Alfalfa-type non-antibiotic low-protein daily ration for reducing pig nitrogen emissions and method of preparation

Abstract

The application discloses alfalfa type non-antibiotic low-protein daily ration for reducing pig nitrogen emission and a preparation method thereof, which is composed of the following components in terms of dry matter weight fractions: corn 48-59 parts, soybean meal 1-5 parts, bran 1-2 parts, alfalfa powder 15 parts, wheat 16-23 parts, soybean oil 4-5 parts, calcium hydrogen phosphate 0.7-0.9 parts, stone powder 0-0.03 parts, salt 0.3 parts, lysine 0.3-0.5 parts, methionine 0.06-0.07 parts, threonine 0.14-0.21 parts, tryptophan 0.02-0.06 parts, valine 0.05-0.2 parts, isoleucine 0.04-0.2 parts, premix 1 part and compound probiotics 1 part. The daily ration improves the growth performance and meat quality of fattening pigs, improves feed conversion rate and economic benefits, reduces serum urea nitrogen content, promotes nitrogen metabolism of the organism, reduces glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase activities in the liver and improves the immune level of the organism, greatly solves the problem of protein feed resource shortage, reduces emission of urine nitrogen, fecal nitrogen and total nitrogen, guarantees food safety and reduces breeding pollution.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of livestock breeding feed, and particularly relates to an alfalfa type antibiotic-free low-protein daily feed for reducing pig nitrogen emission and a preparation method thereof. BACKGROUND

[0002] In the Work Plan for Reducing the Amount of Corn and Soybean Meal in Feed issued by the Bureau of Animal Husbandry and Veterinary Medicine of the Ministry of Agriculture and Rural Affairs, the work goal of optimizing and adjusting the feed formula structure is proposed. Therefore, developing new types of feed protein source feed resources, and researching and developing pig antibiotic-free daily feed preparation technology for reducing soybean meal utilization and nitrogen emission are the most direct and effective measures to cope with the shortage of protein feed resources in China, the ban on antibiotics, improve the utilization efficiency of feed nutrition, reduce breeding pollution, and at the same time ensure the quality of livestock products.

[0003] Alfalfa is a perennial legume forage, which has the advantages of wide planting area, high yield, high quality, rich nutritional value, good palatability, and high digestibility. The previous research of the research group found that the addition of 10%-15% alfalfa grass powder in the daily feed can significantly improve the daily gain and feed conversion rate of fattening pigs, and increase economic benefits; the addition of 20% alfalfa grass powder can improve the meat quality and nutritional value of pigs. The crude protein content of alfalfa is high, and the crude protein content of special alfalfa grass powder is more than 22%, and the crude protein content of alfalfa leaf powder is as high as 30%-36%; in addition, the alfalfa protein contains more than 20 kinds of amino acids, and the amino acid proportion is similar to that of soybean meal, which can be further developed as a new type of protein raw material to replace soybean meal daily feed, and to a certain extent, alleviate the shortage of protein feed. Low-protein daily feed refers to reducing the crude protein level in the daily feed by 2-4 percentage points on the basis of the feeding standard under the premise of not affecting the production performance of animals, and based on the net energy and ileal digestible balanced amino acid technology, appropriate synthetic amino acids are supplemented to meet the amino acid balance and improve the protein utilization efficiency. Studies have shown that reducing the crude protein level of pig daily feed by 1-3 percentage points does not affect the growth performance, and can reduce the NH3 content and nitrogen excretion in the pig house. The use of low-protein daily feed technology in pig breeding can avoid the waste of protein raw materials and reduce environmental pollution caused by nitrogen emission.

