Drug Residues In Food Research Articles

Development of a Method for the Rapid Determination of 17 Veterinary Drug Residues in Foods of Animal Origin by UPLC-MS/MS Combined with Pass-Through SPE Cartridge

Development of a Method for the Rapid Determination of 17 Veterinary Drug Residues in Foods of Animal Origin by UPLC-MS/MS Combined with Pass-Through SPE Cartridge

Screening and Simultaneous Determination of 80 Veterinary Drug Residues in Food by HPLC-MS/MS

Screening and Simultaneous Determination of 80 Veterinary Drug Residues in Food by HPLC-MS/MS

A Recycled-Material-Based Electrochemical Eco-sensor for Sensitive Detection of Antischistosomal Drug Residues in Bovine-Derived Food Samples

Veterinary drug residues in food have emerged as an urgent threat to consumer safety. Herein, we present the first square wave voltammetric method for the trace-level detection of cinnarizine residues, a recently used antischistosomal drug, in bovine food samples. The method depends on the electrochemical oxidation after modification of the carbon paste sensor with recycled Al2O3-NPs functionalized multi-walled carbon nanoparticles. The produced sensor (Al2O3-NPs/ MWCNTs/CPE) was characterized using the transmission electron microscope, scanning electron microscope, Fourier-transform infrared spectroscopy, energy-dispersive spectrometer, and X-ray diffractometer that confirm the successful incorporation of the Al2O3-NPs/MWCNTs composite into the modified electrode. As expected, the active surface area and electron transfer processes were accelerated by the modification, which was evidenced by cyclic voltammetry, chronoamperometric studies, scan rate studies, and electrochemical impedance spectroscopy. Compared to previous techniques, this facile sensor demonstrated enhancements across critical analytical criteria including the detection limit of 0.17 nM, linear response across 5–100 nM (r2 = 0.998), accuracy ranging from 96.5 to 103.2%, precision below 0.81% relative standard deviation, reproducibility within 0.36% range, 20 s response time and applicability in spiked food matrices. In addition, five different greenness and whiteness tools quantified exceptional environmental friendliness, economic feasibility and waste reduction of 63%–93%, reaffirming alignment with sustainability paradigms. These advantages support practical adoption in quality control especially laboratories lacking expensive instrumentation. Overall, the ingenious sensor reconciles nanotechnology innovation with the circular economy ethos to tackle an urgent food safety challenge, guided holistically by sustainability metrics.

Screening of meat sold for human consumption in Benue State, Nigeria for antibiotic residues

The problem of veterinary drug residues in food of animal origin is of great importance in developing countries. The concerns are mostly related to food safety and the development of antibiotic-resistant pathogens. This study was carried out during the hot dry season (March) between 2016 – 2018 to detect antibiotic presence in beef, chevon and pork sold for human consumption in abattoirs in Benue state. Thirty-nine samples each of 100-150g of kidney, liver and muscle were collected from cattle, goats and pigs making a total of 351 samples from abattoirs across the three geopolitical zones of Benue state. The samples were screened for multidrug residues using the modified agar gel diffusion method. A total of 144 were positive out of which 40.3% (58/144) were beef, while 29.2% (42/144) and 30.5% (44/144) were chevon and pork respectively. From the results of this study, it could be inferred that the meat consumed within Benue State contains residues of antibiotics possibly because of non-adherence to the withdrawal period by farmers and lack of knowledge of its consequences on the consumers.

Antibiotic Residues in Foods of Animal Origin in Cameroon: Prevalence, Consumers’ Risk Perceptions, and attitudes

The use of antibiotics in food animals and the nonobservance of the withdrawal period might result in the accumulation and persistence of residues in foods. The contamination of foods by antibiotic residues might induce health risks including allergy, gastrointestinal dysbiosis, antimicrobial resistance, and cancer to consumers. Therefore, this study was initiated to investigate the presence of antibiotic residues in raw eggs, raw milk, and beef collected at the wholesale and retail points in the three major cities of Cameroon and consumers’ perceptions of the risk of antibiotic residues in foods. Qualitative antibiotic residue kits (PremiTest® and Delvotest®) were used to screen 407 samples of foods collected in markets of three towns (Ngaoundéré, Yaoundé, and Douala) in Cameroon. A structured questionnaire was used to evaluate the knowledge and attitudes of 1462 consumers toward microbial drug residues in foods of animal origin. Prevalence of residues of 70.55%, 17.39%, and 69.63% for beef, eggs, and milk, respectively, was observed. More than 1/3 of the respondents believed that the consumption of contaminated foods with antibiotic residues is a risk to their health and thought that allergies and intoxication they often experience are related to the consumption of contaminated foods. Most of them showed their willingness to pay more to acquire quality foods, free from antibiotic residues.

