Feed additive composition, preparation method and application of feed additive composition in improvement of poultry lung health

Abstract

The invention belongs to the technical field of breeding, and particularly relates to a feed additive composition, a preparation method and application of the feed additive composition in improvement of poultry lung health. The composition is prepared from the following components in percentage by weight: 40 to 60 percent of mogroside V, 10 to 20 percent of complex microbial inoculants, 10 to 20 percent of eucalyptus oil and 20 to 40 percent of prebiotics. The feed additive disclosed by the invention can obviously enhance the anti-inflammatory effect, relieve lung inflammation injury caused by environmental factors and improve the respiratory system health of broiler chickens.

Description

Technical Field

[0001] The invention belongs to the technical field of breeding, and in particular, relates to a feed additive composition, a preparation method and an application in improving the lung health of poultry. Background Art

[0002] With the continuous development of modern breeding industry, poor air quality and excessive harmful gas content (such as ammonia, sulfur dioxide, etc.) in broiler breeding have become important factors affecting the health of broilers. In particular, these harmful gases and environmental pollutants have caused significant damage to the respiratory system of broilers, leading to lung inflammation and affecting the growth performance and meat quality of broilers. Traditional prevention and control methods mostly rely on antibiotics or chemical drugs, which often have drug residue problems, and the long-term impact on the environment and animals cannot be ignored.

[0003] Studies in recent years have shown that intestinal flora plays an important role in maintaining body health and promoting immune response. By regulating intestinal flora and then affecting metabolites, systemic immune response and lung health can be regulated. Research on the gut-lung axis further reveals that the intestinal flora affects the inflammatory response and immune status of the lungs through the interaction between the blood circulation and the lung flora and immune cells. As a plant with both medicinal and edible properties, Momordica grosvenori has the effect of clearing cough and nourishing the lungs, but Momordica grosvenori saponin extracts include many types of saponins, and the mechanism of action is still unclear. Therefore, in order to fully utilize the medicinal value of Momordica grosvenori, it is necessary to study the efficacy of each component in depth. In addition, eucalyptus leaves, as a traditional Chinese herbal medicine, have the effects of clearing heat and detoxifying, killing insects and inhibiting bacteria. They have also been used in Chinese veterinary medicine and feed additives. Therefore, it is also necessary to screen eucalyptus leaf extracts with strong antibacterial properties to supplement the efficacy of Momordica grosvenori saponins.

[0004] Based on the above background, it is very necessary to propose a new feed additive, which aims to regulate intestinal flora, improve immune function, reduce lung inflammation, and thus promote the growth and health of broilers. Summary of the invention

[0005] The purpose of the present invention is to provide a feed additive composition, a preparation method and an application in improving the lung health of poultry, so as to achieve the reduction of inflammatory damage to the lungs of poultry, especially broilers, improve the respiratory health of broilers, and improve the production performance of broiler farming.

[0006] To this end, the present invention provides the following technical solutions.

[0007] One aspect of the present invention provides a feed additive composition, which comprises the following components by weight: 40-60% of mogroside V, 10-20% of composite bacterial agent, 10-20% of eucalyptus oil and 20-40% of prebiotics.

[0008] In some preferred embodiments, the composite bacterial agent is composed of Lactobacillus acidophilus and / or Desulfovibrio.

[0009] In some preferred embodiments, the composite bacterial agent is formed by mixing Lactobacillus acidophilus and Desulfovibrio according to a mass ratio of (1-2):1.

[0010] In some preferred embodiments, the eucalyptus oil is rainbow eucalyptus oil.

[0011] In some preferred embodiments, the prebiotics are manno-oligosaccharides and / or galacto-oligosaccharides.

[0012] In some preferred embodiments, the prebiotics are prepared by mixing manno-oligosaccharides and galacto-oligosaccharides in a mass ratio of (1-2):1.

[0013] In some preferred embodiments, the composition further comprises a carrier, and the ratio of the carrier to the feed additive composition is complex: carrier = 1:3.

[0014] In some preferred embodiments, the carrier includes corn flour, wheat bran, and palygorskite.

[0015] The second aspect of the present invention provides a method for preparing the feed additive composition as described above, the method comprising the following steps:

[0016] Weigh each raw material according to the ratio;

[0017] The prebiotics and the composite bacterial agent are mixed to obtain a mixture I;

[0018] Ultrasonic mixing of eucalyptus oil, mogroside V and a carrier to obtain a mixture II;

[0019] The obtained mixed material I and mixed material II are mixed evenly.

[0020] In some preferred embodiments, the ultrasonic conditions are: power 220W; frequency: 28kHz; time: 10 minutes, using intermittent mode, pausing for 10 seconds every 30 seconds of operation; temperature: ≤25°C, using an ice bath or a water-cooled jacket.

[0021] The third aspect of the present invention provides a use of the feed additive composition as described above in the preparation of a product for improving the lung health of poultry.

[0022] In some preferred embodiments, the feed additive composition is applied in an amount of 0.1% to 0.5%.

[0023] In some preferred embodiments, the poultry includes broilers, laying hens, turkeys and quails.

[0024] A fourth aspect of the present invention provides a product for improving the lung health of poultry, the product comprising the feed additive composition as described above.

[0025] In some preferred embodiments, the amount of feed additive added to the product is 0.1%.

[0026] By means of the above technical solution, the present invention has at least the following advantages:

[0027] Based on the study of the mechanism of action of mogroside on the intestinal-pulmonary axis, the present invention creatively screens out the key bacterial groups that affect chicken lung inflammation, namely Lactobacillus acidophilus and Desulfovibrio, and on this basis, compounding is carried out to promote the growth of beneficial bacteria and inhibit harmful bacteria, thereby providing a feed additive composition, a preparation method and an application in improving the lung health of poultry. The feed additive uses mogroside as the main active substance, and further compounding two probiotic groups affected by saponins, namely Lactobacillus acidophilus and Desulfovibrio, and at the same time, because Escherichia-Shigella plays an important role in the induction process of lung inflammation, eucalyptus oil from a specific source with extremely high inhibitory effect on their growth is also screened through in vitro tests. The present invention adds the functional additive obtained by compounding the above components to chicken feed, which can regulate the intestinal flora of chickens, promote the growth of beneficial bacteria, and inhibit the reproduction of harmful bacteria, thereby improving the immune function of broilers and alleviating lung inflammation through the intestinal-pulmonary axis. Animal experiments have shown that the feed additive composition can significantly enhance the anti-inflammatory effect, reduce lung inflammation damage caused by environmental factors, and improve the respiratory health of broiler chickens.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The effects of mogrosides on the species composition of cecal microorganisms in broiler chickens are shown: (A) the top ten dominant bacterial phyla; (B) the top 15 dominant bacterial genera; (C), (D) bacterial differences between the Control group and the 0.20% mogrosides group at the phylum level; (E)-(G) bacterial differences between the Control group and the 0.20% mogrosides group at the genus level. * P<0.05, ** P<0.01, *** P<0.001. Control: control group; 0.20% mogroside: 0.20% mogroside group; All data are expressed as "mean ± SEM", n = 5.

