Composition for improving lung injury of cat after bacterial infection as well as preparation method and application of composition

Abstract

The invention discloses a composition for improving lung injury of cats after bacterial infection as well as a preparation method and application of the composition, and relates to the technical field of animal health-care products. The composition is prepared by compounding fish collagen peptide, glutamine, proline, arginine, glycine, leucine, isoleucine, tyrosine, taurine, ornithine, L-carnitine, vitamins B1, B6 and B12, folic acid, nicotinamide, calcium pantothenate and the like in parts by mass. According to the invention, a cat lung cell infection model is combined with metabonomics, and key metabolic pathways and metabolites influenced by streptococcus pneumoniae infection are determined in a targeting manner. Tests prove that the composition component can effectively reduce lactic dehydrogenase release, relieve cell membrane damage, enhance antioxidant and anti-inflammatory capacities and enhance cell tight junction protein expression. The composition assists in intervention for 7 days on the basis of antibiotic treatment, and residual symptoms such as cat cough, nasal secretion and mental state can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of animal health products, and in particular to a composition for improving lung damage after bacterial infection in cats, a preparation method and an application thereof. Background Art

[0002] As companion animals, cats have significantly different respiratory system structures and physiological mechanisms from dogs, particularly in terms of tissue recovery and immune regulation after lung infection, demonstrating greater sensitivity and delayed responses. Under various stressful conditions, such as climate change, viral complications, or high-density environments, cats are susceptible to secondary bacterial infections.

[0003] Clinical observations have shown that even after prompt control of bacterial infections, cats often continue to exhibit symptoms of "post-infectious lung injury syndrome," such as persistent coughing, increased respiratory secretions, and decreased mental status. Previous studies have shown that this stage is not caused by continued viable bacteria but is closely related to the failure of the host immune and metabolic systems to repair themselves in a timely manner. In particular, in bacterial infections (e.g., Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli), certain virulence factors (e.g., hemolysins and surface toxic proteins) can trigger persistent cellular damage and chronic inflammatory responses even independently of bacterial activity.

[0004] However, current combinations targeting feline respiratory health on the market primarily focus on cough and phlegm relief or traditional Chinese medicines that clear heat, lacking targeted interventions for core mechanisms involved in the post-infection recovery phase, such as epithelial cell damage, oxidative stress, and metabolic disorders. In particular, there is a lack of functional combination strategies tailored to the physiological characteristics of the feline respiratory tract. Summary of the Invention

[0005] To address these issues, the present invention, based on a feline lung FCA-L1 cell model and incorporating the cytotoxicity and metabolic changes induced by Streptococcus pneumoniae (SP), identified a panel of functional ingredients with multiple effects, including barrier repair, anti-inflammatory and antioxidant properties, energy support, and amino acid metabolism regulation. Furthermore, a nutritional intervention composition suitable for the post-SP infection recovery phase in cats was developed.

[0006] Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics analysis showed that the levels of key metabolites such as glutamine, proline, taurine, and leucine in lung cells of cats infected with SP and treated with doxycycline hydrochloride continued to decrease significantly, accompanied by inhibition of mitochondrial energy metabolism pathways, damage to the antioxidant system, and decreased expression of cell junction proteins, suggesting that cell repair function is severely limited.

[0007] Based on the above metabolic characteristics and cell damage mechanism, the present invention provides a composition for improving lung damage after bacterial infection in cats, which comprises the following components in parts by mass:

[0008] Fish collagen peptide: 400-800 parts, glutamine: 100-200 parts; proline: 20-60 parts, arginine: 20-60 parts, glycine: 10-40 parts, taurine: 10-30 parts, L-carnitine: 10-30 parts, vitamin B1: 1-5 parts, vitamin B6: 1-5 parts, vitamin B12: 0.5-2 parts, folic acid: 0.5-2 parts, calcium pantothenate: 1-5 parts, niacinamide: 5-20 parts, isoleucine: 10-40 parts, leucine: 10-40 parts, tyrosine: 5-30 parts, ornithine: 5-25 parts.

