Faculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701Fungal carriage in wild birds from Northwestern Türkiye: a descriptive study45145973766610.30466/vrf.2026.2071615.4912ENBüşra AslanAkyolDepartment of Veterinary Pharmacology and Toxicology, Institute of Health Sciences, Balıkesir University, Balıkesir, Türkiye0000-0002-4123-8408MuradGürsesDepartment of Genetics, Faculty of Veterinary Medicine, Balıkesir University, Balıkesir, Türkiye0000-0002-9982-0476MuharremErolDepartment of Surgery, Faculty of Veterinary Medicine, Balıkesir University, Balıkesir, Türkiye0000-0003-0780-9067Eyup TolgaAkyolDepartment of Surgery, Faculty of Veterinary Medicine, Balıkesir University, Balıkesir, Türkiye0000-0002-9775-7557ZiyaİlhanDepartment of Microbiology, Faculty of Veterinary Medicine, Balıkesir University, Balıkesir, Türkiye0000-0003-3638-9196Journal Article20250917Wild birds play a significant role in the dissemination of micro-organisms, including fungal agents, through feathers, skin debris, and feces, both locally and across regions via migration. Identifying fungal carriage in wild birds is crucial for understanding the prevalence of pathogenic fungi and developing effective strategies to prevent and control mycotic infections. This study investigated fungal carriage in wild pigeons, doves, water birds, birds of prey, and small passerines in Balıkesir province of Türkiye, an ecologically important region characterized by key wetlands, two national parks, and major migratory bird routes. A total of 46 wild bird samples were analyzed by culture method, as the “gold standard”, and several clinically important fungal isolates were obtained and subsequently further analyzed by PCR. Fungi were detected across all bird categories, with 27 birds (58.70%) testing positive for at least one fungal species. In total, 10 distinct fungal taxa were isolated from the wild birds. The most frequently identified organisms were Mucor spp. (28.26%) and Aspergillus niger (6.52%), followed by Sporothrix schenckii (4.35%), Candida glabrata (4.30%), Arthroderma terrestre (2.17%), Trichophyton mentagrophytes (2.17%), Nannizzia gypsea (2.17%), Aspergillus flavus (2.17%), Aspergillus fumigatus (2.17%), Lichtheimia spp. (2.17%), and Beauveria spp. (2.17%). Prevalence was the highest in birds of prey and small passerines (77.78%), moderate in pigeons and doves (58.82%), and the lowest in water birds (27.27%). These results emphasize the role of wild birds as potential reservoirs and vectors of fungal agents, highlighting the importance of continued surveillance and biosecurity measures to mitigate the risk of environmental and zoonotic transmissions.https://vrf.iranjournals.ir/article_737666_449b6042e569e2df824ac92ab1c73154.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701First molecular evidence of bovine ephemeral fever virus in Sindh, Pakistan: phylogenetic insights and risk factor correlation46147073747610.30466/vrf.2025.2066094.4842ENSadafFaizDepartment of Pathology, Faculty of Veterinary Science, University of Agriculture, Faisalabad, PakistanAishaKhatoonDepartment of Pathology, Faculty of Veterinary Science, University of Agriculture, Faisalabad, Pakistan0000-0002-6734-4276FarzanaRizviDepartment of Pathology, Faculty of Veterinary Science, University of Agriculture, Faisalabad, PakistanMuhammadSaqibDepartment of Clinical Medicine and Surgery, Faculty of Veterinary Science, University of Agriculture, Faisalabad, PakistanJournal Article20250716Bovine ephemeral fever (BEF) is a re-emerging arbovirus infection, causing substantial economic losses primarily attributed to decreased milk production. BEF is a frequently reported disease in Pakistan, however, there is a lack of scientific data, particularly regarding gene sequencing and phylogenetic analysis of this viral infection in bovines. This research was planned for the molecular detection of the BEF virus in dairy animals of Sindh province, Pakistan. The association of various risk factors, including seasonal variation, species, breed, sex, age, lactation and feeding pattern was also analyzed. A total of 470 blood samples from cattle and buffaloes were collected across different topographical regions of Sindh from 2021-2022; and subjected to molecular detection through RT-PCR. Sequencing of positive RT-PCR amplicons and phylogenetic analysis were then performed. A questionnaire was designed to get comprehensive information about each animal before sample collection to develop an association between various risk factors. RT-PCR amplification of the glycoprotein gene yielded a 420 bp product and the phylogenetic tree revealed that the Pakistani BEF virus isolates clustered closely with strains from Iran, India and Australia indicating a strong genetic resemblance. The overall prevalence was 13.83% (65/470) which significantly higher in cattle (15.49%) than in buffaloes (3.70%), and cattle had significantly higher chance of infection than buffaloes (odds ratio = 4.31, confidence interval = 1.33 - 13.95). This study provided the first comprehensive gene sequencing data on BEF in Pakistan, significantly enhancing the global understanding of the virus through detailed molecular and phylogenetic analysis.https://vrf.iranjournals.ir/article_737476_591609222b60e50e64e0e8f871015324.