Transcriptional responses in Parascaris univalens after in vitro exposure to ivermectin, pyrantel citrate and thiabendazole.
Abstract: Parascaris univalens is a pathogenic parasite of foals and yearlings worldwide. In recent years, Parascaris spp. worms have developed resistance to several of the commonly used anthelmintics, though currently the mechanisms behind this development are unknown. The aim of this study was to investigate the transcriptional responses in adult P. univalens worms after in vitro exposure to different concentrations of three anthelmintic drugs, focusing on drug targets and drug metabolising pathways. Methods: Adult worms were collected from the intestines of two foals at slaughter. The foals were naturally infected and had never been treated with anthelmintics. Worms were incubated in cell culture media containing different concentrations of either ivermectin (10 M, 10 M, 10 M), pyrantel citrate (10 M, 10 M, 10 M), thiabendazole (10 M, 10 M, 10 M) or without anthelmintics (control) at 37 °C for 24 h. After incubation, the viability of the worms was assessed and RNA extracted from the anterior region of 36 worms and sequenced on an Illumina NovaSeq 6000 system. Results: All worms were alive at the end of the incubation but showed varying degrees of viability depending on the drug and concentration used. Differential expression (Padj < 0.05 and log2 fold change ≥ 1 or ≤ - 1) analysis showed similarities and differences in the transcriptional response after exposure to the different drug classes. Candidate genes upregulated or downregulated in drug exposed worms include members of the phase I metabolic pathway short-chain dehydrogenase/reductase superfamily (SDR), flavin containing monooxygenase superfamily (FMO) and cytochrome P450-family (CYP), as well as members of the membrane transporters major facilitator superfamily (MFS) and solute carrier superfamily (SLC). Generally, different targets of the anthelmintics used were found to be upregulated and downregulated in an unspecific pattern after drug exposure, apart from the GABA receptor subunit lgc-37, which was upregulated only in worms exposed to 10 M of ivermectin. Conclusions: To our knowledge, this is the first time the expression of lgc-37 and members of the FMO, SDR, MFS and SLC superfamilies have been described in P. univalens and future work should be focused on characterising these candidate genes to further explore their potential involvement in drug metabolism and anthelmintic resistance.
Publication Date: 2020-07-09 PubMed ID: 32646465PubMed Central: PMC7346371DOI: 10.1186/s13071-020-04212-0Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This study explored the reactions of a particular horse pathogen, Parascaris univalens, to different doses of common deworming drugs. The results showed varying degrees of resilience dependent on the drug and dosage, with some genes in the worm apparently adapting to resist the drugs.
Introduction
- Parascaris univalens is a pathogenic parasite causing disease in young horses (foals and yearlings).
- These worms have developed resistance recently to several commonly used deworming drugs, or anthelmintics, but how they do this is not well understood.
- The study aims to further understand this resistance by studying the genetic responses of these worms when exposed to different concentrations of three deworming drugs.
Methods
- The worms were harvested from two foals that had naturally contracted the parasite and had not been previously treated with anthelmintics.
- These worms were then exposed to media containing either ivermectin, pyrantel citrate, or thiabendazole or left untreated (control).
- After 24 hours of drug exposure, the survival of the worms was verified and RNA extracted to understand their genetic responses to the drugs.
Results
- All worms survived the incubation, but with different levels of viability based on the specific drug and its concentration.
- Analysis of gene expression revealed that specific genes were either downregulated or upregulated after exposure to the different drugs.
- These genes are part of metabolic pathways, including the short-chain dehydrogenase/reductase superfamily (SDR), the flavin containing monooxygenase superfamily (FMO), the cytochrome P450-family (CYP), and make up part of the cell membrane transport structures (major facilitator superfamily (MFS), and solute carrier superfamily (SLC)).
- Generally, these genes, which are also targets of the anthelmintics used, were either upregulated or downregulated in a nonspecific pattern, with the exception of the GABA receptor subunit lgc-37, which was only upregulated in worms exposed to ivermectin.
Conclusions
- The study reports, for the first time, the response of the lgc-37 gene and members of several superfamilies (FMO, SDR, MFS, SLC) in Parascaris univalens to exposure to anthelmintics.