[0009] Preferably, the composition is composed of the following components in the following mass ratios:

[0010] Fish collagen peptide: 500 parts, glutamine: 150 parts, proline: 40 parts, arginine: 40 parts, glycine: 30 parts, taurine: 20 parts, L-carnitine: 20 parts, vitamin B1: 3 parts, vitamin B6: 3 parts, vitamin B12: 1 part, folic acid: 1 part, calcium pantothenate: 3 parts, niacinamide: 10 parts, isoleucine: 25 parts, leucine: 25 parts, tyrosine: 15 parts, ornithine: 15 parts.

[0011] After model verification and metabolic mechanism research, the efficacy of the composition proposed by the present invention is as follows:

[0012] It can significantly reduce cell membrane damage; downregulate the expression of inflammatory factors, exerting anti-inflammatory regulatory effects; enhance cellular antioxidant capacity; restore the lung epithelial barrier structure; improve cellular energy metabolism capacity, and promote the reconstruction of key amino acid metabolic pathways. Among them, fish collagen peptides, as a structural protein supplement, help epithelial tissue repair; glutamine, proline, arginine, etc. provide nitrogen and carbon sources for structural and energy metabolism; taurine, glycine, and B vitamins provide metabolic support for the antioxidant system; and carnitine and branched-chain amino acids promote the recovery of mitochondrial function.

[0013] The present invention also provides the composition for preparing functional feed, functional health food, health preparation or nutritional supplement.

[0014] The present invention also provides that the composition can be processed together with acceptable feed bases or food supplements to prepare dosage forms such as powders, granules, liquid additives, freeze-dried preparations, coated granules or tablets.

[0015] The present invention also provides a method for preparing tablets of the composition, which is carried out according to the following steps:

[0016] (1) Weighing and preparing materials: weighing the raw materials of each component of the composition, hydroxypropyl methylcellulose, magnesium stearate, sodium carboxymethylcellulose and microcrystalline cellulose;

[0017] (2) Granulation and drying: the composition and part of the auxiliary materials are mixed, water is added to moisten the mixture to form wet granules, the granules are extruded, dried in a fluidized bed dryer to a suitable moisture content, and the granules are sieved;

[0018] (3) Total mixing: Mix the dry granules with the remaining excipients, and finally add magnesium stearate and mix well;

[0019] (4) Tableting: Pressing the mixed material into tablets;

[0020] (5) Packaging: Packaging and encapsulating the tableted preparation.

[0021] The mass fractions of the excipients in the tablets are: 1% to 3% of hydroxypropyl methylcellulose, 0.3% to 2% of magnesium stearate, 0.5% to 3% of sodium carboxymethyl cellulose, and 0.5% to 3% of microcrystalline cellulose, calculated based on the proportion to the total mass of the composition.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) Clear target: Based on the metabolic imbalance of cat lung cells in the late stage of SP infection, precise screening of restorative nutrients;

[0024] (2) Multi-pathway synergistic intervention: covering oxidative stress, inflammation control, barrier repair and metabolic rebalance;

[0025] (3) Adaptable to multiple scenarios: can be used in the form of functional cat food, nutritional supplements, tablets, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 Changes in lactate dehydrogenase (LDH) release in feline lung FCA-L1 cells following infection with Streptococcus pneumoniae (SP) combined with doxycycline hydrochloride (Dox) treatment. The groups included an uninfected control (NC), an antibiotic-treated group (NC+Dox), and SP-treated groups 2 and 4 hours after infection combined with antibiotics (SP 2h+Dox and SP 4h+Dox). The infection doses were set at 0.02 McF and 0.05 McF. Results showed that at an inoculum of 0.05 McF and 4 hours after infection (rightmost group), LDH release significantly increased, indicating increased cell membrane damage. Different letters indicate significant differences between groups (P < 0.05).

[0028] Figure 2Effects of different concentrations of fish collagen peptide (FCP) and glutamine (GLU) on the viability of feline lung FCA-L1 cells. FCA-L1 cells were treated with FCP (0-1000 μg / mL) and GLU (0-80 mM) for 24 hours, and then cell viability was measured using the CCK-8 assay.