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701Protective effect of Micromeria congesta essential oil on lipopolysaccharide-induced acute lung injury in rats47147973766510.30466/vrf.2025.2066594.4850ENFuat SerkanKapucukGAP Agricultural Research Institute, Şanlıurfa, Türkiye0000-0001-9037-0125HikmetDinçDepartment of Pharmacology, Faculty of Medicine, Gaziantep Islamic Science and Technology University, Gaziantep, Türkiye0000-0001-7738-1145Muhammed YaşarDörtbudakDepartment of Aquatic Products and Diseases, Department of Preclinical Sciences, Faculty of Veterinary Medicine, University of Harran, Şanlıurfa, Türkiye0000-0001-7966-5678Journal Article20250721Micromeria congesta (MC) is a medicinal plant traditionally used in the Şanlıurfa, Adıyaman, and Gaziantep provinces of Türkiye for treating respiratory disorders. Despite its ethnobotanical relevance, its pharmacological effects on lung inflammation remain unclear. This study evaluated the protective effects of MC essential oil (MCEO) against lipopolysaccharide (LPS)-induced acute lung injury in rats, with a focus on inflammation and tissue damage. The MC was collected from its natural habitat, and its EO was extracted by hydro-distillation using a Clevenger-type apparatus. The Gas chromatography-mass spectrometry analysis revealed 28 compounds, with piperitenone oxide (33.97%) and pulegone (22.30%) as the main constituents. Thirty-six Wistar albino rats were randomly assigned into six groups, including three MCEO-treated (12.50, 25.00, and 50.00 mg kg<sup>-1</sup>), dexamethasone, LPS-only, and control groups. The MCEO was administered by gavage for seven days, followed by intra-venous LPS on day eight (except for the control group). Blood and lung tissues were collected 6 hr later for biochemical, histopathological, and molecular analyses. The MCEO treatment significantly lowered blood glucose and urea levels compared to the LPS group. It also modulated NLRP3, caspase-3, and tumor necrosis factor alpha genes expressions, as determined by RT-PCR analysis, indicating anti-inflammatory effects. Histopathological findings confirmed a dose-dependent reduction in lung inflammation and tissue damage. The MCEO administration alleviated LPS-induced acute lung injury in rats through anti-inflammatory and protective effects, as confirmed by molecular (NLRP3, caspase-3, and tumor necrosis factor alpha) and histopathological analyses. Additionally, MCEO reduced blood glucose and urea levels, supporting its systemic protective role against endotoxin-induced inflammation.https://vrf.iranjournals.ir/article_737665_3bc79dcea60623c80490d0d40649bd4e.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701Effects of different copper sources on performance, carcass characteristics and intestinal histomorphology in broiler chickens48148873702610.30466/vrf.2025.2060328.4755ENNavarAhmad KazemDepartment of Animal Science, Faculty of Agriculture, Urmia University, Urmia, IranMohsenDaneshyarDepartment of Animal Science, Faculty of Agriculture, Urmia University, Urmia, Iran0000-0003-1854-210XAbbasNikooDepartment of Organic Chemistry, Faculty of Chemistry, Urmia University, Urmia, IranGholamrezaNajafiDepartment of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia, IranSeyyed MeysamAbtahi FroushaniDepartment of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran0000-0003-2579-6618Journal Article20250601This study aimed to evaluate the effects of different copper sources experimental copper sulfate (CS), copper methionine (CM), copper carbohydrate, copper dihydrogen phosphate (CP), and nano copper (CN) on growth performance, carcass characteristics and intestinal histomorphology in broiler chickens. A total number of 300-day-old broilers were randomly assigned to five dietary treatments with six replicates each. During the finisher and the whole experimental periods, CM- and CN-fed birds had the highest and lowest body weight gain, respectively compared to the birds in other treatments. Consumption of the CM diet increased the feed intake compared to the different treatments. Feed conversion ratio was increased by consumption of CN compared to CM during the finisher and the whole experimental periods. In the duodenum, villus height (VH) was significantly increased by CN as compared to control. In the jejunum, consumption of both the CM and CC diets caused the lowest VH, whereas dietary CN inclusion resulted in the highest VH. The VH/crypt depth (CD) ratio was at the lowest and the highest levels by CM and CN, respectively. In the ileum, villus width was numerically decreased by CP. The CS-fed birds had the highest CD between the treatments. The VH/CD ratio was higher in CP and CN-fed birds compared to CS ones. Moreover, the goblet cell number was decreased by dietary CP compared to CM. In conclusion, broiler performance was increased by both CM and CP sources of copper, with methionine-based copper being suggested as a component of chicken diets.https://vrf.iranjournals.ir/article_737026_c5edd90f2be3f63e8e45fbc32a68cbea.