Method for improving conception rate of meat cows by using rumen bypass linseed oil and choline chloride

Abstract

The invention provides a method for improving the conception rate of meat cows by using rumen bypass linseed oil and choline chloride. In the cow pregnancy stage, rumen bypass linseed oil and choline chloride are supplemented in basic ration at the same time, a suitable nutrition environment is provided for pregnancy recognition and the occurrence of the physiological process of embryo implantation, the rumen bypass linseed oil and the choline chloride can promote each other, embryonic development is effectively promoted, the conception rate after artificial insemination is remarkably increased, and the reproductive performance of meat cows is effectively improved. The method can be widely popularized and applied in production.

Description

Technical Field

[0001] The invention belongs to the technical field of beef cattle feed, and in particular relates to a feed containing rumen-bypass unsaturated fatty acids and choline to improve the conception rate of beef cows and application thereof. Background Art

[0002] Cow fertility is an important factor affecting the economic benefits of the beef cattle industry, among which conception rate is the most important indicator of cow fertility. Current studies have shown that oocytes can maintain a high fertilization rate after artificial insemination of beef cattle, but early embryonic death occurs after conception. It is generally believed that prenatal embryo loss is a major problem in the reproduction process of beef cattle and most livestock. The embryonic death of beef cattle during pregnancy is about 20%-40%, of which 70-80% of embryonic deaths occur in the early embryonic development period 1 month after artificial insemination. For a long time, in order to improve the conception rate of beef cattle after artificial insemination, scholars at home and abroad have mainly focused on semen quality, insemination time and site, optimization and improvement of insemination operation, and prevention and treatment of reproductive system diseases. Although some new progress has been made, the effect of improving the conception rate after artificial insemination is not ideal, resulting in low reproductive performance of beef cattle.

[0003] The uterine cavity is a unique place for embryonic development. Early embryonic development involves pregnancy recognition and embryo implantation. The uterine cavity fluid provides a suitable environment for the occurrence of the physiological process of pregnancy recognition and embryo implantation. After the embryo enters the uterine cavity, it interacts and communicates with the maternal endometrium, thereby promoting embryonic development, improving endometrial receptivity, and improving the uterine cavity microenvironment. Current research has made it clear that during the early embryonic development of ruminants such as cattle and sheep after fertilization, the rapid extension of the conceptus is the key to embryo implantation and pregnancy establishment. It is now clear that the extension of the embryo depends on the uterine milk secreted by the endometrial epithelial glands. The early conception of cows is affected by pregnancy, and the progesterone secreted by the corpus luteum of the ovary regulates the secretion of nutrients from the endometrial epithelial glands, thereby promoting the extension and development of the early embryo.

[0004] It is currently believed that uterine milk contains rich lipids such as fatty acids and phospholipids, which are mainly involved in the regulation of embryonic cell energy metabolism, signal transduction, and biological membrane structure. More importantly, recent metabolomics studies have found that during the early embryonic development of beef cows, the content of unsaturated fatty acids and phosphatidylcholine in the uterine milk of cows with high conception rates is significantly higher than that of beef cows with low conception rates, further indicating that the secretion of unsaturated fatty acids and phospholipids by endometrial epithelial glands is an important nutrient for early embryonic development. It is worth noting that the study found that regulating the lipid content in the diet of dairy cows can affect the lipid composition and content of endometrial epithelial tissue, suggesting that supplementing lipids in the diet of beef cows may be an effective way to improve the nutritional environment of the uterus and increase the conception rate.

[0005] n-3 polyunsaturated fatty acids (PUFAs) are essential fatty acids for animals. They not only play a biological role by supplying energy, but are also components of biological membranes and important signaling molecules of cells. They are mainly added to livestock and poultry feeds in the form of linseed oil. Phosphatidylcholine is the main component of biological membranes, and choline is an important substance for synthesizing phosphatidylcholine. They are mainly added to livestock and poultry feeds in the form of choline chloride. However, due to the complex rumen microbial fermentation system of beef cattle, polyunsaturated fatty acids directly added to the diet will be hydrogenated by rumen microorganisms, and choline chloride will be destroyed, affecting its biological efficacy. Therefore, beef cattle diets need to be added in the form of rumen-passing PUFAs and choline chloride.

