The comparative analysis of infection pattern and oocyst output in

Transcription

1 Veterinary World, EISSN: Available at RESEARCH ARTICLE Open Access The comparative analysis of infection pattern and oocyst output in Eimeria tenella, E. maxima and E. acervulina in young broiler chicken doi: 1.122/vetworld How to cite is article: You MJ (21) The comparative analysis of infection pattern and oocyst output in Eimeria tenella, E. maxima and E. acervulina in young broiler chicken, Veterinary World 7(7): Introduction Coccidiosis is a universally important disease of poultry production. Chicken flocks free from coccidia are extremely rare and at least ree species of Eimeria ( E. tenella, E. maxima and E. acervulina) are commonly found in all commercial chickens [1]. The protozoan parasites of e genus Eimeria multiply in e intestinal tract and cause tissue damage, resulting in interruption of feeding and digestive processes or nutrient absorption; dehydration; blood loss; and increased susceptibility to oer disease agents [2]. In India, estimation has revealed at commercial broiler industry is a major suffererdue to coccidiosis wherein 95.61% of e total economic loss occurs due to e disease [3]. The seven species ( E. acervulina, E. brunetti, E. maxima, E. mitis, E. necatrix, E. praecox, and E. tenella) have different properties regarding localisation in e gut, paogenicity, pre-patent period, fecundity and immunogenicity. Diagnosis of coccidiosis is based on comparison of clinical features, gut paology in e host, and parasite properties such as morphology of different parasite stages in feacal material or intestine and pre-patent period []. The development of sexual stages (micro-and macro-gametocytes) and formation of oocysts were Myung-Jo You Laboratory of Veterinary Parasitology, College of Veterinary Medicine and Bio-safety Research Centre, Chonbuk National University, Jeonju , Republic of Korea. tick@chonbuk.ac.kr, Phone: , Fax Received: , Revised: , Accepted: , Published online: Abstract Aim: To assess e pattern of infection pattern by artificially infected Eimeria strains of Korean isolates and assessed e degree of sporulating oocysts at different temperature. Materials and Meods: Birds were orally inoculated wi oocysts of Eimeria tenella, Eimeria maxima and Eimeri acervulina. Oocyst count, oocyst isolation and sporulation were evaluated from e four to e ten day post infection. Histopaological studies also made in e caecum and intestinal to comparative lesions. Results: Mean oocyst counts of ese species increased more quickly on e day of 5 to 6 of post-infection. E. acervulina reached its highest infection level on e 6 day while bo E. tenella and E. maxima had peak on e 7 day. The prepatent period of oocyst output in e E. acervulina started 12 h and ended on e 1 day after inoculation, whereas e E. maxima started oocyst output at 1 h and E. tenella oocyst output at 168 h respectively. The best temperature for optimum sporulation was found to be at 25 C at sporulation rate of 88.91%, while at 2 C sporulated 88.3%, and at 3 C sporulated 82.%. Conclusion: Current study represent e pattern of infection, paogenesis and optimum sporulation temperature and our results suggested at 25 C is optimum for sporulated oocyst of Korean isolates of E. tenella, E. maxima ande. acervulina. Keywords: broiler chick, Eimeria, oocyst, paogen. Copyright: The auors. This article is an open access article licensed under e terms of e Creative Commons Attribution License ( which permits unrestricted use, distribution and reproduction in any medium, provided e work is properly cited. observed wiin epielial cells of e small intestine (duodenum, jejunum) after infection wi E. maxima (1 h post infection (PI) and E. acervulina (96 h PI) and of e caecum after infection wi E. tenella (136 h PI) [5].This intracellular parasite has a complex lifecycle, where it passes rough asexual and sexual stages of development. The final stage of development, e oocyst, is excreted from e host and, under e appropriate conditions of temperature and humidity, undergoes a process known as sporulation, where it becomes infective. The infective form of Eimeria is e highly resistant oocyst, which is shed in e feces of infected animals. Eimeria species identification is based on clinical features, morphological and biological features as sizes of oocysts, sites of infection, prepatent period, sporulation time. E. maxima can be easily identified based on oocyst size, while E. tenella and E. necatrix produce unmistakable lesions [6]. The present experiment was undertaken to study e pattern of infection and oocyst output ofeimeria strains which were isolated in artificially infected situation in Korea, and assessed e degree of sporulation oocysts at different temperature. We also examined e histopaological observations in infection of each Eimeria strain. Materials and Meods Eical approval: Experiment was carried out in Veterinary World, EISSN:

