Cat food with synergistic regulation of intestinal flora by plant source organic selenium, probiotics and prebiotics and preparation method thereof

Abstract

This invention discloses a cat food with added plant-derived organic selenium and its function of regulating intestinal flora, as well as a method for preparing the same. The cat food is based on a standard cat food formula and fortified with probiotics, prebiotics, and plant-derived organic selenium. The probiotics are added at a concentration of 60–80 × 10⁹ CFU / kg, comprising 3–4 strains. The prebiotics include inulin, fructooligosaccharides, and xylooligosaccharides, with inulin at 0.3–0.4%, fructooligosaccharides at 0.1%, and xylooligosaccharides at 50 mg / kg. The total selenium content in the cat food is 0.4–0.5 mg / kg, of which organic selenium accounts for 80–90%. Through the synergistic effect of probiotics, prebiotics, and plant-derived organic selenium, this cat food can improve the intestinal flora structure of cats, promote the growth of beneficial bacteria, enhance digestion, absorption, and immune regulation, and has good safety and application prospects.

Description

Technical Field

[0001] This invention relates to a cat food that regulates the structure of the cat's intestinal flora and improves intestinal health, as well as its preparation method, belonging to the field of pet food and functional feed technology. Background Technology

[0002] In recent years, with the increasing trend of pet ownership in families and the aging of the pet population, pet health management has gradually gained attention, and functional pet food has become an important direction for industry development. Gut health is fundamental to maintaining normal physiological functions and overall health in cats. The gut microbiota plays a crucial role in nutrient digestion and absorption, immune regulation, intestinal barrier maintenance, and inflammatory response control. However, because cats are strict carnivores with relatively short intestines, they are highly sensitive to dietary changes and processed ingredients. Long-term consumption of high-protein, highly processed cat food, or during food changes, stress, or illness, can easily lead to gut microbiota dysbiosis, resulting in a series of gut-related health problems such as diarrhea, constipation, indigestion, and weakened immunity.

[0003] Current technologies for improving feline gut health primarily involve adding probiotics, prebiotics, or dietary fiber. However, probiotics are susceptible to damage from high temperatures and long-term storage conditions during cat food processing, resulting in low survival rates and stability, and limiting the number that actually reach the gut to exert their effects. While prebiotics and dietary fiber can promote the growth of beneficial bacteria to some extent, their effects are indirect, and individual cats exhibit significant differences in response, making it difficult to achieve stable and sustained gut microbiota regulation. Furthermore, relying solely on bacterial or carbohydrate-based regulatory methods often fails to address multiple health needs, including antioxidant and immune regulation.

[0004] Selenium, an essential trace element for animals, is a crucial component of various selenoproteins, including glutathione peroxidase, playing a key role in antioxidant defense, immune function maintenance, and inflammation regulation. Currently, selenium supplementation in pet food mainly includes inorganic selenium (such as sodium selenite) and chemically synthesized organic selenium (such as selenomethionine). Inorganic selenium suffers from low absorption and utilization rates and a narrow toxicity threshold, potentially posing safety risks with long-term or excessive intake. While chemically synthesized organic selenium has improved bioavailability, its metabolic pathway in vivo differs from that of naturally occurring dietary selenium, and its higher cost limits its application.

[0005] Plant-derived organic selenium refers to selenium that, after being absorbed and transformed by plants, naturally binds to plant proteins or peptides in organic forms such as selenocysteine ​​and selenomethionine. Compared to inorganic selenium and artificially synthesized organic selenium, plant-derived organic selenium has advantages such as natural source, high safety, and good bioavailability. Increasing research shows that plant-derived organic selenium, while participating in the body's antioxidant and immune regulation functions, can also improve the intestinal microecological balance by influencing the composition and metabolic function of gut microbiota, promoting the growth of beneficial bacteria and inhibiting the proliferation of potentially harmful bacteria.