Fasciolosis: pathogenesis, host-parasite interactions, and implication in vaccine development.

Fasciola hepatica is distributed worldwide, causing substantial economic losses in the animal husbandry industry. Human fasciolosis is an emerging zoonosis in Andean America, Asia, and Africa. The control of the disease, both in humans and animals, is based on using anthelmintic drugs, which has resulted in increased resistance to the most effective anthelmintics, such as triclabendazole, in many countries. This, together with the concerns about drug residues in food and the environment, has increased the interest in preventive measures such as a vaccine to help control the disease in endemic areas. Despite important efforts over the past two decades and the work carried out with numerous vaccine candidates, none of them has demonstrated consistent and reproducible protection in target species. This is at least in part due to the high immunomodulation capacity of the parasite, making ineffective the host response in susceptible species such as ruminants. It is widely accepted that a deeper knowledge of the host-parasite interactions is needed for a more rational design of vaccine candidates. In recent years, the use of emerging technologies has notably increased the amount of data about these interactions. In the present study, current knowledge of host-parasite interactions and their implication in Fasciola hepatica vaccine development is reviewed.

Improved Detection of Veterinary Drug Residues: Advancing Analytical Techniques to Ensure Food Safety

Abstract: Veterinary drug residues in foods pose risks to consumers and promote antimicrobial resistance. Effective detection methods are needed to monitor and control residues. Recent advancements in analytical techniques for veterinary drug residue detection were reviewed. Key sample preparation methods, including QuEChERS, SPE, ASE, and LLE, were summarized. Instrumental analysis techniques including LC-MS/MS, GC-MS, immunoassays, CE and biosensors were examined. Recent trends and future directions were identified. : LC-MS/MS and GC-MS provide the highest sensitivity and specificity for veterinary drug residue analysis. However, selectivity remains a challenge, particularly for complex matrices like meat and liver. Multi-residue methods now cover over 100 analytes, but analyzing new and legacy drugs lacking established methods is difficult. Increased sensitivity has been achieved through UHPLC and high resolution MS, but detection limits below 1 μg/kg often remain elusive. sSimplified onsite tests are gaining interest. : More selective extraction strategies, data-driven multi-residue methods, microflow LC, and integrated analytical platforms may help address current challenges. Continued advances in sample preparation, instrumentation, data processing, and validation will be needed to fully realize the potential of veterinary drug residue detection and ensure food safety.

Surveillance of veterinary drug residues in food commonly consumed in Singapore and assessment of dietary exposure

Non-judicious and indiscriminate use of veterinary drugs in animal husbandry may result in accumulation of residues in animal tissues, and consequently in food for human consumption. The abuse of veterinary drugs presents a potential risk to consumer health, especially if the residue level is higher than the health-based guidance value (HBGV) such as the acceptable daily intake (ADI). Contamination of drug residues in food also promotes the emergence of antimicrobial resistance (AMR) which poses a serious threat to public health globally. There has been limited information on the occurrence and dietary exposure to veterinary drug residues in Singapore to date. In this study, the occurrence of four classes of veterinary drugs, namely beta-agonists, coccidiostats, fluoroquinolones and macrolides, were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in food widely consumed by Singapore residents. The magnitude of dietary exposure was assessed based on the consumption profile of Singapore population. Out of 216 food samples, 9.72 % were detected positive with veterinary drug residues, where majority of the positive samples were poultry and its derived products, followed by eggs and egg products. 7 veterinary drugs, specifically ciprofloxacin, enrofloxacin, clopidol, diclazuril, lasalocid, nicarbazin and tilmicosin, were detected in the samples, with clopidol and enrofloxacin being the most frequently detected drugs. Dietary exposure was evaluated using the estimated daily intake (EDI) of the detected drugs and benchmarked against the corresponding acceptable daily intake (ADI). All the %ADI values were far less than 100 in both the average and high consumer scenarios, indicating that the health risk associated with dietary exposure to these drugs in Singapore is low.

