Antibiotic-free compound feed for fattening pigs

Abstract

The present invention belongs to the technical field of breeding feeds. Provided in the present invention is an antibiotic-free compound feed for fattening pigs, which antibiotic-free compound feed is prepared by means of adding a compound feed additive to a basal diet. The raw materials used in the compound feed additive comprise, in percentages by weight: 34.5-38% of fumaric acid, 7-10.5% of vitamin E, 23-28% of tea polyphenols, 0.5-1% of boric acid and 25-30% of silica white carbon black. Breeding of fattening pigs using the compound feed can significantly improve the growth performance of the pigs, improve the meat quality, protect the morphology and functional integrity of small intestine tissue, and increase the nutrient utilization efficiency, and can reduce the emission of harmful gases and ammonia nitrogen to exert a certain effect in temrs of protecting the environment. In addition, the compound feed for fattening pigs provided in the present application is suitable for the current focus on antibiotic-free breeding in the breeding industry, can be used in the feed industry to replace antibiotics, and has a huge application space in the pig breeding industry.

Description

Antibiotic-free compound feed for fattening pigs Technical Field

[0001] The invention belongs to the technical field of breeding feed, and in particular relates to a compound feed for fattening pigs that does not contain antibiotics.

[0002] Background Art

[0003] my country is undeniably the world's largest pork producer and consumer, accounting for two-thirds of total meat consumption. Before 2000, my country's pig farming industry was characterized by a fragmented, small-scale, and evenly distributed distribution. Driven by national policies, improved farming techniques, and the restructuring of the industry prompted by the 2018 outbreak of African swine fever, regional bans, and the upgrading of biosafety systems, the withdrawal of individual farmers and some small farms has led to a shift in my country's pig farming industry toward a large-scale, standardized, intensive, and modernized model. However, due to the relatively recent transition, my country's farming techniques, intelligent facilities, and environmental governance experience are still somewhat limited. The industry is still plagued by widespread diseases, overuse of antibiotics, excessive veterinary drug residues, and severe environmental pollution, all of which severely constrain its development.

[0004] Antibiotics are a class of drugs that inhibit and kill bacteria, viruses, and parasites. To date, over 60 types of antibiotics are known to be used as feed additives in livestock farming. This sector consumes a significant amount of antibiotics, accounting for over half of all domestic antibiotic consumption. While antibiotics have demonstrated significant effectiveness in improving pig production and reproductive function, reducing disease incidence, and increasing piglet survival rates, their overuse, excessive dosage, excessive duration, and the use of combination antibiotics, including even banned antibiotics, in the pig farming industry, can lead to widespread antibiotic abuse. The main hazards of antibiotic overuse include: ① the development of drug resistance in pathogens, leading to the emergence of "superbugs"; ② impairing the immune system of livestock and poultry, reducing their resistance to viruses and external infections, leading to increased disease; and ③ harming human health and the ecological environment. Veterinary drug residues lead to the accumulation of some antibiotics in humans through consumption, harming human health, while others are excreted into the environment through feces and urine, causing environmental pollution.

[0005] Relevant studies have shown that residual rates of fluoroquinolones, sulfonamides, and tetracyclines in pig manure samples exceed 70%. Tetracyclines have been detected in nearly 100% of cattle manure samples, with high levels of sulfonamides and fluoroquinolones also found. Although policies to reduce and ban antibiotic use have been implemented, completely eliminating antibiotic abuse in the livestock industry requires further efforts from all stakeholders. Feed researchers, in particular, face a long and arduous task.

[0006] The annual manure discharge of livestock and poultry in my country can reach 250 million tons, and the urine discharge can reach more than 160 million tons, with as much as 1 million tons of nitrogen and phosphorus discharged into the external environment. The large-scale discharge of manure by the pig industry will mainly cause three problems. The first is air pollution, because the metabolism of protein in feed and the decomposition of urine will produce gases such as ammonia and hydrogen sulfide. The second is water and soil pollution. If the manure is discharged without timely treatment, it will cause eutrophication of soil and water bodies, lead to blockage of soil pores, reduce soil permeability and air permeability, and make the land compacted. It will also cause water odor, excessive reproduction of algae, and reduce oxygen solubility, causing large-scale deaths of aquatic animals, damaging the ecology, and endangering human drinking water safety in serious cases. The third is that it will increase the chance of disease transmission. Livestock and poultry manure contains some parasites and a small amount of pathogenic microorganisms, which will lead to an increase in the bacterial index in the environment and easily breed a large number of mosquitoes that spread diseases, threatening human health.

