A method for improving the growth performance of steers

Abstract

The present invention belongs to the field of animal husbandry science in the category of agricultural science and technology, and discloses a method for improving the growth performance of steers, including: testing; slaughtering and sample collection; determining the effect of castration on the growth performance of bulls; determining the effect of castration on intramuscular fat of bulls; testing the changes in the flora of cecal contents; testing the changes in metabolites of cecal contents. The present invention uses metagenomics and metabolomics technology to systematically study the effects of castration on cecal flora and metabolites, revealing the potential mechanism of decreased growth performance of steers; and by studying the effects of oregano essential oil and antimicrobial peptides on the growth performance, cecal flora and metabolites of steers, this mechanism is verified, providing a theoretical and practical basis for improving the growth performance of steers.

Description

Technical Field

[0001] The invention belongs to the field of animal husbandry science in the agricultural science category, and in particular relates to a method for improving the growth performance of castrated cattle. Background Art

[0002] At present, the production of beef from dairy cows is an important part of the beef industry. According to statistics, about 60% of the world's beef comes from culled dairy cows and dairy bull calves. 30% of the beef in the United States comes from dairy cows, and about 73% is fattened from dairy bull calves; more than 90% of the total beef production in the Netherlands comes from dairy bull calves; 80% in the United Kingdom comes from dairy bull calves; about 55% in Japan comes from dairy cows, of which 80% comes from dairy bull calves. my country has 14 million dairy cows, of which about 600,000 are culled dairy cows and 3.5 million dairy bull calves, and has huge potential for meat development.

[0003] Bull castration is a common management practice widely adopted in the beef cattle industry. It can improve muscle marbling scores, promote intramuscular fat deposition and improve meat quality, reduce aggressive behavior of cattle during the feeding stage, and facilitate production management. Steers have more ideal meat quality than bulls to meet human demand for high-quality meat. However, castration reduces the body weight and carcass weight of steers, resulting in increased feeding costs. Therefore, it is of great significance to find the mechanism of weight loss in steers and provide a theoretical basis for improving the growth and development of steers in the future.

[0004] Through the above analysis, the problems and defects of the existing technology are: there is no mechanism for reducing the weight of castrated cattle, and it is impossible to provide a theoretical basis for improving the growth and development of castrated cattle in the future. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for improving the growth performance of steers.

[0006] The present invention is achieved by a method for improving the growth performance of steers, comprising the following steps:

[0007] Step 1: Test;

[0008] Step 2, slaughter and sample collection;

[0009] Step three, determining the effect of castration on the growth performance of bulls;

[0010] Step 4, determining the effect of castration on intramuscular fat in bulls;

[0011] Step 5: Testing the changes in the flora of the cecal contents;

[0012] Step six: test the changes in metabolites in cecal contents.

[0013] Further, the experiment of the method for improving the growth performance of steers comprises the following steps:

[0014] Step 1, 9 Holstein bulls aged 10 months with an average body weight of 341±12.11 kg were selected as the bull group; 27 Holstein steers aged 10 months with an average body weight of 352.91±18.47 kg were selected and randomly divided into 3 groups, namely, the steer group, the oregano essential oil group and the antimicrobial peptide group;

[0015] Step 2, the oregano essential oil group added 20 g / head / day of oregano essential oil to the basal diet, and the antimicrobial peptide group added 8 g / head / day of antimicrobial peptide to the basal diet; the pre-feeding period was 30 days, and the test period was 270 days;

[0016] Step 3. Weigh yourself every 30 days and record your body weight.

[0017] The slaughter and sample collection include: after the end of the trial period, 6 cows were randomly slaughtered in each group; after slaughter, the head, hoof and skin were removed, and the abdominal cavity was immediately opened; the rumen contents and cecal contents were collected from the rumen and cecum, quickly frozen in liquid nitrogen, and then stored at -80°C for the determination of microorganisms and metabolites; 50g of the left half of the longissimus dorsi muscle was taken for the determination of intramuscular fat content; the results showed that compared with the bull group, the intramuscular fat content of the steer group was significantly increased; compared with the steer group, the addition of oregano essential oil and antimicrobial peptides significantly increased the intramuscular fat content.