[0029] Figure 3 Effects of fish collagen peptide (FCP) and glutamine (GLU) on the LDH release rate of cat lung FCA-L1 cells induced by SP infection. The LDH release rate in the SP infection group (SP) was significantly increased; intervention with FCP (500, 1000 μg / mL) and GLU (40, 80 mM) significantly reduced the LDH release rate.

[0030] Figure 4 Effects of fish collagen peptide (FCP, 500 μg / mL) and glutamine (GLU, 40 mM) on the expression of inflammatory factors interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-8 (IL-8) induced by SP infection.

[0031] Figure 5 Effects of fish collagen peptide (FCP, 500 μg / mL) and glutamine (GLU, 40 mM) on oxidative stress in feline lung FCA-L1 cells induced by SP infection were investigated. Groups included a negative control (NC), an infection model group (SP), an SP+GLU intervention group, and an SP+FCP intervention group. Measured indicators included the ratio of total antioxidant capacity to total oxidative status (T-AOC / TOS), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPX) activities.

[0032] Figure 6 Effects of fish collagen peptide (FCP, 500 μg / mL) and glutamine (GLU, 40 mM) on the expression of junction proteins in feline lung FCA-L1 cells induced by SP infection. Groups included a negative control (NC), an infection model group (SP), an SP+GLU intervention group, and an SP+FCP intervention group. Detection indicators included occludin, claudin, zona operon-1 (ZO-1), and E-cadherin.

[0033] Figure 7Effects of fish collagen peptide (FCP, 500 μg / mL) and glutamine (GLU, 40 mM) on the morphology and apoptosis of feline lung FCA-L1 cells following SP infection. Crystal violet staining (top) assesses cell density and morphology; Annexin V-FITC / PI double-staining (bottom) demonstrates apoptosis. NC represents the negative control group, SP represents the infection model group, and SP+GLU and SP+FCP represent the intervention groups. Treatment with the functional components improved cell alignment and reduced the number of apoptotic cells.

[0034] Figure 8 Time curve of the effect of the composition described in Example 2 and Example 3 on the cough frequency score of cats. The experiment was divided into 3 groups: a control group, an intervention group according to Example 2, and an intervention group according to Example 3, with 4 animals in each group (n=4). The cough frequency score ranged from 0 to 3 points, corresponding to 0 = no cough, 1 = occasional, 2 = frequent, and 3 = continuous and severe. The daily scores of each group were averaged. The cough score of the cats in the control group decreased slightly throughout the experimental period; while the scores of the Example 2 group and the Example 3 group decreased significantly after the third day, and the cough symptoms were significantly improved on the seventh day.

[0035] Figure 9 Time curve of the effect of the composition described in Example 2 and Example 3 on the nasal secretion score of cats. The experiment was divided into 3 groups: a control group, an intervention group according to Example 2, and an intervention group according to Example 3, with 4 animals in each group (n=4). The nasal secretion scoring standard is 0-3 points, corresponding to: 0 = clean nasal cavity with no secretions, 1 = mild serous, 2 = obvious mucous, and 3 = moderate to severe purulent secretions. The daily scores of each group were averaged. The nasal secretions of cats in the control group persisted, and the scores decreased slowly; in the intervention group, the nasal secretion scores decreased significantly with the intervention time.

[0036] Figure 10 The time curve of the effect of the composition described in Example 2 and Example 3 on the mental state and physical strength score of cats. The experiment was divided into 3 groups: a control group, an intervention group according to Example 2, and an intervention group according to Example 3, with 4 animals in each group (n=4). The scoring standard is 0-3 points, corresponding to: 0 = normal behavioral activity, 1 = mild decline, 2 = moderate decline, 3 = obvious lethargy. The figure shows the average daily score of each group. The mental scores of cats in the Example 2 and Example 3 groups improved earlier and faster, and their daily activities recovered well; while the recovery trend of the control group was slow, and the scores were still higher than those of the intervention group. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0038] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0039] The fish collagen peptide described in the present invention was purchased from Hainan Huapeptide Biotechnology Co., Ltd.