[0030] Figure 2The functional analysis of broiler cecal microorganisms is shown: (A) KEGG function prediction of 16S sequences using Tax4Fun SILVA annotation; (B) Phenotypic classification and abundance of samples are predicted based on Bugbase; (C) Whether there is a significant difference in the mean functional abundance between the two groups is compared through Tax4Fun; (D) Whether there is a significant difference in the mean functional abundance between the two groups is compared through Bugbase; Control: control group; 0.20% mogroside: 0.20% mogroside group, n=5.

[0031] Figure 3 The effects of mogroside on organ indexes of broiler chickens with lung injury are shown: A: lung index; B: bursa of Fabricius index; C: spleen index; data values ​​are presented as "mean ± standard error"; n = 6; *, P < 0.05.

[0032] Figure 4 The figure shows the effect of momordica saponins on the lung tissue morphology of broiler chickens with lung injury: the long arrows indicate suspected lesions, the short arrows indicate inflammatory cell infiltration, and the triangles indicate destruction of the lung chamber structure; the image scale is 100 μm.

[0033] Figure 5 The effect of Momordica grosvenori saponins on the expression of lung barrier genes in broiler chickens with lung injury is shown: qRT-PCR was used to detect the mRNA expression levels of ZO-1 (A), Claudin (B), Occludin (C), MUC1 (D), and MUC2 (E) in lung tissue; data values ​​are presented as "mean ± standard error"; n = 6; *, P < 0.05, **, P < 0.01.

[0034] Figure 6 The effect of momordica saponins on the gene expression of inflammatory cytokines in broiler chickens with lung injury is shown: the relative expression levels of IL-1β (A), IL-6 (B), IL-4 (C), IL-8 (D), Caspase1 (E), and TGF-β1 (F) in broiler tissues with acute lung injury were determined by qRT-PCR; data values ​​were presented as "mean ± standard error"; n = 6; *, P < 0.05, **, P < 0.01, ***, P < 0.001.

[0035] Figure 7The effect of momordica saponins on the gene expression of Th17 / Treg-related factors in broiler chickens with lung injury is shown: qRT-PCR was used to detect the mRNA expression levels of RORα (A), AhR (B), Foxp3 (C), IL-17A (D), IL-17F (E), IL-10 (F), PD-L1 (G) and PD-1 (H) in lung tissues; data values ​​are presented as "mean ± standard error"; n = 6; *, P < 0.05, **, P < 0.01, ***, P < 0.001.

[0036] Figure 8 The effects of mogrosides on inflammatory factors in broilers with lung injury are shown: the effects of mogrosides on the levels of inflammatory factors TGF-β (A), IL-6 (B), IL-17 (C) and IL-10 (D) in broilers with lung injury; data values ​​are presented as mean ± standard error of the mean; n = 6; *, P < 0.05.

[0037] Fig. 9 The effects of mogrosides on lung microbiota in broiler chickens with acute lung injury are shown: A: dilution curve; B: Simpson index; C: species Venn diagram; D: PLS-DA (partial least squares discriminant analysis) analysis; n=5.

[0038] Fig.10 The effects of mogroside saponins on the composition of lung microbiota in broiler chickens with acute lung injury are shown: A: top ten dominant phyla; B: differential phyla; C: top ten dominant genera; D: differential genera; n=5.

[0039] Fig.11 The figure shows the use of LEFse to analyze the differences in colony colonies between groups, and the prediction of the abundance of related phenotypes in samples based on Bugbase: A: LDA scores of bacterial taxa in each group, covering bacterial taxa from phylum to genus level; P<0.05, LDA score>3.0 indicates statistically significant differences; B: Evolutionary graph shows significantly enriched bacterial taxa; C, D: Bugbase predicts microbial phenotypes at the biological level; n=5; Note: **, P<0.01.

[0040] Fig.12 The effects of fecal microbial transplantation on the lung tissue morphology of broiler chickens with lung injury are shown: CF group: control-fecal filtrate group; MS group: mogroside-sterile fecal filtrate group; MF group: mogroside-fecal filtrate group; the scale of the top three pictures is 500μm, and the scale of the bottom three pictures is 100μm; the arrows indicate bronchial congestion, and the triangles indicate pulmonary capillary fusion.

[0041] Fig.13The effect of fecal microbiota transplantation on the expression of lung barrier genes in broiler chickens with lung injury is shown: CF group: control-fecal filtrate group; MS group: mogroside-sterile fecal filtrate group; MF group: mogroside-fecal filtrate group; data values ​​are presented as "mean ± standard error"; n = 6; **, P < 0.01.

[0042] Fig.14 The effects of fecal microbial transplantation on inflammatory factors in lung tissue of broiler chickens with lung injury are shown: the effects on the levels of inflammatory factors TGF-β (A), IL-6 (B), IL-17 (C) and IL-10 (D) in broiler chickens with lung injury; CF group: control-fecal filtrate group; MS group: mogroside-sterile fecal filtrate group; MF group: mogroside-fecal filtrate group; data values ​​are presented as "mean ± standard error"; n = 6; *, P < 0.05.

[0043] Fig.15 The effect of fecal microbial transplantation on the cecal microbial composition of broiler chickens is shown: A: the top ten dominant bacterial phyla in abundance; B: the top ten dominant bacterial genera in abundance; C: the phyla with significant differences between the CF group and the MF group; D: the genera with significant differences between the CF group and the MF group. Welch's t test was used to compare whether there was a significant difference in the average species abundance between the two groups; CF group: control-fecal filtrate group; MS group: mogroside-sterile fecal filtrate group; MF group: mogroside-fecal filtrate group; n = 5.

[0044] Fig.16 The indicator species analysis of broiler cecal microorganisms is shown: A: random forest analysis at the genus level between the CF group and the MF group; B: indicator species analysis at the genus level between the CF group and the MF group; CF group: control-fecal filtrate group; MS group: mogroside-sterile fecal filtrate group; MF group: mogroside-fecal filtrate group; n=5.

