Feed additive as well as preparation method and application thereof in livestock feed

Abstract

The invention belongs to the technical field of animal feed, and relates to a feed additive as well as a preparation method and application thereof in livestock feed. The feed additive is prepared from the following components in parts by mass: 10-20 parts of pericarpium citri reticulatae, 20-30 parts of radix angelicae sinensis, 8-15 parts of compound plant essential oil, 2.5-3.0 parts of compound microorganisms and 4-8 parts of gamma-aminobutyric acid. By adding the feed additive disclosed by the invention into a feed, the production performance can be improved, the immune function can be enhanced, the generation of skatole and ammonia nitrogen in excrement can be reduced, the breeding benefit of livestock is remarkably improved, and meanwhile, the feed additive is beneficial to improving the environment.

Description

Technical Field

[0001] The invention belongs to the technical field of animal feed, and relates to a feed additive, a preparation method thereof, and application in poultry and livestock feed. Background Art

[0002] my country's livestock and poultry farming industry is developing rapidly, with intensive and large-scale farming methods gradually replacing traditional free-range farming. However, the increasing number of intensive and large-scale farms and the growing number of livestock and poultry raised have led to a sharp increase in the amount of odor generated. Farm odor primarily originates from livestock manure, feed residues, and the odor of the livestock themselves. These odors not only impact the environment but also harm the health of surrounding residents. Long-term exposure of animals to odorous environments increases the risk of disease infection, hindering their healthy growth and ultimately affecting economic returns. Indole and skatole are the primary degradation products of L-tryptophan by anaerobic microorganisms in the hindgut of monogastric animals. In today's rapidly developing livestock industry, the presence of indole and skatole in livestock and poultry seriously impairs their growth performance, while also negatively impacting their health, meat quality, and the farming environment. Therefore, the odor problem generated by livestock and poultry farms needs to be effectively addressed.

[0003] Odor control technologies for farms can be divided into two types: ex situ control technology and in situ control technology. Ex situ control is to eliminate and control the released odor through physical, chemical and biological methods, that is, to carry out process control and end-of-pipe treatment of the odor generated by the farm; in situ control mainly achieves the purpose of deodorization by using internal regulators, such as adding feed enzyme preparations, plant extracts, microecological deodorizers, feed acidifiers, fermentable carbohydrates, Chinese herbal medicine additives, etc. to the feed, that is, to reduce odor emissions at the source.

[0004] Essential oils are a class of volatile aromatic compounds extracted from plants, composed of phenols, aldehydes, and alcohols. They possess a wide range of biological activities, including antioxidant, antimicrobial, anti-inflammatory, and insecticidal properties. As secondary metabolites, essential oils possess antibacterial, antifungal, and antiviral properties, making them a promising alternative to antibiotics and improving animal performance and health. Most essential oils possess both antibacterial and antiviral properties, exhibiting broad-spectrum activity.

[0005] With the development of science and technology, plant essential oils, with their natural, safe, and highly effective properties, have become an alternative to antibiotics, effectively addressing the various adverse stresses and challenges faced in livestock production and becoming an excellent product for promoting healthy farming. Current research shows that plant essential oil products can effectively inhibit the growth of harmful bacteria in feed, extend shelf life, promote animal feed intake, improve production performance, and provide biological functions such as antioxidant and immune enhancement.

[0006] It is necessary to provide a feed additive that can reduce odor pollution in farms, so as to achieve the goal of reducing odor pollution in farms, improving production performance, enhancing the immune function of poultry and livestock, promoting healthy breeding, and improving the breeding environment. Summary of the Invention

[0007] In view of this, the object of the present invention is to provide a feed additive and its preparation method and application in livestock feed. The feed additive of the present invention improves production performance, enhances the immune function of livestock, reduces odor pollution in farms, and significantly improves the breeding efficiency of livestock.