[0040] Experimental Example 1: Metabolic changes in cat lung cells after SP infection and antibiotic treatment

[0041] 1. Test method

[0042] (1) Cat lung cell culture

[0043] Feline lung cells (FCA-L1) were cultured in high-glucose DMEM medium supplemented with 10% fetal bovine serum (FBS) and 1% penicillin-streptomycin in a 37°C, 5% CO2 incubator. Cell passage and experiments were performed when the cells grew to 90% confluence.

[0044] (2) Establishment of Streptococcus pneumoniae infection model

[0045] The damage process of feline lung cells induced by SP infection was simulated in vitro. SP strain (ATCC 6305) was inoculated into brain heart infusion (BHI) medium and cultured at 37°C for 24 hours. The culture medium was centrifuged at 5000 rpm for 10 minutes and then resuspended in MEM to prepare bacterial suspensions for infection. The concentrations were adjusted to 0.02 and 0.05 McFarland turbidimeter. Feline lung cells were cultured at 2×10 4 Cells were seeded at 100 μL / well in a 96-well plate. After 24 hours of adherence, 100 μL of SP suspension was added and infected for 2-4 hours to induce cell damage. After infection, MEM containing 7.5 μg / mL doxycycline hydrochloride (2× concentration) was added to inhibit further bacterial growth and cultured for an additional 18 hours.

[0046] (3) Cytotoxicity assay

[0047] The degree of cell damage was assessed by lactate dehydrogenase (LDH) release. Cell supernatant (100 μL) was collected and centrifuged at 3000 rpm for 5 min. The supernatant was reacted with LDH reagent (Beyotime, C0017) for 30 min, and the absorbance was measured at 490 nm using a microplate reader.

[0048] (4) Metabolomics sample processing and detection process

[0049] A negative control group (NC) was set up: no infection, treated with culture medium only for 4h+18h; SP infection group: SP infection for 4h and then antibiotic treatment for 18h. An equal volume of cell lysate from each group was mixed and set as the quality control sample (QC), and the blank group was treated with 53% methanol solution. All samples were added with 300μL of 80% methanol aqueous solution, quickly frozen in liquid nitrogen, and then thawed on ice, ultrasonicated for 6min, centrifuged at 5000rpm and 4℃, and the supernatant was freeze-dried and re-dissolved with 10% methanol. A Vanquish UHPLC system (Thermo Fisher) was used with QExactive TM HF high-resolution mass spectrometer was used for quantitative detection of metabolites.

[0050] (5) Data processing and differential metabolite screening

[0051] Principal component analysis (PCA) was used to assess intergroup differences and extract variable importance projection (VIP) values. Differential metabolites were identified using a univariate t-test (P value) combined with fold change (FC) analysis. The screening criteria were: VIP > 1, P < 0.05, and FC ≥ 1.2 or FC ≤ 0.83.

[0052] 2. Test results

[0053] (1) Changes in LDH in bacterially infected cat lung cells after antibiotic treatment

[0054] like Figure 1 As shown, SP infection caused significant damage to feline lung FCA-L1 cells, particularly at an infection dose of 0.05 McF and for 4 hours. Even with combined doxycycline hydrochloride (Dox) treatment, LDH release in the cell supernatant remained significantly elevated, reaching over three times that of the control group, indicating compromised cell membrane integrity. This suggests that this model can stably simulate bacterial lung injury under these conditions and is suitable for subsequent screening of functional components and studies of protective mechanisms.

[0055] (2) Metabolic mechanism characteristics and supplementary target analysis after SP infection of cat lung cells

[0056] High-performance liquid chromatography-mass spectrometry metabolomics analysis of cat lung cells infected with SP and treated with antibiotics revealed that a variety of endogenous metabolites closely related to cell structure reconstruction, antioxidant regulation, energy metabolism, and nucleotide synthesis were significantly downregulated in the infected group. The specific changes are shown in Table 1.