Assessment of the Immunoprotective Efficacy of Recombinant 14-3-3 Protein and Dense Granule Protein 10 (GRA10) as Candidate Antigens for Rabbit Vaccines against Eimeria intestinalis.

Eimeria intestinalis infects rabbits, causing severe intestinal coccidiosis. Prolonged anticoccidial drug use might lead to coccidia resistance and drug residues in food. Thus, vaccines are required to control rabbit coccidiosis. In this study, recombinant E. intestinalis 14-3-3 and GRA10 proteins (rEi-14-3-3 and rEi-GRA10) were obtained via prokaryotic expression and used as recombinant subunit vaccines. Fifty 30-day-old rabbits were randomly grouped as follows: PBS-uninfected group, PBS-infected group, Trx-His-S control group, and rEi-14-3-3 and rEi-GRA10 immunized groups. The rabbits were subcutaneously immunized twice at 2-week intervals, challenged with 7 × 104 sporulated oocysts, and sacrificed 14 days later. The protective effects were assessed via clinical signs, relative weight gain, oocyst reduction, mean intestinal lesion score, ACI (anticoccidial index), cytokine, and specific antibody levels in sera. The rEi-14-3-3 and rEi-GRA10 groups had higher relative weight gain rates of 81.94% and 73.61% (p < 0.05), and higher oocyst reduction rates of 86.13% and 84.87% (p < 0.05), respectively. The two immunized groups had fewer intestinal lesions (p < 0.05) and higher IgG levels (p < 0.05). Higher levels of IL-2, IL-4, and IFN-γ cytokines in the rEi-14-3-3 group (p < 0.05) and a higher level of IFN-γ in the rEi-GRA10 group (p < 0.05) were observed. The ACI values of the rEi-14-3-3 and rEi-GRA10 groups were 168.24 and 159.91, with good and moderate protective effects, respectively. Both rEi-14-3-3 and rEi-GRA10 induced humoral immunity in the rabbits. In addition, rEi-14-3-3 induced Th1- and Th2-type immune responses. Both recombinant proteins were protective against E. intestinalis infection in rabbits, with rEi-14-3-3 showing a better protective effect.

Recent Advances in the Determination of Veterinary Drug Residues in Food.

The presence of drug residues in food products has become a growing concern because of the adverse health risks and regulatory implications. Drug residues in food refer to the presence of pharmaceutical compounds or their metabolites in products such as meat, fish, eggs, poultry and ready-to-eat foods, which are intended for human consumption. These residues can come from the use of drugs in the field of veterinary medicine, such as antibiotics, antiparasitic agents, growth promoters and other veterinary drugs given to livestock and aquaculture with the aim of providing them as prophylaxis, therapy and for promoting growth. Various analytical techniques are used for this purpose to control the maximum residue limit. Compliance with the maximum residue limit is very important for food manufacturers according to the Food and Drug Administration (FDA) or European Union (EU) regulations. Effective monitoring and control of drug residues in food requires continuous advances in analytical techniques. Few studies have been reviewed on sample extraction and preparation techniques as well as challenges and future directions for the determination of veterinary drug residues in food. This current review focuses on the overview of regulations, classifications and types of food, as well as the latest analytical methods that have been used in recent years (2020-2023) for the determination of drug residues in food so that appropriate methods and accurate results can be used. The results show that chromatography is still a widely used technique for the determination of drug residue in food. Other approaches have been developed including immunoassay, biosensors, electrophoresis and molecular-based methods. This review provides a new development method that has been used to control veterinary drug residue limit in food.

A Carboxyl Group-Functionalized Ionic Liquid Hybrid Adsorbent for Solid-Phase Extraction and Determination of Trace Diclofenac Sodium in Milk Samples.

A simple and efficient sample pretreatment technology is very important for the accurate determination of trace drug residues in foods to ensure food safety. Herein, we report a new carboxyl group-functionalized ionic liquid hybrid solid- phase adsorbent (PS-IL-COOH) for the highly efficient extraction and quantitative determination of diclofenac sodium (DS) residue in milk samples. It was found that the adsorption efficiency of PS-IL-COOH for the ppb level of DS was greater than 93.0%, the adsorption capacity was 934.1 mg/g, and the enrichment factor was 620.0, which surpass most of the previously reported values for DS adsorbents. The high concentration of salts did not interfere with the adsorption of DS. Importantly, the recovery of DS was above 90% after 16 adsorption--regeneration cycles. The synergistic effect of the multiple interactions was found to be the main factor for the high efficiency of DS adsorption. The proposed method was applied to the extraction and detection of DS in milk samples, with the relative recovery ranging from 88.2 to 103.0%.