- Future research will focus on these genes to better understand their role in the worms’ ability to metabolize the drugs and develop resistance.
Cite This Article
APA
Martin F, Dube F, Karlsson Lindsjö O, Eydal M, Höglund J, Bergström TF, Tydén E.
(2020).
Transcriptional responses in Parascaris univalens after in vitro exposure to ivermectin, pyrantel citrate and thiabendazole.
Parasit Vectors, 13(1), 342.
https://doi.org/10.1186/s13071-020-04212-0 Publication
Researcher Affiliations
- Division of Parasitology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7036, 750 07, Uppsala, Sweden. Frida.Martin@slu.se.
- Division of Parasitology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7036, 750 07, Uppsala, Sweden.
- SLU-Global Bioinformatics Centre, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, 750 07, Uppsala, Sweden.
- Institute for Experimental Pathology at Keldur, University of Iceland, Keldnavegur 3, 112, Reykjavik, Iceland.
- Division of Parasitology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7036, 750 07, Uppsala, Sweden.
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, 750 07, Uppsala, Sweden.
- Division of Parasitology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7036, 750 07, Uppsala, Sweden.
MeSH Terms
- Animals
- Anthelmintics / metabolism
- Anthelmintics / pharmacology
- Ascaridida Infections / metabolism
- Ascaridida Infections / veterinary
- Ascaridoidea / drug effects
- Ascaridoidea / metabolism
- Drug Resistance
- Horse Diseases / metabolism
- Horse Diseases / parasitology
- Horses
- Ivermectin / metabolism
- Ivermectin / pharmacology
- Pyrantel / analogs & derivatives
- Pyrantel / metabolism
- Pyrantel / pharmacology
- Thiabendazole / metabolism
- Thiabendazole / pharmacology
- Transcriptome / drug effects
Grant Funding
- 942-2015-508 / Svenska Forskningsru00e5det Formas
Conflict of Interest Statement
The authors declare that they have no competing interests.
References
This article includes 65 references
- Nielsen MK, Wang J, Davis R, Bellaw JL, Lyons ET, Lear TL, Goday C. Parascaris univalens--a victim of large-scale misidentification?. Parasitol Res 2014 Dec;113(12):4485-90.
- Jabbar A, Littlewood DT, Mohandas N, Briscoe AG, Foster PG, Müller F, von Samson-Himmelstjerna G, Jex AR, Gasser RB. The mitochondrial genome of Parascaris univalens--implications for a "forgotten" parasite.. Parasit Vectors 2014 Sep 4;7:428.
- Martin F, Höglund J, Bergström TF, Karlsson Lindsjö O, Tydén E. Resistance to pyrantel embonate and efficacy of fenbendazole in Parascaris univalens on Swedish stud farms.. Vet Parasitol 2018 Dec 15;264:69-73.
- Cribb NC, Cote NM, Bouré LP, Peregrine AS. Acute small intestinal obstruction associated with Parascaris equorum infection in young horses: 25 cases (1985-2004).. N Z Vet J 2006 Dec;54(6):338-43.
- Clayton HM, Duncan JL. Clinical signs associated with Parascaris equorum infection in worm-free pony foals and yearlings.. Vet Parasitol 1978;4:69–78.
- National Veterinary Institute. Avmaskning mot spolmask. 2019. http://www.sva.se/djurhalsa/hast/parasiter-hos-hast/avmaskning-av-hast. Accessed 3 Mar 2020.
- Martin R, Robertson A, Wolstenholme A. Mode of action of the macrocyclic lactones.. In: Vercruysse J, Rew RS, editors. Macrocyclic lactones in antiparasitic therapy. Wallingford: CABI Publishing; 2002. pp. 125–140.
- Lacey E. Mode of action of benzimidazoles.. Parasitol Today 1990 Apr;6(4):112-5.
- Martin RJ, Robertson AP. Mode of action of levamisole and pyrantel, anthelmintic resistance, E153 and Q57.. Parasitology 2007;134(Pt 8):1093-104.
- Reinemeyer CR. Diagnosis and control of anthelmintic-resistant Parascaris equorum.. Parasit Vectors 2009 Sep 25;2 Suppl 2(Suppl 2):S8.