[0045] Fig.17 The detection of short-chain fatty acids in the cecal contents of broiler chickens is shown: the concentration of SCFAs such as acetate (A), propionate (B), butyrate (C), isobutyrate (D), valeric acid (E), and isovaleric acid (F) in the cecal contents of broiler chickens; (G) qPCR detection of FFAR2 gene expression. CF group: control-fecal filtrate group; MS group: mogroside-sterile fecal filtrate group; MF group: mogroside-fecal filtrate group. Data values ​​are presented as "mean ± standard error". n = 6. *P < 0.05.

[0046] Fig.18 The effect of the feed additive composition on lung tissue is shown (from left to right: control group, LPS injection group, LPS injection plus the present invention feeding group).

[0047] Fig.19The effects of feed additive compositions on the expression of genes associated with lung inflammation are shown. DETAILED DESCRIPTION

[0048] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] As the main active ingredient of the composition of the present invention, mogroside V has anti-inflammatory, antioxidant and immunomodulatory effects, and can reduce lung inflammation caused by harmful gases or pathogens by regulating intestinal flora. Two probiotic groups affected by saponins, Lactobacillus acidophilus and Desulfovibrio, were screened on the basis of mogroside V. Lactobacillus acidophilus has the effect of promoting intestinal health, can inhibit the growth of harmful bacteria, improve the structure of intestinal flora, and promote the normal operation of the immune system. Desulfovibrio, as a probiotic, can help regulate the metabolism of sulfide in the intestine, thereby indirectly improving the body's immune response and reducing lung inflammation. On the above basis, the present invention also screens the rainbow eucalyptus oil with the strongest growth inhibition effect on Gram-positive bacteria, especially Escherichia coli, from eucalyptus leaves from different sources. Manno-oligosaccharides and oligogalactoses as prebiotics can restructure intestinal microbiota by enhancing the abundance of bifidobacteria and lactobacilli.

[0050] By compounding the above six components together, a feed additive suitable for poultry, especially broilers, is made. Through the action of the gut-lung axis, it can significantly improve the lung health of broilers, reduce lung inflammation caused by environmental pollutants, bacteria or viruses, and thereby improve the growth performance, immune function and overall health level of broilers.

[0051] The materials involved in the following embodiments include:

[0052] 1. Raw materials:

[0053] Mogrosides (including 55.12% mogroside V) were purchased from Guilin Yitiancheng Biotechnology Co., Ltd.

[0054] Lactobacillus acidophilus: 1×10^9 CFU / g, provided by the School of Food Science and Engineering of Nanjing Agricultural University, strain number CICC26122.

[0055] Desulfovibrio: 1×10^9 CFU / g, provided by the School of Food Science and Engineering of Nanjing Agricultural University, strain number ATCC29577.

[0056] Rainbow Eucalyptus Oil: Rainbow Eucalyptus essential oil is extracted from the leaves of the plant using steam distillation. Place in a sealed glass bottle and store in a refrigerator at 4°C for later use.

[0057] The basal diet was formulated according to the NRC (2012) broiler nutrition standards.

[0058] LPS (lipopolysaccharide): used to induce lung inflammation in broiler chickens, purchased from Biosharp Company (Hefei, Anhui).

[0059] 2. Experimental Animals

[0060] Arbor Acres chicks were purchased from Nanjing Tegeili Planting Professional Cooperative.

[0061] AA broilers were raised in the experimental animal house of Nanjing Agricultural University, and the feeding and management were carried out according to the broiler feeding and management standards, maintaining consistent light, temperature and humidity. Broilers were allowed to eat and drink freely during their growth.

[0062] 3. Reagents

[0063] Chicken ELISA kits were used to detect TGF-β (H034-1-1, Nanjing), IL-6 (H007-1-1, Nanjing), IL-17 (H014-1-1, Nanjing) and IL-10 (H009-1-1, Nanjing).

[0064] Embodiment 1:

[0065] Mogroside V, Lactobacillus acidophilus, Desulfovibrio sulfovibrio, rainbow eucalyptus oil, mannooligosaccharide and galacto-oligosaccharide are mixed and crushed in a mass ratio of 1:1:1:1:1:1, and then evenly mixed with carrier palygorskite in a weight ratio of 1:3 to obtain a feed additive composition I.

[0066] Embodiment 2:

[0067] The only difference from Example 1 is that mogroside V, Lactobacillus acidophilus, Desulfovibrio sulfovibrio, rainbow eucalyptus oil, mannooligosaccharide and galacto-oligosaccharide are mixed in a mass ratio of 5:1:1:2:2:2, and the rest is consistent with Example 1 to obtain a feed additive composition II.

[0068] Embodiment 3:

[0069] The only difference from Example 1 is that mogroside V, Lactobacillus acidophilus, Desulfovibrio sulfovibrio, rainbow eucalyptus oil, mannooligosaccharide and galacto-oligosaccharide are mixed in a mass ratio of 3:1:1:2:1:1, and the rest is consistent with Example 1 to obtain a feed additive composition III.

[0070] Experiment 1: Effects of Momordica Saponins on Growth Performance and Intestinal Microflora of Broilers

[0071] 1. Experimental Methods

[0072] 192 healthy one-day-old AA broiler chickens were selected and randomly divided into 4 groups, with 6 replicates in each group and 8 chickens in each replicate, namely the control group and experimental groups I to III. The broiler chickens in each group were fed the following feed daily:

[0073] Control group (CON group): basal diet;

[0074] Experimental group I: basal diet + 0.05wt% momordica saponin;

[0075] Experimental group II: basic diet + 0.10wt% momordica saponin;

[0076] Experimental group III: basic diet + 0.20wt% momordica saponin.

[0077] During the entire feeding cycle, feeding and management were carried out in accordance with the broiler feeding and management standards, and the light, temperature and humidity were kept consistent. The broilers were allowed to eat and drink freely during their growth. On the 42nd day of feeding, 6 healthy chickens were randomly selected from each group for slaughter and sampling. After weighing, the broilers were placed in a sealed container filled with carbon dioxide and killed. The lungs, spleen and bursa of Fabricius were weighed. The contents of the cecum were quickly frozen in liquid nitrogen and then stored in a -80°C refrigerator for subsequent determination.

[0078] 2. Experimental results

[0079] 2.1. Effects of Momordica Saponins on Growth Performance of Broilers

[0080] The effects of adding different concentrations of momordica saponins to the diet on the growth performance of broilers during the entire feeding cycle are shown in Table 1.