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701Molecular identification of Avibacterium paragallinarum isolates from backyard and commercial layer chickens in Iran48949673746510.30466/vrf.2025.2064747.4815ENChnoorPoorshamohammadDepartment of Avian Health and Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, IranMohammadHassanzadehDepartment of Avian Health and Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran0000-0003-2288-417XAbbasNouriDepartment of Avian Disease Research and Diagnostics, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, IranMohammad HassanBozorgmehrifardDepartment of Avian Health and Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, IranMohammadAbdoshahDepartment of Avian Disease Research and Diagnostics, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, IranFereshtehSabouriDepartment of Avian Disease Research and Diagnostics, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, IranMohsenBashashatiDepartment of Avian Disease Research and Diagnostics, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran0000-0003-1174-4761Journal Article20250710Infectious coryza, caused by <em>Avibacterium paragallinarum</em>, poses a significant economic threat to the global poultry industry. Although infectious coryza is present in Iran, there is limited molecular data characterizing the circulating strains, particularly regarding key hemagglutinin genes such as hagA. This study aimed to investigate the genetic diversity and phylogenetic relationships of the <em>Av. paragallinarum</em> isolates recovered from commercial and backyard poultry in Iran by sequencing the <em>hagA </em>gene and comparing the findings with those of global strains. Twenty-three <em>Av. paragallinarum</em> isolates collected from Iranian poultry farms underwent PCR amplification and sequencing of the <em>hagA </em>gene. Nucleotide and deduced amino acid sequences were analyzed for homology, subjected to BLAST searches, and used for phylogenetic reconstruction. The isolates showed high sequence identity, ranging from 94.10 - 99.90% at the nucleotide level and 92.10 - 100% at the protein level. Phylogenetic analysis classified the isolates into five distinct clusters (Iran-1 to Iran-5). The largest cluster (Iran-1) showed a strong affiliation with strains from China and India, whereas the other isolates clustered with strains from South Korea, Germany, and Japan. Notably, the Iran-5 group exhibited high similarity to a non-typable strain from USA. Additionally, eight isolates encoded truncated HagA proteins, each consisting of 344 rather than 345 amino acids. This study demonstrates the circulation of genetically diverse <em>Av. paragallinarum</em> strains in Iran. These findings highlight the need for further molecular investigations to improve control measures and assess the efficacy of the vaccines currently used in the country.https://vrf.iranjournals.ir/article_737465_de0ed903fc9889d01e64485414234031.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701In vitro efficacy of Ziziphus vulgaris L. and Camellia sinensis L. extracts against Giardia duodenalis cysts49750373094910.30466/vrf.2025.2064604.4809ENKamalTaheri LakDepartment of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, IranFarnazMalekifardDepartment of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, IranMohammadYakhchaliDepartment of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran0000-0002-5882-1827Journal Article20250701There is an increasing interest in exploring plant extracts as potential new treatment options for these ailments. <em>Ziziphus vulgaris</em> L. and <em>Camellia sinensis</em> (L.) Kuntze are medicinal plants widely used in different traditional medical practices, especially in Iranian traditional medicine, for addressing a range of health issues. Although their biological properties are well-established, their effectiveness against <em>Giardia duodenalis</em> cysts is still uncertain. This research aimed to assess the impact of <em>Z. vulgaris</em> and <em>C. sinensis</em> extracts on <em>G. duodenalis</em> cysts in vitro and to compare their effectiveness with metronidazole. Cysts were extracted from stool samples and concentrated using a 0.85 M sucrose solution. Extracts of <em>Z. vulgaris</em> and <em>C. sinensis</em> were prepared at concentrations of 25.00, 50.00, and 100 mg mL<sup>-1</sup>. The impacts of these extracts at different concentrations were evaluated at 10, 15, 30, 60, and 180 min, and the results were compared to control groups. The collected data were documented and statistically analyzed. The findings revealed that <em>Z. vulgaris</em> extract at a concentration of 100 mg mL<sup>-1</sup> and <em>C. sinensis</em> extract at a concentration of 50.00 mg mL<sup>-1</sup> showed similar effectiveness to metronidazole in eliminating <em>Giardia </em>cysts. In addition, the cytotoxic effects of Z. vulgaris and C. sinensis extracts, in comparison with metronidazole, indicated a rise in fatality rates with prolonged exposure times and higher extract concentrations. Therefore, it could be concluded that extracts of <em>Z. vulgaris</em> and <em>C. sinensis</em> were as effective as metronidazole for killing <em>Giardia </em>cysts in vitro.https://vrf.iranjournals.ir/article_730949_afe394a2ba848309f02c18219cc7d38e.