Re-evaluation of a microbiological acceptable daily intake for tylosin based on its impact on human intestinal microflora

As veterinary drugs available for fish is very restricted, there is growing trials for repurposing livestock drugs as aquatic animal drugs. Tylosin is one of the most effective antibiotics to treat bacterial infections approved for livestock, and would be used in fish. Hence, we investigated the toxicological and microbiological aspects of tylosin to establish health-based guidance value (HBGV) and maximum residue limit (MRL) in fishes, and reevaluated the microbiological acceptable daily intake (mADI) based on updated relevant data and international guildeline. Lastly, exposure assessment was performed to confirm the appropriateness of MRL. By investigating available microbiologcial studies on tylosin, the microbiological point of departure was determined as 0.308 μg/mL, which was mean 50% minimum inhibitory concentration (MIC50), obtained from the Food Safety Committee of Japan (FSCJ) evaluation report. Furthermore, as a factor for the derivation of mADI, the volume of colon content was recently changed to 500 mL in compliance with the International Cooperation on Harmonization of Technical Requirements for Registration of Veterinary Medicinal Products (VICH) guidelines. This was previously defined as the mass of colon content (220 g). We applied correction factor 0.224 to the mean MIC50 for tylosin in the equation of mADI, since the drug is transformed to metabolites with reduced activity prior to entering the colon and bound to fecal materials within the colon of human. The mADI was evaluated as 0.01 mg/kg bw/day. Finally, the hazard index, calculated by dividing the estimated chronic dietary exposure by mADI, did not exceed 100%, suggesting that chronic dietary exposure to tylosin residues from veterinary use was unlikely to be a public health concern. Overall, this study contributes significantly in updating HBGV by application of the concept of mADI for the first time in Korea based on the revised microbiological risk assessment guidelines and in providing scientific rationale for the risk management of veterinary drug residues in food.

A Metasurface Plasmonic Analysis Platform Combined with Gold Nanoparticles for Ultrasensitive Quantitative Detection of Small Molecules.

Food safety related to drug residues in food has become a widespread public concern. Small-molecule drug residue analysis often relies on mass spectrometry, thin-layer chromatography, or enzyme-linked immunosorbent assays (ELISA). Some of these techniques have limited sensitivity and accuracy, while others are time-consuming, costly, and rely on specialized equipment that requires skilled operation. Therefore, the development of a sensitive, fast, and easy-to-operate biosensor could provide an accessible alternative to conventional small-molecule analysis. Here, we developed a nanocup array-enhanced metasurface plasmon resonance (MetaSPR) chip coupled with gold nanoparticles (AuNPs) (MSPRAN) to detect small molecules. As sulfamethazine drug residues in poultry eggs may cause health issues, we selected this as a model to evaluate the feasibility of using MSPRAN for small-molecule detection. The MSPRAN biosensor employed competitive immunoassay technology for sulfamethazine detection. The limit of detection was calculated as 73 pg/mL, with sensitivity approximately twice that of previously reported detection methods. Additionally, the recovery rate of the biosensor, tested in egg samples, was similar to that measured using ELISA. Overall, this newly developed MSPRAN biosensor platform for small-molecule detection provides fast and reliable results, facile operation, and is relatively cost-effective for application in food safety testing, environmental monitoring, or clinical diagnostics.

Integrating high-throughput exposure assessment and in vitro screening data to prioritize endocrine-active potential and dietary risks of pesticides and veterinary drug residues in animal products.