[0081] Table 1 Effects of different concentrations of momordica saponins added to diet on the growth performance of broilers

[0082]

[0083] Note: The superscript letters in each row of data represent significant differences among the groups. The data are presented as “mean ± standard error”, n=6.

[0084] According to the results in Table 1, compared with the control group, the addition of different concentrations of mogrosides to the diet significantly increased the body weight and daily weight gain of broilers at 7, 14, 21 and 42 days of age (P<0.01) (experimental groups I to III). The three additive groups - experimental groups I to III had no significant effect on the average daily feed intake (ADFI) and feed-to-weight ratio (F / G) of broilers (P>0.05).

[0085] 2.2. Effects of Momordica Saponins on Organ Indexes of Broilers

[0086] The effects of adding different concentrations of momordica saponins to the diet on the organ indexes of broiler chickens are shown in Table 2.

[0087] Table 2 Effect of feed additive composition on broiler organ index

[0088]

[0089] Note: The letters in the shoulder of each row of data represent significant differences among the groups. The data are presented as “mean ± standard error”, n=6.

[0090] According to the results in Table 2, at 21 days and 42 days of age, the organ indexes of lung, spleen and bursa of Fabricius in each test group were not significantly different from those in the control group (P>0.05). This result shows that the addition of momordica saponins has no significant effect on the organ index of broiler chickens.

[0091] Effects of Momordica Saponins on the Cecal Microbial Composition of Broiler Chickens

[0092] The cecal microbial communities of the above groups of broiler chickens were analyzed at the phylum and genus levels, and the results are shown in 1. Figure 1 As shown, the relative abundance of Desulfobacteria was significantly increased (P<0.05), and the relative abundance of Proteobacteria was significantly decreased (P<0.001) by adding mogrosides (experimental group III) to the diet. At the genus level, the relative abundance of Desulfovibrio and Lactobacillus was significantly increased in the mogroside group (experimental group III) (P<0.05). In addition, the relative abundance of Ruminococcus_torques_group was significantly decreased in the 0.20% mogroside group (experimental group III) (P<0.05).

[0093] Effects of Momordica Saponins on the Function of Cecal Microorganisms in Broiler Chickens

[0094] Figure 2 The functional prediction and differential analysis results of the intestinal microbiota of each group of broiler chickens are shown. Figure 2As shown, the phenotypic prediction of the microbiota indicated that these changes in bacterial diversity may involve different metabolism as dominant functions. The results of KEGG functional prediction found that the abundance of amino acid metabolism functional bacteria in the 0.20% mogroside group (experimental group III) was extremely significantly reduced (P<0.01), and the abundance of translation, nucleotide metabolism, replication and repair, folding sorting and degradation functional bacteria was extremely significantly increased (P<0.05). The results of Bugbase functional prediction showed that the relative abundance of aerobic bacteria and mobile action elements in the intestine of broiler chickens in the 0.20% mogroside group (experimental group III) was significantly reduced (P<0.05), and the relative abundance of anaerobic bacteria was significantly increased (P<0.05).

[0095] The above results show that the weight growth rate and feed conversion rate of broilers in the experimental group are significantly better than those in the control group. Intestinal flora analysis shows that the number of lactic acid bacteria and Desulfovibrio in the intestines of broilers in the experimental group increased significantly, while the number of harmful bacteria decreased. The addition of momordica saponins and Lactobacillus acidophilus improved the intestinal flora structure of broilers, promoted the growth of probiotics, and inhibited the reproduction of harmful bacteria. This change helps to improve the growth performance of broilers and provides a basis for further research on the gut-lung axis mechanism.

[0096] Experiment 2: Alleviating effect of mogroside on LPS-induced lung inflammation in broiler chickens

[0097] In order to further verify the alleviating effect of mogroside saponins on LPS-induced lung inflammation in broiler chickens, the following experiments were conducted in this example:

[0098] 1. Experimental Methods

[0099] This experiment adopted a two-factor completely randomized experimental design, randomly selecting 192 one-day-old AA broilers and dividing them into four groups, with 6 replicates in each group and 8 chickens in each replicate. They were CON-Saline group, CON-LPS group, Mogroside-Saline group and Mogroside-LPS group, and each group of broilers was treated as follows:

[0100] CON-Saline group: basal diet;

[0101] CON-LPS group: basal diet;

[0102] Mogroside-Saline group: basal diet + 0.20wt% Mogroside;

[0103] Momordica saponin-LPS group: basic diet + 0.20wt% momordica saponin.

[0104] During the entire feeding cycle, feeding and management were carried out in accordance with the broiler feeding and management standards, and the lighting, temperature and humidity were kept consistent. Broilers were allowed to eat and drink freely during their growth. A tracheal instillation test was performed on broilers at 43 days of age: the CON-Saline and mogroside-Saline groups were instilled with 0.75% saline, and the CON-LPS and mogroside-LPS groups were instilled with LPS (1 mg LPS / kg, BW). The tracheal instillation method is briefly described as follows: The broiler was placed in a sealed container filled with ether for inhalation anesthesia. After the ether anesthesia took effect, the broiler was laid flat on the operating table, and its beak was pinched to expose its trachea to the field of vision. The gavage needle was slowly and gently inserted into the trachea, and the liquid was dripped in at a uniform speed.

[0105] After 24 hours of the instillation experiment, samples were collected. One chicken was randomly selected from each replicate and weighed before being slaughtered for sampling. The lungs, spleen, and bursa of Fabricius were separated and weighed. After the lung tissue was weighed, samples were collected from a fixed area of ​​the left lung and fixed in a 4% paraformaldehyde solution. Samples were also collected from a fixed area of ​​the right lung and placed in a cryopreservation tube, immediately frozen in liquid nitrogen, and then transferred to a -80°C refrigerator for long-term storage for subsequent determination.

[0106] 2. Results

[0107] 2.1. Effects of Momordica Saponins on Organ Indexes of Broiler Chickens with Lung Lesion

[0108] Effects of mogrosides on organ indices of broiler chickens with LPS-induced lung injury Figure 3 As shown in the figure, the analysis based on LPS as the main effect showed that the lung index of broiler chickens after instillation (P Instillation =0.025) and bursal index (P Instillation Compared with the CON-Saline group, the bursal index of broiler chickens in the CON-LPS group was significantly decreased (P<0.05).