[0007] In order to better address the problems of antibiotic abuse, veterinary drug residues, and environmental pollution brought about by the rapid development of the pig farming industry, developing new feed additives that are "green, efficient, safe, and have no side effects" and can replace antibiotics is a relatively direct and effective means. Related reports indicate that the appropriate addition of acidifiers, probiotics, enzyme preparations, Chinese herbal medicine extracts, and some nutrient additives to livestock and poultry feed can improve the growth performance and disease resistance of livestock and poultry. These new feed additives are safe and residue-free, and can be used as new green feed additives to replace antibiotics in production practice.

[0008] Acidifiers are common feed additives. Common acidifiers include organic acids, inorganic acids, fatty acids, and their salts. Organic acids primarily include malic acid, lactic acid, citric acid, benzoic acid, and fumaric acid. The mechanisms of action of organic acids are: ① they can penetrate pathogen cell membranes, exerting bactericidal and antibacterial effects; ② they can improve gastrointestinal pH, intestinal flora, and pepsin activity; and ③ they can improve intestinal tissue structure and enhance nutrient digestibility. Citric acid and fumaric acid participate in the tricarboxylic acid cycle and are important intermediates, playing a crucial role in metabolism. Tributyrin is the esterified product of glycerol and butyrate. It cannot be broken down by gastric juice and is broken down by pancreatic lipase after reaching the intestine to exert its effect. Tributyrin can regulate intestinal barrier function, protect intestinal mucosa, enhance intestinal immunity, and promote intestinal development. The application of Chinese herbal materials such as tea polyphenols, astragalus polysaccharides, and ganoderma polysaccharides in the pig farming industry can improve pig production performance, reduce piglet diarrhea rates, and enhance the body's immune function and antioxidant capacity. Vitamin E, as a strong and effective natural antioxidant, can scavenge free radicals and block lipid peroxidation reactions. At the same time, vitamin E is also a component of cell membranes, preventing cell membranes from being oxidized, thereby protecting the integrity of tissue structure.

[0009] There are many types of additives that can be purchased directly on the market, and their functions are different. However, adding a large number of various additives to the basic feed without planning is obviously not the best choice. Although this rough method of adding additives may also have a certain growth-promoting effect, it is inevitable that it will be difficult to maximize the effectiveness of various additives without purpose and planning. In addition, the large-scale addition of multiple types of additives will obviously greatly increase the preparation cost of the feed, which is less economical. It will undoubtedly cause greater cost investment pressure to farmers, especially small farmers, and affect the final economic benefits. Therefore, taking into account the economy and practicality of the feed as well as the fattening effect and fattening quality, the reasonable selection of the composition of the additives in the feed and the precise control of the addition ratio of each component are the problems that need to be solved in the current process of compound feed preparation and research and development. If a compound feed with simple composition, controllable cost, suitable for use in the conventional fattening pig feeding process, and which can significantly improve the growth performance, digestive function, muscle quality of fattening pigs and effectively reduce the emission of harmful substances in their feces can be developed, it will provide reliable support for the sustainable development of large-scale fattening pig farming, and also provide theoretical support for the healthy development of my country's pig farming industry. Summary of the Invention

[0010] The object of the present invention is to provide an antibiotic-free compound feed for fattening pigs, which achieves the purpose of improving the feeding effect by adding a certain amount of additives to the basic feed. By rationally regulating the amount of additives added, the growth performance, digestive function and muscle quality of fattening pigs are improved and the emission of harmful substances in feces is reduced. At the same time, the feed does not contain antibiotics, which is in line with the national theme of antibiotic-free breeding and has broad application prospects.

[0011] The specific technical solution of the present invention is: an antibiotic-free compound feed for fattening pigs, which is formed by adding a compound feed additive to a basic feed. The raw materials used in the compound feed additive include, by weight percentage, 34.5-38% fumaric acid, 7-10.5% vitamin E, 23-28% tea polyphenols, 25-30% white carbon black, and 0.5-1% boric acid.

[0012] Furthermore, the compound feed contains 99.2% of basic feed and 0.8% of compound feed additives by weight.

[0013] Furthermore, the raw materials used in the compound feed additive include, by weight percentage, 37.5% fumaric acid, 7.5% vitamin E, 25% tea polyphenols, 0.72% boric acid, and 29.28% white carbon black.

[0014] Furthermore, the content of catechins in the tea polyphenols used is not less than 75%.

[0015] Furthermore, vitamin E is used in powder form with a content of ≥50%.

[0016] Furthermore, the fumaric acid used is food grade, with a content of ≥98%.

[0017] Furthermore, the raw materials used in the basic feed include, by weight percentage, 25.05% corn, 25% wheat, 18.5% mixed wheat bran, 15% flour, 12.5% ​​rice bran meal, 1.03% stone powder, 0.95% calcium hydrogen phosphate, 0.8% refined soybean oil, 0.28% baking soda, 0.2% salt, 0.58% lysine hydrochloride, 0.1% L-threonine, and 0.03% 33% ethoxyquinoline.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. This application creatively selects fumaric acid, vitamin E, tea polyphenols, boric acid, and white carbon black, several feed ingredients beneficial to fattening pigs, and mixes these ingredients in a reasonable ratio to produce a novel compound feed additive. When used in combination with a basic feed, this compound feed additive can significantly improve the growth performance and muscle quality of fattening pigs, protect the morphological and functional integrity of small intestinal tissue, increase nutrient utilization, and reduce the emission of harmful gases and ammonia nitrogen, thereby having a certain effect on environmental protection.

[0020] 2. This application determines the optimal dosage by conducting experimental comparisons of the dosage of each component in the additive, avoiding the waste of raw materials and suppression of effects caused by blind addition of additives, which helps to improve feeding results more economically and efficiently.

[0021] 3. The compound feed for fattening pigs proposed in this application is in line with the current theme of antibiotic-free farming in the livestock industry. It can replace antibiotics in the feed industry and has huge application potential in the pig farming industry.

[0022] 4. The new feed additive formula disclosed in this application has a small number of raw material components, which are easy to obtain, and does not require the addition of expensive special materials such as enzyme preparations and fermentation agents during preparation. Overall, the cost is low, which will not cause great purchasing pressure on small and medium-sized farmers, and is conducive to promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 shows the effects of different compound feed additives on the growth performance of fattening pigs;

[0024] Figure 2 shows the effects of different compound feed additives on serum biochemical indicators in fattening pigs;

[0025] Figure 3 shows the effects of different compound feed additives on the digestive enzyme activities in the duodenum of fattening pigs;

[0026] Figure 4 shows the effects of different compound feed additives on the digestive enzyme activities in the jejunum of fattening pigs;

[0027] Figure 5 shows the effects of different compound feed additives on nutrient digestibility in fattening pigs;

[0028] Figure 6 shows the effects of different compound feed additives on the morphology of duodenal tissue in fattening pigs (HE staining 40×10);

[0029] Figure 7 shows the effects of different compound feed additives on histological parameters of the duodenum of fattening pigs;

[0030] Figure 8 shows the effects of different compound feed additives on the jejunum tissue morphology of fattening pigs (HE staining 40×10);

[0031] Figure 9 shows the effects of different compound feed additives on histological parameters of the jejunum in fattening pigs;

[0032] Figure 10 shows the effects of different compound feed additives on the ileum tissue morphology of fattening pigs (HE staining 40×10);

[0033] Figure 11 shows the effects of different compound feed additives on ileum histological parameters in fattening pigs;

[0034] Figure 12 shows the effects of different compound feed additives on harmful gases and ammonia nitrogen emissions from fattening pig feces;

[0035] FIG13 shows the effects of different compound feed additives on the muscle quality of the longissimus dorsi muscle of fattening pigs;

[0036] Figure 14 shows the effects of different compound feed additives on the muscle quality of the psoas major muscle in fattening pigs;

[0037] Figure 15 shows the effects of different compound feed additives on the quality of fattening pig hind leg muscle;

[0038] FIG16 shows the effects of different compound feed additives on the antioxidant capacity of the longissimus dorsi muscle of fattening pigs;

[0039] FIG17 shows the effects of different compound feed additives on the antioxidant capacity of psoas major muscle in fattening pigs;

[0040] FIG18 shows the effects of different compound feed additives on the antioxidant capacity of fattening pig hind leg muscles;

[0041] FIG19 shows the effects of compound feed additives with different component ratios on the growth performance of fattening pigs;

[0042] FIG20 shows the effects of compound feed additives with different component ratios on the digestive enzyme activities in the jejunum of fattening pigs;

[0043] FIG21 shows the effects of compound feed additives with different component ratios on the digestive enzyme activities in the jejunum of fattening pigs;

[0044] Figure 22 shows the effects of compound feed additives with different component ratios on harmful gases and ammonia nitrogen emissions from fattening pig feces;

[0045] FIG23 shows the effects of compound feed additives with different component ratios on the muscle quality of the longissimus dorsi muscle of fattening pigs;

[0046] Figure 24 shows the effects of compound feed additives with different component ratios on serum biochemical indicators of fattening pigs. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below with reference to the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0048] Example 1: Feeding fattening pigs with compound feeds with different additive formulas

[0049] 1. Experimental Preparation and Design

[0050] The study used a single-factor, completely randomized design and was conducted at the pig farm of Anhui Hefeng Agriculture and Animal Husbandry Co., Ltd. Seventy-two healthy, 90-day-old, three-way fattening pigs (Du × Chang × Da) were randomly divided into four groups: a control group and three experimental groups (Experimental Groups I, II, and III), with three replicates per group and six pigs per replicate. The control group was fed a basal diet, while Experimental Groups I, II, and III were fed a basal diet supplemented with 0.8% of a different formula of compound feed additive (i.e., by weight, the compound feed consisted of 99.2% basal diet and 0.8% of a formulated additive). The experimental period was 90 days.

[0051] The nutritional composition and nutritional level of the basic feed are as follows (air-dried basis)

[0052]

[0053] Note: This feed formula comes from Anhui Wellcome Animal Husbandry Co., Ltd., and the nutritional levels are calculated.

[0054] The additive formulas and main ingredient contents corresponding to test groups I, II, and III are as follows.

[0055]

[0056] (1) Fumaric acid: food grade, content 98%.

[0057] (2) Boric acid: 98.5%, 200 mesh.

[0058] (3) Tea polyphenols: active ingredient content ≥98%, powder, 80 mesh.

[0059] (4) Vitamin E: 50% content, white fine powder.

[0060] (5) Silica: 600 mesh.

[0061] (6) Citric acid: Food grade citric acid monohydrate, content ≥98%.

[0062] (7) Lipoic acid: α-lipoic acid, content ≥98%.

[0063] (8) Tributyrin: food grade.

[0064] (9) Astragalus polysaccharide: content 50%, 80 mesh.

[0065] 2. Feeding and management

[0066] This experiment was conducted for 90 days at the pig farm of Anhui Wellcome Animal Husbandry Co., Ltd. Pigs were fed once daily at 8:00 AM and 4:00 PM, with free access to feed and water from one hopper feeder and two drinkers per replicate. Daily care and immunization procedures were implemented according to the Anhui Wellcome Animal Husbandry Fattening Pig Husbandry Manual. Feces was regularly cleaned and ventilation was maintained to maintain pig house hygiene and air quality. Feeding habits and mental state were observed and recorded daily.

[0067] 2. Related test results and analysis

[0068] 1. Effects of compound feed additives on growth performance of fattening pigs

[0069] 1.1. Effects of compound feed additives on growth performance of fattening pigs

[0070] Indicators for evaluating the growth performance of finishing pigs include average daily gain (ADG), average daily feed intake (ADFI), and feed-to-gain ratio (FGR), which reflect the growth rate and production level of finishing pigs. ADG reflects the growth rate of finishing pigs; higher ADG indicates faster growth. A lower FGR indicates higher production levels, while a higher FGR indicates lower production levels. Figure 1 shows that compared with the control group, ADG in Experimental Groups I and II significantly increased (P < 0.05), while Group III showed no significant change. ADFI significantly increased in Experimental Group I (P < 0.05), while there was no significant difference between Experimental Groups II and III (P > 0.05), although there was an upward trend. The FGR in Experimental Groups I and II decreased significantly (P < 0.05), while there was no significant difference in Experimental Group III (P > 0.05).

[0071] Judging from the results reflected in the figure, the addition effects of test groups I and II are better.

[0072] 1.2. Effects of compound feed additives on serum biochemical parameters in fattening pigs

[0073] Nutrients in the diet enter the bloodstream of livestock and poultry after being absorbed by the small intestine. Therefore, changes in serum biochemical parameters can, to a certain extent, reflect the intestinal nutrient metabolism and digestive and absorptive functions of the body. Serum TP (total protein) levels reflect dietary protein levels and the body's ability to metabolize protein. Protein and amino acids are metabolized through the urea nitrogen cycle to produce urea nitrogen, so serum urea nitrogen levels can reflect the body's nitrogen metabolism. Figure 2 shows that serum TP, ALB (albumin), GLB (globulin), and BUN (urea nitrogen) did not change significantly across the experimental groups. However, TP, ALB, and GLB levels showed an upward trend. BUN showed a downward trend across all experimental groups, with the greatest decrease in Experimental Group I. Decreased BUN levels indicate increased amino acid utilization and enhanced protein synthesis. Serum AST (aspartate aminotransferase) and ALT (alanine aminotransferase) levels reflect liver function. When liver function is lost, serum AST and ALT levels will increase. The results in the figure show that there is no significant change in AST and ALT levels in each test group, suggesting that the liver function of each test group is not affected and the liver function of each group is normal.

[0074] 2. Effects of compound feed additives on small intestinal digestive enzymes and nutrient digestibility in fattening pigs

[0075] Effects of compound feed additives on small intestinal digestive enzyme activities in fattening pigs

[0076] At the end of the trial, six pigs of similar growth status were randomly selected from each experimental group (two pigs per replicate) and slaughtered for sampling. The duodenum, jejunum, and mid-ileum were removed and rinsed with saline to remove the contents. Approximately 10 g of the sample was placed in a cryovial and immediately frozen in liquid nitrogen before being transferred to a -80°C freezer. Small intestinal tissue homogenates were later prepared for digestive enzyme activity assays.

[0077] The small intestine is the primary site of digestion and absorption in livestock and poultry. The activity of digestive enzymes in the small intestine can, to a certain extent, reflect the strength of the body's digestive function. As shown in Figure 3, compared with the control, the activity of trypsin in the duodenum of Experimental Group I was significantly increased (P < 0.05), while there was no significant difference in Experimental Groups II and III (P > 0.05). Trypsin hydrolyzes proteins, primarily secreted by the pancreas through enterokinase or after its own activation. The activity and content of trypsin can reflect the level of nitrogen metabolism in animals. Duodenal maltase activity was significantly increased in Experimental Group I (P < 0.05), while there was no significant change in Experimental Groups II and III (P > 0.05). As can be seen from Figure 4, compared with the control group, the jejunal trypsin activity of test group I was significantly increased (P<0.05), while the difference between test groups II and III was not significant (P>0.05); the jejunal maltase activity of test groups I and II was significantly increased (P<0.05), and the test group III showed an increasing trend but the difference was not significant (P>0.05); and the lipase activity showed a significant increase only in test group I (P>0.05), and there was no significant change in the other test groups.

[0078] From this part of the data, it can be seen that the digestive function of the fattening pigs in Experimental Group I has been significantly improved.

[0079] 2.2. Effects of compound feed additives on nutrient digestibility in finishing pigs

[0080] As shown in Figure 5, compared with the control group, the crude protein utilization rate of experimental groups I and II was significantly increased (P<0.05), while there was no significant change in group III (P>0.05); the crude fat utilization rate of experimental group II was significantly increased (P<0.05), while there was no significant change in experimental groups I and III (P>0.05); the calcium absorption of experimental group I was significantly increased (P<0.05), while there was no significant change in other experimental groups (P>0.05); the phosphorus absorption of experimental group I was also significantly increased (P<0.05), while there was no significant change in other experimental groups (P>0.05); there was no significant difference in the digestibility of crude fiber and crude ash among all experimental groups (P>0.05).

[0081] Nutrient digestibility can intuitively show the body's digestive metabolism level. A higher nutrient digestibility is beneficial to improving growth performance, shortening the feeding cycle, and saving production costs. A comprehensive analysis of the intestinal nutrient digestibility of the experimental pigs shows that the compound feed additive in Experimental Group I performs better in improving the growth performance of fattening pigs.

[0082] 3. Effects of compound feed additives on small intestinal tissue morphology in fattening pigs

[0083] Nutrients ingested by livestock and poultry are primarily digested and absorbed in the small intestine to sustain production and various life activities. The small intestine consists of three sections: the duodenum, jejunum, and ileum. Its inner walls are covered with numerous villi and microvilli, effectively increasing the contact area with chyme and enhancing digestion and absorption. Furthermore, the mucosal layer contains numerous intestinal glands (crypt depth), which secrete enteropeptidases and lysozymes, promote trypsin synthesis, and protect the intestine from harmful bacteria. Therefore, measuring villus height (VH), crypt depth (CD), and the VH / CD ratio in the small intestine can reflect the integrity of the intestinal tissue structure and its proper function.

[0084] 3.1 Effects of compound feed additives on duodenal tissue morphology in fattening pigs

[0085] As shown in Figure 6, compared to the control group, the duodenal villi in Experimental Groups I to III were more intact, densely distributed, neatly arranged, and taller. The intestinal epithelial cell structure was clear, and the submucosal duodenal glands were well developed. The duodenal tissue morphology and structure were more developed in Experimental Group I.

[0086] As shown in Figure 7, compared with the control group, the duodenal villus height (VH) of test group I was significantly increased (P<0.05), while there was no significant change in test groups II and III (P>0.05); the duodenal crypt depth (CD) of test group I was significantly increased compared with the control group (P<0.05), while there was no significant change in test groups II and III (P>0.05); the duodenal VH / CD value of test groups I and III was significantly increased (P<0.05), while there was no significant difference in test group II (P>0.05).

[0087] 3.2 Effects of compound feed additives on jejunal tissue morphology in fattening pigs

[0088] As shown in Figure 8, compared with the control group, the villi in the jejunum of groups I to III were denser, taller, and more numerous. The intestinal villi had clear outlines and goblet cells were neatly arranged. The jejunal tissue morphology and structure were well developed.

[0089] As shown in Figure 9, the jejunal VH of experimental groups I and III increased significantly compared with the control group (P<0.05), while there was no significant difference in experimental group II (P>0.05); the jejunal CD of experimental group I increased significantly compared with the control group (P<0.05), while there was no significant change in experimental groups II and III (P>0.05); the V / C values ​​of all experimental groups showed no difference compared with the control group (P>0.05).

[0090] 3.3 Effects of compound feed additives on ileum tissue morphology in fattening pigs

[0091] Figure 10 shows a significant increase in goblet cells in the ileum, with a greater number of isolated or collected lymph nodes distributed within the lamina propria. Compared with the control group, the ileum tissue in groups I to III showed improvement, with increased villus width and height, and well-developed intestinal glands within the lamina propria.

[0092] Figure 11 shows that compared with the control group, the ileal villus height, crypt depth, and V / C ratio in Experimental Groups I to III increased, but the differences were not significant (P>0.05). This may be because the ileum is located at the end of the small intestine, and the digestion and absorption of nutrients are largely completed earlier. As a result, less nutrients flow into the ileum, which has less impact on the ileal tissue morphology and structure.

[0093] Adding compound feed additives to the diet can increase the height of the small intestinal villi and the V / C ratio of fattening pigs, improve the morphology of the small intestine, and protect the integrity of the intestinal structure and function. Based on the results of 3.1-3.3, Group I performed best.

[0094] 4. Effects of compound feed additives on harmful substances in fattening pig feces

[0095] 4.1 Effects of compound feed additives on harmful gases and ammonia nitrogen emissions from fattening pig feces

[0096] As shown in Figure 12, compared with the control group, the emission of ammonia (NH3) in the feces of test group I was significantly reduced (P<0.05), while there was no significant change in test groups II and III (P>0.05); compared with the control group, the emission of hydrogen sulfide (H2S) gas in the feces of test group I was significantly reduced (P<0.05), while there was no significant change in test groups II and III (P>0.05); the emission of ammonia nitrogen in the feces of test groups I to III did not decrease to varying degrees compared with the control group, but the difference was not significant (P>0.05).

[0097] The main odorous gases in pig manure are NH3 and H2S. These gases are pungent and toxic, making them hazardous gases. Ammonia can cause respiratory problems, while hydrogen sulfide can damage the nervous system. If large amounts of NH3 and H2S are emitted from livestock and poultry manure, they can pollute the air and harm human health. Based on these results, the compound feeds in all experimental groups helped reduce the emission of harmful substances in fattening pig manure, with Group I achieving the greatest effect.

[0098] 5. Effects of compound feed additives on muscle quality of fattening pigs

[0099] 5.1 Effects of compound feed additives on muscle quality of the longissimus dorsi muscle in fattening pigs

[0100] The results of the effects of different compound feed additives on the muscle quality of the longissimus dorsi of fattening pigs are shown in 13. Compared with the control group, the drip loss rate of the longissimus dorsi in test groups I, II, and III was significantly reduced (P<0.05); the water loss rate of test group I was significantly decreased (P<0.05), while there was no significant difference in test groups II and III (P>0.05); the shear force of test groups I and II was significantly reduced (P<0.05), while there was no significant change in test group III (P>0.05).

[0101] 5.2 Effects of compound feed additives on psoas muscle quality in fattening pigs

[0102] The results of the effects of different compound feed additives on the muscle quality of psoas major in fattening pigs are shown in Figure 14. Compared with the control group, the yellowness (b) of the psoas major in test groups II and III was significantly reduced (P<0.05), while there was no difference in test group I (P>0.05); the drip loss rate and shear force of all test groups were significantly reduced compared with the control group (P<0.05).

[0103] 5.3 Effects of compound feed additives on hind leg muscle quality in fattening pigs

[0104] The results of the effects of different compound feed additives on the muscle quality of the hind leg muscles of fattening pigs are shown in Figure 15. Compared with the control group, the meat color brightness L of test group I was significantly reduced (P<0.05), while there was no significant difference in test groups II and III (P>0.05); the drip loss rate of test groups I and III was significantly reduced (P>0.05), while there was no significant change in test group II (P>0.05); the water loss rate of test groups I and II was significantly reduced (P<0.05), while there was no significant change in test group III (P>0.05); the shear force of test group III was significantly reduced (P<0.05), while there was no difference between test groups I and II (P>0.05).

[0105] 5.4 Effects of compound feed additives on the antioxidant function of the longissimus dorsi muscle in fattening pigs

[0106] As shown in Figure 16, compared with the control group, the levels of total superoxide dismutase (T-SOD) in the longissimus dorsi muscle of test groups I to III were significantly increased (P<0.05); the content of glutathione peroxidase (GSH-Px) in the longissimus dorsi muscle of test group I was also significantly increased (P<0.05), while there was no significant change in test groups II and III (P>0.05); the content of MDA in test group I was significantly decreased (P<0.05).

[0107] 5.5 Effects of compound feed additives on the antioxidant function of psoas major muscle in fattening pigs

[0108] As shown in Figure 17, compared with the control, the T-SOD content of the psoas major muscle in Experimental Groups I to III increased significantly (P<0.05); the MDA levels in Experimental Groups I and II decreased significantly (P<0.05), while the MDA content in Experimental Group III did not change significantly (P>0.05).

[0109] 5.6 Effects of compound feed additives on antioxidant activity in hind leg muscles of fattening pigs

[0110] As shown in Figure 18, compared with the control group, the T-SOD level in the hind leg muscles of Experiment I was significantly increased, while there was no significant difference in the other experimental groups (P>0.05); there was no significant difference in T-AOC, MDA, and GSH-PX in the muscles of Experiment I to III groups (P>0.05).

[0111] Drip loss rate, water loss rate, and cooked meat rate reflect the water-binding capacity of muscle quality; lower values ​​indicate better water-binding capacity. Shear force reflects muscle tenderness; lower shear force indicates more tenderness. Overall, the results showed that Group I showed significant improvements in muscle quality, with significantly enhanced water-binding capacity, increased tenderness, and a more juicy and flavorful texture. This may be due to the addition of fumaric acid to the formula. Fumaric acid improves intestinal tissue structure, promoting digestion, metabolism, and nutrient absorption, thereby improving meat quality. Citric acid, used in Group II, has similar functions to fumaric acid, but the feeding effect of this group was not as good as that of Group I. This may be due to the added dosage, or perhaps fumaric acid is more suitable for the growth of finishing pigs.

[0112] T-SOD, GSH-Px, T-AOC, MDA, etc. are important indicators that reflect the antioxidant capacity of the animal body. Changes in their activity or content can directly reflect the body's antioxidant function. T-AOC can reflect the body's total antioxidant capacity. Higher T-AOC, T-SOD, and GSH-Px activity and content, and lower MDA levels indicate stronger antioxidant capacity. Studying the levels of T-AOC, T-SOD, GSH-Px, and MDA in muscle can evaluate the quality of livestock and poultry muscle at the molecular level. The results of this experiment showed that compared with the control group, the muscle antioxidant capacity of Experiment I was significantly higher, and the supplementation effect was the best. It is speculated that this may be related to the vitamin E and boric acid added to Experimental Group I. Vitamin E is a natural antioxidant, and boric acid can inhibit the peroxidation of cell membrane lipids and has strong antioxidant capacity. Both can scavenge free radicals and block peroxidation reactions. Although zinc sulfate and astragalus polysaccharide added to Experimental Groups II and III also have the function of enhancing receptor immunity and antioxidant, compared with these two substances, vitamin E may be more suitable for fattening pigs.

[0113] Based on the above analysis, the additive formula disclosed in Experimental Group I can significantly improve the growth performance and muscle quality of fattening pigs, protect the morphological and functional integrity of small intestinal tissue, improve nutrient utilization, and reduce the emission of harmful gases and ammonia nitrogen, thus contributing to environmental protection. This formula not only aligns with the current focus on antibiotic-free farming, but can also replace antibiotics in the feed industry, thus having significant potential for application in the pig farming industry. It also provides a reference for research on the emission of harmful substances in feces from feed additives, providing a theoretical basis for practical pig farming operations.

[0114] Example 2: Based on the formula disclosed in Experiment I, the effects of compound feeds with different ratios on feeding effects were observed by adjusting the ratios of each group to determine the optimal ratio range.

[0115] 1. Experimental Preparation and Design

[0116] The study used a single-factor, completely randomized design and was conducted at the pig fattening farm of Anhui Hefeng Agriculture and Animal Husbandry Co., Ltd. Ninety healthy, 90-day-old, three-way fattening pigs (Du × Chang × Da) were randomly divided into five groups (A, B, C, D, and E), with three replicates per group and six pigs per replicate. Groups A, B, C, D, and E were fed a compound feed consisting of a basal diet supplemented with 0.8% of various compound feed additives for a 90-day trial.

[0117] The additive formulas and main ingredient contents corresponding to test groups A, B, C, D, and E are as follows.

[0118]

[0119] 2. Related performance tests

[0120] Effects of compound feed additives with different component ratios on growth performance of fattening pigs

[0121] As shown in Figure 19: compared with experimental group A, the average daily weight gain of fattening pigs in experimental groups B, C, D and E was significantly reduced (P<0.05); the average daily feed intake of fattening pigs in experimental groups D and E was also significantly reduced (P<0.05), but there was no significant difference between groups B and C (P>0.05); the feed-to-weight ratio of fattening pigs in experimental groups C and E was significantly increased (P<0.05), while there was no significant difference between groups B and D (P>0.05).

[0122] Effects of different ratios of compound feed additives on jejunal digestive enzyme activities in fattening pigs

[0123] As shown in Figure 20, compared with group A, the jejunal trypsin activity of fattening pigs in groups C and E was significantly reduced (P<0.05), while there was no significant difference between groups B and D (P>0.05); the jejunal maltase of fattening pigs in groups B, C, D and E were all significantly reduced (P<0.05).

[0124] Effects of different ratios of compound feed additives on nutrient digestibility in fattening pigs

[0125] As shown in Figure 21, compared with experimental group A, the crude protein digestibility of fattening pigs in experimental groups C and E was significantly reduced (P<0.05), while there was no significant difference between experimental groups B and D (P>0.05); the crude fat digestibility and calcium absorption rate of fattening pigs in experimental groups C and E were also significantly reduced (P<0.05), while there was no significant difference between experimental groups B and D (P>0.05).