- Boersema JH, Eysker M, Nas JW. Apparent resistance of Parascaris equorum to macrocylic lactones.. Vet Rec 2002 Mar 2;150(9):279-81.
- Peregrine AS, Molento MB, Kaplan RM, Nielsen MK. Anthelmintic resistance in important parasites of horses: does it really matter?. Vet Parasitol 2014 Mar 17;201(1-2):1-8.
- Lyons ET, Tolliver SC, Ionita M, Collins SS. Evaluation of parasiticidal activity of fenbendazole, ivermectin, oxibendazole, and pyrantel pamoate in horse foals with emphasis on ascarids (Parascaris equorum) in field studies on five farms in Central Kentucky in 2007.. Parasitol Res 2008 Jul;103(2):287-91.
- Armstrong SK, Woodgate RG, Gough S, Heller J, Sangster NC, Hughes KJ. The efficacy of ivermectin, pyrantel and fenbendazole against Parascaris equorum infection in foals on farms in Australia.. Vet Parasitol 2014 Oct 15;205(3-4):575-80.
- Hautala K, Näreaho A, Kauppinen O, Nielsen MK, Sukura A, Rajala-Schultz PJ. Risk factors for equine intestinal parasite infections and reduced efficacy of pyrantel embonate against Parascaris sp.. Vet Parasitol 2019 Sep;273:52-59.
- Alanazi AD, Mukbel RM, Alyousif MS, AlShehri ZS, Alanazi IO, Al-Mohammed HI. A field study on the anthelmintic resistance of Parascaris spp. in Arab foals in the Riyadh region, Saudi Arabia.. Vet Q 2017 Dec;37(1):200-205.
- Wang J, Gao S, Mostovoy Y, Kang Y, Zagoskin M, Sun Y, Zhang B, White LK, Easton A, Nutman TB, Kwok PY, Hu S, Nielsen MK, Davis RE. Comparative genome analysis of programmed DNA elimination in nematodes.. Genome Res 2017 Dec;27(12):2001-2014.
- Kwa MS, Veenstra JG, Roos MH. Benzimidazole resistance in Haemonchus contortus is correlated with a conserved mutation at amino acid 200 in beta-tubulin isotype 1.. Mol Biochem Parasitol 1994 Feb;63(2):299-303.
- Silvestre A, Cabaret J. Mutation in position 167 of isotype 1 beta-tubulin gene of Trichostrongylid nematodes: role in benzimidazole resistance?. Mol Biochem Parasitol 2002 Apr 9;120(2):297-300.
- Ghisi M, Kaminsky R, Mäser P. Phenotyping and genotyping of Haemonchus contortus isolates reveals a new putative candidate mutation for benzimidazole resistance in nematodes.. Vet Parasitol 2007 Mar 31;144(3-4):313-20.
- Feng XP, Hayashi J, Beech RN, Prichard RK. Study of the nematode putative GABA type-A receptor subunits: evidence for modulation by ivermectin.. J Neurochem 2002 Nov;83(4):870-8.
- Beech R, Levitt N, Cambos M, Zhou S, Forrester SG. Association of ion-channel genotype and macrocyclic lactone sensitivity traits in Haemonchus contortus.. Mol Biochem Parasitol 2010 Jun;171(2):74-80.
- Laing R, Maitland K, Lecová L, Skuce PJ, Tait A, Devaney E. Analysis of putative resistance gene loci in UK field populations of Haemonchus contortus after 6years of macrocyclic lactone use.. Int J Parasitol 2016 Sep;46(10):621-30.
- El-Abdellati A, De Graef J, Van Zeveren A, Donnan A, Skuce P, Walsh T, Wolstenholme A, Tait A, Vercruysse J, Claerebout E, Geldhof P. Altered avr-14B gene transcription patterns in ivermectin-resistant isolates of the cattle parasites, Cooperia oncophora and Ostertagia ostertagi.. Int J Parasitol 2011 Aug 1;41(9):951-7.
- James CE, Hudson AL, Davey MW. Drug resistance mechanisms in helminths: is it survival of the fittest?. Trends Parasitol 2009 Jul;25(7):328-35.