[0109] Effects of Momordica Saponins on Lung Morphology in Broiler Chickens with Lung Injury

[0110] Effects of mogroside saponins on lung tissue morphology in broiler chickens with LPS-induced lung injury Figure 4 As shown. Figure 4 It can be seen that the lung tissue morphology of the CON-Saline group and the mogroside-Saline group is clearly discernible. The pulmonary lobular septa of the CON-LPS group are very blurred, the lumen of the tertiary bronchus is narrowed, and a large number of inflammatory cells can be seen in the lumen. A small amount of inflammatory cells can be seen in the mogroside-LPS group, and the pulmonary lobular septa are clearly visible.

[0111] Effects of mogroside saponins on the expression of lung barrier genes in broiler chickens with lung injury

[0112] Pulmonary inflammation is manifested by the destruction of the pulmonary epithelial barrier. Therefore, this application further analyzes the effect of momordica saponins on the pulmonary barrier of broiler chickens. The results are shown in Figure 5 After intratracheal instillation of LPS, Claudin (P Instillation =0.022, Figure 5 B) and Occludin (P Instillation =0.014, Figure 5 C) gene expression was significantly reduced. There was a significant interaction between the expression of ZO-1 gene in broiler lung tissue (P Interaction =0.008, Figure 5 A). Compared with the CON-LPS group, the expression of ZO-1 gene in the mogroside-LPS group was significantly increased after tracheal instillation (P<0.01, Figure 5 In addition, compared with the mogroside-Saline group, the expression level of ZO-1 gene in the mogroside-LPS group was also significantly increased (P<0.01, Figure 5 A). However, compared with the CON-Saline group, the expression of Occludin gene in the CON-LPS group was significantly decreased (P<0.05, Figure 5 C). There was no significant change in the expression of MUC1 and MUC2 genes (P>0.05, Figure 5 D, E).

[0113] Effects of Momordica Saponins on Gene Expression of Pulmonary Inflammatory Cytokines in Broiler Chickens with Lung Injury

[0114] The effects of mogroside on the expression of inflammatory factors IL-1β, IL-6, IL-4, IL-8, Caspase1 and TGF-β1 in lung tissue of broiler chickens with LPS-induced lung injury were detected. The results are shown in 6. The analysis of the main effect of instillation showed that the instillation of LPS increased the expression of IL-1β (P Instillation =0.003, Figure 6 A), IL-6 (P Instillation =0.023, Figure 6 B) and TGF-β1 (P Instillation =0.001, Figure 6 The analysis of the main effect of feeding diet showed that the addition of mogroside significantly reduced the expression of IL-1β (P Diet =0.011, Figure 6 A), IL-6 (P Diet =0.007, Figure 6 B) and Caspase1(P Diet =0.008, Figure 6 E) gene expression level. Interaction =0.006, Figure 6 A), IL-6 (P Interaction =0.001, Figure 6 B) and Caspase1(P Interaction =0.020, Figure 6 E) There is a significant interaction between gene expression levels.

[0115] After intratracheal instillation of LPS, the inflammatory factor IL-1β in the lungs of broilers in the CON-LPS group was significantly increased compared with that in the CON-Saline group (P<0.01, Figure 6 A), IL-6 (P<0.001, Figure 6 A) and TGF-β1 (P<0.05, Figure 6 F) gene expression was significantly increased. The addition of mogroside significantly reduced IL-1β (P<0.01, Figure 6 A), IL-6 (P<0.001, Figure 6 B) and Caspase1 (P<0.01, Figure 6 F) gene expression. There was no difference in other inflammatory cytokines ( Figure 6 ).

[0116] Effects of Momordica Saponins on Gene Expression of Th17 / Treg-related Factors in Broilers with Lung Injury

[0117] Effects of mogroside saponins on the expression of Th17 / Treg-related genes in lung tissue of broiler chickens with LPS-induced lung injury Figure 7 The results of the main effect analysis based on LPS instillation showed that LPS could significantly increase the expression of RORα in broiler lung tissue (P Instillation =0.040, Figure 7 A) and AhR(P Instillation =0.038, Figure 7 B). Based on the analysis of the main effect of feeding diet, the addition of mogrosides significantly reduced the expression of RORα in the lung tissue of broiler chickens (P Diet =0.002, Figure 7 A), Foxp3(P Diet =0.024, Figure 7 C) IL-17A (P Diet =0.015, Figure 7 D), IL-17F (P Diet =0.007, Figure 7 E), IL-10 (P Diet =0.007, Figure 7 F), PD-L1 (P Diet =0.015, Figure 7 G) and PD-1 (P Diet =0.004, Figure 7Effects of feeding mogrosides and instilling LPS on RORα (P Interaction =0.006, Figure 7 A), IL-10 (P Interaction =0.031, Figure 7 A) and PD-1(P Interaction =0.017, Figure 7 A) There was a significant interaction in gene expression level. Under LPS instillation conditions, mogroside significantly reduced RORα (P<0.001, Figure 7 A), IL-17F (P<0.05, Figure 7 E), IL-10 (P<0.01, Figure 7 F), PD-L1 (P<0.01, Figure 7 G) and PD-1 (P<0.001, Figure 7 In addition, compared with the CON-Saline group, the expression of RORα and IL-10 genes in lung tissues of the CON-LPS group was significantly increased (P<0.05, Figure 7 A, 7F). At the same time, compared with the mogroside-Saline group, the PD-1 gene expression level in the mogroside-LPS group was significantly decreased (P<0.01, Figure 7 H).

[0118] Effects of Momordica Saponins on Protein Levels of Inflammatory Factors in Broilers with Lung Injury

[0119] Figure 8 The concentrations of inflammatory cytokines in the lungs of broiler chickens are shown. Figure 8 As shown in the results, the main effect analysis of feeding diet showed that mogroside saponins could significantly reduce the concentration of TGF-β in the lung (P Diet =0.007, Figure 8 A). The analysis of the main effect of LPS instillation showed that after tracheal instillation of LPS, the concentration of IL-17 in the lung (P Instillation =0.005, Figure 8 The concentration of TGF-β in the lung of the mogroside-LPS group was significantly lower than that of the CON-LPS group (P<0.05, Figure 8 A). There was no significant difference in the concentrations of IL-6 and IL-10 among the groups (P>0.05, Figure 8 B, D).