[0004] At present, the research on adding alfalfa meal in the daily feed of fattening pigs in China mainly focuses on improving pork quality, etc., while the ordinary low-protein daily feed technology mainly reduces the protein level and supplements synthetic amino acids to meet the basic growth performance of fattening pigs. It has been reported that alfalfa meal used in the feed of fattening pigs can improve the production performance of fattening pigs and improve pork quality. For example, Chinese patent application CN107410723A discloses a method for preparing alfalfa feed for meat pigs, however, the technical content recorded therein is too rough, when the fresh alfalfa is kneaded, twisted and cooled to make the water content in the range of 50%-70%, it is impossible to carry out bundling and it is also impossible to obtain alfalfa meal by powdering, so it is difficult to obtain the corresponding feed product. For the formula disclosed in the patent, it is impossible to know the nutrient content of the final feed product, it is also impossible to know whether it meets the corresponding national standard, and the actual effect of the pig feeding has not been verified, therefore, it is not sufficient to provide effective support for the development and production of refined feed. The rough general feed can no longer meet the long-term development of the current pig breeding industry, and various feed formulas also exist, but for different age and different breed of pigs, the research on refined feed formula is still a research hotspot and difficulty in the field. At present, there is no alfalfa as a new type of protein feed to replace soybean meal, on the one hand, the use of alfalfa amino acid composition advantage reduces the addition of synthetic amino acids, on the other hand, the use of rich nutritional ingredients of alfalfa improves the production performance of fattening pigs and meat quality, improves feed conversion rate, and reduces antibiotics and nitrogen emissions. SUMMARY

[0005] In view of the problems of shortage of feed protein raw materials, high dependence on imports, prominent conflict between human and livestock for food, ban on antibiotics, serious pollution of pig farm manure and urine, etc. in China, the present application provides a method for preparing alfalfa type antibiotic-free low-protein daily feed, which reduces or replaces soybean meal, reduces cost, improves the production performance of fattening pigs and meat quality, improves feed conversion rate, reduces antibiotics and nitrogen emissions and breeding pollution, and provides a reference for the production of grain-saving, emission-reducing, antibiotic-free and healthy refined feed formula.

[0006] In the first aspect, the present application provides an alfalfa type antibiotic-free low-protein daily feed for reducing nitrogen emissions of pigs, which is composed of the following ingredients by weight fraction of dry matter: corn 48-59 parts, soybean meal 1-5 parts, bran 1-2 parts, alfalfa meal 15 parts, wheat 16-23 parts, soybean oil 4-5 parts, dicalcium phosphate 0.7-0.9 parts, stone powder 0-0.03 parts, salt 0.3 parts, lysine 0.3-0.5 parts, methionine 0.06-0.07 parts, threonine 0.14-0.21 parts, tryptophan 0.02-0.06 parts, valine 0.05-0.2 parts, isoleucine 0.04-0.2 parts, premix 1 part, and compound probiotics 1 part.

[0007] Further, the weight composition of 1 kg of premix is: copper 23.66 mg, iron 108 mg, zinc 95.22 mg, manganese 38.16 mg, 1% cobalt 0.48 mg, 5% iodine 0.6 mg, 1% selenium 0.3 mg, 10% chromium nicotinate 0.225 mg; VA, 7500 IU; VD, 2000 IU; VE, 20 mg; VK, 9 mg; VB1, 0.39 mg; VB2, 6.4 mg; VB3, 28.12 mg; VB5, 14.22 mg; VB6, 0.78 mg; VB7, 0.02 mg; VB9, 0.39 mg; VB12, 0.03 mg; choline, 300 mg. The complex probiotic bacteria include: Enterococcus faecalis, 100 billion cfu / g; Bacillus licheniformis, 100 billion cfu / g; Clostridium butyricum, 100 billion cfu / g; and a suitable amount of sweetener. The mass ratio of each component in the complex probiotic bacteria is 20:4:4:1.

[0008] In a preferred embodiment, the alfalfa type non-antibiotic low-protein diet for reducing nitrogen emissions of pigs of the present application is composed of the following ingredients by weight fraction of dry matter: corn 48.51 parts, soybean meal 4.65 parts, bran 1.972 parts, alfalfa meal 15 parts, wheat 22.16 parts, soybean oil 5 parts, calcium hydrogen phosphate 0.72 parts, stone powder 0.03 parts, salt 0.3 parts, lysine 0.35 parts, methionine 0.06 parts, threonine 0.14 parts, tryptophan 0.02 parts, valine 0.05 parts, isoleucine 0.04 parts, premix 1 part, and complex probiotic bacteria 1 part.