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701Hematological, biochemical, and oxidative stress changes in lambs with atresia ani50551073747710.30466/vrf.2025.2065164.4822ENSeyed Amir HosseinHafezianDVM Graduate, Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, IranAbbasRaisiDepartment of Clinical Sciences, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran0000-0001-8769-4284MeysamTehrani-SharifDepartment of Clinical Science, Faculty of Veterinary Medicine, Islamic Azad University, Garmsar Branch, Garmsar, IranKhosroSafari NikrooResident of Veterinary Surgery and Anesthesia, Department of Clinical Science, Faculty of Veterinary Medicine, Ferdowsi University, Mashhad, IranAmirZakianDepartment of Clinical Sciences, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, IranJournal Article20250708Anal atresia (AA) is a congenital anorectal malformation in neonatal lambs characterized by failure of the anal membrane to perforate, resulting in the absence of an anal opening. Early diagnosis and surgical correction are essential for improving survival and outcomes. This study evaluated hematobiochemical and oxidative stress parameters in neonatal lambs with non-segmental AA undergoing surgical intervention. Forty-five male lambs diagnosed with non-segmental AA were enrolled and stratified by time of presentation: within 24 hours of birth or 24-72 hours. An additional 45 healthy male lambs served as controls. Hematological and biochemical parameters, including white blood cell count, red blood cell count, hemoglobin, packed cell volume, total protein, C-reactive protein, superoxide dismutase, malondialdehyde, globulin, fibrinogen, and urea were measured at presentation and 3 days post-operatively. All AA lambs underwent surgical correction, with clinical follow-up for 30 days. Significant differences in hematobiochemical indices and oxidative stress markers were observed between AA lambs and healthy controls. Early surgical intervention (within 24 hours) was associated with significantly reduced levels of urea, fibrinogen, and C-reactive protein. It also resulted in lower malondialdehyde concentrations and higher superoxide dismutase activity, indicating decreased oxidative stress and inflammation compared with later intervention. These findings highlight the critical importance of early surgical intervention in neonatal lambs with anal atresia. Timely surgery improves hematological stability, mitigates oxidative damage, and supports better overall recovery.https://vrf.iranjournals.ir/article_737477_36835e144d1485488c41a4e119ac55b2.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701Therapeutic effects of ethanol extract of propolis on experimental cutaneous candidiasis in horse51151873509110.30466/vrf.2025.2067879.4863ENSayyed ZakariaMahmoodiDVM Graduate, Faculty of Veterinary Medicine, Urmia University, Urmia, IranVahidNajarnezhadDepartment of Internal Medicine, Faculty of Veterinary Medicine, Urmia University, Urmia, IranGhaderJalilzadeh-AminDepartment of Internal Medicine, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran0000-0003-2869-5492AbdolghaffarOwnaghDepartment of Pathobiology, Faculty of Veterinary Medicine, Amol University of Special Modern, Amol, Iran0000-0002-0119-2310NavidehMirzakhaniPhD Graduated from Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, IranJournal Article20250804<em>Candida albicans</em> is a commensal opportunistic yeast colonizing the skin and mucosal surfaces of humans and animals, which, under specific predisposing conditions, can proliferate excessively and lead to clinical manifestations of candidiasis. The widespread prophylactic and therapeutic use of antifungal agents has led to the emergence of drug-resistant strains, necessitating the exploration of novel therapeutic alternatives. Considering the clinical and conformational significance of equine skin health, the present study aimed to evaluate the therapeutic <em>efficacy</em> of ethanol extract of propolis in an experimental model of cutaneous candidiasis in horses. In 2022, two clinically healthy, six-year-old female horses (approximately 400 kg) were selected for the study. Immunosuppression was induced using dexamethasone and four intradermal inoculation sites were created on the shaved thoracic and flank regions of both lateral aspects