[0008] To achieve the above objectives, this application adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a feed additive, which comprises, in parts by mass: 10-20 parts of dried tangerine peel, 20-30 parts of angelica sinensis, 8-15 parts of compound plant essential oil, 2.5-3.0 parts of compound microorganisms, and 4-8 parts of gamma-aminobutyric acid;

[0010] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0011] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0012] In one embodiment of the present invention, the feed additive comprises, by weight, 15 parts of dried tangerine peel, 25 parts of angelica sinensis, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

[0013] In one embodiment of the present invention, the feed additive comprises, by weight, 10 parts of dried tangerine peel, 30 parts of angelica sinensis, 8 parts of compound plant essential oil, 3.0 parts of compound microorganisms, and 8 parts of gamma-aminobutyric acid.

[0014] In one embodiment of the present invention, the feed additive comprises, by weight, 20 parts of dried tangerine peel, 20 parts of angelica sinensis, 15 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 4 parts of gamma-aminobutyric acid.

[0015] In a second aspect, the present invention provides a preparation method for the above-mentioned feed additive, which comprises: pre-mixing a formula amount of angelica and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, stirring the mixture evenly, and obtaining the feed additive.

[0016] In a third aspect, the present invention provides use of the above feed additive or the feed additive prepared by the above preparation method in preparing poultry and livestock feed.

[0017] Furthermore, the present invention provides the use of the above feed additive in preparing feed for enhancing the immune function of poultry and livestock and improving production performance.

[0018] Furthermore, the present invention provides the use of the above feed additive in preparing feed for reducing the formation of skatole and ammonia nitrogen in feces.

[0019] Furthermore, the amount of the feed additive is 2.5% of the basic diet.

[0020] The feed additive of the present invention is supplemented with plant essential oil, which can not only increase the average daily feed intake, but also regulate the expression of ileal mucus genes and stimulate digestive secretion, thereby improving the digestibility of nutrients.

[0021] Plant essential oils act as digestive stimulants by activating peripheral sensory mechanisms. Oral and nasal induction prepares the gastrointestinal tract for food intake, while also stimulating digestive juice secretion and intestinal motility. The carvacrol, thymol, and cinnamaldehyde in this feed additive accelerate the renewal rate of mature intestinal epithelial cells on the surface of intestinal villi, promoting maturation of the digestive tract endothelium, stimulating intestinal villus development, and increasing the digestive and absorptive area. Furthermore, they stimulate the gastrointestinal tract, promoting the secretion of various digestive enzymes, improving the animal's digestive and absorptive functions, and thereby increasing the digestibility and utilization of feed.

[0022] Microorganisms such as Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis have the functions of improving the balance of intestinal flora in livestock and poultry, promoting digestion and absorption, and enhancing the immune function of livestock and poultry.

[0023] As feed additives, angelica and tangerine peel can enhance the digestion, absorption and anabolism of poultry and livestock, significantly improve the growth performance of poultry and livestock, and enhance immunity.

[0024] The feed additive of the present invention has synergistic effects of various plant essential oils, microorganisms and Chinese medicinal materials to improve the production performance of livestock and poultry, enhance immune function, reduce the generation of skatole and ammonia nitrogen in feces, significantly improve the breeding efficiency of livestock and poultry, and improve the breeding environment.

[0025] The beneficial effects achieved by the present invention are:

[0026] Undigested protein in the small intestine is broken down by anaerobic microorganisms in the large intestine to produce tryptophan. Further degradation of tryptophan produces two aromatic substances: 3-methylindole (skatole) and indole. Skatole is absorbed through the intestinal wall and enters the bloodstream. Some skatole is metabolized by the liver and excreted in the urine, while the remainder is stored in fat and muscle tissue. High levels of skatole in these tissues can impart an unpleasant odor and flavor to pork.

[0027] Adding the feed additive of the present invention into the feed can not only improve the production performance of livestock and poultry and enhance the immune function, but also reduce the generation of skatole and ammonia nitrogen in feces, which is beneficial to improving the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the specific implementation methods.