[0018] The effects of castration on the growth performance of bulls include: compared with the bull group, the final weight and average daily weight gain of the steer group were significantly reduced; compared with the steer group, the addition of oregano essential oil and antimicrobial peptides significantly increased the final weight and average daily weight gain.

[0019] The study on the effect of castration on intramuscular fat of bulls includes: taking 5g of the longissimus dorsi muscle and measuring the intramuscular fat content; the results show that compared with the bull group, the intramuscular fat content of the steer group increased significantly; compared with the steer group, adding oregano essential oil and antimicrobial peptides significantly increased the intramuscular fat content.

[0020] The method for testing changes in cecal content flora comprises: sequencing the cecal content and analyzing changes in the cecal content flora.

[0021] The method for testing changes in cecal content metabolites comprises: weighing rumen contents and cecal contents respectively for ultra-high performance liquid chromatography and tandem mass spectrometry analysis.

[0022] Furthermore, the changes in the flora of the cecal contents include: adding oregano essential oil and antimicrobial peptides to feed steers, the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecal contents increases, and the growth performance of the steers is improved.

[0023] Furthermore, the method for testing changes in metabolites of cecal contents includes: adding oregano essential oil and antimicrobial peptides to the feed and feeding steers, which can increase the concentration of α-ketoglutaric acid in the cecal contents and improve growth performance.

[0024] Furthermore, the method for testing changes in metabolites in cecal contents includes: detecting metabolites in rumen contents, and there is no difference in α-ketoglutarate in the rumen. The results show that rumen-bypass α-ketoglutarate can improve the growth performance of steers.

[0025] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0026] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving the problems, the technical solutions to be protected by the present invention and the results and data during the research and development process are closely combined to analyze in detail and deeply how the technical solutions of the present invention solve the technical problems, and some creative technical effects brought about after solving the problems. The specific description is as follows:

[0027] Castration can improve muscle marbling score, promote intramuscular fat deposition, and improve meat quality; but at the same time, it inhibits the growth of cattle and limits the production of high-grade snowflakes. At present, the mechanism by which castration inhibits cattle growth is still unclear. The present invention studies the effect of castration on intramuscular fat content, and systematically studies the effect of castration on cecal flora and metabolites using metagenomics and metabolomics techniques, revealing the potential mechanism of decreased growth performance of steers; and by studying the effects of oregano essential oil and antimicrobial peptides on intramuscular fat content, growth performance, cecal flora and metabolites of steers, this mechanism is verified, and the intramuscular fat content is increased, providing a theoretical and practical basis for improving the growth performance of steers.

[0028] The technical solution of the present invention solves the problem of reducing the intramuscular fat content while improving the growth performance of steers. The present invention improves the intramuscular fat content and the yield of high-grade meat while improving the growth performance of steers.

[0029] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are described in detail as follows:

[0030] Previous studies on steers have mainly focused on meat quality and carcass traits; research on growth performance has mainly focused on the mechanism by which additives improve the growth performance of steers. Different additives will improve the growth performance of steers through different mechanisms and affect the content of intramuscular fat. None of them revealed the mechanism of decreased growth performance of steers, and could not provide an accurate potential mechanism for improving the growth of steers. Cecal flora is particularly important for animal growth, and no research on the effect of cecal flora on the growth performance of steers has been reported. The present invention, without using additives, for the first time reveals the potential mechanism of decreased growth performance of steers.