using <em>C. albicans</em> (PTCC: 5027) suspension (5 × 10⁶ CFU mL<sup>-1</sup>). The experimental sites on the right thorax were treated with ethanol extract of propolis while those on the left thorax received topical nystatin. Lesions on the right flank were treated with glycerin as a vehicle control, and lesions on the left flank were left untreated. Cutaneous candidiasis was successfully induced within five days post-inoculation. Clinical resolution was observed following five days of treatment with ethanol extract of propolis, whereas, nystatin required eight days to achieve complete lesion resolution. The findings of this study suggested that topical ethanol extract of propolis demonstrated superior efficacy in accelerating the resolution of <em>C. albicans</em>-induced cutaneous lesions in horses compared to nystatin.https://vrf.iranjournals.ir/article_735091_44703a92fa8938b9de1ba34718a664f9.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701Spontaneous primary B cell lymphoblastic lymphoma of the spleen of a 24-month-old male C57BL/6 mouse51952273748710.30466/vrf.2025.2065919.4839ENSoo-EunSungPreclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South KoreaMinkyoungSungPreclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South KoreaKyung-KuKangPreclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South KoreaJae WooParkPreclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South KoreaYe-jinKimPreclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South KoreaSun HeeParkBiotoxtech Co. Ltd., Cheongju, South KoreaDuyeolKimBiotoxtech Co. Ltd., Cheongju, South KoreaSijoonLeePreclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South KoreaJournal Article20250720Spontaneous lymphoid neoplasms are common among aged C57BL/6 mice, predominantly manifesting as T cell lymphomas. However, primary B cell lymphoblastic lymphomas are rare and poorly characterized, especially in laboratory animals. This case report describes a primary B cell lymphoblastic lymphoma in the spleen of a 24-month-old male C57BL/6 mouse. Gross examination revealed an enlarged spleen with a homogenous, white, firm mass replacing the normal parenchyma. Histopathological analysis revealed that the splenic architecture was diffusely replaced by neoplastic lymphoid cells with high mitotic activity. Immunohistochemical staining confirmed the B cell origin of the neoplasm, demonstrating strong CD20 positivity and CD3 negativity. This case underscores the importance of detailed pathological evaluation in aged laboratory mice, especially to distinguish spontaneous lesions from treatment-induced effects in experimental studies. These findings contribute to the understanding of lymphoid neoplasms in laboratory animals, as well as provide valuable reference data for pre-clinical research in toxicology and oncology.https://vrf.iranjournals.ir/article_737487_3a0cc47e57ab00dc9ba87aa222753611.pdfFaculty of Veterinary Medicine, Urmia UniversityVeterinary Research Forum2008-814017720260701A rare case report of active Babesia caballi infection in a mare from Gonbad-e-Kavus, Iran52352573744510.30466/vrf.2026.2070698.4898ENAmiraliAvarsejiDepartment of Clinical Science, Faculty of Veterinary Medicine University of Tehran, Tehran, Iran0009-0003-6014-9683FarimaJahromiDepartment of clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, IranBarsamPirali HamedaneeDepartment of Veterinary Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, IranSoheilMohammadparastDepartment of Veterinary Medicine, Faculty of Veterinary Medicine, Islamic Azad University, Tabriz Branch, Tabriz, IranJournal Article20250908<em>Babesia caballi</em> is a tick-borne protozoan parasite responsible for causing equine babesiosis, a disease with considerable variation in prevalence across different regions of the world. This report presented a confirmed case of <em>B. caballi</em> infection in a three-year-old mare originating from Gonbad-e Kavus, Iran, highlighting the clinical, laboratory and diagnostic aspects of the disease. The affected mare showed classical clinical signs including persistent fever, generalized weakness, tachycardia and pale mucous membranes, which are indicative of systemic infection and anemia. Laboratory evaluations revealed evidence of hepatic and renal compromise as well as hematological parameters consistent with active inflammatory processes. Microscopic examination of blood smears and molecular techniques such as PCR were employed to confirm the presence of <em>B. caballi</em>, while simultaneously excluding co-infections with other common equine pathogens including <em>Theileria equi</em> and <em>Anaplasma phagocytophilum</em>. This case underscored the critical need to combine conventional diagnostic approaches with molecular methods to achieve accurate detection, effective treatment and appropriate management strategies for equine babesiosis in endemic regions.https://vrf.iranjournals.ir/article_737445_7149a0fa984bd17e705717acc19c3bea.pdf