[0006] So far, flaxseed oil and choline chloride have been added to feed as nutritional supplements, mainly to improve production performance and the quality of livestock and poultry products. However, there are no reports on the application of rumen-bypass n-3 PUFAs combined with choline chloride in regulating the conception rate of beef cows in early pregnancy. Summary of the invention

[0007] The invention aims to provide a method for improving the conception rate of cows in view of the problem that the conception rate of cows after fertilization is insufficient.

[0008] The present invention has found that feeding linseed oil and choline chloride simultaneously can improve the conception rate of fertilized cows. Accordingly, the scheme of the present invention is as follows:

[0009] Firstly, the present invention provides the use of linseed oil and choline chloride in improving the conception rate of cows. The cows can be dairy cows or beef cows.

[0010] Preferably, the linseed oil is rumen-bypass linseed oil, and the choline chloride is rumen-bypass choline chloride.

[0011] The invention also provides application of linseed oil and choline chloride in preparing feed additive or feed.

[0012] Preferably, the weight percentage of the linseed oil and choline chloride is 10-100: 1-10. More preferably, the weight percentage of the linseed oil and choline chloride is 10-40: 3-9. In a preferred embodiment of the present invention, the weight percentage of the linseed oil and choline chloride is 10:3.

[0013] Preferably, the linseed oil is rumen-bypass linseed oil, and the choline chloride is rumen-bypass choline chloride.

[0014] The present invention also provides a method for improving the conception rate of cows, which comprises feeding an effective amount of rumen bypass linseed oil and choline chloride on the basis of a basic diet after fertilization of the cows, preferably for 20 to 40 days, more preferably for 30 days. After a period of feeding, the basic diet can be continued.

[0015] Preferably, the feeding amount of the rumen bypassed linseed oil and the rumen bypassed choline chloride is 30-120 g / day of the rumen bypassed linseed oil calculated as linseed oil, and 9-27 g / day of the rumen bypassed choline chloride calculated as choline chloride. In one embodiment of the present invention, the feeding amount of the rumen bypassed linseed oil and the rumen bypassed choline chloride is 78 g / day of the rumen bypassed linseed oil calculated as linseed oil, and 18 g / day of the rumen bypassed choline chloride calculated as choline chloride.

[0016] The present invention is based on the characteristic that the uterine milk of beef cows is rich in lipid content after pregnancy. After artificial insemination of the cows, rumen-bypass linseed oil and choline chloride are simultaneously supplemented in the basic diet to provide a suitable nutritional environment for the occurrence of pregnancy recognition and embryo implantation physiological processes. Studies have shown that the two can promote each other, effectively promote embryo development, significantly improve the conception rate after artificial insemination, and effectively improve the reproductive performance of beef cows.

[0017] The present invention adds linseed oil and choline chloride in the form of rumen bypassed linseed oil and choline chloride, which can avoid the consumption of linseed oil and choline chloride by the rumen microbial fermentation system and effectively retain the biological activity thereof.

[0018] In addition, rumen-pass unsaturated fatty acids and choline chloride are functional nutrients for the growth and development of livestock and poultry, have no side effects, and can become important components of beef cattle concentrate and be promoted and applied in production. DETAILED DESCRIPTION

[0019] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention.

[0020] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0021] In the present invention, the combined effect of linseed oil and choline chloride is used to promote the embryonic development of cows and improve the conception rate. It should be understood that the combined effect of linseed oil and choline chloride is always present. When facing cows of different varieties, those skilled in the art can moderately adjust and optimize the optimal feeding amount according to the method in the embodiment of the present invention. In an embodiment of the present invention, those skilled in the art can feed linseed oil 10g, 50g, 100g, 150g, 200g on the basis of the basic diet, preferably feed 39g, 60g, 78g, 117g, 156g, for example; and feed choline chloride such as 1g, 5g, 10g, 20g, 30g, 40g, 50g at the same time, preferably feed 9g, 18g, 27g, for example. In the present invention, linseed oil and choline chloride are both added in the form of rumen bypass.