[0031] To verify the mechanism of discovery, most scientists will use mice to carry out verification tests. Since mice are monogastric animals and cattle are ruminants, the verification tests of mice cannot truly verify the mechanism of discovery. The verification test of the present invention is a test done using the same batch of steers, which can truly verify the mechanism found in the steer research test. By studying the effects of oregano essential oil and antimicrobial peptides on intramuscular fat content, growth performance, cecal flora and metabolites of steers, the mechanism of decreased growth performance of steers was verified, and the content of intramuscular fat was increased, which provides a theoretical basis for improving the growth and development of steers in the future, which is of great significance.

[0032] Third, as auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0033] The expected benefits and commercial value of the technical solution of the present invention after transformation are as follows: the present invention improves the growth performance of steers while increasing the content of intramuscular fat, thereby increasing the yield of high-grade meat and improving economic benefits. The present invention increases the benefits of farmers, breeders, food processing plants and other related personnel and industries. The present invention meets people's demand for high-grade meat.

[0034] The technical solution of the present invention fills the technical gap in the industry at home and abroad: the present invention reveals for the first time the mechanism of the decline in growth performance of castrated cattle.

[0035] (3) Whether the technical solution of the present invention solves the technical problems that people have been eager to solve but have not been able to solve successfully:

[0036] The invention improves the growth performance of steers and increases the intramuscular fat deposition at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1It is a system structure diagram of a method for improving the growth performance of steers provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] In order to enable those skilled in the art to fully understand how to implement the present invention in detail, this section is an explanatory embodiment that expands and describes the technical solution of the claims.

[0041] In view of the problems existing in the prior art, the present invention provides a method for improving the growth performance of steers, which is described in detail below in conjunction with the accompanying drawings.

[0042] Step 1: Test;

[0043] Step 2, slaughter and sample collection;

[0044] Step three, determining the effect of castration on the growth performance of bulls;

[0045] Step 4, determining the effect of castration on intramuscular fat in bulls;

[0046] Step 5: Testing the changes in the flora of the cecal contents;

[0047] Step six: test the changes in metabolites in cecal contents.

[0048] The test of the method for improving the growth performance of steers comprises the following steps:

[0049] Step 1, 9 Holstein bulls aged 10 months with an average body weight of 341±12.11 kg were selected as the bull group; 27 Holstein steers aged 10 months with an average body weight of 352.91±18.47 kg were selected and randomly divided into 3 groups, namely, the steer group, the oregano essential oil group and the antimicrobial peptide group;

[0050] Step 2, the oregano essential oil group added 20 g / head / day of oregano essential oil to the basal diet, and the antimicrobial peptide group added 8 g / head / day of antimicrobial peptide to the basal diet; the pre-feeding period was 30 days, and the test period was 270 days;

[0051] Step 3: Weigh and record the body weight every 30 days. Prepare the basic diet according to the 2016 NRC standard, feed once a day at 08:00 and 16:00, provide sufficient feed and free drinking water.

[0052] The slaughter and sample collection include: after the end of the trial period, 6 cows were randomly slaughtered in each group; after slaughter, the head, hoof and skin were removed, and the abdominal cavity was immediately opened; the rumen contents and cecal contents were collected from the rumen and cecum, quickly frozen in liquid nitrogen, and then stored at -80°C for the determination of microorganisms and metabolites; 50g of the left half of the longissimus dorsi muscle was taken for the determination of intramuscular fat content; the results showed that compared with the bull group, the intramuscular fat content of the steer group was significantly increased; compared with the steer group, the addition of oregano essential oil and antimicrobial peptides significantly increased the intramuscular fat content.

[0053] The effects of castration on bull growth performance include:

[0054] Compared with the bull group, the final weight and average daily weight gain of the steers group were significantly lower;

[0055] Table 1 Effects of castration on growth performance of bulls

[0056]

[0057] Further, the effects of the oregano essential oil and antimicrobial peptides on the growth performance of steers;

[0058] The addition of oregano essential oil and antimicrobial peptides significantly increased final body weight and average daily gain compared to the steer group.

