Hostname: page-component-76fb5796d-x4r87 Total loading time: 0 Render date: 2024-04-29T05:49:36.735Z Has data issue: false hasContentIssue false
  • English
  • Français

An Evaluation of the Supplementation of Dietary-Modified Palygorskite on Growth Performance, Zearalenone Residue, Serum Metabolites, and Antioxidant Capacities in Broilers Fed a Zearalenone-Contaminated Diet

Published online by Cambridge University Press:  01 January 2024

Qiao Xu ,
Yueping Chen ,
Yefei Cheng ,
Yue Su ,
Chao Wen ,
Wenbo Wang ,
Aiqin Wang  and
Yanmin Zhou
Qiao Xu
Affiliation:
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P.R. China
Yueping Chen
Affiliation:
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P.R. China
Yefei Cheng
Affiliation:
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P.R. China
Yue Su
Affiliation:
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P.R. China
Chao Wen
Affiliation:
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P.R. China
Wenbo Wang
Affiliation:
Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P.R. China R&D Center of Xuyi Palygorskite Applied Technology, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Xuyi 211700, P.R. China
Aiqin Wang
Affiliation:
Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P.R. China R&D Center of Xuyi Palygorskite Applied Technology, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Xuyi 211700, P.R. China
Yanmin Zhou*
Affiliation:
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P.R. China
*
*E-mail address of corresponding author: zhouym6308@163.com
Get access Rights & Permissions [Opens in a new window]

Abstract

Zearalenone (ZEA), a common contaminant in food and feedstuffs, threatens human and animal health. The present study aimed to investigate the protective effects of modified palygorskite (MPal), a ZEA-targeted adsorbent, on broilers (young chickens) fed a ZEA-contaminated diet. Broilers were subjected to one of three treatments for a period of 42 days: a basal diet (control group), a ZEA- contaminated diet, and a ZEA-contaminated diet supplemented with 1 g/kg of MPal. Blood was collected for serum metabolite assay, and liver and kidney were sampled to determine ZEA residue and antioxidant-related parameters, using commercial spectrophotometric kits. Compared with the basal diet, the ZEA- contaminated diet resulted in compromised growth performance (reduced daily gain and feed intake during finisher period), disordered relative liver weight (decreased at 21 days but increased at 42 days), increased ZEA residue in liver and kidney, abnormal serum metabolites (decreased total protein content but increased alanine aminotransferase activity at 21 and 42 days, reduced albumin content at 21 days, and elevated aspartate aminotransferase activity at 42 days), and disrupted antioxidant capacities of broilers (increased total superoxide dismutase (T-SOD) activity in liver at 21 and 42 days, decreased T-SOD activity in kidney at 21 and 42 days, and in serum at 42 days, greater malondialdehyde accumulation in liver and kidney at 42 days, and lower glutathione content in kidney at 21 days). The adverse consequences resulting from the ZEA-contaminated diet were relieved by the supplementation of MPal (except albumin concentration in serum and T-SOD activity in liver at 21 days), with the values of growth-performance parameters, liver weight, renal ZEA accumulation, total protein content, transaminase activity at 42 days, and antioxidant indexes being similar to those in the control group. These results suggested that MPal supplementation could promote growth performance, attenuate liver damage, and improve the antioxidant abilities of broilers fed ZEA-contaminated diet by reducing ZEA accumulation.