[0022] In the present invention, rumen bypassed linseed oil and rumen bypassed choline chloride refer to linseed oil or choline chloride coated by rumen bypassed nutrition technology to prevent it from being degraded by rumen microorganisms after entering the rumen. So as to maintain its biological activity. The rumen bypassed linseed oil and rumen bypassed choline chloride used in the experiment were provided by Liaoning Yahe Nutrition Technology Co., Ltd. and coated by DPL-500 fluidized bed coating technology, wherein the rumen bypassed linseed oil is prepared from linseed oil, silicon dioxide and palmitic acid, containing 39% linseed oil, 36% silicon dioxide and 25% palmitic acid, and the rumen bypassed choline chloride is prepared from choline chloride, silicon dioxide and palmitic acid, containing 30% choline chloride, 45% silicon dioxide and 25% palmitic acid. The main process is to mix linseed oil or choline chloride with silicon dioxide for adsorption, and then put it into a reciprocating vibrating fluidized bed for drying, and after drying, it is sprayed with melted palmitic acid for coating.

[0023] In the embodiments of the present invention, Chinese Simmental cows were used to carry out relevant experiments, but it should be understood that similar effects are also achieved for cows of other breeds.

[0024] Example 1

[0025] 76 Chinese Simmental empty-breasted cows with similar weight and parity and good health were selected and randomly divided into 4 groups, 19 in each group. The cows were subjected to synchronous estrus and artificial insemination, and the feeding experiment began on the day of artificial insemination (counted as day 0 of pregnancy). The 4 groups were control group, experimental group 1, experimental group 2 and experimental group 3. The control group was fed with a basic diet; the experimental group 1 was fed with 100g of rumen-passed flaxseed oil per cow per day on the basis of the basic diet; the experimental group 2 was fed with 200g of rumen-passed flaxseed oil per cow per day on the basis of the basic diet; the experimental group 3 was fed with 400g of rumen-passed flaxseed oil per cow per day on the basis of the basic diet. The rumen-passed flaxseed oil was first mixed with the concentrate, and then mixed with the roughage to make a total mixed diet (TMR), which was fed once in the morning and evening every day, with free drinking water. After feeding for 30 days, the cows in each group were fed with a unified basic diet until delivery. The nutritional needs of cows shall refer to the "Beef Cattle Feeding Standards" (NY / T815-2004). The basic diet composition and nutritional level are shown in Table 1.

[0026] Table 1 Composition and nutritional level of the basic diet of experimental cows (dry matter basis)

[0027]

[0028] Pregnancy diagnosis was performed using a portable B-ultrasound instrument 45 days after artificial insemination of each treatment cow. First, the cow was placed in a standing position and the feces in the rectum of the cow should be removed before the examination to ensure the cleanliness of the examination area. The B-ultrasound probe was slowly placed in the rectum of the examined cow, and moved slowly along the rectal wall close to the uterine horn, and the exploration angle was constantly adjusted to observe the real-time B-ultrasound image to determine whether conception occurred and calculate the conception rate. The results are shown in Table 2.

[0029] Table 2 Effect of adding rumen bypass flaxseed oil to the diet on the conception rate of cows

[0030]

[0031] The results showed that after artificial insemination, the conception rate of cows supplemented with different levels of rumen bypass flaxseed oil in their diet was improved compared with the control group, among which the effects of Experimental Groups 1 and 2 were better, but the differences among the groups were not significant (P>0.05).