[0059] Table 2 Effects of oregano essential oil and antimicrobial peptides on growth performance of steers

[0060]

[0061] The study on the effect of castration on intramuscular fat in bulls includes:

[0062] Take 5g of the longissimus dorsi muscle and use Soxtec TM —2043 automatic extractor to determine intramuscular fat content;

[0063] As shown in Table 4 , the intramuscular fat content of the steer group was significantly increased compared with the bull group;

[0064] Table 4 Effect of castration on intramuscular fat in bulls (%)

[0065]

[0066] Further, the effects of oregano essential oil and antimicrobial peptides on intramuscular fat in steers;

[0067] As shown in Table 5, the addition of oregano essential oil and antimicrobial peptides significantly increased the intramuscular fat content compared to the steer group.

[0068] Table 5 Effects of oregano essential oil and antimicrobial peptides on intramuscular fat in steers (%)

[0069]

[0070] The cecal content flora change testing method comprises:

[0071] The cecal contents were sent to Shanghai Meiji Biopharmaceutical Technology Co., Ltd. for sequencing using the Illumina HiSeq3000 high-throughput platform. The original sequencing sequences were quality controlled, spliced ​​and filtered to obtain valid sequence data for subsequent analysis, which was used to further analyze the changes in the cecal content flora.

[0072] As shown in Table 6, the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the steer group was significantly reduced compared with the bull group. As shown in Table 7, the addition of oregano essential oil and antimicrobial peptides significantly increased the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecum compared with the steer group.

[0073] Table 6 Effect of castration on the cecal flora of bulls (%)

[0074]

[0075] Table 7 Effects of oregano essential oil and antimicrobial peptides on cecal flora of steers (%)

[0076]

[0077]

[0078] Ruminococcaceae_bacterium can degrade cellulose and hemicellulose components in plants, produce short-chain fatty acids that can be absorbed by the host, and provide energy for cattle growth. Oscillibacter_sp. plays an important role in starch degradation and complex sugar fermentation. Correlation analysis showed that Oscillibacter_sp. was positively correlated with butyrate and cellulase, and negatively correlated with α-amylase. This suggests that a decrease in the relative abundance of Oscillibacter_sp. may lead to an increase in α-amylase, a decrease in cellulase, and a decrease in butyrate concentration, further inhibiting the growth of steers. In summary, after castration, the decrease in the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecal contents of steers may lead to reduced growth performance. To verify this conclusion, the present invention added oregano essential oil and antimicrobial peptides to the feed and fed it to steers. The results showed that the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecal contents increased, and the growth performance of the steers was improved.

[0079] The test method for changes in cecal content metabolites includes:

[0080] Weigh 50 mg of rumen contents and 50 mg of cecal contents respectively, add 500 uL of pre-cooled 70% methanol water (containing 1 ug / mL 2-chlorophenylalanine as internal standard), then vortex for 3 min, centrifuge at 16,260 × g and 4 °C for 10 min, and pipette the supernatant into a sample injection bottle for ultra-high performance liquid chromatography and tandem mass spectrometry analysis;

[0081] The experiment screened the differentially expressed metabolites based on the criteria of VIP≥1, FC≥1.5 or ≤0.7. Compared with the bull group, the concentration of α-ketoglutarate in the cecal contents of the steer group was reduced; compared with the steer group, the addition of oregano essential oil and antimicrobial peptides increased the concentration of α-ketoglutarate in the cecal contents, as shown in Table 8;

[0082] Table 8 α-ketoglutarate in cecal contents

[0083]

[0084] α-Ketoglutarate is an important intermediate in amino acid metabolism and has multiple physiological functions such as regulating energy and amino acid metabolism and promoting intestinal development. α-Ketoglutarate is also necessary for the oxidation of fatty acids and amino acids. During the in vitro rumen fermentation of wheat straw, the final concentrations of acetate, propionate, and butyrate increased linearly with the concentration of α-ketoglutarate. In this study, the lack of α-ketoglutarate may lead to a decrease in the concentration of SCFAs in the cecum, thereby inhibiting the growth of steers. The decrease in α-ketoglutarate concentration may be another reason for the decline in the growth performance of steers. Feeding steers with oregano essential oil and antimicrobial peptides in the diet can increase the concentration of α-ketoglutarate in the cecal contents and improve growth performance.