Keywords

BroilersKidneyLiverModified PalygorskiteZearalenone
Type
Article
Information
Clays and Clay Minerals , Volume 66 , Issue 6 , December 2018 , pp. 474 - 484
Copyright
Copyright © Clay Minerals Society 2018

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abbès, S. Ouanes, Z. Salah-Abbès, J.B. Houas, Z. Oueslati, R. Bacha, H. and Othman, O., 2006 The protective effect of hydrated sodium calcium aluminosilicate against haematological, biochemical and pathological changes induced by Zearalenone in mice Toxicon 47 567–574.CrossRefGoogle ScholarPubMed
Abidessefi, S. Ouanes, Z. Hassen, W. Baudrimont, I. Creppy, E. and Bacha, H., 2004 Cytotoxicity, inhibition of DNA and protein syntheses and oxidative damage in cultured cells exposed to zearalenone Toxicology in Vitro 18 467–474.CrossRefGoogle ScholarPubMed
Allen, N.K. Mirocha, C.J. Aakhus-Allen, S. Bitgood, J.J. Weaver, G. and Bates, F., 1981 Effect of dietary zearalenone on reproduction of chickens Poultry Science 60 1165–1174.CrossRefGoogle ScholarPubMed
Allen, N.K. Mirocha, C.J. Weaver, G. Aakhusallen, S. and Bates, F., 1981 Effects of dietary zearalenone on finishing broiler chickens and young turkey poults Poultry Science 60 124–131.CrossRefGoogle ScholarPubMed
Allen, N.K. Peguri, A. Mirocha, C.J. and Newman, J.A., 1983 Effects of fusarium cultures, T-2 toxin, and zearalenone on reproduction of turkey females Poultry Science 62 282–289.CrossRefGoogle ScholarPubMed
AQSIQ, GB/T 13078-2017 Hygienical Standard for Feeds. 2017 Inspection and Quarantine of the People’s Republic of China General Administration of Quality Supervision.Google Scholar
Aravind, K.L. Patil, V.S. Devegowda, G.B. Umakantha, B. and Ganpule, S.P., 2003 Efficacy of esterified glucomannan to counteract mycotoxicosis in naturally contaminated feed on performance and serum biochemical and hematological parameters in broilers Poultry Science 82 571–576.CrossRefGoogle ScholarPubMed
Ben, S.I. Boussabbeh, M. Helali, S. Abid-Essefi, S. and Bacha, H., 2015 Protective effect of Crocin against zearalenone-induced oxidative stress in liver and kidney of Balb/c mice Environmental Science and Pollution Research 22 19069–19076.Google Scholar
Bergaya, F. and Lagaly, G. e., 2013 Handbook of Clay Science 2nd Amsterdam Elsevier.Google Scholar
Binder, E.M. Tan, L.M. Chin, L.J. Handl, J. and Richard, J., 2007 Worldwide occurrence of mycotoxins in commodities, feeds and feed ingredients Animal Feed Science and Technology 137 265–282.CrossRefGoogle Scholar
Bočarovstančić, A. Adamovic, M. Salma, N. Bodrozasolarov, M. Vučković, J. and Pantić, V., 2011 In vitro efficacy of mycotoxins’ adsorption by natural mineral adsorbents Biotechnology in Animal Husbandry 27 1241–1251.CrossRefGoogle Scholar
Bradford, M., 1976 A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding Analytical Biochemistry 72 248–254.CrossRefGoogle ScholarPubMed
Buranatragool, K. Poapolathep, S. Isariyodom, S. Imsilp, K. Klangkaew, N. and Poapolathep, A., 2015 Dispositions and tissue residue of zearalenone and its metabolites α-zearalenol and β-zearalenol in broilers Toxicology Reports 2 351–356.CrossRefGoogle ScholarPubMed
Cavret, S. and Lecoeur, S., 2006 Fusariotoxin transfer in animal Food and Chemistry Toxicology 44 444–453.CrossRefGoogle ScholarPubMed
Chalvatzi, S. Arsenos, G. Tserveni-Goussi, A. and Fortomaris, P., 2014 Tolerance and efficacy study of palygorskite incorporation in the diet of laying hens Applied Clay Science 101 643–647.CrossRefGoogle Scholar
Che, Z. Liu, Y. Wang, H. Zhu, H. Hou, Y. and Ding, B., 2011 The protective effects of different mycotoxin adsorbents against blood and liver pathological changes induced by mold-contaminated feed in broilers Asian-Australasian Journal of Animal Science 24 250–257.CrossRefGoogle Scholar
Chowdhury, S.R. and Smith, T.K., 2007 Effects of feed-borne Fusarium mycotoxins on performance, plasma chemistry and hepatic fractional protein synthesis rates of turkeys Canadian Journal of Animal Science 87 543–551.CrossRefGoogle Scholar
Čonkovaá, E. Laciakovaá, A. Paástorovaá, B. Seidel, H. and Kovaác, G., 2001 The effect of zearalenone on some enzymatic parameters in rabbits Toxicology Letters 121 145–149.CrossRefGoogle Scholar
Daković, A. Matijašević, S. Rottinghaus, G.E. Dondur, V. Pietrass, T. and Clewett, C.F., 2007 Adsorption of zearalenone by organomodified natural zeolitic tuff Jounal of Colloid and Interface Science 311 8–13.CrossRefGoogle ScholarPubMed
Daković, A. Matijasevic, S. Rottinghaus, G.E. Ledoux, D.R. Butkeraitis, P. and Sekulic, Z., 2008 Aflatoxin B1 adsorption by natural and copper modified montmorillonite Colloids and Surfaces B: Biointerfaces 66 20–25.CrossRefGoogle ScholarPubMed
Daković, A. Kragović, M. Rottinghaus, G.E. Ledoux, D.R. Butkeraitis, P. Vojislavljević, D.Z. Zarić, S.D. and Stamenić, L., 2012 Preparation and characterization of zinc-exchanged montmorillonite and its effectiveness as aflatoxin B1 adsorbent Materials Chemistry and Physics 137 213–220.CrossRefGoogle Scholar
Daänicke, S. Ueberschaär, K.H. Halle, I. Matthes, S. Valenta, H. and Flachowsky, G., 2002 Effect of addition of a detoxifying agent to laying hen diets containing uncontaminated or Fusarium toxin-contaminated maize on performance of hens and on carryover of zearalenone Poultry Science 81 1671–1680.CrossRefGoogle Scholar
Daänicke, S. Matthes, S. Halle, I. Ueberschaär, K.H. Döll, S. and Valenta, H., 2003 Effects of graded levels of Fusarium toxin-contaminated wheat and of a detoxifying agent in broiler diets on performance, nutrient digestibility and blood chemical parameters British Poultry Science 44 113–126.CrossRefGoogle Scholar
Denli, M. Blandon, J.C. Salado, S. Guynot, M.E. and Pérez, J.F., 2017 Effect of dietary zearalenone on the performance, reproduction tract and serum biochemistry in young rats Journal of Applied Animal Research 45 619–622.CrossRefGoogle Scholar
D’Mello, J.P.F. Placinta, C.M. and Macdonald, A.M.C., 1999 Fusarium mycotoxins: a review of global implications for animal health, welfare and productivity Animal Feed Science and Technology 80 183–205.CrossRefGoogle Scholar
Feng, J. Shan, M. Du, H. Han, X. and Xu, Z., 2008 In vitro adsorption of zearalenone by cetyltrimethyl ammonium bromide-modified montmorillonite nanocomposites Microporous and Mesoporous Materials 113 99–105.CrossRefGoogle Scholar
Ferrer, E. Juan-García, A. Font, G. and Ruiz, M., 2009 Reactive oxygen species induced by beauvericin, patulin and zearalenone in CHO-K1 cells Toxicology in Vitro 23 1504–1509.CrossRefGoogle ScholarPubMed
Girish, C.K. Smith, T.K. Boermans, H.J. and Karrow, N.A., 2005 Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on performance, hematology, metabolism, and immunocompetence of turkeys Poultry Science 84 1179–1185.Google Scholar
Glenn, A.E., 2007 Mycotoxigenic Fusarium species in animal feed Animal Feed Science and Technology 137 213–240.CrossRefGoogle Scholar