[0006] However, current research and products applying plant-derived organic selenium systems to cat food are still relatively scarce, lacking specialized formulation design and processing techniques tailored to the physiological characteristics and intestinal microecology of cats. Furthermore, the stability of plant-derived organic selenium during cat food processing, its appropriate addition levels, and its effects on intestinal flora regulation are not yet clearly defined, limiting its widespread application in the functional cat food sector. Therefore, it is necessary to develop a cat food product using plant-derived organic selenium as a functional ingredient, ensuring comprehensive nutrition and processing stability while effectively regulating the structure of the cat's intestinal flora, thereby improving intestinal health, enhancing immune function, and meeting the demands for functional and high-value-added pet food development. Summary of the Invention

[0007] To address the problems of limited functionality, unstable effects, and low utilization rate of functional components in existing cat food products for regulating intestinal flora, this invention provides a cat food with intestinal flora regulation function and its preparation method. The first objective of this invention is to provide a functional cat food that can effectively improve the intestinal microecological structure of cats by adding probiotics, prebiotics, and plant-derived organic selenium to a basic cat food, thereby achieving comprehensive regulation of the intestinal flora. The second objective is to construct a nutritional regulation system with synergistic effects of probiotics, prebiotics, and plant-derived organic selenium, improving the stability and sustainability of the intestinal flora regulation effect through the rational design of the types and amounts of each component. The third objective is to provide a cat food preparation method suitable for industrial production, ensuring the activity of probiotics and the stability of plant-derived organic selenium by optimizing the order of addition of functional components and processing conditions.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: probiotics, prebiotics, and plant-derived organic selenium are added to the basic cat food, wherein the amount of probiotics added is 60–80 × 10⁻⁶. 9 The cat food contains CFU / kg and includes 3–4 different strains of bacteria; prebiotics include inulin, fructooligosaccharides and xylooligosaccharides; the total selenium content in the cat food is 0.4–0.5 mg / kg, of which organic selenium accounts for 80–90% of the total selenium content.

[0009] The probiotics are selected from Bacillus subtilis, Lactobacillus plantarum, Bifidobacterium longum, Saccharomyces boulardii, or combinations thereof;

[0010] The amount of inulin added is 0.3–0.4%, the amount of fructooligosaccharide added is 0.1%, and the amount of xylooligosaccharide added is 50 mg / kg;

[0011] The plant-derived organic selenium is selected from selenium-enriched plant proteins, selenium-enriched plant peptides, or combinations thereof, and the selenium exists in the form of selenocysteine ​​and / or selenomethionine.

[0012] The present invention also provides a method for preparing the above-mentioned cat food, comprising mixing the cat food base raw materials evenly, adding prebiotics and plant-derived organic selenium and mixing them thoroughly, adding probiotics under low temperature conditions and mixing them evenly, and then molding, drying and packaging to obtain the finished cat food.

[0013] Beneficial effects:

[0014] This invention constructs a stable intestinal flora regulation system by synergistically adding specific doses of probiotics, prebiotics, and plant-derived organic selenium to the basic cat food. This system can promote the growth of beneficial bacteria in the cat's gut and inhibit the reproduction of potentially harmful bacteria, thereby improving the intestinal flora structure and microecological balance, and has the following beneficial effects:

[0015] (1) The probiotics are formulated with 3-4 strains and combined with compound prebiotics such as inulin, fructooligosaccharides and xylooligosaccharides, which helps to improve the survival rate and colonization ability of probiotics in the cat's intestines, enhance the stability and persistence of the intestinal flora regulation effect, and improve digestive and absorptive functions and fecal characteristics.

[0016] (2) Plant-derived organic selenium, under the condition that the total selenium content is controlled at 0.4-0.5 mg / kg and the organic selenium content reaches 80-90%, takes into account both safety and high bioavailability, can enhance the body's antioxidant and immune regulation capabilities, and has a synergistic effect with probiotics and prebiotics, thereby improving the overall health efficacy and application value of cat food.