[0009] In a preferred embodiment, the alfalfa meal is purple alfalfa harvested at the budding to early flowering stage, which is naturally or artificially dried and then crushed by a 2mm sieve crusher to form a certain fineness of powder, and the powder bag is made of high-density cloth. The moisture content is not more than 12%, and the crude ash content is not more than 12%. The alfalfa meal is dark green, green or light green powder, has a grassy smell, no odor, no impurities, no fermentation, no mold, no caking phenomenon, and contains no toxic and harmful substances. It meets the quality grading standard of the first level or above of the Chinese Association of Animal Husbandry (T / CAAA 086-2022). The inventors found that the quality of alfalfa meal has an important influence on the nutritional composition of feed. The crude protein content of the first level or above of alfalfa meal is >18%, and the neutral detergent fiber and acid detergent fiber contents are low. Adding 15% of the first level or above of alfalfa meal can replace about 28% of soybean meal, and has a good improvement effect on the growth performance and meat quality of finishing pigs. However, the use effect of alfalfa meal with lower protein content in replacing soybean meal and finishing pig breeding is not good.

[0010] In a preferred embodiment, the alfalfa type low-protein non-antibiotic daily ration for reducing nitrogen emission of pigs of the present application has a crude protein content of 10.5%-12.5%, preferably 12.5%. If the crude protein content is too low, it will have adverse effects on the growth performance, economic benefits, nutrient digestion, meat quality and health status of the finishing pigs.

[0011] In another aspect, the present application provides a preparation method of the above-mentioned alfalfa type low-protein non-antibiotic daily ration for reducing nitrogen emission of pigs, which comprises: cutting the Medicago polymorpha in the budding stage to the early flowering stage, naturally or artificially drying the Medicago polymorpha, and then crushing the Medicago polymorpha by a 2mm sieve crusher to obtain first alfalfa grass powder with a water content of not more than 12% and a crude ash content of not more than 12%; and adding a compound probiotic: Enterococcus faecalis, 100 billion cfu / g; Bacillus licheniformis, 100 billion cfu / g; Clostridium butyricum, 100 billion cfu / g; and a suitable amount of sweetener. The mass ratio of the components in the compound probiotic is 20:4:4:1, which completely replaces the antibiotics in the ordinary daily ration. The substances in the formula are weighed and mixed to obtain the alfalfa type low-protein non-antibiotic daily ration for reducing nitrogen emission of pigs. In yet another aspect, the present application provides an application of the above-mentioned alfalfa type low-protein non-antibiotic daily ration for reducing nitrogen emission of pigs in the breeding of finishing pigs, wherein the body weight of the finishing pigs is 55-130 kg.

[0012] Technical effects

[0013] In order to reduce the nitrogen emission of finishing pigs, an effective idea is to reduce the crude protein content in the daily ration. However, research has found that under the same crude protein content, different raw material ratios will still have effects on the growth performance, economic benefits, serum biochemistry, nutrient digestion and other indicators. If the crude protein content is reduced too much, it will have adverse effects on the growth performance, economic benefits, nutrient digestion, health status and meat quality of the finishing pigs. Therefore, the fine feed ratio research is still of great significance.

[0014] 1. Using the alfalfa type low-protein non-antibiotic daily ration (AMLP-I group) provided by the present application with a 2% CP reduction, the feed conversion rate is significantly improved, the growth performance of the finishing pigs is improved, and the economic benefits are improved; the serum urea nitrogen content is reduced, the nitrogen metabolism and protein utilization efficiency of the body are promoted; the activities of glutathione transaminase and glutathione transaminase in the liver are reduced, the immune level of the body is improved, the liver function of the finishing pigs is protected from damage, and the health status of the finishing pigs is improved.

[0015] 2. The alfalfa-based antibiotic-free, low-protein diet (AMLP-I group) with a 2% reduced CP provided by this invention significantly improved digestion and metabolism, promoted muscle fat deposition and phosphorus digestion and absorption, and increased muscle marbling score and eye muscle area. It had a significant effect on improving carcass traits and meat quality in fattening pigs. The amino acid and fatty acid content in pork was increased to varying degrees, especially the content of flavor amino acids, linoleic acid, α-linolenic acid, and ω-6, which significantly improved pork flavor, quality, nutritional value, and health benefits.