Hassen, W. Ayed-Boussema, I. Oscoz, A.A. Lopez, A.C. and Bacha, H., 2007 The role of oxidative stress in zearale-none-mediated toxicity in Hep G2 cells: Oxidative DNA damage, gluthatione depletion and stress proteins induction Toxicology 232 294–302.CrossRefGoogle ScholarPubMed
Hestbjerg, H. Nielsen, K.F. Thrane, U. and Elmholt, S., 2002 Production of trichothecenes and other secondary metabolites by Fusarium culmorum and Fusarium equiseti on common laboratory media and a soil organic matter agar: an ecological interpretation Journal of Agricultural and Food Chemistry 50 7593–7599.CrossRefGoogle Scholar
Homolka, J., 1969 Clinic Biochemistry Czech Republic Publishing House SZN, Prague.Google Scholar
Jia, Z. Liu, M. Qu, Z. Zhang, Y. Yin, S. and Shan, A., 2014 Toxic effects of zearalenone on oxidative stress, inflammatory cytokines, biochemical and pathological changes induced by this toxin in the kidney of pregnant rats Environmental Toxicology and Pharmacology 37 580–591.CrossRefGoogle ScholarPubMed
Jiang, S.Z. Yang, Z.B. Yang, W.R. Yao, B.Q. Zhao, H. Liu, F.X. Chen, C.C. and Chi, F., 2010 Effects of feeding purified zearalenone contaminated diets with or without clay enterosorbent on growth, nutrient availability, and genital organs in post-weaning female pigs Asian-Australasian Journal of Animal Science 23 74–81.CrossRefGoogle Scholar
Jiang, S.Z. Yang, Z.B. Yang, W.R. Gao, J. Liu, F.X. Broomhead, J. and Chi, F., 2011 Effects of purified zearalenone on growth performance, organ size, serum metabolites, and oxidative stress in postweaning gilts Journal of Animal Science 89 3008–3015.CrossRefGoogle ScholarPubMed
Jiang, S.Z. Yang, Z.B. Yang, W.R. Wang, S.J. Wang, Y. Broomhead, J. Johnston, S. L. and Chi, F., 2012 Effect on hepatonephric organs, serum metabolites and oxidative stress in post-weaning piglets fed purified zearalenone-contaminated diets with or without Calibrin-Z Journal of Animal Physiology and Animal Nutrition 96 1147–1156.CrossRefGoogle ScholarPubMed
Jiang, S.Z. Li, Z. Wang, G.Y. Yang, Z.B. Yang, W.R. Zhang, G.G. and Wu, Y.B., 2014 Effects of Fusarium mycotoxins with yeast cell wall absorbent on hematology, serum biochemistry, and oxidative stress in broiler chickens Journal of Applied Poultry Research 23 165–173.CrossRefGoogle Scholar
Koraichi, F. Videmann, B. Mazallon, M. Benahmed, M. Prouillac, C. and Lecoeur, S., 2012 Zearalenone exposure modulates the expression of ABC transporters and nuclear receptors in pregnant rats and fetal liver Toxicology Letters 211 246–256.CrossRefGoogle ScholarPubMed
Kouadio, J.H. Mobio, T.A. Baudrimont, I. Moukha, S. Dano, S.D. and Creppy, E.E., 2005 Comparative study of cytotoxicity and oxidative stress induced by deoxynivalenol, zearalenone or fumonisin B1 in human intestinal cell line Caco-2 Toxicology 213 56–65.CrossRefGoogle ScholarPubMed
Kramer, R.A. Zakher, J. and Kim, G., 1988 Role of the glutathione redox cycle in acquired and de novo multidrug resistance Science 241 694–697.CrossRefGoogle ScholarPubMed
Lemke, S.L. Mayura, K. Reeves, W.R. Wang, N. Fickey, C. and Phillips, T.D., 2001 Investigation of organophilic montmorillonite clay inclusion in zearalenone-contaminated diets using the mouse uterine weight bioassay Journal of Toxicology and Environmental Health, Part A 62 243–258.CrossRefGoogle ScholarPubMed
Li, Z. Yang, Z.B. Yang, W.R. Wang, S.J. Jiang, S.Z. and Wu, Y.B., 2012 Effects of feed-borne Fusarium mycotoxins with or without yeast cell wall adsorbent on organ weight, serum biochemistry, and immunological parameters of broiler chickens Poultry Science 91 2487–2495.CrossRefGoogle ScholarPubMed
Liu, M., Gao, R., Meng, Q., Zhang, Y., Bi, C., and Shan, A. (2014) Toxic effects of maternal zearalenone exposure on intestinal oxidative stress, barrier function, immunological and morphological changes in rats. PLoS One, 9, e106412.Google ScholarPubMed
Malekinejad, H. Maas-Bakker, R. and Fink-Gremmels, J., 2006 Species differences in the hepatic biotransformation of zearalenone The Veterinary Journal 172 96–102.CrossRefGoogle ScholarPubMed
Marin, D.E. Pistol, G.C. Neagoe, I.V. Calin, L. and Taranu, I., 2013 Effects of zearalenone on oxidative stress and inflammation in weanling piglets Food and Chemical Toxicology 58 408–415.CrossRefGoogle ScholarPubMed
Meister, A., 1994 Glutathione-ascorbic acid antioxidant system in animals Journal of Biological Chemistry 269 9397–9400.CrossRefGoogle ScholarPubMed
Mirocha, C.J. Robison, T.S. Pawlosky, R.J. and Allen, N.K., 1982 Distribution and residue determination of [3H] zearalenone in broilers Toxicology and Applied Pharmacology 66 77–87.CrossRefGoogle ScholarPubMed
Nesic, K. Pupavac, S. and Sinovec, Z.J., 2005 Efficacy of different adsorbents in alleviating zearalenone effects on performance of pigs Zbornik Matice Srpske Za Prirodne Nauke 108 173–179.CrossRefGoogle Scholar
NRC, 1994 Nutrient Requirements of Poultry. 9th Washington, DC National Academy Press.Google Scholar
Othmen, O.B. Golli, E.E. Abid-Essefi, S. and Bacha, H., 2008 Cytotoxicity effects induced by Zearalenone meta-bolites, alpha Zearalenol and beta Zearalenol, on cultured Vero cells Toxicology 252 72–77.CrossRefGoogle Scholar
Ouanes, Z. Abid, S. Ayed, I. Anane, R. Mobio, T. Creppy, E.E. and Bacha, H., 2003 Induction of micronuclei by Zearalenone in Vero monkey kidney cells and in bone marrow cells of mice: protective effect of Vitamin E Mutation Research/Genetic Toxicology and Environmental Mutagenesis 538 63–70.CrossRefGoogle ScholarPubMed
Schell, T. Lindemann, M. Kornegay, E. Blodgett, D. and Doerr, J., 1993 Effectiveness of different types of clay for reducing the detrimental effects of aflatoxin-contaminated diets on performance and serum profiles of weanling pigs Journal of Animal Science 71 1226–1231.CrossRefGoogle ScholarPubMed
Seong, H. Whang, H.S. and Ko, S., 2000 Synthesis of a quaternary ammonium derivative of chito-oligosaccharide as antimicrobial agent for cellulosic fibers Journal of Applied Polymer Science 76 2009–2015.3.0.CO;2-W>CrossRefGoogle Scholar
Sies, H., 1991 Oxidative stress: from basic research to clinical application American Journal of Medicine 91 31S–38S.CrossRefGoogle ScholarPubMed
Šperanda, M. Liker, B. Šperanda, T. Šerić, V. Antunović, Z. Grabarević, and Steiner, Z., 2006 Haematological and biochemical parameters of weaned piglets fed on fodder mixture contaminated by zearalenone with addition of clinoptilolite Acta Veterinaria 6 121–136.Google Scholar
Swamy, H. Smith, T. Cotter, P. Boermans, H. and Sefton, A., 2002 Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on production and metabolism in broilers Poultry Science 81 966–975.CrossRefGoogle ScholarPubMed
Swamy, H.V. Smith, T.K. MacDonald, E.J. Boermans, H.J. and Squires, E.J., 2002 Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on swine performance, brain regional neurochemistry, and serum chemistry and the efficacy of a polymeric glucomannan mycotoxin adsorbent Journal of Animal Science 80 3257–3267.CrossRefGoogle ScholarPubMed