[0017] (3) The cat food of the present invention can improve the digestive and absorptive functions of cats, optimize fecal characteristics, reduce intestinal stress and inflammation risk, and achieve stable regulation of intestinal flora structure while ensuring nutritional balance. It has good safety, functional stability and application promotion value, and is suitable for long-term feeding and large-scale production. Attached Figure Description

[0018] Figure 1 This invention relates to the effects of cat food on the content of short-chain fatty acids in cat feces in Example 1 and Comparative Example 1 of the present invention.

[0019] Figure 2 This study analyzes the α-diversity of feces in cats after being fed cat food in Example 1 and Comparative Example 1 of the present invention.

[0020] Figure 3 This study analyzes the β-diversity of feces in cats after being fed cat food in Example 1 and Comparative Example 1 of the present invention.

[0021] Figure 4 This study analyzes the fecal microbiota structure of cats fed with cat food in Example 1 and Comparative Example 1 of the present invention.

[0022] Figure 5 LEfSe analysis of fecal microbiota structure after cat food feeding in Example 1 and Comparative Example 1 of this invention.

[0023] Figure 6 This study presents a KEGG functional prediction analysis of fecal microbiota structure in Examples 1 and 1 of the present invention after cat food feeding. Detailed Implementation

[0024] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0025] Measurement methods involved in the embodiments

[0026] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0027] In the following embodiments, the measurements were performed according to the following methods:

[0028] 1. Method for determining total selenium

[0029] Take 0.1–0.2 g of sample into a microwave digestion tube, add 3.5 mL of concentrated nitric acid, and digest overnight in a cold environment. Then add 5.0 mL of ultrapure water, seal the tube with both inner and outer stoppers, and proceed with microwave digestion. After the program is complete, dilute the digested solution to the appropriate volume with ultrapure water and mix thoroughly. Take approximately 15 mL of the solution, pass it through a 0.22 μm nylon membrane, and place it in a 15 mL centrifuge tube. Perform a reagent blank simultaneously.

[0030] Total selenium was determined using an iCAP TQ inductively coupled plasma mass spectrometer in TQ-O2 reaction mode. 80 Se isotopes were monitored by the instrument, and the sampling cone was a nickel cone. A pig liver standard (selenium content 1.54 ± 0.29 mg / kg) was used as the quality control sample for total selenium determination. A series of standard solutions were prepared, and the selenium content was calculated using the external standard method.

[0031] The formula for calculating selenium content is:

[0032]

[0033] Where X: selenium content of the sample (mg / kg); C: selenium concentration measured after sample digestion and volume adjustment (μg / L); K: dilution factor; V: volume of sample after digestion and volume adjustment (mL); M: amount of digested sample (g).

[0034] 2. Methods for determining selenium speciation

[0035] The content of organic selenium forms was determined by HPLC-ICP MS.

[0036] 1) Sample pretreatment:

[0037] Take 100 mg of sample into a 20 mL sealed hydrolysis flask. Add 5% w / w alkaline protease (purchased from DUPONT, enzyme activity ≥580000 DU / g), 5% w / w trypsin (purchased from Hefei Bomei Biotechnology Co., Ltd., enzyme activity ≥250 NFU / mg), and 5% w / w proteinase K (purchased from Hefei Bomei Biotechnology Co., Ltd., enzyme activity ≥40 U / mg) sequentially to each flask. Then add 15 mL of 30 mmol / L Tris-HCl (pH 8.5). Stir magnetically at 45 ℃ and 400 rpm for 4 h. After reaction, collect the enzymatic hydrolysate, filter it through a 0.22 μm aqueous membrane, and inject it into the sample.