[0029] Figure 1 Comparison of IgA levels in each group,

[0030] Compared with the CK group, * P<0.05, ** P<0.01; compared with group A, # P<0.05, ## P<0.01.

[0031] Figure 2 Comparison of IgG content in each group,

[0032] Compared with the CK group, * P<0.05, ** P<0.01; compared with group A, # P<0.05, ## P<0.01.

[0033] Figure 3 Comparison of skatole content in each group,

[0034] Compared with the CK group, * P<0.05.

[0035] Figure 4 Comparison of indole content in each group

[0036] Compared with the CK group, * P<0.05, ** P<0.01; compared with group A, # P<0.05, ## P<0.01. DETAILED DESCRIPTION

[0037] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0038] Unless otherwise specified, the components used in the present invention can be purchased by those skilled in the art.

[0039] Example 1

[0040] A feed additive comprises, by weight, 15 parts of dried tangerine peel, 25 parts of angelica sinensis, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

[0041] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0042] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0043] The preparation method comprises the following steps: pre-mixing a formula amount of angelica sinensis and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, and stirring the mixture uniformly to obtain a feed additive.

[0044] Example 2

[0045] A feed additive comprises, by weight, 10 parts of dried tangerine peel, 30 parts of angelica sinensis, 8 parts of compound plant essential oil, 3.0 parts of compound microorganisms, and 8 parts of gamma-aminobutyric acid.

[0046] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0047] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0048] The preparation method comprises the following steps: pre-mixing a formula amount of angelica sinensis and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, and stirring the mixture uniformly to obtain a feed additive.

[0049] Example 3

[0050] A feed additive comprises, by weight, 20 parts of dried tangerine peel, 20 parts of angelica sinensis, 15 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 4 parts of gamma-aminobutyric acid.

[0051] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0052] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0053] The preparation method comprises the following steps: pre-mixing a formula amount of angelica sinensis and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, and stirring the mixture uniformly to obtain a feed additive.

[0054] Example 4

[0055] A feed additive comprises, by weight, 15 parts of dried tangerine peel, 30 parts of angelica sinensis, 8 parts of compound plant essential oil, 3.0 parts of compound microorganisms, and 4 parts of gamma-aminobutyric acid.

[0056] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0057] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0058] The preparation method comprises the following steps: pre-mixing a formula amount of angelica sinensis and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, and stirring the mixture uniformly to obtain a feed additive.

[0059] Example 5

[0060] A feed additive comprises, by weight, 10 parts of dried tangerine peel, 25 parts of angelica sinensis, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 8 parts of gamma-aminobutyric acid.

[0061] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0062] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0063] The preparation method comprises the following steps: pre-mixing a formula amount of angelica sinensis and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, and stirring the mixture uniformly to obtain a feed additive.

[0064] Example 6

[0065] A feed additive comprises, by weight, 20 parts of dried tangerine peel, 20 parts of angelica sinensis, 15 parts of compound plant essential oil, 2.8 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

[0066] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0067] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0068] The preparation method comprises the following steps: pre-mixing a formula amount of angelica sinensis and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, and stirring the mixture uniformly to obtain a feed additive.

[0069] Comparative Example 1

[0070] Compared with Example 1, the difference is that Angelica sinensis is not contained.

[0071] A feed additive comprises, by weight, 15 parts of dried tangerine peel, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

[0072] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0073] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0074] The preparation method is as in Example 1.

[0075] Comparative Example 2

[0076] Compared with Example 1, the difference is that the components of the composite plant essential oil are different.

[0077] A feed additive comprises, by weight, 15 parts of dried tangerine peel, 25 parts of angelica sinensis, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

[0078] The composite plant essential oil consists of carvacrol and cinnamaldehyde in a mass ratio of 1:1;

[0079] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0080] The preparation method is as in Example 1.

[0081] Comparative Example 3

[0082] Compared with Example 1, the difference lies in the different components of the composite microorganisms.

[0083] A feed additive comprises, by weight, 15 parts of dried tangerine peel, 25 parts of angelica sinensis, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

[0084] The composite plant essential oil consists of carvacrol, cinnamaldehyde and thymol in a mass ratio of 1:3:1;

[0085] The composite microorganism is Clostridium butyricum.

[0086] The preparation method is as in Example 1.

[0087] Comparative Example 4

[0088] Compared with Example 1, the difference lies in the different components of the composite plant essential oil in the feed additive.

[0089] A feed additive comprises, by weight, 15 parts of dried tangerine peel, 25 parts of angelica sinensis, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

[0090] The composite plant essential oil is cinnamaldehyde;

[0091] The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:2.

[0092] The preparation method is as in Example 1.

[0093] Effects of the feed additive of the present invention on growth performance and immune function of pigs

[0094] 1. Experimental Methods

[0095] A total of 210 healthy fattening pigs with good growth and an average weight of (34.31 ± 1.48) kg were randomly divided into seven groups: a control group (CK group), Example 1 group (Group A), Example 2 group (Group B), Comparative Example 1 group (Group C), Comparative Example 2 group (Group D), Comparative Example 3 group (Group E), and Comparative Example 4 group (Group F). Each group had six replicates, with five pigs per replicate. The experimental period was 45 days. The control group was fed a basal diet, while each experimental group supplemented the basal diet with 2.5% of the corresponding product.

[0096] Table 1 Basic diet composition (air-dry basis) (%)

[0097] Feed composition Proportion corn 71.72 wheat bran 10.00 soybean meal 16.40 Calcium hydrogen phosphate 0.32 Stone powder 0.56 1% premix 1.00 total 100

[0098] The premix provides per kilogram of feed: VA 1500IU, VD3 200IU, VE 10IU, VK 30.5mg, biotin 0.05mg, choline 0.3g, folic acid 0.3mg, niacin 10.0mg, pantothenic acid 10.0mg, VB 1.0mg, VB22.5mg, VB6 1.0mg, VB 12 10.0μg, Cu 4mg, Fe 60mg, Zn 65mg, Mn 3mg, Se0.25 mg, I 0.15mg.

[0099] Pigs were allowed to eat and drink freely. The pig houses were cleaned and disinfected every day. The pens were kept dry and ventilated. They were fed three times a day. Other feeding and management were carried out according to routine procedures.

[0100] 2. Measurement indicators

[0101] On the day the experiment ended, one pig with a weight close to the average was selected for each replicate, 10 mL of blood was collected from the jugular vein, placed in a procoagulant blood collection tube, allowed to stand for 2-3 hours, and centrifuged at 4°C for 10 minutes. The supernatant was divided into 1.5 mL centrifuge tubes and stored at -20°C for later use.

[0102] 2.1 Growth performance

[0103] The pigs were weighed on an empty stomach before and at the end of the experiment. During the experiment, the feed intake of each replicate was recorded daily. The average daily gain (ADG), average daily feed intake (ADFI) and feed-to-gain ratio (F / G) were calculated based on the body weight and feed intake data. The calculation formula is as follows:

[0104] ADG = (final weight - initial weight) / feeding days;

[0105] ADFI = (total feed amount - residual feed amount) / (feeding days × number of pigs raised);

[0106] F / G=ADFI / ADG.

[0107] 2.2 Determination of serum immune indicators

[0108] The levels of serum immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) were determined using biotin double antibody sandwich enzyme-linked immunosorbent assay.

[0109] 2.3 Determination of skatole and indole content in feces

[0110] Skatole and indole content were determined using high-performance liquid chromatography. A 2.00 g sample was vortex-mixed with 10 mL of methanol and then placed in a 40°C waterbath for 20 minutes, mixing every 5 minutes. After the waterbath, the sample was incubated at -20°C for 30 minutes and then centrifuged at 12,000 rpm for 10 minutes. The supernatant was then stored at 4°C for analysis.

[0111] The chromatographic conditions were as follows: mobile phase A was double-distilled water; mobile phase B was acetonitrile; the flow rate was 1 mL / min; and the column temperature was 30°C.

[0112] Fluorescence detection was performed with an excitation wavelength of 270 nm and an emission wavelength of 350 nm.

[0113] Elution conditions: mobile phase B 0-3.5 min, 40%; 4.5-9.0 min, 75%; 11.0-15 min, 40%.

[0114] 3. Data Processing

[0115] Graphpad Prism 7.0 software was used for data statistical analysis and graphing.

[0116] 4. Test results

[0117] 4.1 Effects on growth performance

[0118] As shown in Table 2, compared with the CK group, treatments in Groups A and B significantly increased ADG. Treatment in Group A had the most significant effect on increasing ADG, while treatment in Group B also had a significant effect. The effects of Groups A and B on increasing ADG were significantly greater than those in Groups C, D, E, and F.

[0119] Table 2 Effects on growth performance of each group ( )

[0120] Group Initial weight (kg) Final weight (kg) ADG(kg) ADFI(kg) F / G control group 34.64±0.79 65.59±1.80 0.68±0.04 1.85±0.04 2.70±0.23 Group A 34.86±1.06 <![CDATA[72.28±2.06 ** ]]> <![CDATA[0.83±0.05 ** ]]> 1.83±0.04 <![CDATA[2.21±0.13 ** ]]> Group B 33.85±2.26 <![CDATA[69.75±4.19 * ]]> <![CDATA[0.80±0.10 * ]]> 1.81±0.06 <![CDATA[2.30±0.26 * ]]> Group C 34.62±1.67 <![CDATA[67.55±3.41 # ]]> <![CDATA[0.73±0.06 # ]]> 1.85±0.07 <![CDATA[2.54±0.24 # ]]> Group D 34.56±0.68 <![CDATA[66.42±3.57 ## ]]> <![CDATA[0.71±0.07 ## ]]> 1.86±0.06 <![CDATA[2.65±0.25 ## ]]> Group E 33.95±1.73 <![CDATA[66.20±2.69 ## ]]> <![CDATA[0.72±0.04 ## ]]> 1.82±0.06 <![CDATA[2.55±0.17 # ]]> Group F 33.70±1.85 <![CDATA[67.03±3.46 ## ]]> <![CDATA[0.74±0.09 # ]]> 1.85±0.05 <![CDATA[2.53±0.32 # ]]>

[0121] Note: Compared with CK group, * P<0.05, ** P<0.01; compared with group A, # P<0.05, ## P<0.01.

[0122] Compared with the CK group, treatments in groups A and B significantly reduced F / G. Group A had the most significant effect in reducing F / G, while treatment in group B also significantly reduced F / G. Groups A and B were significantly better than groups C, D, E, and F in increasing and decreasing F / G.

[0123] 4.2 Effects on serum immune indicators

[0124] like Figure 1 、 2 As shown in the figure, compared with the CK group, the treatment of group A and group B significantly increased the levels of IgA and IgG. The effect of group A and group B in increasing the levels of IgA and IgG was significantly better than that of group C, group D, group E, and group F.

[0125] The difference between Comparative Example 1 and Example 1 is that no angelica is added, the difference between Comparative Example 2 and Comparative Example 4 and Example 1 is that the components of the composite plant essential oil are different, and the difference between Comparative Example 3 and Example 1 is that the components of the composite microorganisms are different. The obtained feed additive has a significantly weakened effect on improving the production performance of fattening pigs and enhancing the immune function.

[0126] In the feed additive of the present invention, the types of medicinal materials, the components of the composite plant essential oil and the components of the composite microorganism all have a great influence on the improvement of production performance and the enhancement of immune function.

[0127] 4.3 Effects on skatole and indole levels in feces

[0128] Undigested protein in the small intestine is broken down by anaerobic microorganisms in the large intestine to produce tryptophan. Further degradation of tryptophan produces two aromatic substances: 3-methylindole (skatole) and indole. Skatole is absorbed through the intestinal wall and enters the bloodstream. Some skatole is metabolized by the liver and excreted in the urine, while the remainder is stored in fat and muscle tissue. High levels of skatole in these tissues can impart an unpleasant odor and flavor to pork.