[0085] Furthermore, to prove that α-ketoglutarate plays a role in the growth of steers in the cecum, metabolites in the rumen contents were detected, and the results showed that there was no difference in α-ketoglutarate in the rumen, as shown in Table 9; the above results indicate that rumen-bypass α-ketoglutarate can improve the growth performance of steers.

[0086] Table 9 α-ketoglutarate in rumen contents

[0087]

[0088] In order to prove the creativity and technical value of the technical solution of the present invention, this section is an application example of applying the technical solution of the claims to specific products or related technologies.

[0089] 1. Adding oregano essential oil to the diet can increase the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. and the level of α-ketoglutarate in the cecum, and improve the growth performance and intramuscular fat content of steers.

[0090] 2. Adding antimicrobial peptides to the feed can increase the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. and the level of α-ketoglutaric acid in the cecum, and improve the growth performance and intramuscular fat content of steers.

[0091] The embodiments of the present invention have achieved some positive effects during the development or use process, and indeed have great advantages over the prior art. The following content is described in conjunction with data, charts, etc. of the test process.

[0092] Step 1: Verification test;

[0093] Step 2, slaughter and sample collection;

[0094] Step 3, determining the effects of oregano essential oil and antimicrobial peptides on the growth performance of steers;

[0095] Step 4, determining the effects of oregano essential oil and antimicrobial peptides on intramuscular fat in steers;

[0096] Step 5: Testing the changes in the flora of the cecal contents;

[0097] Step six, test the changes in metabolites of rumen and cecal contents.

[0098] Step 1, 27 Holstein steers aged 10 months with an average body weight of 352.91±18.47 kg were selected and randomly divided into three groups, namely, a steer group, an oregano essential oil group, and an antimicrobial peptide group;

[0099] Step 2, the oregano essential oil group added 20 g / head / day of oregano essential oil to the basal diet, and the antimicrobial peptide group added 8 g / head / day of antimicrobial peptide to the basal diet; the pre-feeding period was 30 days, and the test period was 270 days;

[0100] Step 3: Weigh and record the body weight every 30 days. Prepare the basic diet according to the 2016 NRC standard, feed once a day at 08:00 and 16:00, provide sufficient feed and free drinking water.

[0101] The slaughter and sample collection include: after the end of the trial period, 6 cows are randomly slaughtered in each group; after slaughter, the head, hoof and skin are removed, and the abdominal cavity is immediately opened; the rumen contents and cecal contents are collected from the rumen and cecum, quickly frozen in liquid nitrogen, and then stored at -80°C for the determination of microorganisms and metabolites; 50g of the left half of the longissimus dorsi muscle is taken for the determination of intramuscular fat content; the results show that compared with the steer group, the addition of oregano essential oil and antimicrobial peptides significantly increased the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecum; increased the concentration of α-ketoglutaric acid in the cecum; and increased the intramuscular fat content.

[0102] The effects of oregano essential oil and antimicrobial peptides on the growth performance of steers;

[0103] The addition of oregano essential oil and antimicrobial peptides significantly increased final body weight and average daily gain compared to the steer group.

[0104] Table 10 Effects of oregano essential oil and antimicrobial peptides on growth performance of steers

[0105]

[0106] The effects of oregano essential oil and antimicrobial peptides on intramuscular fat in steers;

[0107] As shown in Table 11, the addition of oregano essential oil and antimicrobial peptides significantly increased the intramuscular fat content compared to the steer group.