New approach methodologies in toxicology, such as in vitro high-throughput screening (HTS), can minimize the use of experimental animals and allow mechanism-based predictions of in vivo toxicity. HTS data has been increasingly used in the regulatory context; however, only a few studies integrated dietary exposure and HTS data to foster chemical prioritization in food. Additionally, the endocrine-associated risk of veterinary drug residues in food is yet to be fully characterized. This study aims to systematically compare the translated HTS data with the acceptable daily intake (ADI) values and prioritize the pesticides and veterinary drug residues (n=294) in food using the exposure-activity ratio (EAR) and Toxicological Prioritization index (ToxPi). The dietary exposure assessment was accomplished using a stochastic human exposure and dose simulation high-throughput model (SHEDS-HT). We selected 76 HTS assays from 12 nuclear receptors to represent the molecular initiating event (MIE) of endocrine-disrupting phenotypes. Chemical prioritization was achieved using 4 methods (i.e., EAR-OED, EAR-ADI, ToxPi-exposure+ADI, and ToxPi-exposure+endocrine score), where the consensus prioritized chemicals were fipronil, furazolidone, oxolinic acid, and oxytetracycline for the Taiwanese population. This case study demonstrates the utility of HTS data in fostering regulatory decisions on chemicals, especially for those lacking comprehensive toxicity data.

Public Health Significance of Veterinary Drug Residue in Food Animal Products - A Review

The objective of this review paper was to investigate the public health significance of veterinary drug residues in food of animal origin. Data were collected by means of the search engine and all relevant journals published between 2019 and 2022 and stocked under Google Scholar were retrieved for analysis. The use of veterinary medications in animals that produce food has the potential to leave residues in animal-derived products (meat, milk, eggs and honey), which puts the consumer's health at risk. The inability to follow the withdrawal period and incorrect drug use are the most likely causes of drug residues. The development of antimicrobial drug resistance, hypersensitivity reaction, carcinogenicity, mutagenicity, teratogenicity and alteration of intestine natural flora are the main public health implications of drug residue. The frequent application of tandem or high-resolution mass spectrometry along with liquid chromatography has greatly enhanced analytical methods for residue analysis. This advancement made it possible to quickly conduct targeted searches for hundreds of target compounds in complicated matrices like milk, eggs, honey, or meat and organs after slaughter. Reduction of antimicrobial drug resistance problem has been indicated as one of the most challenging issues related to food safety in the forthcoming years. There is little data available on the extent of veterinary drug residue globally. Therefore, a significant amount of work must be done to assess the scope of the issue, prevent the occurrence of veterinary drug residues and to familiarize animal health professionals with the pharmacokinetics, pharmacodynamics and toxicological effects of veterinary drugs in order to reduce the potential public health risk posed by drug residues in food derived from animals.

A sensitive sensing system based on fluorescence dipeptide nanoparticles for sulfadimethoxine determination

Various types of fluorescent nanoparticles have been proposed for the detection of veterinary drug residues in food. However, structure-induced fluorescence nanoparticles with biodegradability and the capacity to conjugate with molecular recognition elements are lacking. Here, a biodegradable tryptophan-phenylalanine dipeptide-based nanomaterial was assembled and modified with a sulfadimethoxine aptamer (TPNPs@aptamer). Then, a novel and efficient fluorescence sensing strategy, based on TPNPs@aptamer and BHQ1-labeled single-stranded DNA (BHQ1@cDNA), was developed for sulfadimethoxine determination. Under optimal conditions, the fluorescence was linear in the range of 0–200 ng/mL sulfadimethoxine with a detection limit of 1.47 ng/mL (S/N = 3). Satisfactory recoveries of standard additions were found between 92.88 % and 114.15 % for water and milk samples with a relative standard deviation less than 5.0 %, suggesting that the proposed fluorescence sensing strategy can be applied reliably in sulfadimethoxine analysis of liquid foods.

Extended coverage of veterinary drug residues in food by LC-HRMS to ensure food compliance and prevent the spread of antimicrobial resistance

This study investigated the feasibility to monitor ca. 400 veterinary drug residues in various foodstuffs by a single method. For this, a generic QuEChERS-based approach was applied for sample preparation while liquid chromatography-high resolution mass spectrometry (LC-HRMS) was considered as detection technique. The LC-HRMS based method was eventually found suitable to screen for 353 parent compounds and marker residues in raw materials of animal sources (dairy-, meat-, fish-, egg-, and animal by-products), but also in related processed ingredients and end commercialized items. The screening approach was fully validated according to the European Guidelines in 70 samples, ending with false positive- and false negative rates below 5 %. Simultaneously, quantitative method performances were found acceptable in terms of recovery (70–120 % range) and precision (<20 %) for 184 out of the 353 compounds. A set of 114 samples originating from Europe, Asia, USA, Brazil, New Zealand and Australia, were subsequently analyzed to collect occurrence and quantitative data. The survey highlighted a high incidence of Antiparasitics (Benzimidazoles in eggs and Coccidiostats in poultry samples), though only one poultry sample for monensin (22 µg kg−1) exceeded the Maximum Residue Level set at 10 µg kg−1 by the European Union. The presented LC-HRMS approach was complemented with a dedicated LC-MS/MS method to improve quantitative measurements of such recurringly found Coccidiostats but also to achieve enhanced sensitivity for Macrocylic lactones.