[0129] like Figure 3 、 4 As shown in the figure, compared with the CK group, the treatment of groups A and B reduced the levels of skatole and indole in feces. The effect of groups A and B in reducing the content of indole in feces was significantly better than that of groups C, D, E, and F.

[0130] The difference between Comparative Example 1 and Example 1 is that no angelica is added, the difference between Comparative Example 2 and Comparative Example 4 and Example 1 is that the components of the composite plant essential oil are different, and the difference between Comparative Example 3 and Example 1 is that the components of the composite microorganism are different. The effect of the obtained feed additive on reducing the content of skatole and indole in feces is significantly weakened.

[0131] In the feed additive of the present invention, the types of medicinal materials, the components of the composite plant essential oil and the components of the composite microorganisms have a great influence on the effect of reducing the contents of skatole and indole in feces.

[0132] Adding the feed additive of the present invention into the daily diet significantly increases the average daily weight gain, reduces the feed-to-weight ratio, significantly increases the IgA and IgG contents of pigs, and effectively reduces the skatole and indole contents in feces.

[0133] Adding the feed additive of the present invention to the feed can not only improve production performance and enhance immune function, but also reduce the generation of skatole and ammonia nitrogen in feces, which is beneficial to improving the environment.

[0134] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A feed additive, characterized in that The feed additive comprises, by weight, 10-20 parts of dried tangerine peel, 20-30 parts of angelica sinensis, 8-15 parts of compound plant essential oil, 2.5-3.0 parts of compound microorganisms, and 4-8 parts of gamma-aminobutyric acid; The compound plant essential oil is composed of carvacrol, cinnamaldehyde, and thymol; The composite microorganisms consist of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis.

2. The feed additive according to claim 1, characterized in that In the feed additive, the composite plant essential oil is composed of carvacrol, cinnamaldehyde, and thymol in a mass ratio of 1:3:1; The composite microorganism consists of Lactobacillus reuteri, Clostridium butyricum and Bacillus subtilis in a mass ratio of 3:1:

2.

3. The feed additive according to claim 1, characterized in that The feed additive comprises, by weight, 15 parts of dried tangerine peel, 25 parts of angelica sinensis, 10 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 6 parts of gamma-aminobutyric acid.

4. The feed additive according to claim 1, characterized in that The feed additive comprises, by weight, 10 parts of dried tangerine peel, 30 parts of angelica sinensis, 8 parts of compound plant essential oil, 3.0 parts of compound microorganisms, and 8 parts of gamma-aminobutyric acid.

5. The feed additive according to claim 1, characterized in that The feed additive comprises, by weight, 20 parts of dried tangerine peel, 20 parts of angelica sinensis, 15 parts of compound plant essential oil, 2.5 parts of compound microorganisms, and 4 parts of gamma-aminobutyric acid.

6. The feed additive according to claim 1, characterized in that The preparation method comprises the following steps: pre-mixing a formula amount of angelica and dried tangerine peel, crushing the mixture, and sieving to obtain a mixture 1; uniformly mixing carvacrol, cinnamaldehyde, and thymol according to a formula amount to obtain a mixture 2; and mixing a formula amount of Lactobacillus reuteri, Clostridium butyricum, and Bacillus subtilis with the mixture 1 and the mixture 2, stirring the mixture uniformly, and obtaining a feed additive.

7. Use of the feed additive according to any one of claims 1 to 5 in preparing livestock feed.

8. The use according to claim 7, characterized in that The feed additive is used in preparing feed for enhancing the immune function of poultry and livestock and improving production performance.

9. The use according to claim 7, characterized in that The feed additive is used in preparing feed for reducing the skatole and indole contents in feces.

10. The use according to claim 7, characterized in that The amount of the feed additive is 2.5% of the basic diet.

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