[0038] 2) HPLC chromatographic conditions:

[0039] The chromatographic column was a TechMate C18-ST reversed-phase column (4.6 mm × 250 mm, 5 μm); the mobile phase was a 30 mmol / L diammonium hydrogen phosphate solution containing 0.5 mmol / L tetrabutylammonium hydroxide and 3.0% (v / v) methanol, and the pH of the mobile phase was adjusted to 6.0 with 10% formic acid. Isocratic elution was performed at a flow rate of 1.0 mL / min, the column temperature was 30 ℃, and the injection volume was 10 μL.

[0040] The ICP-MS conditions are shown in Table 2. A nickel cone with a high-sensitivity pad was used. The measurement mode was TQ-O2 mode, and the isotope sites were collected as follows: 80 Se, the dwell time is 0.05 s.

[0041] The contents of five selenium forms in the sample, namely methylselenocysteine ​​(MeSeCys), selenomethionine (SeMet), selenocysteine ​​(SeCys2), tetravalent selenium (Se(IV)), and hexavalent selenium (Se(VI)), were calculated using the external standard method.

[0042] 3. Animal feeding and indicator testing

[0043] Five healthy adult cats of the same breed and similar weight were selected for each group. Before the experiment, all cats were fed standard commercial cat food for one week. After the acclimatization period, they were fed different experimental group cat foods for 30 days. All cats were housed individually in cages, and all groups were kept under the same feeding and management conditions, with adequate room temperature and ventilation. They were fed regularly each day, with free access to food and water. The living environment and equipment were cleaned and disinfected daily, and the cages were thoroughly cleaned.

[0044] 4. Cat diarrhea status score

[0045] The feces of the experimental cats with diarrhea were scored, and the specific scoring results are as follows:

[0046] 1 point: The stool is a single ball, hard and dry; it leaves no trace when picked up; this indicates mild constipation.

[0047] 2 points. The feces are long and thin, with a soft and flexible surface, and are segmented; they leave almost no trace when picked up; this is considered healthy feces.

[0048] 3 points. The stool is long and smooth with almost no segments; it leaves slight marks when picked up; it is considered healthy stool.

[0049] 4 points. The stool is short and columnar, with a moist surface; it leaves a mark and sticks when picked up, but still retains a certain shape; it belongs to the sub-healthy stool category.

[0050] 5 points. The stool is moist and pasty on the surface, but has a certain shape; it cannot be picked up; this indicates mild diarrhea.

[0051] 6 points, stool texture is present, but no fixed shape; it is a mixture of loose and liquid stools; it cannot be picked up; this indicates moderate diarrhea.

[0052] 7 points, no fecal texture; watery stool with no solid parts; unable to be picked up; classified as severe diarrhea.

[0053] 5. Determination of short-chain fatty acids

[0054] The content of short-chain fatty acids in cat feces was detected by gas chromatography-mass spectrometry (GC-MS). 100 mg of feces was added to 800 μL of saturated sodium chloride solution and homogenized by vortexing. Then, 100 μL of 10% sulfuric acid solution and 100 μL of 0.1 mg / mL internal standard solution (2-ethylbutyric acid) were added to the homogenate, vortexed, and sonicated in an ice-water bath. After sonication, the mixture was centrifuged at 12000 r / min for 10 min at 4 °C. 500 μL of the supernatant was collected, and 2 mL of ethyl acetate was added. The mixture was then vortexed thoroughly to extract the short-chain fatty acids. The upper organic layer was collected, and 0.25 g of anhydrous sodium sulfate was added to remove moisture. The mixture was centrifuged at 4000 r / min at 4 °C, and the supernatant was filtered through a 0.22 μm organic filter before being analyzed by GC-MS.

[0055] A mixed standard solution of acetic acid, propionic acid, butyric acid, valeric acid, isobutyric acid, and isovaleric acid at a concentration of 200 mg / L was prepared. After serial dilution, a series of solutions with concentrations of 100 mg / L, 50 mg / L, 20 mg / L, 10 mg / L, and 5 mg / L were obtained. The content of short-chain fatty acids in the samples was calculated based on the standard curve.