Combining portable mass spectrometer with bamboo stir bar sorptive extraction for the on-site detection of malachite green, crystal violet and their metabolites in fishes

In this work, a disposable and inexpensive bamboo stir bar containing an organic membrane was constructed to perform stir bar sorptive extraction (SBSE), followed by portable mass spectrometry to achieve on-site detection of four residual drugs (malachite green, crystal violet and their metabolites) in fishes. The entire method uses only microliter quantities of organic solvents, enabling environmentally friendly pretreatment. The portable mass spectrometer can simultaneously detect four target analytes in a sample in approximately ten seconds. Under the optimal conditions, the proposed method was successfully applied to simultaneously detect four drugs in fish samples with detection limits of 0.16-0.59 µg/kg. The spiked recoveries for mandarin fish and lateolabrax maculatus were 74.5-96.5%, with relative standard deviations (RSD) of 4.4-16%. In addition, the matrix effects of the four analytical targets in the method were experimentally verified to range from 7.30% to 20.62%. The method can potentially be extended to the on-site detection of other veterinary drug residues in foods.

Validated Screening Method for 81 Multiclass Veterinary Drug Residues in Food via Online-Coupling High-Throughput Planar Solid-Phase Extraction to High-Performance Liquid Chromatography-Orbitrap Tandem Mass Spectrometry.

Current screening capabilities for veterinary drugs (VDs) in foods are limited, requiring time-consuming and expensive trace-level analyses. For the first time, a high-throughput planar solid-phase extraction (HTpSPE) cleanup, controlled by UV/vis/FLD imaging, was developed for screening 81 VDs from 6 different groups (glucocorticoids, anthelmintics, antiparasitics, coccidiostats, nonsteroidal anti-inflammatory drugs, and antibiotics) in 4 different matrices (honey, pig muscle, cow milk, and chicken eggs). It consumed 13 times less solvent and was more eco-friendly and 5 times faster than routine methods. The VDs were automatically eluted using the autoTLC-LC-MS interface, separated online on a high-performance liquid chromatography column via a 10-min gradient, and detected by Orbitrap high-resolution tandem mass spectrometry. The screening method was validated according to the latest European Commission Implementing Regulation 2021/808. Most VDs except penicillins and cephalosporins were detected at the 5-μg/kg level in pig muscle, cow milk, and chicken eggs and 25-μg/kg level in honey.

Effect of Cistanche deserticola on Rumen Microbiota and Rumen Function in Grazing Sheep

For a long time, veterinary drugs and chemical additives have been widely used in livestock and poultry breeding to improve production performance. However, problems such as drug residues in food are causing serious concerns. The use of functional plants and their extracts to improve production performance is becoming increasingly popular. This study aimed to evaluate the effect of Cistanche deserticola in sheep feed on rumen flora and to analyze the causes to provide a theoretical basis for the future use of Cistanche deserticola as a functional substance to improve sheep production performance. A completely randomized experimental design was adopted using 24 six-month-old sheep males divided into four groups (six animals in each group) which were fed a basic diet composed of alfalfa and tall fescue grass. The C. deserticola feed was provided to sheep at different levels (0, 2, 4, and 6%) as experimental treatments. On the last day (Day 75), ruminal fluid was collected through a rumen tube for evaluating changes in rumen flora. The test results showed that Prevotella_1, Lactobacillus, and Rikenellaceae_RC9_gut_group were the dominant species at the genus level in all samples. Lactobacillus, Rikenellaceae_RC9_gut_group, Ruminococcaceae_NK4A214_group, Butyrivibrio_2, and Christensenellaceae_R-7_group differed significantly in relative abundance among the treatment groups. The polysaccharides in C. deserticola was the major factor influencing the alteration in rumen flora abundance, and had the functions of improving rumen fermentation environment and regulating rumen flora structure, etc. Hence, C. deserticola can be used to regulate rumen fermentation in grazing sheep to improve production efficiency.