[0032] Example 2

[0033] A total of 64 Chinese Simmental empty-breasted cows with similar body weight and parity and good health were selected and randomly divided into 4 groups, with 16 cows in each group. The cows were subjected to synchronous estrus and artificial insemination, and the feeding experiment began on the day of artificial insemination (counted as day 0 of pregnancy). The 4 groups were control group, experimental group 1, experimental group 2 and experimental group 3. The control group was fed with a basic diet; the experimental group 1 was fed with 30g of rumen-permeable choline chloride per cow per day on the basis of the basic diet; the experimental group 2 was fed with 60g of rumen-permeable choline chloride per cow per day on the basis of the basic diet; the experimental group 3 was fed with 90g of rumen-permeable choline chloride per cow per day on the basis of the basic diet. The rumen-permeable choline chloride was first mixed with the concentrate, and then mixed with roughage to make a total mixed diet (TMR), which was fed once in the morning and evening every day, with free drinking water. After feeding for 30 days, the cows in each group were uniformly fed with the basic diet until delivery. The nutritional requirements of cows were implemented in accordance with the "Beef Cattle Feeding Standards" (NY / T815-2004), and the basic diet composition and nutritional level are shown in Table 1. The conception rate was then calculated using the method in Example 1, and the results are shown in Table 3.

[0034] Table 3 Effect of adding rumen bypass choline chloride to the diet on the conception rate of cows

[0035]

[0036] The results showed that after artificial insemination of cows, supplementing the diet with different levels of rumen bypass choline chloride did not significantly increase the conception rate compared with the control (P>0.05), among which the effect of experimental group 2 was relatively better.

[0037] Example 3

[0038] A total of 76 Chinese Simmental open-breasted cows with similar body weight and parity and good health were selected and randomly divided into 4 groups, with 19 cows in each group. The cows were subjected to synchronous estrus and artificial insemination, and the feeding experiment began on the day of artificial insemination (counted as day 0 of pregnancy). The 4 groups were control group, experimental group 1, experimental group 2 and experimental group 3, among which the control group was fed with a basic diet; experimental group 1 was fed with 200g of rumen bypassed flaxseed oil per cow per day on the basis of the basic diet; experimental group 2 was fed with 60g of rumen bypassed choline chloride per cow per day on the basis of the basic diet; experimental group 3 was fed with 200g of rumen bypassed flaxseed oil and 60g of rumen bypassed choline chloride per cow per day on the basis of the basic diet. Rumen bypassed linseed oil and rumen bypassed choline chloride were first mixed with concentrate, and then mixed with roughage to make a total mixed ration (TMR), which was fed once in the morning and evening every day, with free drinking water. After 30 days of feeding, each group of cows was fed a unified basic diet until delivery. The nutritional needs of cows were implemented in accordance with the "Beef Cattle Feeding Standards" (NY / T815-2004). The composition and nutritional level of the basic diet are shown in Table 1.

[0039] Pregnancy diagnosis was performed on cows in each group 45 days after artificial insemination using a portable B-ultrasound instrument, and then the conception rate was calculated using the method in Example 1. The results are shown in Table 4.

[0040] The serum biochemical indexes were detected by automatic biochemical analyzer; the serum progesterone, interferon-Tau (IFNT), prostagiandin D2 (PGD2), PGE2 PGI2 and phospholipid levels were detected by enzyme-linked immunosorbent assay, and the test was performed according to the steps in the kit instructions; the serum fatty acid level was detected by gas chromatography-mass spectrometry. During the experiment, the cows were fed in a single pen, with free drinking water and free food, and the experimental cows were dewormed and prevented according to the production arrangements of the cattle farm.

[0041] Table 4 Effects of adding rumen bypass linseed oil and choline chloride to the diet on reproductive performance of cows

[0042]

[0043] Note: Different lowercase letters in the same row indicate significant differences (P<0.05).

[0044] The results showed that after artificial insemination, the conception rate of cows supplemented with rumen-passed linseed oil, rumen-passed choline chloride or a combination of rumen-passed linseed oil and choline chloride was improved compared with the control group, among which the effect of test group 3 was the most obvious, which greatly improved the conception rate and was significantly higher than the control group and test groups 1 and 2 (P<0.05). Test group 1 still had an advantage over the control group and test group 2, but there was no significant difference between them (P>0.05).

[0045] 14 days and 30 days after artificial insemination of cows, 10 mL of blood was collected from the jugular vein of each cow in the morning in a fasting state, and the blood was left to stand at room temperature for 30 minutes and centrifuged at 3500 r / min for 15 minutes. The serum was collected in a dry EP tube and stored at -80°C for the determination of biochemical indicators such as serum total protein, glucose, triglyceride and urea nitrogen content, as well as alanine aminotransferase and aspartate aminotransferase activities. The results are shown in Table 5.