- Matoušková P, Vokřál I, Lamka J, Skálová L. The Role of Xenobiotic-Metabolizing Enzymes in Anthelmintic Deactivation and Resistance in Helminths.. Trends Parasitol 2016 Jun;32(6):481-491.
- Daborn P, Boundy S, Yen J, Pittendrigh B, ffrench-Constant R. DDT resistance in Drosophila correlates with Cyp6g1 over-expression and confers cross-resistance to the neonicotinoid imidacloprid.. Mol Genet Genomics 2001 Dec;266(4):556-63.
- Yilmaz E, Ramünke S, Demeler J, Krücken J. Comparison of constitutive and thiabendazole-induced expression of five cytochrome P450 genes in fourth-stage larvae of Haemonchus contortus isolates with different drug susceptibility identifies one gene with high constitutive expression in a multi-resistant isolate.. Int J Parasitol Drugs Drug Resist 2017 Dec;7(3):362-369.
- Matoušková P, Lecová L, Laing R, Dimunová D, Vogel H, Raisová Stuchlíková L, Nguyen LT, Kellerová P, Vokřál I, Lamka J, Szotáková B, Várady M, Skálová L. UDP-glycosyltransferase family in Haemonchus contortus: Phylogenetic analysis, constitutive expression, sex-differences and resistance-related differences.. Int J Parasitol Drugs Drug Resist 2018 Dec;8(3):420-429.
- Xu M, Molento M, Blackhall W, Ribeiro P, Beech R, Prichard R. Ivermectin resistance in nematodes may be caused by alteration of P-glycoprotein homolog.. Mol Biochem Parasitol 1998 Mar 15;91(2):327-35.
- Dicker AJ, Nisbet AJ, Skuce PJ. Gene expression changes in a P-glycoprotein (Tci-pgp-9) putatively associated with ivermectin resistance in Teladorsagia circumcincta.. Int J Parasitol 2011 Aug 1;41(9):935-42.
- Raza A, Kopp SR, Bagnall NH, Jabbar A, Kotze AC. Effects of in vitro exposure to ivermectin and levamisole on the expression patterns of ABC transporters in Haemonchus contortus larvae.. Int J Parasitol Drugs Drug Resist 2016 Aug;6(2):103-15.
- Scare JA, Dini P, Norris JK, Steuer AE, Scoggin K, Gravatte HS, Howe DK, Slusarewicz P, Nielsen MK. Ascarids exposed: a method for in vitro drug exposure and gene expression analysis of anthelmintic naïve Parascaris spp.. Parasitology 2020 May;147(6):659-666.
- Janssen IJ, Krücken J, Demeler J, Basiaga M, Kornaś S, von Samson-Himmelstjerna G. Genetic variants and increased expression of Parascaris equorum P-glycoprotein-11 in populations with decreased ivermectin susceptibility.. PLoS One 2013;8(4):e61635.
- Zhao J, Williams AR, Hansen TVA, Thamsborg SM, Cai J, Song S, Chen G, Kang M, Zhang Z, Liu Q, Han Q. An in vitro larval migration assay for assessing anthelmintic activity of different drug classes against Ascaris suum.. Vet Parasitol 2017 Apr 30;238:43-48.
- Scare JA, Steuer AE, Shaffer CL, Slusarewicz P, Mousley A, Nielsen MK. Long live the worms: methods for maintaining and assessing the viability of intestinal stages of Parascaris spp. in vitro.. Parasitology 2019 Apr;146(5):685-693.
- Chen S, Zhou Y, Chen Y, Gu J. fastp: an ultra-fast all-in-one FASTQ preprocessor.. Bioinformatics 2018 Sep 1;34(17):i884-i890.
- Patro R, Duggal G, Love MI, Irizarry RA, Kingsford C. Salmon provides fast and bias-aware quantification of transcript expression.. Nat Methods 2017 Apr;14(4):417-419.
- Soneson C, Love MI, Robinson MD. Differential analyses for RNA-seq: transcript-level estimates improve gene-level inferences.. F1000Res 2015;4:1521.
- Love MI, Huber W, Anders S. Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2.. Genome Biol 2014;15(12):550.
