Application of itaconic acid as feed additive and odor-reducing feed

Abstract

The invention relates to the technical field of feed preparation, and particularly discloses application of itaconic acid as a feed additive and an odor-reducing feed, and the feed additive is used for reducing generation of odor substances in livestock and poultry breeding. Itaconic acid can be used as a feed additive not only for concentration of odor substances in cecum of livestock and poultry, but also for improving production performance of livestock and poultry bodies, and the structural formula of itaconic acid is as follows: # imgabs0 #

Description

Technical Field

[0001] The invention relates to the technical field of feed preparation, and in particular to application of itaconic acid as a feed additive and a deodorized feed. Background Art

[0002] With the development of the economy, people's demand for meat, eggs, milk and other products is increasing, and livestock and poultry farming has received great attention in society. In commercial chicken farming, feed costs account for more than 85% of the total breeding costs. The rise in global feed prices has led to the poultry industry's urgent need to find non-traditional feed ingredients to improve profitability. The abuse of antibiotics will seriously damage the body functions of livestock and poultry, endanger human health, and cause ecological pollution. This substance has been expressly prohibited from being used as an additive in feed. At present, there is a lack of antibiotic substitutes that can not only improve the production performance of livestock and poultry, but also ensure food safety and environmental safety. In the context of the increasing demand for protein products by humans, responding to the national call and adapting to the development of the situation, researching and finding feed additives that can replace antibiotics is of great significance to my country's national security and animal husbandry development.

[0003] Odor pollution caused by livestock and poultry breeding and production has an adverse effect on animal growth and the surrounding environment. The causes of odor in livestock and poultry excrement are complex, and the odor substances are also diverse. For example, chicken manure contains more than 130 kinds of odor substances, and pig excrement contains more than 230 kinds of odor substances. According to the chemical properties, the odor substances emitted by livestock and poultry mainly include volatile nitrogen-containing compounds (such as ammonia (NH3), putrescine, etc.), volatile sulfur-containing compounds (such as hydrogen sulfide (H2S), mercaptans, sulfides, etc.), volatile fatty acids (such as acetic acid, propionic acid, butyric acid, etc.) and aromatic compounds (such as indole, skatole, phenols, etc.). Among them, skatole (3-methylindole, 3MI) is considered to be the third largest harmful odor substance emitted by livestock and poultry after NH3 and H2S. It has a strong fecal odor and the odor threshold is less than 0.003mg / m 3 , can still be sensed by humans and livestock at extremely low concentrations (Dun lop et al., 2016; Liu et al., 2018). Along with the large-scale discharge of manure, the emission and discharge of odorous substances have also had an adverse impact on livestock and poultry production, residents' health, air quality, etc. In addition, skatole is moderately toxic and can induce intestinal epithelial cell dysfunction and cause intestinal diseases; it can easily cause acute pulmonary edema and emphysema in ruminants; it is deposited in adipose tissue, causing meat to have a strong smell and reducing the quality of meat. Therefore, it is urgent to reduce the occurrence of odorous substances in livestock and poultry farming. Summary of the invention

[0004] In order to develop a feed additive that replaces antibiotics for improving the production performance of livestock and poultry, the present invention provides the use of itaconic acid as a feed additive and a deodorizing feed. In the present invention, itaconic acid is used as a feed additive to improve the growth performance of broilers, improve the nutrient metabolism rate of broilers, improve the slaughter rate of broilers, improve the antioxidant capacity of broilers and reduce the generation of odor substances.

[0005] The present invention provides the use of itaconic acid as a feed additive, wherein the feed additive is used to reduce the generation of odorous substances in livestock and poultry breeding; the structural formula of the itaconic acid is as follows:

[0006]

[0007] The invention reduces the concentration of indole and skatole in the cecum of broiler chickens by using itaconic acid as a feed additive, thereby reducing the generation of odor substances.

[0008] Furthermore, the odorous substance is cecal odorous substance from livestock and poultry.

[0009] Furthermore, the livestock and poultry cecal odor substances are skatole and indole.

[0010] Furthermore, the livestock and poultry are chickens.

[0011] Furthermore, feed additives are also used to improve the growth performance of livestock and poultry, improve the nutrient metabolism rate of livestock and poultry, increase the slaughter rate of livestock and poultry, and improve the antioxidant capacity of livestock and poultry.