[0056] 6. Intestinal flora analysis

[0057] Fecal samples were collected from cats on days 0 and 30 of the formal experiment. The middle portion of the feces was taken, ensuring the sample was clean and free of other contaminants, and placed in a 1.5 mL EP tube, stored at -80 °C until analysis. Genomic DNA samples were extracted, and the quantity and quality of DNA were determined by spectrophotometry and agarose gel electrophoresis. PCR products were purified using a DNA purification kit and quantified using a DNA quantification kit. Microbial genomic DNA was extracted from the fecal samples by Shanghai Ouyi Biotechnology Co., Ltd., and specific regions of 16S rDNA were amplified. Microbial community sequence data were obtained using the Illumina MiSeq sequencing platform.

[0058] After quality control, sequence assembly, and dechimeric processing of the sequencing data, high-quality and valid sequences were obtained and annotated for species classification. Based on this, alpha diversity analysis (including Shannon and Simpson indices) was used to evaluate the richness and evenness of the gut microbiota in each group; beta diversity analysis (principal coordinate analysis, PCoA) was used to compare differences in microbiota structure among different groups. Furthermore, microbiota composition was analyzed at different taxonomic levels (phylum, family, and genus) to assess the impact of different cat diets on gut microbiota structure.

[0059] To screen for significantly different gut microbiota among different groups, linear discriminant analysis (LEfSe) was used to analyze the differentially expressed microbiota and identify microbial groups significantly enriched at different taxonomic levels. Furthermore, based on 16S rDNA sequencing data, the potential functions of the gut microbiota were predicted using PICRUSt software, and related metabolic pathways were annotated and analyzed using the KEGG database to evaluate the regulatory effects of different cat foods on the gut microbiota at a functional level.

[0060] Basic cat food

[0061] The cat food base used in the examples and comparative examples is the same, and by weight percentage, it includes: animal protein ingredients (chicken meal, fish meal, etc.): 40%; grain or tuber ingredients: 25%; fat ingredients (chicken oil, fish oil): 12%; dietary fiber ingredients: 5%; vitamin and mineral premix: 3%; except for the functional additives, the composition of other ingredients and the preparation process are the same.

[0062] Example 1

[0063] Functional ingredients are added to the basic cat food, with a total probiotic content of 70×10. 9 The probiotics, expressed as CFU / kg, include *Lactobacillus acidophilus*, *Lactobacillus plantarum*, *Bifidobacterium animalis*, and *Bacillus coagulans*. The prebiotics include 0.35% inulin, 0.1% fructooligosaccharides, and 50 mg / kg xylooligosaccharides. The total selenium content in the cat food is 0.45 mg / kg, of which 85% is plant-derived organic selenium, sourced from selenium-rich plant protein. The preparation method is as follows: Basic cat food ingredients are mixed evenly, then prebiotics and plant-derived organic selenium are added and thoroughly mixed. After conditioning and molding, probiotics are added under low-temperature conditions and mixed evenly. The mixture is then dried and packaged to obtain the finished cat food.

[0064] Example 2

[0065] Functional ingredients are added to the basic cat food, with a total probiotic content of 60×10. 9 The probiotics, expressed as CFU / kg, include *Lactobacillus plantarum*, *Bifidobacterium longum*, and *Bacillus subtilis*. The prebiotics include 0.3% inulin, 0.1% fructooligosaccharides, and 50 mg / kg xylooligosaccharides. The total selenium content in the cat food is 0.4 mg / kg, of which 80% is plant-derived organic selenium, sourced from selenium-enriched plant peptides. The preparation method is as follows: Basic cat food ingredients are mixed evenly, then prebiotics and plant-derived organic selenium are added and thoroughly mixed. After conditioning and molding, probiotics are added under low-temperature conditions and mixed evenly. The mixture is then dried and packaged to obtain the finished cat food.

[0066] Example 3

[0067] Functional ingredients are added to the basic cat food, with a total probiotic content of 80×10. 9The probiotics, expressed as CFU / kg, include Bacillus subtilis, Lactobacillus plantarum, Bifidobacterium longum, and Saccharomyces boulardii; the prebiotics include inulin 0.4%, fructooligosaccharides 0.1%, and xylooligosaccharides 50 mg / kg; the total selenium content in the cat food is 0.5 mg / kg, of which plant-derived organic selenium accounts for 90% of the total selenium content, and the organic selenium source is a combination of selenium-enriched plant protein and selenium-enriched plant peptides. The preparation method is as follows: after uniformly mixing the basic cat food ingredients, prebiotics and plant-derived organic selenium are added and thoroughly mixed. After conditioning and molding, probiotics are added under low-temperature conditions and mixed evenly, followed by drying and packaging to obtain the finished cat food.

[0068] Comparison Example 1 (Basic Cat Food)

[0069] The same basic cat food formula as in Example 1 was used, but without the addition of probiotics, prebiotics, and plant-derived organic selenium.

[0070] Comparative Example 2

[0071] Add only probiotics to the basic cat food, at a dosage of 70 x 10. 9 CFU / kg, without added prebiotics or plant-derived organic selenium.

[0072] Comparative Example 3

[0073] Inulin, fructooligosaccharides, and xylooligosaccharides were added to the basic cat food in the same amounts as in Example 1.

[0074] Comparative Example 4

[0075] Inorganic selenium is added to the basic cat food to bring the total selenium content to 0.45 mg / kg, but no plant-derived organic selenium, probiotics, or prebiotics are added.

[0076] Table 1. Diarrhea scores after feeding with the feeds used in the examples and comparison examples.

[0077]

[0078] According to the fecal scores (Table 1), in the initial stage of the experiment (Day 1), the fecal scores of all groups of experimental cats were between 2.6 and 3.0, indicating healthy or near-healthy feces, suggesting that the baseline conditions of each group were basically consistent. As the feeding time increased, the effects of different cat food formulas on intestinal condition gradually became apparent. The fecal scores of groups 1-3 remained consistently within the range of 2.6-3.0 throughout the entire experimental period, with minimal fluctuations, and all fell within the healthy fecal score range. This indicates that the cat food supplemented with probiotics, prebiotics, and plant-derived organic selenium could maintain good intestinal stability, without significant diarrhea or constipation. Among them, Example 1 showed the most stable performance, suggesting that its formula combination has a superior effect in maintaining intestinal microecological balance.

[0079] In contrast, the fecal scores of the control groups showed a significant upward trend during the feeding process, especially on days 20 and 30. The scores of controls 1, 2, and 3 rose to above 3.5, with some reaching 4.0 or higher, indicating loose, sticky, or even pasty feces, suggesting a sub-healthy or mild diarrheal state. Control 3 reached 4.2 on both days 20 and 30, indicating a significant impact on intestinal function. Control 4, although fluctuating less, remained around 3.5 in the later stages, failing to recover to a healthy fecal state. The results show that cat food with only a single functional ingredient or no functional components is unlikely to maintain long-term intestinal health. The embodiments of this invention, through the synergistic effect of probiotics, prebiotics, and plant-derived organic selenium, effectively stabilized the intestinal environment, inhibited the tendency for diarrhea, and maintained fecal characteristics within a healthy range, demonstrating a good intestinal regulatory effect and application value.

[0080] The content of short-chain fatty acids (SCFAs) in the feces of cats in each group of experiments was detected and analyzed using gas chromatography-mass spectrometry (GC-MS). The results are as follows: Figure 1 As shown. Short-chain fatty acids, mainly including acetic acid, propionic acid, butyric acid, isobutyric acid, isovaleric acid, and valeric acid, are important products of intestinal flora metabolism, and changes in their content can reflect the state of the intestinal microecology. Figure 1 As shown in (A)–(F), compared to Comparative Example 1, the content of various short-chain fatty acids in Example 1 changed significantly after 30 days of continuous feeding. The contents of acetic acid, butyric acid, isobutyric acid, isovaleric acid, and valeric acid all showed an increasing trend, and the increase was significant, indicating that Example 1 can promote the metabolic activity of beneficial intestinal bacteria. Acetic acid, as one of the most abundant short-chain fatty acids in the intestine, increased by approximately 8% compared to Comparative Example 1, indicating that the cat food of this invention has a positive promoting effect on the fermentation function of intestinal flora. The increase in butyric acid content is particularly important, as it is the main energy source for colonic epithelial cells and helps maintain the integrity of the intestinal barrier function. Unlike the above trends, propionic acid content decreased in both Example 1 and Comparative Example 1, which may be related to changes in the composition of intestinal flora and adjustments in its metabolic pathways, indicating a certain metabolic balance between different short-chain fatty acids. Furthermore, from Figure 1 As shown in (G), the total short-chain fatty acid content in Example 1 was significantly higher than that in Comparative Example 1, increasing from 8682.23 μg / g to 9250.24 μg / g. This indicates that the cat food described in this invention can promote the fermentation activity of intestinal microorganisms and increase the level of metabolite production, thereby improving the intestinal microecological environment as a whole.

[0081] High-throughput sequencing technology was used to analyze the gut microbiota structure in fecal samples from each group of experimental cats. Figure 2As shown in (A), the sparse curves of each sample gradually flatten and reach a plateau as the sequencing depth increases, indicating that the sequencing data is sufficient to cover the vast majority of microbial species in the samples and can comprehensively reflect the composition of the gut microbiota in each group. The rank-abundance curves further show that the curves of each sample are relatively long and smoothly distributed, indicating that the species richness in the samples is high and the distribution is well uniform.

[0082] In terms of alpha diversity analysis, after 30 days of feeding, compared with the initial state, both the Shannon index and Simpson index of Comparative Example 1 and Example 1 were increased, indicating that both cat foods improved the diversity and evenness of the gut microbiota to some extent and could regulate the gut microbiota structure. Among them, the overall change trend of Example 1 was more obvious, suggesting that it has a better regulatory effect in improving the microbiota structure.

[0083] Further, β-diversity analysis was used to assess the differences in gut microbiota structure among different groups. Figure 3 The principal coordinate analysis (PCoA) results show that the contribution rates of the first principal coordinate (PC1) and the second principal coordinate (PC2) are 12.97% and 8.54%, respectively, which can explain the differences between samples to some extent. The distribution of samples from different groups in the coordinate space indicates that after 30 days of feeding, there was a certain degree of separation in the community structure between Example 1 group and Comparative Example 1 group, suggesting that the two cat foods had different effects on the composition of the gut microbiota. Although there is still some overlap between the two groups, Example 1 group as a whole showed a relatively independent distribution trend, indicating that its regulatory effect on the gut microbiota has certain differences and directions.

[0084] Depend on Figure 4The analysis results of the gut microbiota composition show that, at the phylum level, there are significant differences in the gut microbiota structure between Example 1 and Comparative Example 1. Specifically, Example 1 optimized the overall gut microbiota structure by increasing the relative abundance of Bacteroidota while decreasing the relative abundance of Actinobacteriota and Verrucomicrobiota. Bacteroidota is generally involved in the catabolism of polysaccharides and proteins, and its increased abundance helps improve intestinal fermentation capacity and nutrient utilization efficiency. While Comparative Example 1 also showed an increase in Bacteroidota abundance, it was accompanied by an increase in Fusobacteriota abundance, suggesting certain limitations in its microbiota regulation. In the family-level analysis, Example 1 showed a decrease in the abundance of Actinobacter-related bacteria and Peptostreptococcaceae, some members of which are associated with potential pathogenicity or intestinal inflammation. In contrast, Comparative Example 1 showed an increase in the abundance of some potentially pathogenic bacteria to some extent, indicating a relatively weak regulatory effect on the gut microbiota. Furthermore, at the genus level, there were significant differences between Example 1 and Comparative Example 1 in the abundance trends of the genus *Prevotella*, with Example 1 significantly increasing the relative abundance of this genus. *Prevotella* plays an important role in the catabolism of carbohydrates and proteins; its increased abundance suggests that Example 1 can promote substrate fermentation and utilization, thereby improving the gut microbiota environment.