- Benjamini Y, Hochberg Y. Controlling the false discovery rate: a practical and powerful approach to multiple testing.. J R Stat Soc Series B Stat Methodol 1995;57:289–300.
- R Development Core Team. R: a language and environment for statistical computing.. Vienna: R Foundation for Statistical Computing; 2018.
- . UniProt: a worldwide hub of protein knowledge.. Nucleic Acids Res 2019 Jan 8;47(D1):D506-D515.
- Chen H, Boutros PC. VennDiagram: a package for the generation of highly-customizable Venn and Euler diagrams in R.. BMC Bioinformatics 2011 Jan 26;12:35.
- Tydén E, Dahlberg J, Karlberg O, Höglund J. Deep amplicon sequencing of preselected isolates of Parascaris equorum in β-tubulin codons associated with benzimidazole resistance in other nematodes.. Parasit Vectors 2014 Aug 29;7:410.
- Kopp SR, Coleman GT, Traub RJ, McCarthy JS, Kotze AC. Acetylcholine receptor subunit genes from Ancylostoma caninum: altered transcription patterns associated with pyrantel resistance.. Int J Parasitol 2009 Mar;39(4):435-41.
- Neveu C, Charvet CL, Fauvin A, Cortet J, Beech RN, Cabaret J. Genetic diversity of levamisole receptor subunits in parasitic nematode species and abbreviated transcripts associated with resistance.. Pharmacogenet Genomics 2010 Jul;20(7):414-25.
- Tydén E, Engström A, Morrison DA, Höglund J. Sequencing of the β-tubulin genes in the ascarid nematodes Parascaris equorum and Ascaridia galli.. Mol Biochem Parasitol 2013 Jul;190(1):38-43.
- Martis MM, Tarbiat B, Tydén E, Jansson DS, Höglund J. RNA-Seq de novo assembly and differential transcriptome analysis of the nematode Ascaridia galli in relation to in vivo exposure to flubendazole.. PLoS One 2017;12(11):e0185182.
- Kotze AC, Hunt PW, Skuce P, von Samson-Himmelstjerna G, Martin RJ, Sager H, Krücken J, Hodgkinson J, Lespine A, Jex AR, Gilleard JS, Beech RN, Wolstenholme AJ, Demeler J, Robertson AP, Charvet CL, Neveu C, Kaminsky R, Rufener L, Alberich M, Menez C, Prichard RK. Recent advances in candidate-gene and whole-genome approaches to the discovery of anthelmintic resistance markers and the description of drug/receptor interactions.. Int J Parasitol Drugs Drug Resist 2014 Dec;4(3):164-84.
- Tydén E, Skarin M, Andersson-Franko M, Sjöblom M, Höglund J. Differential expression of β-tubulin isotypes in different life stages of Parascaris spp after exposure to thiabendazole.. Mol Biochem Parasitol 2016 Jan-Feb;205(1-2):22-8.
- Cheung CH, Wu SY, Lee TR, Chang CY, Wu JS, Hsieh HP, Chang JY. Cancer cells acquire mitotic drug resistance properties through beta I-tubulin mutations and alterations in the expression of beta-tubulin isotypes.. PLoS One 2010 Sep 3;5(9):e12564.
- Kavallaris M, Kuo DY, Burkhart CA, Regl DL, Norris MD, Haber M, Horwitz SB. Taxol-resistant epithelial ovarian tumors are associated with altered expression of specific beta-tubulin isotypes.. J Clin Invest 1997 Sep 1;100(5):1282-93.
- Kallberg Y, Oppermann U, Persson B. Classification of the short-chain dehydrogenase/reductase superfamily using hidden Markov models.. FEBS J 2010 May;277(10):2375-86.
- Matsunaga T, Shintani S, Hara A. Multiplicity of mammalian reductases for xenobiotic carbonyl compounds.. Drug Metab Pharmacokinet 2006 Feb;21(1):1-18.
- Kisiela M, El-Hawari Y, Martin HJ, Maser E. Bioinformatic and biochemical characterization of DCXR and DHRS2/4 from Caenorhabditis elegans.. Chem Biol Interact 2011 May 30;191(1-3):75-82.