[0057] Among them, the relative abundance of Pro-Arg-Leu (proline-arginine-leucine) was significantly decreased in the SP infection group. Its constituent amino acids are the main raw materials for collagen and intercellular junction proteins, and are involved in extracellular matrix reconstruction, barrier repair, and structural stability. This result suggests that the structural repair capacity of lung epithelial cells is significantly limited in the context of SP infection and antibiotic intervention. Tyr-Gln-Phe (tyrosine-glutamine-phenylalanine), Glycylprolylarginine (glycine-proline-arginine), and Ile-Pro-Ile (isoleucine-proline-isoleucine), which were also significantly downregulated, are all composed of multiple key amino acids and are widely involved in cell proliferation, stress response, anti-inflammatory regulation, and membrane structure maintenance. Among them, glutamine is an important nitrogen source for lung epithelial cells, which can support cell synthesis and antioxidant responses; tyrosine and phenylalanine are closely related to stress signaling and neuroimmune regulation. The decreased abundance of these metabolites in the infected state suggests that structural protein synthesis, barrier homeostasis, and anti-inflammatory response capacity are all impaired.

[0058] In addition, significant changes were also seen in substances related to energy metabolism, with the relative abundance of adenosine triphosphate (ATP) decreasing by 28.6% and guanosine triphosphate (GTP) decreasing by 73.3%. ATP is the main energy carrier in cells, and its decrease reflects impaired mitochondrial function and insufficient energy supply; GTP is involved in purine metabolism and signal transduction, and its decrease indicates a decrease in nucleic acid synthesis and the ability to regulate cellular metabolism. In combination with metabolic pathway functions, the present invention selects ingredients such as nicotinamide, L-carnitine, vitamins B1, B6, B12, folic acid, and calcium pantothenate as metabolic support factors to enhance cellular energy synthesis, maintain mitochondrial function, and assist in repairing metabolic disorders caused by infection.

[0059] Table 1 Changes in key metabolites based on which the composition of the present invention is designed

[0060]

[0061]

[0062] Experimental Example 2 Effect of the Main Functional Components on Lung Injury in Dogs

[0063] 1. Test method

[0064] (1) Determination of the concentration of functional ingredients

[0065] Fish collagen peptide (FCP) and glutamine (GLU) were prepared into different concentrations of working solution, and cat lung cells were treated for 24 hours. Cell viability was detected by CCK-8 method to determine the non-toxic concentration range. Among them, the cell seeding density was 2×10 5 cells / mL.

[0066] (2) Evaluation of the mitigating effect of functional ingredients on cytotoxicity after SP infection

[0067] In a 96-well plate, 2 × 10 4 After inoculating cells at 400 μg / well and culturing for 24 hours, cells were infected with SP suspension (0.05 McF) for 4 hours. MEM containing 7.5 μg / mL doxycycline and various concentrations of functional components was then added for an additional 18 hours. The cell supernatant was used to measure LDH release.

[0068] (3) Cell morphology observation and apoptosis analysis:

[0069] After plating and treatment in 6-well plates, cells were fixed with 4% paraformaldehyde and stained with crystal violet to assess morphology. Apoptosis was assessed by Annexin V-FITC / PI double staining and observed under a fluorescence microscope.

[0070] (4) Detection of oxidative stress indicators

[0071] Cell lysates were used to measure indicators such as T-AOC, TOS, MDA, SOD, and GPX. Protein concentrations were quantified using the BCA assay, and indicators were measured using commercial kits. Detection wavelengths were: T-AOC (593 nm), TOS (560 nm), MDA (532 nm), and GPX (412 nm).

[0072] (5) Determination of cell junction protein content

[0073] Feline-specific ELISA kits were used to quantitatively measure the levels of cell junction proteins, including E-cadherin, occludin, ZO-1, and claudin, in cell lysates. 50 μL of sample was added to each well, incubated at 37°C for 1 hour, and then the plates were washed. HRP-conjugated antibodies and TMB colorimetric solution were added, and the absorbance was measured at 450 nm after the reaction was terminated.

[0074] (6) Detection of inflammatory factor levels

[0075] Canine ELISA kits were used to detect the concentrations of IL-1β, TNF-α, and IL-8 in the cell culture supernatant. The operating procedures were consistent with those of the connexin ELISA test.

[0076] 2. Test results

[0077] (1) Concentration screening of functional ingredients

[0078] like Figure 2As shown, fish collagen peptide (FCP) had no significant toxic effect on feline lung FCA-L1 cells within the concentration range of 0-1000 μg / mL, with cell viability maintained above 100%, and no statistically significant differences between groups (P>0.05). Glutamine (GLU) significantly increased cell viability at concentrations of 40 mM and 80 mM (P<0.05), while no significant differences were observed in the low-concentration treatment group (1.25-20 mM). Considering safety and functional trends, 500 and 1000 μg / mL for FCP and 40 and 80 mM for GLU were selected as intervention concentrations in subsequent trials.

[0079] (2) Repair effect of functional ingredients on lung cell membrane damage

[0080] like Figure 3 As shown, LDH release assay results indicate that both fish collagen peptide (FCP) and glutamine (GLU) significantly reduced SP infection-induced feline lung FCA-L1 cell membrane damage. GLU, at 40mM and 80mM, was more effective than FCP, as evidenced by a significant decrease in LDH release. These results demonstrate that the functional ingredients selected in this invention can alleviate lung cell membrane damage and improve cell integrity following infection.

[0081] (3) Functional ingredients downregulate the expression levels of inflammatory factors induced by SP infection

[0082] like Figure 4 As shown, SP infection significantly upregulated the expression of IL-1β, TNF-α, and IL-8 in the culture supernatant of feline lung FCA-L1 cells, suggesting that infection induces a significant inflammatory response. Intervention with glutamine (40 mM GLU) or fish collagen peptide (500 μg / mL FCP) significantly decreased the secretion of IL-1β and TNF-α (P < 0.05), with the decrease being more pronounced in the GLU-treated group. IL-8 levels showed a downward trend in the intervention groups, but the difference was not significant compared with the infection group. These results indicate that, at these concentrations, both GLU and FCP effectively alleviated the release of proinflammatory cytokines induced by SP infection, demonstrating a certain anti-inflammatory regulatory effect.

[0083] (4) Functional ingredients can improve the oxidative stress state induced by SP infection

[0084] like Figure 5As shown, after SP infection, the T-AOC / TOS ratio of cat lung FCA-L1 cells decreased, MDA content increased, and SOD and GPX activities decreased, indicating elevated cellular oxidative stress. Intervention with fish collagen peptide (FCP, 500 μg / mL) or glutamine (GLU, 40 mM) increased the T-AOC / TOS ratio, decreased MDA content, and significantly increased SOD and GPX enzyme activities (P < 0.05). These results demonstrate that the functional ingredients described herein can alleviate oxidative damage and improve cellular antioxidant status.

[0085] (5) Functional components enhance the expression level of cell junction proteins after infection

[0086] like Figure 6 As shown, SP infection leads to decreased expression of multiple junction proteins in feline lung FCA-L1 cells, including occludin, claudin, zonula-associated protein-1 (ZO-1), and E-cadherin. After intervention with fish collagen peptide (FCP, 500 μg / mL) or glutamine (GLU, 40 mM), the levels of these junction proteins were significantly increased (P < 0.05), indicating that the functional ingredients of the present invention can repair the epithelial barrier damage caused by SP infection to a certain extent and maintain the integrity of cell junctions.

[0087] (6) Functional ingredients can improve cell morphology and reduce apoptosis levels

[0088] like Figure 7 As shown in the data, after infection with SP, the density of FCA-L1 cells in the feline lung was significantly reduced, the intercellular spaces increased, and the morphology was fragmented and incomplete, indicating severe cell damage. After treatment with fish collagen peptide (FCP, 500μg / mL) or glutamine (GLU, 40mM), the cells were arranged more closely, the morphological structure was restored, and the number of broken cells decreased. Annexin V-FITC / PI double staining fluorescence results showed that the number of apoptotic cells in the SP group increased significantly, while after treatment with the functional components, the fluorescence signal intensity weakened and the proportion of apoptotic cells decreased. The results show that the functional components of the present invention can effectively improve infection-induced cell morphological damage and have the effect of inhibiting cell apoptosis.

[0089] Examples 1 to 3

[0090] Examples 1 to 3 were prepared according to the formulations shown in Table 2 and in the following manner:

[0091] (1) Weighing and preparing materials:

[0092] The active ingredients listed in each example, including fish collagen peptides, glutamine, proline, arginine, glycine, taurine, L-carnitine, B vitamins (B1, B6, B12), folic acid, calcium pantothenate, niacinamide, isoleucine, leucine, tyrosine, and ornithine, were weighed separately, along with the excipients hydroxypropyl methylcellulose, magnesium stearate, sodium carboxymethylcellulose, and microcrystalline cellulose. All raw materials were commercially available feed-grade or pharmaceutical-food-grade products and met the standards for use in animal nutritional supplements.

[0093] (2) Granulation and drying:

[0094] Weigh fish collagen peptides, proline, arginine, glycine, isoleucine, leucine, tyrosine, ornithine, and the excipients hydroxypropyl methylcellulose and sodium carboxymethylcellulose, then mix thoroughly. Premix in a mixer for 20 minutes. Slowly spray an appropriate amount of purified water to wet granulate. Mix until granules are formed. Pellet the mixture using an extruder and dry it in a fluidized bed dryer at low temperature (≤45°C) until the moisture content is less than 5%. After drying, sieve the granules and set aside.

[0095] (3) Total mixing:

[0096] The above-mentioned dried granules were transferred to the total mixing equipment, and glutamine, taurine, L-carnitine, niacinamide, vitamins B1, B6, B12, folic acid, and calcium pantothenate were added in sequence, and then the auxiliary material microcrystalline cellulose was added and mixed for 20 minutes; finally, magnesium stearate was added and mixed for another 10 minutes to obtain a uniform tableting mixture.

[0097] (4) Tableting:

[0098] The mixture was fed into a rotary tablet press and tableted using a round die. The weights of the tablets obtained in the three groups of examples were:

[0099] Example 1: 0.432 g / tablet;

[0100] Example 2: 0.64 g / tablet;

[0101] Example 3: 1.0 g / tablet.

[0102] (5) Packaging:

[0103] The obtained tablets are packaged in aluminum-plastic blister packaging or sealed bottles and stored at room temperature away from light.

[0104] Table 2 Formulas used in each embodiment

[0105]

[0106] Test Example 3 Case Observation Test

[0107] 1. Test Method

[0108] Twelve domestic cats with lower respiratory tract infections were screened at a pet hospital. All were diagnosed with lung infection by veterinarians based on clinical manifestations and chest imaging. Some cats had a history of viral infection and were currently showing symptoms related to bacterial infection. They had received antibiotic treatment including doxycycline hydrochloride for more than one day and still had varying degrees of residual respiratory symptoms. During the trial, all cats maintained their original diet and drug treatment regimen and were randomly divided into three groups (4 cats in each group):

[0109] Control group: only continued routine antibiotic treatment and daily feeding;

[0110] Group 2 of Example: On the basis of the original treatment, 4 tablets prepared in Example 2 were orally taken daily, divided into 2 doses, for 7 consecutive days;

[0111] Group 3 of Example: On the basis of the original treatment, the patients were orally administered 4 tablets prepared in Example 3 in 2 doses daily for 7 consecutive days.

[0112] From before intervention (day 0) to day 7 of intervention, the following three indicators were recorded to evaluate respiratory system recovery:

[0113] I. Cough frequency score: 0-3 points, corresponding to 0: no cough, 1: occasional cough, 2: frequent cough, and 3: severe cough;

[0114] II. Nasal discharge score: 0-3 points, corresponding to 0: clean, 1: mild serous, 2: mucous, and 3: moderate to severe purulent;

[0115] III. Mental and physical status score: 0-3 points, corresponding to 0 normal, 1 slightly reduced, 2 moderately reduced and 3 significantly reduced.

[0116] Cats in each group were scored daily, the average values ​​of each group were calculated, and a score trend curve was drawn to analyze the intervention effect.

[0117] 2. Test Results

[0118] like Figure 8-10 As shown, during the 7-day intervention period, both Example 2 and Example 3 groups showed an improvement trend in various observation indicators that was superior to that of the control group:

[0119] (1) Cough frequency score

[0120] like Figure 8 As shown in the results, the cough scores of cats in the control group decreased slowly during the trial, and moderate coughing was still present on day 7. In contrast, the scores of cats in groups 2 and 3 decreased significantly from day 3, and stabilized and approached 1 and 0 (occasional cough and no cough) on days 6-7, indicating that the intervention composition can effectively promote the recovery of respiratory symptoms.

[0121] (2) Nasal secretion score

[0122] like Figure 9 As shown, the score of the control group decreased to a limited extent, and some cats continued to have mucus or purulent secretions. The score of the Example 2 group decreased significantly after the 4th day and approached 0 on the 6th-7th day; the score of the Example 3 group decreased earlier, showing a faster trend of secretion clearance.

[0123] (3) Mental state and physical strength score

[0124] like Figure 10 As shown, the control group's mental and physical strength recovered slowly, with scores still above 1.5 (moderate decline) on day 7. The mental scores of the two intervention groups continued to decline from day 3, and the scores on day 7 were generally close to 0.5 (mild decline), indicating that the composition of the present invention helps accelerate the recovery of the body's overall state.

[0125] The above results show that supplementing the composition of the present invention on the basis of standard treatment can significantly improve the clinical manifestations such as cough, secretions and mental state of cats in the recovery period of lung infection, and has a good auxiliary intervention effect.

[0126] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composition for improving lung damage after bacterial infection in cats, characterized in that: The composition comprises the following main components by weight: fish collagen peptide: 400-800 parts, glutamine: 100-200 parts; Proline: 20-60 parts, Arginine: 20-60 parts, Glycine: 10-40 parts, Taurine: 10-30 parts, L-Carnitine: 10-30 parts, Vitamin B1: 1-5 parts, Vitamin B6: 1-5 parts, Vitamin B12: 0.5-2 parts, Folic Acid: 0.5-2 parts, Calcium Pantothenate: 1-5 parts, Nicotinamide: 5-20 parts, Isoleucine: 10-40 parts, Leucine: 10-40 parts, Tyrosine: 5-30 parts, Ornithine: 5-25 parts.

2. The composition for improving lung damage after bacterial infection in cats according to claim 1, characterized in that The composition has the following proportions by weight: 500 parts of fish collagen peptide, 150 parts of glutamine, 40 parts of proline, 40 parts of arginine, 30 parts of glycine, 20 parts of taurine, 20 parts of L-carnitine, 3 parts of vitamin B1, 3 parts of vitamin B6, 1 part of vitamin B12, 1 part of folic acid, 3 parts of calcium pantothenate, 10 parts of niacinamide, 25 parts of isoleucine, 25 parts of leucine, 15 parts of tyrosine, and 15 parts of ornithine.

3. The composition for improving lung damage after bacterial infection in cats according to claim 1-2, characterized in that The composition is used for preparing functional feed, functional health food, health preparation or nutritional supplement.

4. The composition for improving lung damage after bacterial infection in cats according to claim 1-2, characterized in that The composition can be processed together with acceptable feed bases or food supplements to prepare dosage forms such as powders, granules, liquid additives, freeze-dried preparations, coated granules or tablets.

5. The method for preparing the composition for improving lung damage after bacterial infection in cats according to claim 1-2, characterized in that: Follow the steps below: (1) Weighing and preparing materials: weighing the raw materials of each component of the composition, hydroxypropyl methylcellulose, magnesium stearate, sodium carboxymethylcellulose and microcrystalline cellulose; (2) Granulation and drying: the composition and part of the auxiliary materials are mixed, water is added to moisten the mixture to form wet granules, the granules are extruded, dried in a fluidized bed dryer to a suitable moisture content, and the granules are sieved; (3) Total mixing: Mix the dry granules with the remaining excipients, and finally add magnesium stearate and mix well; (4) Tableting: Pressing the mixed material into tablets; (5) Packaging: Packaging and encapsulating the tableted preparation.

6. The method for preparing the composition for improving lung injury after bacterial infection in cats according to claim 5, characterized in that: The mass fractions of the excipients in the tablets are: 1% to 3% of hydroxypropyl methylcellulose, 0.3% to 2% of magnesium stearate, 0.5% to 3% of sodium carboxymethyl cellulose, and 0.5% to 3% of microcrystalline cellulose, calculated based on the proportion to the total mass of the composition.

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