[0120] Effects of mogroside saponins on the diversity of lung microbiota in broiler chickens with acute lung injury

[0121] To investigate the composition of broiler lung microbiota, broiler lung tissue samples were collected and 16S rDNA sequencing was performed. The results are shown in Fig. 9 .like Fig. 9 As shown, the rarefaction curve (richness curve) indicates that the amount of sequencing is sufficient to cover all taxa ( Fig. 9 A). Compared with the CON-Saline group, the Simpson index of the CON-LPS group was higher; the addition of momordica grosvenori saponins to the diet increased the α diversity of broilers and had the same effect on LPS-challenged broilers, but there was no significant difference (P>0.05, Fig. 9 B). The Venn diagram then shows the number of OUTs common to each group and unique to each group ( Fig. 9 C). PLS-DA at the OTU level was plotted to evaluate the β diversity between groups. It can be seen that the main components of bacterial clusters in the CON-LPS group and the mogroside-LPS group were clearly separated ( Fig. 9 D).

[0122] Effects of mogroside saponins on the composition of lung microbiota in broiler chickens with acute lung injury

[0123] like Fig.10 As shown in Figure 2, at the phylum level, Proteobacteria, Firmicutes, Bacteroidota, Campylobacterota, etc. are the dominant phyla in the lungs ( Fig.10 A). Compared with the CON-Saline group, the addition of mogroside to the diet significantly increased the relative abundance of Firmicutes and Cyanobacteria (P<0.05). In addition, the relative abundance of Proteobacteria decreased significantly ( Fig.10 B, P<0.05). After LPS instillation, the relative abundance of Actinobacteriota in the mogroside-LPS group was significantly increased compared with that in the CON-LPS group (P<0.05, Fig.10 B). At the genus level, Acinetobacter, Escherichia-Shigella, Bacteroides, and Chryseobacterium were the dominant genera in broiler lungs ( Fig.10 C). The addition of mogroside to the diet significantly increased the relative abundance of Faecalibacterium and Blautia, and decreased the relative abundance of Acinetobacter (P<0.05, Fig.10 D) Fig.10As shown in D, the Eubacterium_hallii_group in LPS-challenged broilers increased significantly (P<0.05). In addition, the addition of momordica saponins to the diet significantly increased the relative abundance of Methylobacterium-Methylorubrum, Burkholderia-Caballeronia-Paraburkholderia, and Sediminibacterium in the lungs of broilers with acute lung injury ( Fig.10 D).

[0124] Effects of mogroside saponins on characteristic bacterial groups in the lungs of broilers with acute lung injury

[0125] In order to further determine the specific bacterial groups in the lungs of broiler chickens with acute lung injury affected by mogroside saponins, the differences in bacterial groups between groups were analyzed by LEFse to find out the specific main bacterial groups between groups. Fig.11 A total of 60 different characteristic bacteria were found from the phylum to the genus level ( Fig.11 A, 11B). By integrating the genetic information of species in the database, the phenotypic characteristics of each group of species were analyzed. The results showed that there was no significant difference in the ratio of Gram-positive bacteria to Gram-negative bacteria among the groups (P>0.05, Fig.11 C). Compared with the CON-Saline group, the abundance of aerobic bacteria in the CON-LPS group and the mogroside-Saline group was significantly reduced (P<0.05, Fig.11 D).

[0126] The above results show that mogroside saponins have a protective effect on LPS-induced lung inflammation in broiler chickens, significantly increasing the tight junction protein ZO-1, reducing the expression of inflammatory mediators IL-1β and IL-6, and increasing the gene and protein levels of TGF-β. In addition, mogroside saponins can also regulate Th17 / Treg-related immune factors and affect the structure of lung flora. The results show that mogroside saponins may protect broilers with lung injury by protecting the tight junctions between alveolar epithelial cells, regulating the Th17 / Treg balance and maintaining the stability of lung flora to inhibit the release of inflammatory cytokines, maintain the barrier function of the lungs, and thus play a protective role.

[0127] Experiment 3: Effect of microbiota transplantation on pulmonary inflammatory damage in broiler chickens

[0128] 1. Experimental Methods

[0129] 1.1 According to different experimental treatments, broilers were divided into donor group broilers and recipient group broilers:

[0130] Donor groups: control donor group, 0.20% MG donor group;

[0131] Recipient groups: control-feces filtrate group (CF group), MG-sterile feces filtrate group (MS group), MG-feces filtrate group.

[0132] 1.2 Test content

[0133] 1.2.1 Donor group treatment method:

[0134] Feces of broilers fed the basal diet and the basal diet supplemented with 0.20% MG were collected, urate crystals on the surface of the feces were removed, and the feces were stored in sterile plastic bags, which were then immediately stored in a refrigerator for the preparation of fecal suspensions. The feces of each group were collected and homogenized and diluted with 0.75% sterile saline to a final concentration of 250 mg / mL. The mixed samples were centrifuged at 1800×g for 10 min, and the supernatant was filtered through a 100 μm filter (BS-100-CS, Biosharp, Hefei, China), glycerol was added, and stored in a refrigerator at -80°C for use. In addition, the supernatant was sterilized by high pressure to prepare a sterile fecal suspension.

[0135] 1.2.2 Receptor group treatment method:

[0136] Thirty-six 21-day-old AA broiler chickens were randomly divided into three treatment groups according to body weight, with four cages in each treatment and three chickens in each cage. These AA broiler chickens were raised as recipients for subsequent FMT experiments. The treatments for each group were as follows:

[0137] (1) CF group: fecal filtrate of broiler chickens fed a basal diet was gavaged for 1 week at 22-28 days of age;

[0138] (2) MS group: Broilers fed a diet supplemented with 0.20% MG were gavaged with sterile fecal filtrate for 1 week at 22 to 28 days of age;

[0139] (3) MF group: Fecal filtrate of broiler chickens fed a diet supplemented with 0.20% MG was gavaged for 1 week at 22-28 days of age.

[0140] One week after FMT, six broilers were randomly selected from each group at 29 days of age, and LPS was instilled intratracheally to establish an acute lung injury model. Sample collection began 24 hours after the instillation experiment. One chicken was randomly selected from each replicate and weighed before slaughter and sampling. The heart, liver, lungs, spleen, and bursa of Fabricius were separated and weighed. After the lung tissue was weighed, samples were collected from a fixed area of ​​the left lung and fixed in a 4% paraformaldehyde solution. Samples were also collected from a fixed area of ​​the right lung and placed in a cryopreservation tube, immediately frozen in liquid nitrogen, and then transferred to a -80°C refrigerator for long-term storage for subsequent determination. Similarly, the cecal contents were collected, frozen in liquid nitrogen in a cryopreservation tube, and then transferred to a -80°C refrigerator for storage.