- Soldan M, Netter KJ, Maser E. Induction of daunorubicin carbonyl reducing enzymes by daunorubicin in sensitive and resistant pancreas carcinoma cells.. Biochem Pharmacol 1996 Jan 26;51(2):117-23.
- Stasiuk SJ, MacNevin G, Workentine ML, Gray D, Redman E, Bartley D, Morrison A, Sharma N, Colwell D, Ro DK, Gilleard JS. Similarities and differences in the biotransformation and transcriptomic responses of Caenorhabditis elegans and Haemonchus contortus to five different benzimidazole drugs.. Int J Parasitol Drugs Drug Resist 2019 Dec;11:13-29.
- Cvilink V, Kubícek V, Nobilis M, Krízová V, Szotáková B, Lamka J, Várady M, Kubenová M, Novotná R, Gavelová M, Skálová L. Biotransformation of flubendazole and selected model xenobiotics in Haemonchus contortus.. Vet Parasitol 2008 Feb 14;151(2-4):242-8.
- Cashman JR. Monoamine oxidases and flavin-containing monooxygenases.. In: McQueen CA, editor. Comprehensice toxicology. Amsterdam: Elsevier; 2018. pp. 87–125.
- Alvarez LI, Solana HD, Mottier ML, Virkel GL, Fairweather I, Lanusse CE. Altered drug influx/efflux and enhanced metabolic activity in triclabendazole-resistant liver flukes.. Parasitology 2005 Oct;131(Pt 4):501-10.
- Brennan GP, Fairweather I, Trudgett A, Hoey E, McCoy, McConville M, Meaney M, Robinson M, McFerran N, Ryan L, Lanusse C, Mottier L, Alvarez L, Solana H, Virkel G, Brophy PM. Understanding triclabendazole resistance.. Exp Mol Pathol 2007 Apr;82(2):104-9.
- Vokřál I, Jirásko R, Stuchlíková L, Bártíková H, Szotáková B, Lamka J, Várady M, Skálová L. Biotransformation of albendazole and activities of selected detoxification enzymes in Haemonchus contortus strains susceptible and resistant to anthelmintics.. Vet Parasitol 2013 Sep 23;196(3-4):373-81.
- Paulsen IT, Brown MH, Skurray RA. Proton-dependent multidrug efflux systems.. Microbiol Rev 1996 Dec;60(4):575-608.
- Höglund PJ, Nordström KJ, Schiöth HB, Fredriksson R. The solute carrier families have a remarkably long evolutionary history with the majority of the human families present before divergence of Bilaterian species.. Mol Biol Evol 2011 Apr;28(4):1531-41.
Citations
This article has been cited 6 times.- Cain JL, Nielsen MK. The equine ascarids: resuscitating historic model organisms for modern purposes.. Parasitol Res 2022 Oct;121(10):2775-2791.
- Tuersong W, Zhou C, Wu S, Qin P, Wang C, Di W, Liu L, Liu H, Hu M. Comparative analysis on transcriptomics of ivermectin resistant and susceptible strains of Haemonchus contortus.. Parasit Vectors 2022 May 7;15(1):159.
- Dube F, Hinas A, Roy S, Martin F, Åbrink M, Svärd S, Tydén E. Ivermectin-induced gene expression changes in adult Parascaris univalens and Caenorhabditis elegans: a comparative approach to study anthelminthic metabolism and resistance in vitro.. Parasit Vectors 2022 May 5;15(1):158.
- Polak I, Stryiński R, Podolska M, Pawlak J, Bittner MW, Wiśniewski G, Sienkiewicz-Szłapka E, Łopieńska-Biernat E. Drug efficacy on zoonotic nematodes of the Anisakidae family: new metabolic data.. Parasitology 2022 Jul;149(8):1065-1077.
- Guo Q, Atkinson SD, Xiao B, Zhai Y, Bartholomew JL, Gu Z. A myxozoan genome reveals mosaic evolution in a parasitic cnidarian.. BMC Biol 2022 Feb 18;20(1):51.
- Martin F, Halvarsson P, Delhomme N, Höglund J, Tydén E. Exploring the β-tubulin gene family in a benzimidazole-resistant Parascaris univalens population.. Int J Parasitol Drugs Drug Resist 2021 Dec;17:84-91.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists