg / kg, vitamin B 12 0.01 mg / kg, biotin 0.24 mg / kg, pantothenic acid 4 mg / kg, folic acid 1.12 mg / kg, L-ascorbic acid 50 mg / kg, vitamin K3 1.2 mg / kg, iron 154 mg / kg, zinc 100 mg / kg, copper 22 mg / kg, manganese 50 mg / kg, iodine 0.56 mg / kg, selenium 0.5 mg / kg, cobalt 0.56 mg / kg.

7. Use of the lysozyme oligomer as described in claim 1 in the preparation of a feed additive for increasing the birth weight of piglets and improving placental inflammation in sows.

8. A feed additive for increasing the birth weight of piglets and improving placental inflammation in sows, characterized in that, The active ingredient includes the lysozyme oligomer as described in claim 1.

9. Use of the lysozyme oligomer as described in claim 1 in the preparation of a diet for pregnant sows for increasing the birth weight of piglets and improving placental inflammation in sows.

10. Use of the feed additive as described in claim 8 in the preparation of a diet for pregnant sows for increasing the birth weight of piglets and improving placental inflammation in sows.

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