[0012] Furthermore, improving the growth performance of livestock and poultry is manifested by increasing the average daily feed intake of livestock and poultry; improving the nutrient metabolism rate of livestock and poultry is manifested by increasing the dry matter metabolism rate and crude protein metabolism rate of livestock and poultry; improving the slaughter rate of livestock and poultry is manifested by increasing the breast muscle rate and leg muscle rate; improving the antioxidant capacity of livestock and poultry is manifested by increasing the concentrations of serum superoxide dismutase, alanine aminotransferase, aspartate aminotransferase and catalase of livestock and poultry.

[0013] Furthermore, the amount of itaconic acid added as a feed additive is 0.2% to 0.8% in terms of mass percentage of the total mass of the feed.

[0014] The present invention also provides a feed, wherein the feed is obtained by adding itaconic acid in an amount of 0.2% to 0.8% by mass to a basic feed;

[0015] Each kilogram of the basic feed contains 15mg-16mg of copper, 178mg-180mg of iron, 85mg-87mg of manganese, 98mg-100mg of zinc, 0.69mg-0.70mg of iodine, 0.39mg-0.40mg of selenium, 9000I U-10000I U of vitamin A, 3100I U-3130I U of vitamin D, and 1000I U-10000I U of vitamin E. 47.40mg~47.448mg, vitamin K2.60mg~2.622mg, thiamine 5.20mg~5.24mg, riboflavin 9.50mg~9.565mg, pyridoxine 13.10mg~13.192mg, cobalamin 0.01mg~cobalamin 0.02mg, niacin 49.80mg~49.848mg, pantothenic acid 17.30mg~17.321mg, folic acid 0.300mg~0.303mg, biotin 0.204mg~0.244mg.

[0016] Furthermore, the added itaconic acid accounts for 0.483% to 0.690% of the mass percentage of the basic feed.

[0017] Furthermore, the added itaconic acid accounts for 0.619% to 0.645% of the mass percentage of the basic feed. When the added itaconic acid accounts for 0.645% of the mass percentage of the basic feed, the cecal indole concentration is the lowest, and when the added itaconic acid accounts for 0.619% of the mass percentage of the basic feed, the skatole concentration is the lowest.

[0018] Furthermore, the nutrient content of each kilogram of the basic feed is: copper 16 mg, iron 180 mg, manganese 87 mg, zinc 100 mg, iodine 0.70 mg, selenium 0.40 mg, vitamin A 10000 I U, vitamin D 3130 I U, vitamin E 47.448 mg, vitamin K 2.622 mg, thiamine 5.24 mg, riboflavin 9.565 mg, pyridoxine 13.192 mg, cobalamin 0.01 mg, niacin 49.848 mg, pantothenic acid 17.321 mg, folic acid 0.303 mg, and biotin 0.244 mg.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The invention uses itaconic acid as a feed additive to significantly reduce the concentrations of indole and skatole in the cecum of broilers, thereby reducing the generation of odorous substances.

[0021] The present invention can significantly increase the average daily feed intake of broilers and significantly increase the dry matter and crude protein metabolism rate of 42-day-old broilers by adding itaconic acid to feed for broiler feeding. Itaconic acid is added to feed for broiler feeding, which can significantly increase the breast muscle rate and leg muscle rate of broilers, significantly reduce the abdominal fat rate, and significantly increase the serum superoxide dismutase (SOD), alanine aminotransferase (ALT), aspartate aminotransferase (AST), catalase (CAT) concentrations of 21-day-old broilers and the total antioxidant capacity of 42 days. Itaconic acid added to feed can significantly affect the morphology of the duodenum and ileum mucosa of broilers, and the villus height / crypt depth ratio of the duodenum and ileum of 21-day-old broilers is significantly increased (P < 0.05), and the villus height and crypt depth of the ileum of 42-day-old broilers are significantly increased. Itaconic acid is added to feed for broiler feeding, so that the concentrations of indole and skatole in the cecum are significantly reduced. This shows that itaconic acid is beneficial to promoting the growth and development of broiler chickens and reducing the generation of odorous substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 To investigate the effect of itaconic acid supplementation on duodenal tissue morphology;

[0024] In the figure, A shows the effect of itaconic acid addition on the duodenal tissue morphology of 21-day-old broiler chickens;

[0025] B shows the effect of itaconic acid supplementation on the duodenal tissue morphology of 42-day-old broiler chickens.

[0026] Figure 2 To investigate the effect of itaconic acid supplementation on jejunal histomorphology;

[0027] In the figure, A shows the effect of itaconic acid addition on the jejunal tissue morphology of 21-day-old broiler chickens;

[0028] B shows the effect of itaconic acid supplementation on the jejunal tissue morphology of 42-day-old broiler chickens.

[0029] Figure 3 To investigate the effect of itaconic acid supplementation on ileal histomorphology;

[0030] In the figure, A shows the effect of itaconic acid supplementation on the ileum tissue morphology of 21-day-old broiler chickens;

[0031] B shows the effect of itaconic acid supplementation on the ileum tissue morphology of 42-day-old broiler chickens. DETAILED DESCRIPTION

[0032] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0033] Example 1: Research on the application of itaconic acid in the preparation of broiler feed.

[0034] 1. Experimental Design and Methods

[0035] 1. Test materials

[0036] The itaconic acid used in this experiment was provided by Fujian Youqiyi Pharmaceutical Trading Co., Ltd. Itaconic acid (methylene succinic acid) was white crystal, superior grade, with a purity of 99.60%. The corn-soybean meal type basal diet used in this experiment was provided by Shenyang Boeing Feed Co., Ltd. The corn-soybean meal type basal diet (Table 1) was designed according to the Chicken Feeding Standard (2004) and made into pellet feed, which did not contain any antibiotic products.

[0037] Table 1 Basic feed composition and nutritional level (air-dried basis, %)

[0038] raw material 1 to 21 days old 22-42 days old Nutritional Levels 1 to 21 days old 22-42 days old corn 58.92 60.00 Metabolizable energy ME (MJ / kg) 12.15 12.98 Soybean meal 28.00 27.60 Crude protein CP (%) 21.19 20.49 Rice bran 4.00 - Fat EE (%) 3.24 6.13 Corn Gluten Meal 2.00 3.50 Calcium (%) 0.99 0.75 Soybean Oil 0.80 3.50 Total phosphorus TP (%) 0.89 0.64 Bacterial protein 1.50 1.50 Available phosphorus AP (%) 0.37 0.30 Stone powder 1.50 1.00 Lysine (%) 1.34 1.28 Calcium Hydrogen Phosphate 1.40 1.00 MethionineMet(%) 0.50 0.51 Premix 0.28 0.60 Threonine Thr(%) 1.00 0.83 salt 0.30 0.25 Tryptophan (%) 0.28 0.21 baking soda 0.14 - Choline chloride 0.10 0.10 Lysine 0.60 0.65 Methionine 0.18 0.20 Threonine 0.23 0.10 Tryptophan 0.05 - total 100.00 100.00

[0039] Note: 1. Each kilogram of basic feed contains: copper 16mg, iron 180mg, manganese 87mg, zinc 100mg, iodine 0.70mg, selenium 0.40mg, VA 10000IU, VD 3130I U, VE 47.448mg, VK 2.622mg, thiamine 5.24mg, riboflavin 9.565mg, pyridoxine 13.192mg, cobalamin 0.01mg, niacin 49.848mg, pantothenic acid 17.321mg, folic acid 0.303mg, biotin 0.244mg.

[0040] 2. The crude protein, fat, calcium and total phosphorus in the nutritional level are measured values, and the other indicators are calculated values.

[0041] 2. Experimental Animals

[0042] The experimental animals were 360 ​​one-day-old Arbor Acres broiler chickens, which were required to be healthy, of similar weight, and half male and half female. The feeding experiment was completed at the Shenyang Agricultural University Research Chicken Farm from September 5 to October 17, 2020, and the remaining indicators were tested in the laboratory of the College of Animal Science and Medicine of Shenyang Agricultural University.

[0043] 3. Experimental design

[0044] This experiment adopted a single-factor completely randomized group design. 360 broiler chickens were randomly divided into 6 groups, with 6 replicates in each group and 10 chickens in each replicate, ensuring that each replicate was half male and half female. The control group was fed only the basic diet, and the experimental group was supplemented with 0.2%, 0.4%, 0.6%, 0.8% or 1.0% of itaconic acid by mass fraction on the basis of the basic diet, which were recorded as IA0.2, IA 0.4, IA 0.6, IA 0.8, and IA 1.0 respectively. The basic diet formula was designed and prepared according to the Chicken Feeding Standard (2004). The feeding period was 42 days.

[0045] 4. Feeding and management

[0046] Cleaning procedure: Before the start of the experiment, carefully clean the remaining feces on each chicken cage, clean the water trough, feed trough, water pipes, and water lines, and then thoroughly sweep the ground and disinfect it with high-temperature fire. Use peracetic acid solution for spraying and disinfection on the same day, and use formaldehyde solution and potassium permanganate solution for fumigation and disinfection the next day.

[0047] Feeding procedure: A ladder cage model is adopted, with a total of three layers. The size of each cage is 80×65×40cm. Artificial feeding is carried out twice a day at 8:00 am and 5:00 pm. The chickens are fed with nipple automatic waterers to ensure that they can eat and drink freely. A hot air furnace is used for heating to ensure normal temperature and humidity in the chicken house and reasonable ventilation. The chicken house needs to reach 34℃ when the broilers are one day old, and it can be reduced by 3℃ every 7 days until the broilers are 35 days old and then no longer cooled down. 24 hours of uninterrupted lighting is guaranteed. A mechanical scraper is used to remove manure, and the feed trough is cleaned manually regularly.

[0048] Immunization procedure: When the broilers were 7 days old, all chickens were immunized with Newcastle disease bronchial and bursal vaccines, respectively, by nose drops and eye drops; at 12 days old, fowl pox vaccine was immunized by pricking; at 28 days old, Newcastle disease-bursal bivalent inactivated vaccine was immunized by drinking water. No antibiotics were used during the entire trial.

[0049] 5. Sample collection

[0050] Blood samples: When the broilers were 21 days old and 42 days old, one chicken was selected for each replicate, that is, 6 chickens were selected for each treatment, ensuring that there were 3 females and 3 males and that the weight of each chicken was close to the average weight of the chickens in the replicate group. The venous blood under the wings of the broilers was collected in a 10mL centrifuge tube. After the blood was rested for 30 minutes, it was centrifuged at 10000g for 10 minutes. The upper serum was aspirated and divided into 2mL cryotubes and stored at -20℃.

[0051] Intestinal samples: One broiler was selected for each replicate at the 21st and 42nd day of age. After slaughter, the tissues of about 1 cm near the middle of the duodenum, jejunum and ileum were cut off, rinsed with saline, and fixed in 8% formalin solution.

[0052] Cecal content samples: When the broilers were 42 days old, one chicken was selected from each replicate, and the cecal contents were quickly removed after slaughter. They were quickly frozen with liquid nitrogen for about 20 minutes and then stored in an ultra-low temperature refrigerator at -80°C.

[0053] Excrement collection method: When the broilers are 19-21 and 40-42 days old, select one cage for each replicate, use a cardboard shell covered with plastic cloth to collect the excrement under the cage, mix the excrement that is not stained with feathers, feed, and dandruff, select some excrement samples, put them into self-sealing bags, and store them at -20℃.

[0054] 6. Measurement indicators and methods

[0055] (1) Growth performance

[0056] The broilers were fasted at night on days 0, 20, and 41, but not water. The feed intake of each replicate group was recorded after feeding. All broilers that had fasted for 12 hours were weighed the next morning, and the average daily feed intake (ADF I) of the broilers was calculated according to the following formula. The number of deaths and cullings was recorded every day to correct the ADF I.

[0057]

[0058] (2) Nutrient metabolism rate

[0059] Feces were collected using the above method on days 19 to 21 and days 40 to 42, and the nutrient metabolic rate was determined and calculated using the endogenous indicator hydrochloric acid insoluble ash (AIA).

[0060] Preparation of air-dried samples: In units of repetition, the collected feed and excrement samples are processed according to the steps of drying, rehumidification, crushing, sieving, and sealing. The oven temperature is required to be 65°C, the rehumidification time is 24h, and the sieve is 40 mesh, i.e. the aperture is 0.45mm.

[0061] Items measured in feed and excrement samples: The contents of gross energy (GE), dry matter (DM), crude protein (CP) and crude ash (ASH) in the samples were measured according to the experimental steps in the paper (Zhang Liying. Feed analysis and feed quality detection technology. Beijing: China Agricultural University Press. 2016). Among them, the energy was measured using I KAC2000 basic calorimeter, and the crude protein was measured using Leimagnet KDN-1 Kjeldahl nitrogen analyzer.

[0062] Determination method of hydrochloric acid insoluble ash (AIA): Put about 1g of sample in a cellulose bag and seal it with a plastic sealing machine. Soak 30 cellulose bags containing samples in a 5L beaker containing 3L 3mol / LHCl, heat with an electric furnace in a fume hood until the liquid boils, and keep it at a slight boil for about 1h after boiling. Take out the boiled cellulose bag, wash the residual HCl on the surface with clean water, and bake at 105℃ until completely dry. Move the sample into a crucible that has been baked to a constant weight in advance, and the subsequent test steps are the same as the method for measuring crude ash. The formula for hydrochloric acid insoluble ash content and nutrient metabolism rate is as follows:

[0063]

[0064] (3) Serum biochemical indicators

[0065] The kits used to measure serum indicators were purchased from Jinhui Biotechnology Co., Ltd., and all testing processes were carried out strictly in accordance with the steps in the instructions of the kit. The determination methods of the indicators to be tested are shown in Table 2.

[0066] Table 2 Serum biochemical index determination method

[0067] project Kit Name Determination method Measurement wavelength (nm) Superoxide dismutase Superoxide dismutase test kit Micro-volume method 560 ALT Alanine aminotransferase test kit Micro-volume method 505 Aspartate aminotransferase Aspartate aminotransferase test kit Micro-volume method 505 Catalase Catalase Test Kit Micro-volume method 240 Total antioxidant capacity Total Antioxidant Capacity Assay Kit Micro-volume method 593

[0068] (4) Intestinal mucosal morphology indicators

[0069] The intestinal mucosal tissues were sectioned, stained and analyzed under a microscope using HE staining.

[0070] The staining effect and sample morphology were observed with an optical microscope, and the morphological structure, shape of villi and shape of crypts were photographed at 40×1-40×3 and 100×4-100×6. The villus height (V) and crypt depth (C) of intestinal samples were measured using IPP6.0 image analysis software (MED IACYBERNET I CS, USA). At least 5 measurement points were selected for each sample, and the ratio of villus height to crypt depth (V / C) was calculated.

[0071] (5) Slaughter index

[0072] One chicken was selected from each replicate at 42 days of age, that is, 6 chickens for the same treatment, ensuring 3 cocks and 3 hens, with the weights of the 3 cocks being similar and the weights of the 3 hens being similar. Before slaughter, ensure that all chickens to be slaughtered are fasted for 12 hours, and measure the pre-slaughter weight; they are sacrificed by cervical exsanguination, and the dressed weight, eviscerated weight, pectoral muscle weight, leg muscle weight, and abdominal fat weight of the chickens are weighed. Calculate the ratios of each part according to the following formula:

[0073]

[0074] (6) Cecal volatile fatty acids, lactic acid, indole, and skatole

[0075] One cecal sample was taken from each replicate at 42 days of age, and the contents of volatile fatty acids, lactic acid, indole, and skatole in the cecum were determined by high-performance liquid chromatography. The specific methods refer to Wang Qi (2017) and Yang Hang (2017) respectively. The standards used in the determination were provided by Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0076] 7. Data processing

[0077] The data obtained from the experiment were first preliminarily statistically analyzed using Excel software, and then one-way analysis of variance (one-way ANOVA) was performed using SPSS 23.0 statistical software. Tukey was selected for multiple comparisons of the data, and linear and quadratic trend analyses were performed on the indicators with significant trends according to different levels of itaconic acid to obtain the equation. The experimental results were finally listed in the form of mean ± standard error (M ± SE). When 0.01 < P < 0.05, it indicates a significant difference between groups; when P < 0.01, the difference between groups is extremely significant.

[0078] II. Experimental results

[0079] 1. Effects of itaconic acid on the production performance of broilers

[0080] Table 3 Effects of different addition levels of itaconic acid on the production performance of broilers

[0081]

[0082]

[0083] Note: If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or no shoulder, it means that the difference is not significant (P>0.05). Control: fed with basal diet, set as control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0084] The results are shown in Table 3. The average daily feed intake (ADF I) was significantly different among the treatment groups (P < 0.05), and had a certain trend. With the increase in the proportion of itaconic acid added, the average daily feed intake showed a trend of first increasing and then decreasing, with a significant quadratic curve relationship (P < 0.05). The ADF I of the IA 0.6 group was the highest, and the ADF I of the IA 1.0 group was the lowest, and IA 1.0 was significantly lower than IA 0.6 (P < 0.05). It can be seen that the addition of itaconic acid in the present invention is beneficial to increase the average daily feed intake of broilers.

[0085] 2. Effects of itaconic acid on nutrient metabolism in broiler chickens

[0086] Table 4 Effects of different levels of itaconic acid on nutrient metabolism rate in broiler chickens

[0087]

[0088]

[0089] Note: If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or no shoulder, it means that the difference is not significant (P>0.05). Control: fed with basal diet, set as control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0090] As shown in Table 4, the apparent metabolic rate of dry matter (DM) between groups with different levels of itaconic acid was significantly different between 1 and 21 days of age (P < 0.05). Among them, there was a significant difference between IA0.6 and the control group (P < 0.05). During the period of 22 to 42 days of age, the apparent metabolic rates of dry matter (DM) and crude protein (CP) in each treatment group were significantly different (P < 0.05). With the increase in the amount of itaconic acid added, the DM metabolic rate in each treatment group had a trend of first increasing and then decreasing, among which the IA0.6 group was the highest and the control group was the lowest, and the difference between the two was significant (P < 0.05); the apparent metabolic rate of CP in each group was quite different, and the metabolic rate of the control group was lower than that of each test group, among which IA0.6 was significantly higher than that of the control group (P < 0.05). It can be seen that the present invention is beneficial to improving the metabolic rate of dry matter (DM) and crude protein (CP) in broilers by adding itaconic acid.

[0091] 3. Effect of itaconic acid on the slaughter performance of broiler chickens

[0092] Table 5 Effects of different levels of itaconic acid on slaughter performance of 42-day-old broilers

[0093]

[0094]

[0095] Note: If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or no shoulder, it means that the difference is not significant (P>0.05). Control: fed with basal diet, set as control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0096] As shown in Table 5, at 42 days of age, the effects of adding itaconic acid on breast muscle rate, leg muscle rate and abdominal fat rate were significantly different (P < 0.05), indicating that adding itaconic acid to feed is beneficial to significantly improve the meat quality of broilers, thereby generating high economic benefits.

[0097] 4. Effects of itaconic acid on serum biochemical parameters of broiler chickens

[0098] Table 6 Effects of different levels of itaconic acid on serum biochemical parameters of broiler chickens

[0099]

[0100] Note: The meanings of the English abbreviations are as follows: SOD: superoxide dismutase; ALT: alanine aminotransferase; AST: aspartate aminotransferase; CAT: catalase; T-AOC: total antioxidant capacity. If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or no shoulder, it means that the difference is not significant (P>0.05). Control: fed with the basic diet, set as the control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0101] As shown in Table 6, at 21 days of age, the concentrations of superoxide dismutase (SOD), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and catalase (CAT) were significantly different among the treatment groups (P < 0.05). With the addition of itaconic acid, SOD showed a significant linear change, and the SOD concentrations of IA 0.6, IA 0.8 and IA 1.0 groups were higher, all showing significant differences from the control group (P < 0.05); the ALT concentrations of each treatment group showed a linear and quadratic linear change trend, and the concentration of IA 0.6 group was the highest, reaching 120.36 ng / L, which was significantly different from the other five groups (P < 0.05); the CAT concentration of the control group was lower than that of each experimental group, among which the concentration of IA 0.4 group was the highest, significantly higher than that of the control group (P < 0.05). At 42 days of age, the T-AOC content of each group was significantly different (P < 0.05). It can be seen that itaconic acid can significantly increase the concentrations of serum superoxide dismutase (SOD), alanine aminotransferase (ALT), aspartate aminotransferase (AST), catalase (CAT) in 21-day-old broilers and total antioxidant capacity (T-AOC) in 42-day-old broilers (P<0.05). The addition of itaconic acid improves the antioxidant capacity of broilers.

[0102] 5. Effects of itaconic acid on the intestinal mucosal morphology of broiler chickens

[0103] (1) Effects of different levels of itaconic acid supplementation on duodenal mucosal morphology

[0104] Table 7 Effects of different levels of itaconic acid on the morphology of duodenal mucosa in broiler chickens

[0105]

[0106] Note: If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or no shoulder, it means that the difference is not significant (P>0.05). Control: fed with basal diet, set as control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0107] The results are shown in Table 7 and Figure 1 As shown in the figure, at 21 days of age, after adding itaconic acid, the IA 0.8 group had the highest chorioindigo ratio, and the control group had the lowest chorioindigo ratio, and the difference between the two groups was significant (P < 0.05).

[0108] At 42 days of age, the villus height and crypt depth of the experimental group were lower than those of the control group, and the villus crypt ratio was higher than that of the control group. Among them, the IA 1.0 group had the largest difference with the control group in all indicators.

[0109] (2) Effects of different levels of itaconic acid supplementation on jejunal mucosal morphology

[0110] Table 8 Effects of different levels of itaconic acid on the jejunal mucosal morphology of broiler chickens

[0111]

[0112] Note: If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or no shoulder, it means that the difference is not significant (P>0.05). Control: fed with basal diet, set as control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0113] The results are shown in Table 8 and Figure 2 As shown in the figure, at 21 days of age, the villus height and crypt depth after different levels of itaconic acid treatment were higher than those in the control group, and both showed significant linear correlation. At 42 days of age, the jejunal villus height values ​​of the experimental group were higher than those of the control group.

[0114] (3) Effects of different levels of itaconic acid supplementation on ileal mucosal morphology

[0115] Table 9 Effects of different levels of itaconic acid on ileal mucosal morphology in broiler chickens

[0116]

[0117] Note: If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or no shoulder, it means that the difference is not significant (P>0.05). Control: fed with basal diet, set as control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0118] The results are shown in Table 9. At 21 days of age, the villus heights were significantly different among the treatments (P < 0.05), and the ratio of the villus height to the crypt depth (villus-crypt ratio) among the treatments was significantly different compared with the control group (P < 0.05). Figure 3 As shown, the crypts in the control group were the deepest, and those in the IA 0.6 group were the shallowest, showing a significant quadratic linear relationship. Trend analysis yielded y=50.221x2-52.798x+71.440, with a minimum value at x=0.526, meaning that the ileal crypts were the shallowest when 0.526% itaconic acid was added (Table 11).

[0119] At 42 days of age, the villus height and crypt depth of the ileum morphological indicators of broiler chickens showed significant changes among the groups (P < 0.05). The villus height gradually increased among the groups, and the height in the control group was the lowest, which was significantly different from the IA 0.6, IA 0.8 and IA 1.0 groups (P < 0.05). The villus height in the IA 1.0 group was the highest, which was 52.82% higher than that in the control group, and the differences between IA 1.0 and all groups except IA 0.8 were significant (P < 0.05); the crypt depth gradually increased among the groups, and the control group was the lowest, which was significantly different from IA 0.8 and IA 1.0 (P < 0.05).

[0120] In summary, itaconic acid as a feed additive can significantly promote the development of intestinal tissue.

[0121] 6. Effects of different levels of itaconic acid addition on the production of volatile fatty acids and fecal odor substances in the cecum of broiler chickens

[0122] Table 10 Effects of different levels of itaconic acid addition on the production of indole and fecal odor substances in the cecum of broiler chickens

[0123]

[0124] Note: Chinese and English meanings, lactic acid: Lactic acid; acetic acid: Acetic acid; propionic acid: Propionic acid; butyric acid: Butyric acid; indole: Indole; skatole: 3-Methyl indole. If the shoulder of the same data is marked with different lowercase letters, it means that the difference is significant (P<0.05). If the shoulder contains the same lowercase letter or there is no shoulder, it means that the difference is not significant (P>0.05). Control: fed with a basic diet, set as the control group; IA 0.2 = Control + 0.2% itaconic acid; IA 0.4 = Control + 0.4% itaconic acid; IA 0.6 = Control + 0.6% itaconic acid; IA 0.8 = Control + 0.8% itaconic acid; IA1.0 = Control + 1.0% itaconic acid.

[0125] The results are shown in Table 1:0. The addition of itaconic acid significantly affected the concentrations of indole and skatole in the cecal contents (P < 0.05). The indole concentration showed significant linear and quadratic changes with the addition of itaconic acid. The linear and quadratic linear analysis obtained the results shown in Table 12. In addition, the indole concentration in the cecum of the experimental group was lower than that of the control group, among which the IA 0.6 group had the lowest concentration, which was 6.54% different from the control group, and the difference between the two groups was significant (P < 0.05). The trend of skatole concentration among the treatment groups was the same as that of indole concentration. IA 0.6 was the lowest concentration group, and the control group was the highest concentration group, with a difference of 3.84 ng / mL (P < 0.05). The linear and quadratic linear analysis of each group was shown in Table 11. The minimum values ​​of indole and skatole were obtained when x = 0.645 and x = 0.619, respectively.

[0126] It can be seen that the addition of itaconic acid can significantly reduce the concentrations of indole and skatole in the cecal contents, indicating that feeding broilers with itaconic acid as a feed additive can significantly improve the digestive capacity of broilers.

[0127] 7. Secondary regression analysis of itaconic acid and related indicators

[0128] Table 11 Regression relationship between different levels of itaconic acid addition and broiler production performance, biochemical indexes, intestinal mucosal morphology and fecal odor production

[0129]

[0130]

[0131] As shown in Table 11, according to different addition levels of itaconic acid, regression analysis was performed on the production performance, serum biochemical indexes, intestinal mucosal morphology and fecal odor substances of broilers. According to the results of the quadratic regression curve, when the addition amount of itaconic acid was 0.483%, 0.486%, 0.584%, 0.652% and 0.690%, the average daily feed intake, slaughter rate, breast muscle rate and leg muscle rate of broilers were the highest, and the abdominal fat rate was the lowest; when the addition amount was 0.612%, 0.555% and 0.590%, the serum ALT and CAT concentrations of 21-day-old broilers and the serum SOD concentration of 42-day-old broilers could reach the highest; when the addition level was 0.645% and 0.619%, the content of indole and skatole in the cecal content was the lowest.

[0132] In summary, adding itaconic acid to the feed can significantly increase the average daily feed intake and nutrient metabolism rate of broilers, significantly increase the breast muscle rate and leg muscle rate of broilers, and reduce the abdominal fat rate; adding itaconic acid can improve the biochemical performance of broilers; improve the intestinal mucosal morphology of the duodenum and ileum of broilers; and significantly reduce the concentrations of indole and skatole in the cecal contents of broilers.

[0133] Although preferred embodiments of the present invention have been described, additional changes and modifications may occur to these embodiments once those skilled in the art are aware of the basic inventive concepts.

[0134] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. Use of itaconic acid as a feed additive, characterized in that: The feed additive is used to reduce the generation of odorous substances in livestock and poultry farming; the structural formula of itaconic acid is as follows:

2. The use of itaconic acid as a feed additive according to claim 1, characterized in that: The odorous substances are cecal odorous substances of livestock and poultry.

3. The use of itaconic acid as a feed additive according to claim 2, characterized in that: The livestock and poultry cecal odor substances are skatole and indole.

4. The use of itaconic acid as a feed additive according to claim 3, characterized in that: The livestock and poultry are chickens.

5. The use of itaconic acid as a feed additive according to claim 1, characterized in that: Feed additives are also used to improve the growth performance of livestock and poultry, increase the nutrient metabolism rate of livestock and poultry, increase the slaughter rate of livestock and poultry, and improve the antioxidant capacity of livestock and poultry.

6. The use of itaconic acid as a feed additive according to claim 5, characterized in that: Improving the growth performance of livestock and poultry is manifested by increasing the average daily feed intake of livestock and poultry; improving the nutrient metabolism rate of livestock and poultry is manifested by increasing the dry matter metabolism rate and crude protein metabolism rate; improving the slaughter rate of livestock and poultry is manifested by increasing the breast muscle rate and leg muscle rate of livestock and poultry; improving the antioxidant capacity of livestock and poultry is manifested by increasing the concentrations of serum superoxide dismutase, alanine aminotransferase, aspartate aminotransferase and catalase of livestock and poultry.

7. The use of itaconic acid as a feed additive according to claim 1, characterized in that: Calculated as a mass percentage of the total mass of the feed, the addition amount of itaconic acid as a feed additive is 0.2% to 0.8%.

8. A feed, characterized in that: The feed is obtained by adding the itaconic acid in claim 1 to a basic feed in an amount of 0.2% to 0.8% by mass; Each kilogram of the basic feed contains 15mg-16mg of copper, 178mg-180mg of iron, 85mg-87mg of manganese, 98mg-100mg of zinc, 0.69mg-0.70mg of iodine, 0.39mg-0.40mg of selenium, 9000IU-10000IU of vitamin A, 3100IU-3130IU of vitamin D, and 100mg-200mg of vitamin E. 47.40mg~47.448mg, vitamin K2.60mg~2.622mg, thiamine 5.20mg~5.24mg, riboflavin 9.50mg~9.565mg, pyridoxine 13.10mg~13.192mg, cobalamin 0.01mg~cobalamin 0.02mg, niacin 49.80mg~49.848mg, pantothenic acid 17.30mg~17.321mg, folic acid 0.300mg~0.303mg, biotin 0.204mg~0.244mg.

9. The feed according to claim 8, characterized in that The added itaconic acid accounts for 0.483% to 0.690% of the mass percentage of the basic feed.

10. The feed according to claim 8, characterized in that Each kilogram of the basic feed contains 16 mg of copper, 180 mg of iron, 87 mg of manganese, 100 mg of zinc, 0.70 mg of iodine, 0.40 mg of selenium, 10000 IU of vitamin A, 3130 IU of vitamin D, 47.448 mg of vitamin E, 2.622 mg of vitamin K, 5.24 mg of thiamine, 9.565 mg of riboflavin, 13.192 mg of pyridoxine, 0.01 mg of cobalamin, 49.848 mg of niacin, 17.321 mg of pantothenic acid, 0.303 mg of folic acid, and 0.244 mg of biotin.

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