[0046] Table 5 Effects of adding rumen bypass linseed oil and choline chloride to the diet on serum biochemical parameters of cows

[0047]

[0048] Note: Different lowercase letters in the same row indicate significant differences (P<0.05).

[0049] As shown in Table 5, there were no significant differences in serum total protein, glucose, triglyceride and alanine aminotransferase levels between the experimental group and the control group (P>0.05), but the serum urea nitrogen and aspartate aminotransferase levels of the experimental group 3 were significantly lower than those of the control, experimental group 1 and experimental group 2 (P<0.05). At the same time, the urea nitrogen of the experimental group 2 was significantly lower than that of the control group and the experimental group 1 on the 14th day (P<0.05), and the aspartate aminotransferase was significantly lower than that of the control group on the 30th day (P<0.05).

[0050] The serum progesterone and IFNT levels were detected by enzyme-linked immunosorbent assay. The test was performed according to the instructions of the kit. The test results are shown in Tables 6 and 7.

[0051] Table 6 Effects of adding rumen bypass linseed oil and choline chloride to the diet on serum progesterone levels in cows

[0052]

[0053] Note: Different lowercase letters in the same row indicate significant differences (P<0.05).

[0054] Table 7 Effects of adding rumen bypass linseed oil and choline chloride to the diet on serum IFNT levels in cows

[0055]

[0056]

[0057] Note: Different lowercase letters in the same row indicate significant differences (P<0.05).

[0058] As shown in Tables 6 and 7, the serum progesterone and IFNT levels of the experimental group cows were higher than those of the control group, among which the experimental group 3 had the best effect, and its serum progesterone and IFNT levels were significantly higher than those of the control, experimental group 1 and experimental group 2 (P<0.05). Since the corpus luteum of the ovary of the cow secretes progesterone after conception, high levels of progesterone are beneficial to the establishment and maintenance of pregnancy. The maternal progesterone level is positively correlated with the conception rate, and high levels of progesterone induce the extension of the conceptus, promote the production of IFNT, and help improve the conception rate. In the early pregnancy of the cow, as the embryo develops, its trophoblast cells secrete IFNT, which acts on the uterine mucosa as a pregnancy signal, inhibits the secretion of prostaglandin F 2α and prevents it from dissolving the corpus luteum, which is beneficial to the corpus luteum to continue to secrete a higher level of progesterone and maintain pregnancy. Therefore, the increase in serum progesterone and IFNT levels is beneficial to improve the conception rate and maintain pregnancy.

[0059] The levels of PGD2, PGE2 and PGI2 were detected by enzyme-linked immunosorbent assay. The test was performed according to the instructions of the kit. The results are shown in Table 8.

[0060] Table 8 Effects of adding rumen bypass linseed oil and choline chloride to the diet on serum prostate hormone levels in cows

[0061]

[0062] Note: Different lowercase letters in the same row indicate significant differences (P<0.05).

[0063] As shown in Table 8, the serum PGD2, PGE2 and PGI2 levels of the experimental group cows were higher than those of the control group, among which the experimental group 3 had the best effect, and the serum PGD2, PGE2 and PGI2 levels of the experimental group 3 and the experimental group 1 were significantly higher than those of the control group and the experimental group 2 (P<0.05). PGE2 has the effect of anti-luteolysis, accelerates the blood circulation of the uterus and ovary by affecting the secretion of nitric oxide, acts on the ovarian corpus luteum to promote its expression of luteinizing hormone receptors, and then enhances the synthesis of progesterone by the corpus luteum, which is beneficial to early embryonic development and embryo implantation. Prostaglandins such as PGD2 and PGI2 can enhance early embryonic lipid metabolism by activating peroxisome proliferator-activated receptors, thereby promoting the extension of the conceptus. Therefore, the increase in the levels of PGD2, PGE2 and PGI2 in serum is beneficial to improving the conception rate and maintaining pregnancy in cows.