[0108] Table 11 Effects of oregano essential oil and antimicrobial peptides on intramuscular fat in steers (%)

[0109]

[0110] The cecal content flora change testing method comprises:

[0111] The cecal contents were sent to Shanghai Meiji Biopharmaceutical Technology Co., Ltd. for sequencing using the Illumina HiSeq3000 high-throughput platform. The original sequencing sequences were quality controlled, spliced ​​and filtered to obtain valid sequence data for subsequent analysis, which was used to further analyze the changes in the cecal content flora.

[0112] As shown in Table 12, the addition of oregano essential oil and antimicrobial peptides significantly increased the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecum compared with the steer group.

[0113] Table 12 Effects of oregano essential oil and antimicrobial peptides on cecal flora of steers (%)

[0114]

[0115] Ruminococcaceae_bacterium can degrade cellulose and hemicellulose components in plants, produce short-chain fatty acids that can be absorbed by the host, and provide energy for cattle growth. Oscillibacter_sp. plays an important role in starch degradation and complex sugar fermentation. Correlation analysis showed that Oscillibacter_sp. was positively correlated with butyrate and cellulase, and negatively correlated with α-amylase. This indicates that the decrease in the relative abundance of Oscillibacter_sp. may lead to an increase in α-amylase, a decrease in cellulase, and a decrease in butyrate concentration, further inhibiting the growth of steers. In summary, the addition of oregano essential oil and antimicrobial peptides significantly increased the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecum, and the growth performance of steers was improved. It was verified that the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. decreased, inhibiting the growth of steers.

[0116] The test method for changes in cecal content metabolites includes:

[0117] Weigh 50 mg of rumen contents and 50 mg of cecal contents respectively, add 500 uL of pre-cooled 70% methanol water (containing 1 ug / mL 2-chlorophenylalanine as internal standard), then vortex for 3 min, centrifuge at 16,260 × g and 4 °C for 10 min, and pipette the supernatant into a sample injection bottle for ultra-high performance liquid chromatography and tandem mass spectrometry analysis;

[0118] The experiment used VIP≥1, FC≥1.5 or ≤0.7 as the standard to screen the differentially expressed metabolites. Compared with the steer group, the addition of oregano essential oil and antimicrobial peptides increased the concentration of α-ketoglutarate in the cecal contents, as shown in Table 13;

[0119] Table 13 α-ketoglutarate in cecal contents

[0120]

[0121] α-Ketoglutarate is an important intermediate in amino acid metabolism and has multiple physiological functions such as regulating energy and amino acid metabolism and promoting intestinal development. α-Ketoglutarate is also necessary for the oxidation of fatty acids and amino acids. During the in vitro rumen fermentation of wheat straw, the final concentrations of acetate, propionate, and butyrate increased linearly with the concentration of α-ketoglutarate. In this study, feeding steers with oregano essential oil and antimicrobial peptides in the diet increased the concentration of α-ketoglutarate in the cecal contents and improved growth performance. It was verified that the reduction of cecal α-ketoglutarate concentration inhibited the growth of cattle.

[0122] Furthermore, to prove that α-ketoglutarate plays a role in the growth of steers in the cecum, metabolites in the rumen contents were detected, and the results showed that there was no difference in α-ketoglutarate in the rumen, as shown in Table 14; the above results indicate that rumen-bypass α-ketoglutarate can improve the growth performance of steers.

[0123] Table 14 α-ketoglutarate in rumen contents

[0124]

[0125] The test results include:

[0126] 1. Adding oregano essential oil to the diet can increase the intramuscular fat content, increase the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. and the level of α-ketoglutaric acid in the cecum, and improve the growth performance of steers.

[0127] 2. Adding antimicrobial peptides to the feed can increase the intramuscular fat content, increase the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecum and the level of α-ketoglutaric acid, and improve the growth performance of steers.

[0128] The test conclusions include:

[0129] 1. The relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecum decreased, which are microorganisms that inhibit the growth of steers.

[0130] 2. Decreased levels of α-ketoglutarate in the cecum, a metabolite that inhibits growth in steers.

[0131] 3. Adding oregano essential oil to the feed can increase the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. and the level of α-ketoglutaric acid in the cecum, improve the growth performance of steers, and promote intramuscular fat deposition.

[0132] 4. Adding antimicrobial peptides to the feed can increase the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. and the level of α-ketoglutaric acid in the cecum, improve the growth performance of steers, and promote intramuscular fat deposition.

[0133] In summary, adding Ruminococcaceae_bacterium and Oscillibacter_sp. to the feed can improve the growth performance of steers and promote intramuscular fat deposition; rumen bypass α-ketoglutarate can improve the growth performance of steers and promote intramuscular fat deposition.

[0134] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for improving the growth performance of steers, characterized in that: The method for improving the growth performance of steers comprises the following steps: Step 1: Comparative group test, record the weight of cattle; Step 2, slaughter and sample collection; Step three, determining the effect of castration on the growth performance of bulls; Step 4, determining the effect of castration on intramuscular fat in bulls; Step 5: Testing the changes in the flora of the cecal contents; Step six, testing the changes in metabolites in cecal contents; The test of the method for improving the growth performance of steers comprises the following steps: Step 1, 9 Holstein bulls aged 10 months with an average body weight of 341 ± 12.11 kg were selected as the bull group; Twenty-seven Holstein steers aged 10 months with an average body weight of 352.91±18.47kg were randomly divided into three groups: steer group, oregano essential oil group, and antimicrobial peptide group. Step 2, the oregano essential oil group added 20 g / head / day of oregano essential oil to the basal diet, and the antimicrobial peptide group added 8 g / head / day of antimicrobial peptide to the basal diet; the pre-feeding period was 30 days, and the test period was 270 days; Step 3, weigh and record body weight every 30 days; The slaughter and sample collection include: after the end of the trial period, 6 cattle were randomly slaughtered in each group; after slaughter, the head, hoof and skin were removed, and the abdominal cavity was immediately opened; the rumen contents and cecal contents were collected from the rumen and cecum, quickly frozen in liquid nitrogen, and then stored at -80°C for the determination of microorganisms and metabolites; 50g of the left half of the longissimus dorsi muscle was taken for the determination of intramuscular fat content; compared with the bull group, the intramuscular fat content of the steer group was significantly increased; compared with the steer group, the addition of oregano essential oil and antimicrobial peptides significantly increased the intramuscular fat content; The changes in the flora of the cecal contents include: adding oregano essential oil and antimicrobial peptides to feed steers, the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp. in the cecal contents increases, and the growth performance of the steers is improved; The test method for changes in cecal content metabolites includes: adding oregano essential oil and antimicrobial peptides to feed steers, which can increase the concentration of α-ketoglutaric acid in the cecal content and improve growth performance; The method for testing changes in metabolites in cecal contents includes: detecting metabolites in rumen contents, α-ketoglutarate has no difference in the rumen, and the results show that rumen-passing α-ketoglutarate can improve the growth performance of steers; The method for testing changes in cecal content flora comprises: sequencing cecal content to analyze changes in cecal content flora; The method for testing changes in cecal content metabolites comprises: weighing rumen contents and cecal contents respectively for ultra-high performance liquid chromatography and tandem mass spectrometry analysis.

2. The method for improving the growth performance of steers as claimed in claim 1, characterized in that: The effects of castration on the growth performance of bulls include: compared with the bull group, the final body weight and average daily weight gain of the steer group were significantly reduced; compared with the steer group, the addition of oregano essential oil and antimicrobial peptides significantly increased the final body weight and average daily weight gain.

3. The method for improving the growth performance of steers as claimed in claim 1, characterized in that: The study on the effect of castration on intramuscular fat of bulls includes: taking 5g of the longissimus dorsi muscle and measuring the intramuscular fat content; the results show that compared with the bull group, the intramuscular fat content of the steer group increased significantly; compared with the steer group, adding oregano essential oil and antimicrobial peptides significantly increased the intramuscular fat content.

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