[0085] Linear discriminant analysis (LDA) and effect size (LEfSe) were used to screen bacterial communities with significant differences among different groups. Figure 5 As shown, after 30 days of feeding, a total of 16 taxa with significant differences at different taxonomic levels were identified. Compared with Comparative Example 1, Example 1 was mainly enriched in Bacteroidetes-related groups, especially at the order (o-Bacteroidales), class (c-Bacteroidia), and phylum (p-Bacteroidota) levels, indicating that Example 1 promoted a favorable shift in the overall gut microbiota structure by selectively enriching dominant bacterial groups related to nutrient metabolism.

[0086] In terms of functional prediction analysis, based on 16S rDNA sequencing data, PICRUSt software was used to annotate and compare potential functional genes in the samples. Figure 6As shown, Example 1 group exhibited an upregulation trend in multiple functional pathways related to metabolism and immune regulation, mainly including acyl-CoA synthetase, major promoting transport system proteins (MFS transporters), and Lrp / AsnC family transcriptional regulators. These functional pathways are closely related to lipid metabolism, substance transport, immune response, and inflammation regulation, indicating that Example 1 can further improve the host's intestinal health by regulating the functional potential of gut microbiota. In contrast, Comparative Example 1 group mainly showed downregulation of some metabolism-related enzymes (such as 6-phosphate-β-glucosidase) and nucleoside metabolism pathways, and its effect on intestinal function regulation was relatively limited.

[0087] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A cat food with the function of regulating intestinal flora, characterized in that, In addition to the basic cat food formula, probiotics, prebiotics, and plant-derived organic selenium are added, including: The amount of probiotics added is 60–80 × 10⁻⁶. 9 CFU / kg, and the probiotics include 3–4 different strains; Prebiotics include inulin, fructooligosaccharides, and xylooligosaccharides; The total selenium content in cat food is 0.4–0.5 mg / kg, of which organic selenium accounts for 80–90% of the total selenium content.

2. The cat food according to claim 1, characterized in that, The probiotics are selected from Bacillus subtilis, Lactobacillus plantarum, Bifidobacterium longum, Saccharomyces boulardii, or combinations thereof.

3. The cat food according to claim 1, characterized in that, The amount of inulin added is 0.3–0.4% of the total mass of the cat food.

4. The cat food according to claim 1, characterized in that, The amount of fructooligosaccharides (FOS) added is 0.1% of the total mass of the cat food.

5. The cat food according to claim 1, characterized in that, The amount of xylooligosaccharide (XOS) added is 50 mg / kg.

6. The cat food according to claim 1, characterized in that, The plant-derived organic selenium is selected from selenium-enriched plant proteins, selenium-enriched plant peptides, or combinations thereof.

7. The cat food according to claim 7, characterized in that, The selenium in the plant-derived organic selenium exists in the form of selenocysteine ​​and / or selenomethionine.

8. The cat food according to claim 1, characterized in that, The probiotics, prebiotics, and plant-derived organic selenium work synergistically to promote the growth of beneficial bacteria and inhibit the reproduction of harmful bacteria, thereby regulating the structure of the cat's intestinal flora.

9. A method for preparing cat food according to any one of claims 1-9, characterized in that, Includes the following steps: 1) Mix the basic cat food ingredients evenly; 2) Add prebiotics and plant-derived organic selenium to the mixture and mix thoroughly; 3) Add probiotics under low temperature conditions and mix evenly; 4) After molding, drying and packaging, the finished cat food is obtained.

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