Tian, G. Wang, W. Mu, B. Kang, Y. and Wang, A., 2015 Facile fabrication of carbon/attapulgite composite for bleaching of palm oil Journal of the Taiwan Institute of Chemical Engineers 50 252–258.CrossRefGoogle Scholar
Trailović, J.N. Stefanović, S. and Trailović, S.M., 2013 In vitro and in vivo protective effects of three mycotoxin adsorbents against ochratoxin a in broiler chickens British Poultry Science 54 515.CrossRefGoogle ScholarPubMed
Turcotte, J.C. Hunt, P.J.B. and Blaustein, J.D., 2005 Estrogenic effects of zearalenone on the expression of progestin receptors and sexual behavior in female rats Hormones and Behavior 47 178–184.CrossRefGoogle ScholarPubMed
Vaca, C.E. Wilhelm, J. and Harmsringdahl, M., 1988 Interaction of lipid peroxidation products with DNA: A review Mutation Research/Reviews in Genetic Toxicology 195 137–149.CrossRefGoogle ScholarPubMed
Wang, D.F. Zhang, N.Y. Peng, Y.Z. and Qi, D.S., 2010 Interaction of zearalenone and soybean isoflavone on the development of reproductive organs, reproductive hormones and estrogen receptor expression in prepubertal gilts Animal Reproduction Science 122 317–323.CrossRefGoogle ScholarPubMed
Wang, D.F. Zhang, N.Y. Peng, Y.Z. and Qi, D.S., 2012 Interaction of zearalenone and soybean isoflavone in diets on the growth performance, organ development and serum parameters in prepubertal gilts Journal of Animal Physiology and Animal Nutrition 96 939–946.CrossRefGoogle ScholarPubMed
Wang, D.F. Zhou, H.L. Hou, G.Y. Qi, D.S. and Zhang, N.Y., 2013 Soybean isoflavone reduces the residue of zearalenone in the muscle and liver of prepubertal gilts Animal 7 699–703.CrossRefGoogle ScholarPubMed
Wang, W. Tian, G. Zhang, Z. and Wang, A., 2015 A simple hydrothermal approach to modify palygorskite for high-efficient adsorption of Methylene blue and Cu(II) ations Chemical Engineering Journal 265 228–238.CrossRefGoogle Scholar
Yegani, M. Smith, T.K. Leeson, S. and Boermans, H.J., 2006 Effects of feeding grains naturally contaminated with Fusarium mycotoxins on performance and metabolism of broiler breeders Poultry Science 85 1541.CrossRefGoogle ScholarPubMed
Yiannikouris, A. Kettunen, H. Apajalahti, J. Pennala, E. and Moran, C.A., 2013 Comparison of the sequestering properties of yeast cell wall extract and hydrated sodium calcium aluminosilicate in three in vitro models accounting for the animal physiological bioavailability of zearalenone Food Additives and Contaminants Part A: Chemistry Analysis Control Exposure and Risk Assessment 30 1641–1650.CrossRefGoogle ScholarPubMed
Zelko, I.N. Mariani, T.J. and Folz, R.J., 2002 Superoxide dismutase multigene family: a comparison of the CuZn-SOD (SOD1), Mn-SOD (SOD2), and EC-SOD (SOD3) gene structures, evolution, and expression Free Radical Biology and Medicine 33 337–349.CrossRefGoogle ScholarPubMed
Zhang, L. Yan, R. Zhang, R. Wen, C. and Zhou, Y., 2017 Effect of different levels of palygorskite inclusion on pellet quality, growth performance and nutrient utilization in broilers Animal Feed Science and Technology 223 73–81.CrossRefGoogle Scholar
Zinedine, A. Soriano, J.M. Moltó, J.C. and Mañes, J., 2007 Review on the toxicity, occurrence, metabolism, detoxification, regulations and intake of zearalenone: An oestrogenic mycotoxin Food and Chemical Toxicology 45 1–18.CrossRefGoogle ScholarPubMed
Zourgui, L. Golli, E.E. Bouaziz, C. Bacha, H. and Hassen, W., 2008 Cactus (Opuntia ficus-indica) cladodes prevent oxidative damage induced by the mycotoxin zearalenone in Balb/C mice Food and Chemical Toxicology 46 1817–1824.CrossRefGoogle ScholarPubMed