[0141] 2. Results

[0142] Effects of fecal microbiota transplantation on lung tissue morphology in broiler chickens with lung injury

[0143] Depend on Fig.12 It can be seen that the three groups of broilers had different degrees of lung damage after LPS injection. A large number of red blood cells infiltrated the cavity in the tertiary bronchus of the CF group. In addition, the pulmonary capillaries around the bronchi collapsed and fused significantly, and the boundaries between the pulmonary lobules could not be clearly seen. The pulmonary bronchi of the MS group were partially congested, and the fusion of pulmonary capillaries was also observed. There was only a small amount of bleeding in the MF group, but the intervals between the pulmonary lobules were clearly visible.

[0144] Effects of fecal microbiota transplantation on lung barrier gene expression in broiler chickens with lung injury

[0145] The expression levels of ZO-1 (A), Claudin (B), Occludin (C), MUC1 (D), and MUC2 (E) mRNA in lung tissue were detected by qRT-PCR, and the expression of genes related to the mechanical barrier and chemical barrier in lung tissue was determined. The results are shown in Fig.13 .like Fig.13 As shown in Figure 2, compared with the CF group, the expression of Occludin gene in the MF group was significantly increased ( Fig.13 C, P<0.01). Compared with the CF group, the expression levels of MUC1 and MUC2 genes in the MF group were significantly increased, while compared with the MF group, the expression levels of MUC1 and MUC2 genes in the MS group were significantly decreased ( Fig.13 D, 13E, P<0.01). There was no significant difference in the gene expression of ZO-1 and Claudin among the three groups ( Fig.13 A, 13B, P>0.05).

[0146] Effects of fecal microbiota transplantation on inflammatory factor protein levels in broiler chickens with lung injury

[0147] The protein concentration of inflammatory factors in broiler lungs was detected to determine the effect of fecal microbial transplantation on the protein level of inflammatory factors in broiler lung injury. Fig.14 .according to Fig.14 The results showed that the concentration of TGF-β in the lung tissue of broiler chickens in the MS and MF groups was significantly higher than that in the CF group ( Fig.14 A, P<0.05). In addition, compared with the CF group, the MF group had a higher level of IL-6 in the lung tissue of broiler chickens ( Fig.14 B) and IL-17 ( Fig.14 C) concentration was significantly decreased (P<0.05).

[0148] Effects of fecal microbiota transplantation on cecal microbial composition in broiler chickens

[0149] The species composition of cecal microorganisms in each group was analyzed at different taxonomic levels. Fig.15 .according to Fig.15 The results show that at the phylum level, the relative abundance of Firmicutes, Bacteroidota, Euryarchaeota, Proteobacteria and Cyanobacteria accounts for a large proportion ( Fig.15 A). At the same time, it was found that at the genus level, Lactobacillus, Bacteroides, Ruminococcus_torques_group, Methanobrevibacter and Lachnoclostridium were the dominant genera ( Fig.15 B).

[0150] Comparison of species abundance between groups to determine if there were statistically significant differences showed that at the phylum level, the relative abundance of Campylobacterota and Patescibacteria in the MF group was significantly lower than that in the CF group (P<0.05). Fig.15 C). At the same time, at the genus level, the abundance of Escherichia-Shigella and Helicobacter pylori in the MF group was significantly lower than that in the CF group (P<0.05) ( Fig.15 D).

[0151] 2.5. Analysis of indicator species of cecal microorganisms in broiler chickens

[0152] Fig.16 The cecal microbial indicator species analysis of broiler chickens is shown. Fig.16 As shown in Figure 2, the random forest analysis results showed that Escherichia-Shigella had the highest Gini coefficient and could be used as a potential indicator species between the CF and MF groups ( Fig.16 A). The results of indicator species analysis also pointed to Escherichia-Shigella ( Fig.16 B).

[0153] 2.6. Detection of short-chain fatty acids in cecal contents of broiler chickens

[0154] Fig.17 The results of the determination of SCFAs concentration in cecal contents are shown. Fig.17As described above, the six most abundant SCFAs in the three experimental groups were acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid. The concentration of valerate in the cecal contents of the MF group was significantly higher than that of the CF group ( Fig.17 E, P<0.05, and there were no significant differences in other SCFAs among the groups ( Fig.17 AD, F, P>0.05). In addition, the gene expression of fatty acid receptor FFAR2 was measured, and the results showed that the expression of FFAR2 in the MF group was significantly higher than that in the CF group ( Fig.17 F, P<0.05).

[0155] The above results suggest that transplantation of fecal microbiota regulated by mogroside significantly increased the gene expression levels of tight junction protein Occludin, mucin MUC1 and MUC2 in lung tissue of broilers with LPS-induced lung injury, and affected the expression levels of Th17 / Treg pathway-related factors. In addition, the microbial community structure of broilers transplanted with fecal filtrate from the control group and the mogroside group was significantly separated, and the abundance of Escherichia-Shigella and Helicobacter pylori in the cecum of broilers transplanted with fecal microbiota regulated by mogroside was significantly reduced. This suggests that fecal microbiota regulated by mogroside can reduce the abundance of harmful intestinal microbiota in the intestine of broilers with lung injury to alleviate LPS-induced lung inflammation in broilers.

[0156] Experiment 4: Screening of eucalyptus oil from different sources

[0157] Based on the key role of Gram-negative bacteria, especially Escherichia-Shigella, in chicken lung damage found in the above test process, this example further screened the eucalyptus oil with the best inhibitory effect on this type of bacteria, and the specific method included:

[0158] 1. Test materials

[0159] Eucalyptus oil samples: E.accedens, E.cladocalyx, E.lesouefii, E.melliodora, E.punctata, E.robusta, E.wandoo.

[0160] Bacteria: Escherichia coli, Haemophilus influenzae, Streptococcus pneumoniae, gentamicin (as a positive control).

[0161] 2. Test methods

[0162] 2.1. Extraction of eucalyptus oil: After the leaves of each eucalyptus species were collected, eucalyptus essential oil was extracted by steam distillation. The extracted essential oil was stored in a sealed glass bottle and stored in a refrigerator at 4°C for later use.

[0163] 2.2. Inhibition zone experiment:

[0164] 2.2.1 Culture medium preparation: Use nutrient agar medium containing 0.5% agar, pour into a culture dish after fully dissolving, and cool to room temperature.