[0016] 3. In response to the current shortage of protein feed resources, the ban on antibiotics, and serious pollution from livestock farming in my country, the alfalfa-based antibiotic-free low-protein diet (AMLP-I group) provided by this invention can replace antibiotics, inhibit harmful bacteria, increase the number of beneficial bacteria, and improve the intestinal health of fattening pigs. This invention uses alfalfa hay meal to replace 67.3% of soybean meal, while reducing the crude protein content in the diet by 2%, significantly reducing the daily nitrogen intake of fattening pigs, avoiding the waste of protein raw materials, greatly reducing the emission of urinary nitrogen, fecal nitrogen, and total nitrogen, and reducing environmental pollution caused by nitrogen emissions from pig farms. It has broad application prospects and provides a scientific and standardized reference for the production of refined feed formulations. Detailed Implementation

[0017] This invention discloses a method for formulating a nitrogen-saving, emission-reducing, antibiotic-free, low-protein alfalfa diet and its application. The invention is further illustrated below with specific embodiments, but the invention is not limited to these embodiments. Unless otherwise specified, the methods described are conventional methods. Unless otherwise specified, the raw materials are all available from publicly available commercial sources. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0018] Examples and Comparative Examples

[0019] Alfalfa harvested from the budding stage to the initial flowering stage was naturally or artificially dried, then pulverized through a 2mm sieve to obtain Grade 1 alfalfa meal, with a moisture content not exceeding 12% and a crude ash content not exceeding 12%. Based on the weights of the raw materials shown in Table 1 below, four diets were formulated: control group (CK, corn-soybean meal basal diet, Example 1), alfalfa-based normal protein group (AM, Example 2), alfalfa-based antibiotic-free low-protein diet group I (AMLP-I, Example 1), and alfalfa-based antibiotic-free low-protein diet group II (AMLP-II, Example 2). The crude protein (CP) content of each group was 14.5%, 14.5%, 12.5%, and 10.5%, respectively.

[0020] Table 1. Composition and nutrient levels of the experimental diets (dry matter basis) (%)

[0021]

[0022] Both Control Example 1 and Control Example 2 diets contained 0.075 parts of chlortetracycline for broad-spectrum antibacterial purposes. The diets of Examples 1 and 2 did not use antibiotics but contained a compound probiotic: Enterococcus faecalis (10 billion CFU / g), Bacillus licheniformis (10 billion CFU / g), Clostridium butyricum (10 billion CFU / g), and a suitable amount of sweetener. The ratio of the components in the compound probiotic was 20:4:4:1.

[0023] Experimental Examples:

[0024] The effects of alfalfa-based antibiotic-free, low-protein diets on growth performance, economic benefits, serum biochemistry and antioxidant properties, nutrient digestibility, meat quality, fecal microorganisms, and nitrogen emissions in 55-130kg fattening pigs.

[0025] Three hundred healthy, three-way crossbred (Duroc × Landrace × Large White) fattening pigs of similar weight were selected from the same population, weighed, and numbered. They were then randomly divided into four groups, with five replicates in each group and 15 pigs in each replicate. The pre-trial period was 7 days, and the formal trial period was 80 days.

[0026] The experimental diets were formulated according to the NRC (2012) nutritional requirements for pigs, using standard ileal digestible amino acids to calculate nutrient indicators. Six additional amino acids—Lys, Met, Thr, Trp, Val, and Ile—were supplemented to meet the essential amino acid requirements of finishing pigs. Before the experiment, the pigsty was thoroughly cleaned and disinfected. The experimental pigs were housed in the same pigsty, with free access to feed and water. The pigsty was cleaned twice daily, with good ventilation maintained, and routine feeding and management procedures were followed. Feeding was conducted at 6:30, 11:00, and 17:30 daily, and the eating and excretion of each group were observed to ensure good health during the experiment. The composition and nutrient levels of the experimental diets are shown in Table 1.

[0027] Experimental results:

[0028] 1. Growth performance

[0029] As shown in Table 2, the daily feed intake of the CK group was significantly higher than that of the other three groups (P < 0.05), while the feed conversion ratio was significantly higher than that of the AM and AMLP-I groups (P < 0.05); the average daily weight gain of the AMLP-II group was significantly lower than that of the other three groups (P < 0.05). These results indicate that compared with a corn-soybean meal basal diet, the AMLP-I group with a 2% reduction in CP can effectively improve the feed conversion ratio and growth performance of finishing pigs, but the AMLP-II group with a 4% reduction in CP may reduce the growth rate of finishing pigs.