[0064] Gas chromatography-mass spectrometry was used to detect the levels of serum α-linolenic acid, eicosapentaenoic acid (EPA), linoleic acid, arachidonic acid, eicosadienoic acid and eicosatrienoic acid. The results are shown in Table 9.

[0065] Table 9 Effects of adding rumen bypass linseed oil and choline chloride to the diet on the level of unsaturated fatty acids in the serum of cows

[0066]

[0067] Note: Different lowercase letters in the same row indicate significant differences (P<0.05).

[0068] As shown in Table 9, the serum α-linolenic acid and linoleic acid levels of the cows in the experimental group 1 and the experimental group 3 were significantly higher than those in the control group and the experimental group 2 (P<0.05), but there was no significant difference between the experimental group 1 and the experimental group 3 (P>0.05). Although the serum arachidonic acid and EPA levels of the experimental group 1 and the experimental group 3 were not significantly different from those in the control group and the experimental group 2, they showed a trend of significant increase. Since polyunsaturated fatty acids are structural components of animal cell membrane phospholipids, and studies have found that dietary supplementation with n-3 or n-6 polyunsaturated fatty acids can not only promote the establishment of pregnancy in cows and increase the conception rate, but also benefit the fetal development, offspring health and growth and development. Therefore, the levels of α-linolenic acid, EPA, linoleic acid and arachidonic acid in the serum of cows after conception increase, which is beneficial to improving the conception rate and maintaining pregnancy.

[0069] The levels of phospholipids such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol (PI) were detected by enzyme-linked immunosorbent assay. The results are shown in Table 10.

[0070] Table 10 Effects of adding rumen bypass linseed oil and choline chloride to the diet on serum phospholipid levels in cows

[0071]

[0072] Note: Different lowercase letters in the same row indicate significant differences (P<0.05).

[0073] As shown in Table 10, the serum PC, PE, PS and PI levels of the cows in the experimental groups were higher than those in the control group, among which the effect of experimental group 3 was the best, and its serum PC, PE and PI levels were significantly higher than those of the control group, experimental group 1 and experimental group 2 (P<0.05). In addition, the serum PS level of the cows in experimental group 3 on the 14th day of pregnancy was significantly higher than that of the control group and experimental group 2, and the serum PS level on the 30th day of pregnancy was significantly higher than that of the control group, experimental group 1 and experimental group 2. Phospholipids such as PC, PE, PS and PI are important components of cell membranes and are essential for the normal growth and development of embryos. Therefore, the increase in the levels of PC, PE, PS and PI in the serum of cows after conception is beneficial to early embryonic development, promoting embryo implantation and pregnancy establishment.

Claims

1. Application of linseed oil and choline chloride in improving conception rate of cows.

2. The use according to claim 1, characterized in that The linseed oil and choline chloride are rumen bypassed linseed oil and rumen bypassed choline chloride.

3. Application of linseed oil and choline chloride in the preparation of feed additives or feed for improving the conception rate of cows.

4. The use according to claim 3, characterized in that The weight percentage of the linseed oil and choline chloride is 10-100:1-10.

5. The use according to claim 4, characterized in that The weight percentage of the linseed oil and choline chloride is 13-52:3-9.

6. The use according to claim 5, characterized in that The weight percentage of the linseed oil and choline chloride is 13:

3.

7. The use according to any one of claims 3 to 6, characterized in that: The linseed oil is rumen bypassed linseed oil, and the choline chloride is rumen bypassed choline chloride.

8. A method for improving the conception rate of cows, which comprises feeding the cows with an effective amount of rumen bypass linseed oil and choline chloride on the basis of a basic diet after fertilization, preferably for 20-40 days, more preferably for 30 days.

9. The method according to claim 8, characterized in that The feeding amount of the rumen bypassed linseed oil and the rumen bypassed choline chloride is 39-156 g / day of the rumen bypassed linseed oil calculated as linseed oil, and 9-27 g / day of the rumen bypassed choline chloride calculated as choline chloride.

10. The method according to claim 8, characterized in that The feeding amount of the rumen bypassed linseed oil and the rumen bypassed choline chloride was 78 g / day, calculated as linseed oil, and 18 g / day, calculated as choline chloride.

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