[0165] 2.2.2 Inoculation method: Gram-negative bacteria (Escherichia coli, Haemophilus influenzae, Streptococcus pneumoniae) were selected for inoculation. Before inoculation, the bacterial culture solution (OD 600 =0.6) is evenly spread on the surface of the culture medium.

[0166] 2.2.3 Eucalyptus oil addition: Using the well plate method, eucalyptus oil (20 μL) was added to the pre-punched hole in the center of the culture dish, the diameter of the hole was 6 mm. For gentamicin as a positive control, 20 μL of gentamicin solution (concentration of 50 μg / mL) was added to each well.

[0167] 2.2.4 Culture conditions: All samples were cultured in a 37°C incubator for 24 hours.

[0168] 2.2.5 Observation and measurement: The inhibitory effect of different eucalyptus oils on bacteria was evaluated by measuring the diameter of the inhibition zone (unit: mm).

[0169] 3. Results

[0170] The diameter of the inhibition zone was recorded according to the following standard: The antibacterial effect of each eucalyptus oil sample was expressed as mean ± standard deviation, and the test results were statistically analyzed, and the results are shown in Table 3 .

[0171] Table 3 Inhibition zone results of each group (mm)

[0172]

[0173] Note: "≤6.0" means no inhibition (the inhibition zone does not exceed the edge of the punch).

[0174] According to the results in Table 3, it can be seen that the eucalyptus oil extracted from the rainbow eucalyptus source has the best antibacterial effect on Escherichia coli. Therefore, the eucalyptus oil with the best effect is determined to be the rainbow eucalyptus oil.

[0175] Experiment 5: Effect of adding feed additive combination to diet on improving lung inflammation in broiler chickens

[0176] 1. Experimental Methods

[0177] Eighteen healthy 35-day-old yellow-feathered broilers with similar body weight were randomly divided into three groups: CON group, LPS injection group, and LPS injection + combination feeding group. Each group had six replicates, with one chicken in each replicate. The broilers in each group were treated as follows:

[0178] LPS injection + composition feeding group: LPS was injected at a rate of 1 mg LPS / kg body weight; and the basic diet + 0.05 wt% of the composition of Example 1 was fed;

[0179] LPS injection group: injected with LPS at a dose of 1 mg LPS / kg body weight; fed with a basal diet;

[0180] CON group: saline injection group; fed with basal diet.

[0181] During the entire feeding cycle, feeding and management were carried out in accordance with the broiler feeding and management standards, and the lighting, temperature and humidity were kept consistent. The broilers were free to eat and drink during their growth. On the 42nd day of the experiment, all chickens in each group were slaughtered. After weighing, the broilers were placed in a sealed container filled with carbon dioxide and killed. The lungs, spleen and bursa of Fabricius were weighed. The abdominal tissue was quickly frozen in liquid nitrogen and then stored in a -80°C refrigerator for subsequent determination.

[0182] 2. Test results:

[0183] 2.1. Effects of the Composition on Pulmonary Inflammation

[0184] The lung tissues of broilers in each group were stained. Fig.18 .like Fig.18 As described above, during the entire feeding cycle, compared with the control group, after LPS injection, increased vascular permeability may lead to pulmonary edema and hemorrhage, and accumulation of tissue fluid and blood exudation were observed. The increase of cavitary areas in the sections indicated damage to the alveolar wall and alveoli, accompanied by abnormal nuclear staining and a decrease in number. After adding the composition of Example 1 of the present invention, the lung tissue of broiler chickens tended to be normal.

[0185] 2.2. Effects of Momordica Saponin Complex on the Expression of Pulmonary Inflammation-Related Genes

[0186] In addition, the content of inflammatory factors in the lungs of broiler chickens in each group was detected. Fig.19 .like Fig.19 As shown, compared with the control group, the group adding the composition of Example 1 of the present invention (corresponding to Medicine in the figure) significantly increased the content of intestinal epithelial barrier-related gene Occludin and anti-inflammatory factor IL-10.

[0187] In the present invention, it was found through Experiment 1 that mogroside can improve the growth performance and intestinal health of broilers. In Experiment 2, LPS-induced pneumonia was further conducted, and it was found that mogroside can inhibit pneumonia and change the composition of intestinal flora. In Experiment 3, fecal microbiota transplantation was conducted, and it was found that the intestinal flora acted through the intestinal-lung axis, and the key beneficial and harmful bacteria in this pathway were screened. Therefore, Experiment 4 was designed to screen the eucalyptus oil with the strongest antibacterial activity against Gram-negative bacteria, and Experiment 5 proved the effectiveness of the composition of the present invention.

[0188] In summary, the composite feed additive composition provided by the present invention, which is based on mogroside and is compounded with Lactobacillus acidophilus, Desulfovibrio, mannooligosaccharide, galacto-oligosaccharide and rainbow eucalyptus oil, can regulate the intestinal microecology, promote the growth of beneficial bacteria, and inhibit the reproduction of harmful bacteria, thereby regulating the immune response of broilers through the intestinal-lung axis, relieving lung inflammation caused by environmental factors, and significantly improving the growth performance and overall health of broilers. This provides a new direction for the research and development of products that improve the lung health of broilers.

[0189] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A feed additive composition, characterized in that: According to weight percentage, the composition comprises the following components by weight: 40-60% of mogroside V, 10-20% of composite bacterial agent, 10-20% of eucalyptus oil and 20-40% of prebiotics.

2. The feed additive composition according to claim 1, characterized in that The composite bacterial agent is composed of Lactobacillus acidophilus and / or Desulfovibrio.

3. The feed additive composition according to claim 2, characterized in that The composite bacterial agent is prepared by mixing Lactobacillus acidophilus and Desulfovibrio according to a mass ratio of (1-2):

1.

4. The feed additive composition according to claim 1, characterized in that The eucalyptus oil is rainbow eucalyptus oil.

5. The feed additive composition according to claim 1, characterized in that: The prebiotics are manno-oligosaccharides and / or galacto-oligosaccharides.

6. The feed additive composition according to claim 5, characterized in that: The prebiotics are prepared by mixing manno-oligosaccharides and galacto-oligosaccharides in a mass ratio of (1-2):

1.

7. The feed additive composition according to any one of claims 1 to 6, characterized in that: Also included are vectors.

8. The feed additive composition according to claim 7, characterized in that: The carrier includes corn flour, wheat bran and palygorskite.

9. Use of the feed additive composition according to any one of claims 1 to 8 in the preparation of a product for improving poultry lung health.

10. A product for improving the lung health of poultry, characterized in that: The product comprises the feed additive composition according to any one of claims 1 to 8.

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