[0126] Effects of different ratios of compound feed additives on harmful gases and ammonia nitrogen emissions from fattening pig feces

[0127] As shown in Figure 22, compared with experimental group A, the ammonia content in the feces of fattening pigs in experimental groups C and E increased significantly (P<0.05), while there was no significant difference in experimental groups B and D (P>0.05); the hydrogen sulfide content in the feces of fattening pigs in experimental groups B, C, D and E increased significantly (P<0.05).

[0128] Effects of different compound feed additive ratios on muscle quality of the longissimus dorsi muscle in fattening pigs

[0129] As shown in Figure 23, compared with group A, the drip loss rate of the longissimus dorsi muscle of fattening pigs in groups D and E was significantly increased (P<0.05), while there was no significant difference between groups B and C (P>0.05); the water loss rate of the longissimus dorsi muscle of fattening pigs in groups B, C, D and E was significantly increased (P<0.05); the shear force of fattening pigs in groups C, D and E was also significantly increased (P<0.05).

[0130] Effects of compound feed additives with different component ratios on serum biochemical parameters in fattening pigs

[0131] As shown in Figure 24, the serum BUN content of fattening pigs in test groups A and C was significantly lower than that in test groups D and E (P<0.05), but had no significant difference compared with test groups B and C (P>0.05); the serum ALT content of fattening pigs in test groups B and D was significantly higher than that in test groups A and C (P<0.05), but had no significant difference compared with test group E (P>0.05); the serum AST content of fattening pigs in test group D was significantly higher than that in test groups A, B, C and E (P<0.05).

[0132] Based on the above results, it can be seen that adding different proportions of tea polyphenols and vitamin E to compound feed affects the production performance, digestive enzyme activity, nutrient digestibility, harmful gas emissions in feces, and muscle quality of fattening pigs. Among them, Group A was more effective in improving the production performance of fattening pigs, enhancing the activity of digestive enzymes, improving nutrient digestibility and muscle quality, and reducing harmful gas emissions in feces. The effects of Groups B and C were second. Considering that excessive addition of tea polyphenols to compound feed may cause liver damage in fattening pigs, while smaller additions do not have a good antioxidant and free radical scavenging effect, resulting in different breeding results, it has a direct impact on the growth performance of fattening pigs. Therefore, the composition of the compound feed additive for fattening pigs disclosed in the present application is specifically limited. The components, calculated by weight percentage, include: 34.5-38% 98% fumaric acid, 7-10.5% 50% vitamin E, 23-28% 98% tea polyphenols, 25-30% white carbon black, and 0.5-1% 98.5% boric acid; in particular, the best effect is achieved when the components in the compound feed additive, calculated by weight percentage, are: 37.5% 98% fumaric acid, 7.5% 50% vitamin E, 25% 98% tea polyphenols, 0.72% boric acid, and 29.28% white carbon black.

[0133] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A compound feed for fattening pigs without antibiotics, characterized in that: It is formed by adding a compound feed additive to a basic feed. The raw materials used in the compound feed additive include, by weight percentage: 34.5-38% fumaric acid, 7-10.5% vitamin E, 23-28% tea polyphenols, 25-30% white carbon black, and 0.5-1% boric acid.

2. The compound feed for fattening pigs without antibiotics according to claim 1, characterized in that: In terms of weight percentage, the compound feed contains 99.2% of the basic feed and 0.8% of the compound feed additive.

3. The compound feed for fattening pigs without antibiotics according to claim 1, characterized in that: The raw materials used in the compound feed additive include, by weight percentage, 37.5% fumaric acid, 7.5% vitamin E, 25% tea polyphenols, 0.72% boric acid, and 29.28% white carbon black.

4. The compound feed for fattening pigs without antibiotics according to claim 1, characterized in that: The content of catechins in the tea polyphenols used is not less than 75%.

5. The antibiotic-free compound feed for fattening pigs according to claim 1, characterized in that: Vitamin E is in powder form with a content ≥50%.

6. The compound feed for fattening pigs without antibiotics according to claim 1, characterized in that: The fumaric acid used is food grade, with a content of ≥98%.

7. The compound feed for fattening pigs without antibiotics according to claim 1, characterized in that: The raw materials used in the basic feed, by weight percentage, include: 25.05% corn, 25% wheat, 18.5% mixed wheat bran, 15% flour, 12.5% ​​rice bran meal, 1.03% stone powder, 0.95% calcium hydrogen phosphate, 0.8% refined soybean oil, 0.28% baking soda, 0.2% salt, 0.58% lysine hydrochloride, 0.1% L-threonine, and 0.03% 33% ethoxyquinoline.

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