[0030] Table 2. Effects of different diet groups on the growth performance of fattening pigs

[0031]

[0032] Note: Different lowercase letters in the superscript of data in the same row indicate significant differences (P < 0.05), while the same letters indicate no significant differences (P > 0.05). The same applies below.

[0033] 2. Economic benefits

[0034] Table 3 shows that the feed unit price of the AM, AMLP-I, and AMLP-II groups was 0.26, 0.15, and 0.13 yuan / kg higher than that of the CK group, respectively. However, the total feed intake of fattening pigs decreased after the addition of alfalfa meal. The gross profit of the AM and AMLP-I groups increased by 30.73 and 46.85 yuan / head, respectively, compared to the CK group. Due to the reduced weight gain, the gross profit of the AMLP-II group decreased by 109.51 yuan / head compared to the CK group. This indicates that the AMLP-I group had the highest gross profit, effectively improving the economic benefits of fattening pigs and increasing the profits of pig farms.

[0035] Table 3. Impact of each diet group on the economic benefits of fattening pigs

[0036]

[0037] 3. Serum biochemical indicators

[0038] The effects of different diets on serum biochemical and antioxidant indicators in finishing pigs are shown in Table 4. The albumin and high-density lipoprotein cholesterol levels in the MLP-II group were significantly lower than those in the AM and AMLP-I groups (P < 0.05), but not significantly different from the CK group (P > 0.05). Compared with the CK group, the urea nitrogen levels in the AM, AMLP-I, and MLP-II groups were significantly lower (P < 0.05). There were no significant differences in total protein, globulin, triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels among the groups (P > 0.05). Serum biochemical indicators in animals reflect the metabolic status of nutrients to varying degrees. Serum urea nitrogen in pigs is an important indicator for measuring protein metabolism and reflects the body's protein metabolism status. Low serum urea nitrogen indicates high protein utilization efficiency, while low urea nitrogen indicates low protein utilization efficiency. The alfalfa-based antibiotic-free, low-protein diet provided by this invention does not restrict the normal nutritional requirements of fattening pigs for protein, thereby ensuring that the growth performance of fattening pigs is not affected, and can also promote the body's nitrogen metabolism and protein utilization efficiency, and reduce nitrogen emissions.

[0039] As shown in Table 4, different diets had no significant effect on the serum antioxidant index of fattening pigs (P>0.05), indicating that adding alfalfa meal to the diet or reducing the protein content on this basis would not have an adverse effect on the antioxidant performance of fattening pigs.

[0040] Table 4. Effects of different dietary groups on serum biochemical and antioxidant indicators in fattening pigs.

[0041]

[0042]

[0043] 4. Liver biochemical indicators

[0044] As shown in Table 5, the alanine aminotransferase (ALT) activities in the AM, AMLP-I, and AMLP-II groups were significantly lower than those in the CK group (P < 0.05). The aspartate aminotransferase (AST) activity in the AMLP-I group was lower than that in the AM group (P > 0.05), but significantly lower than that in the CK and AMLP-II groups (P < 0.05). ALT is mainly found in various cells, especially hepatocytes, with the total ALT content in the liver being approximately 100 times that in the blood, making it a sensitive marker of acute hepatocellular damage. AST is mainly distributed in the myocardium, followed by the liver, skeletal muscle, and kidneys. Normally, AST levels are low, but they increase when cells are damaged. This indicates that antibiotics can damage liver function, while the alfalfa-based antibiotic-free low-protein diet (AMLP-I group) can promote amino acid metabolism, enhance immunity, and protect the liver function of fattening pigs from damage.

[0045] Table 5. Effects of different diets on liver biochemical indicators of fattening pigs

[0046]

[0047] 5. Nutrient digestibility

[0048] Table 6 shows that the crude protein digestibility of the AM and AMLP-I groups was higher than that of the CK group, but there was no significant difference among the three groups (P>0.05), and both were significantly higher than that of the AMLP-II group (P<0.05). The crude fat digestibility of the CK group was significantly lower than that of the other three groups (P<0.05), and the phosphorus digestibility of the CK group was the lowest, significantly lower than that of the AMLP-I group (P<0.05). This indicates that the AMLP-I group has a promoting effect on fat deposition and phosphorus digestion and absorption in fattening pigs.

[0049] Table 6. Effects of different diets on nutrient digestibility in fattening pigs (%)

[0050]

[0051] 6. Carcass characteristics and meat quality

[0052] The effects of different diets on carcass traits and meat quality of finishing pigs are shown in Table 7. The marbling score and eye muscle area of ​​the AMLP-I group were significantly higher than those of the CK group (P < 0.05). This indicates that the alfalfa-based antibiotic-free low-protein diet (AMLP-I group) has a better effect on improving carcass traits and meat quality of finishing pigs.

[0053] Table 7. Effects of different diet groups on carcass traits and meat quality of finishing pigs.

[0054]

[0055] 7. Muscle amino acids

[0056] Table 8 shows that the AM and AMLP-I groups had higher levels of flavor-enhancing amino acids in their muscle, significantly higher than the AMLP-II group (P < 0.05), but no significant difference compared to the CK group (P > 0.05). The AMLP-II group had significantly lower levels of essential amino acids and total amino acids in its muscle compared to the other three groups (P < 0.05), while there were no significant differences among the other three groups (P > 0.05). This indicates that the alfalfa-based antibiotic-free low-protein diet (AMLP-I group) can improve pork flavor, enhance pork quality, and increase its nutritional value.

[0057] Table 8. Effects of different diets on amino acid levels in the muscle of fattening pigs (mg / g)

[0058]

[0059] 8. Muscle fatty acids

[0060] In this embodiment, 12 fatty acids were detected in the muscle samples, including 5 saturated fatty acids, 3 monounsaturated fatty acids, and 4 polyunsaturated fatty acids (Table 9). The CK group had the highest contents of myristic acid, stearic acid, arachidic acid, and arachidonic acid, significantly higher than the other three groups (P < 0.05); the CK group had a significantly higher palmitic acid content than the AMLP-II group (P < 0.05). With the addition of alfalfa meal and the decrease in protein content, the total saturated fatty acid content in the muscle gradually decreased, and the total saturated fatty acid content in the AMLP-I and AMLP-II groups was significantly lower than that in the CK and AM groups (P < 0.05). Regarding unsaturated fatty acids, the AM and AMLP-I groups had significantly higher contents of linoleic acid, polyunsaturated fatty acids, and ω-6 than the CK and AMLP-II groups (P < 0.05); the AM group had the highest α-linolenic acid content, followed by the AMLP-I group, both significantly higher than the CK group (P < 0.05). Fatty acids in muscle not only affect the flavor of pork but also play a crucial role in human health and physiological functions, especially polyunsaturated fatty acids. This invention demonstrates that the alfalfa-based antibiotic-free low-protein diet (AMLP-I group) provided by this invention has the potential to improve muscle fatty acid composition, has a positive impact on the nutritional value of pork, and greatly improves the health level of pork consumption.

[0061] Table 9. Effects of different diets on fatty acids in the muscle of fattening pigs (mg / g)

[0062]

[0063] 9. Number of microorganisms in feces

[0064] The effects of different diets on the number of microorganisms in the feces of fattening pigs are shown in Table 10. The number of lactobacilli increased and the number of Escherichia coli and Salmonella decreased in the feces of fattening pigs in the AMLP-I group. The number of Salmonella was significantly lower than that in the other three groups (P<0.05), indicating that the alfalfa-based antibiotic-free low-protein diet (AMLP-I group) provided by this invention can replace antibiotics, inhibit harmful bacteria, increase the number of beneficial bacteria, and improve the intestinal health of fattening pigs.

[0065] Table 10. Effects of different diets on the number of microorganisms in the feces of fattening pigs (lg CFU / g)

[0066]

[0067] 10. Nitrogen emissions

[0068] As the protein content in the diet decreased, the nitrogen intake of fattening pigs gradually decreased, and nitrogen emissions also decreased significantly (Table 11). Compared with the control group, nitrogen intake in the AM group, AMLP-I group, and AMLP-II group decreased by 3.64%, 21.85%, and 42.40%, respectively (P < 0.05); fecal nitrogen emissions decreased by 9.44%, 23.14%, and 43.39%, respectively (P < 0.05); urinary nitrogen emissions decreased by 3.42%, 44.11%, and 87.87%, respectively (P < 0.05); and total nitrogen emissions decreased by 4.49%, 30.75%, and 60.35%, respectively (P < 0.05). However, there was no significant change in nitrogen deposition among the groups (P > 0.05). The results show that the alfalfa-based antibiotic-free low-protein diet provided by this invention can significantly reduce the daily nitrogen intake of fattening pigs, avoid the waste of protein raw materials, greatly reduce the emissions of urinary nitrogen, fecal nitrogen and total nitrogen, and reduce environmental pollution caused by nitrogen emissions from pig farms.

[0069] Table 11. Effects of different dietary groups on nitrogen emissions in fattening pigs (g / d)

[0070]

[0071] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An alfalfa-based antibiotic-free, low-protein diet for fattening pigs that reduces nitrogen emissions, comprising the following components by dry matter weight: The ingredients are: corn 48.51 parts, soybean meal 4.65 parts, wheat bran 1.97 parts, alfalfa meal 15 parts, wheat 22.16 parts, soybean oil 5 parts, dicalcium phosphate 0.72 parts, limestone powder 0.03 parts, salt 0.3 parts, lysine 0.35 parts, methionine 0.06 parts, threonine 0.14 parts, tryptophan 0.02 parts, valine 0.05 parts, isoleucine 0.04 parts, premix 1 part, and compound probiotics 1 part; the crude protein content is 12.5%. The alfalfa meal meets or exceeds the first-class quality grading standard of the China Animal Husbandry Association standard T / CAAA 086-2022, and the crude protein content of the alfalfa meal is >18%. The compound probiotics include: Enterococcus faecalis, 10 billion CFU / g; Bacillus licheniformis, 10 billion CFU / g; Clostridium butyricum, 10 billion CFU / g; and a sweetener; wherein the mass ratio of Enterococcus faecalis: Bacillus licheniformis: Clostridium butyricum: sweetener in the compound probiotics is 20:4:4:

1.

2. The alfalfa-based antibiotic-free, low-protein finishing pig diet for reducing nitrogen emissions in pigs according to claim 1, wherein, The premix weight composition of 1 kg is as follows: copper 23.66 mg, iron 108 mg, zinc 95.22 mg, manganese 38.16 mg, 1% cobalt 0.48 mg, 5% iodine 0.6 mg, 1% selenium 0.3 mg, 10% chromium nicotinate 0.225 mg; vitamin A, 7500 IU; vitamin D, 2000 IU; vitamin E, 20 mg; vitamin K, 9 mg; vitamin B1, 0.39 mg; vitamin B2, 6.4 mg; vitamin B3, 28.12 mg; vitamin B5, 14.22 mg; vitamin B6, 0.78 mg; vitamin B7, 0.02 mg; vitamin B9, 0.39 mg; vitamin B12, 0.03 mg; choline, 300 mg.

3. The method for formulating an alfalfa-based antibiotic-free, low-protein finishing pig diet with reduced nitrogen emissions as described in claim 1 or 2, comprising: Alfalfa harvested from the budding stage to the initial flowering stage is dried naturally or artificially, and then pulverized through a 2mm sieve pulverizer to obtain first-grade alfalfa meal. Weigh out 48.51 parts corn, 4.65 parts soybean meal, 1.97 parts wheat bran, 15 parts alfalfa meal, 22.16 parts wheat, 5 parts soybean oil, 0.72 parts dicalcium phosphate, 0.03 parts limestone powder, 0.3 parts salt, 0.35 parts lysine, 0.06 parts methionine, 0.14 parts threonine, 0.02 parts tryptophan, 0.05 parts valine, 0.04 parts isoleucine, 1 part premix, and 1 part compound probiotics by weight. Mix them to obtain an alfalfa-based antibiotic-free, low-protein fattening pig diet that reduces nitrogen emissions in pigs.

4. The application of the alfalfa-based antibiotic-free, low-protein fattening pig diet with reduced nitrogen emissions as described in claim 1 or 2 in fattening pig farming, wherein, The fattening pigs weighed 55-130 kg.

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