2 Available at accordance wi e guidelines approved by e Chonbuk Animal Care and Use (Approval no. CBU 211-6). Parasites and birds: Oocysts of E. tenella ( Fj768 ), E. acervulina (FJ767) and pure strain E. maxima were obtained from e Laboratory of Vererinary Parasitology, College of Veterinary Medicine, Chonbuk National University (Jeonju, Republic of Korea). These strains were propagated in chicks; oocysts were preserved in 2.5% potassium dichromate solution to induce sporulation at 28 C in water ba for -7 days. Then ree of ese isolates, E. tenella ( FJ768, Sou Korea ), E. acervulina (FJ767, Sou Korea) and pure strain E. maxima had been stored in 2.5% potassium dichromate at C until use.fifty-one dayold broiler chicks (Samhwa breeding co.; Ross) were fed wi coccidian-free food. On 1 days, 5 healy chicks were chosen for e following experiments. Experimental design: Sporulated oocysts were isolated in e 2.5% potassium dichromate, and washed ree times wi distilled water, and counted using a MacMaster meod under a light microscope. Artificial infestation was done as describe by You [7]. Shortly, each of 1 days old chicks was divided into 3 groups of 15 individuals and was infected orally wi a suspension of 1.x1 oocysts/chick from a stock of E. tenella (chickens group I), E. maxima (chickens group II) and E. acervulina (chickens group III) per bird, respectively. The chickens were given unlimited access to food and water and constant light was provided for e duration of e experiment. Fecal materials were collected from 5 to 1 days post-infection, and e number of oocysts was assessed using a MacMaster meod counting chamber. Total oocyst numbers were calculated and histopaological examinations were evaluated. Paological lesion, oocyst isolation and sporulation was done as describe byamer et al. [8]. Oocyst count: Oocyst count per gram of fecal material (OPG) was evaluated from e four to e ten day PI. All e feces of each chicken group were collected daily and OPGs were counted using e MacMaster meod counting technique [9]. Oocyst isolation and sporulation: After 12 h of e post infection, fecal samples were collected and isolated oocysts following our laboratory's procedures. Briefly, chicken fecal was mixed in e water (1:2 w/v) and filtered by mesh (~1 mm). Suspension of feces was centrifuged at 3 rpm for 1 min in a 5-ml centrifuge tube, e supernatant was removed, and e pellet was resuspended wi sucrose solution (128g granulated sugar + 1ml tap water) and on vortex and centrifuged at 3 rpm 1 min. Supernatant was collected, and was added wi 1 times water and centrifuged at 3 rpm 1 min. After removing e supernatant, e pellet was transferred into a 5-ml centrifuge tube and centrifuged at 3 rpm 1 min. Pellet was resuspended wi a similar volume of saturated salt solution (~g Salt + 1ml DW; species gravity), and on vortex and centrifuged at 3 rpm 1 min. Supernatant were en transferred into new 5 ml centrifuge tubes, 1 times water was added and centrifuged at 3 rpm 1 min. Finally pellets were resuspended in 2.5% K 2Cr 2O 7. Pure oocysts ( E. tenella, E. maxima and E. acervulina) were incubated at 2 C, 25 C, 3 C and 35 C for 6 days, en e sporulation rates were determined by counting 1 oocysts under x1 magnification (four replications) at 2, 8, 72, 96, 12 and 1 h of sporulation, respectively. Sporulation was considered to be completed when sporozoites wiin e sporocysts were identified and e Stieda body, which appeared as a clear protuberance at e narrow end of e sporocysts, was visible. The number of sporulated oocysts was calculated by e number of harvested oocysts and eir sporulation rate. Histopaological examination: Histopaological studies were made in e caecum and intestinal (jejunum, duodenum) two randomly chosen chicks per rd group were killed every day between 3 and 6 days PI. Tissues were taken from e mid-jejunum, duodenum and caecum and fixed in 1% formalin solution. After fixation, samples were dehydrated in alcohol, cleared in xylene, finally e specimens were embedded in paraffin wax, sectioned at 5 µm and stained by haematoxylin and eosin (H&E), mounted and examined under a light microscope. Results Sporulation and physical condition of oocysts: To provide quantitative data, e structural integrity of oocyst walls, sporocysts and sporozoites were assessed microscopically. Figure-1 comprises photomicrographs of sporulated and unsporulated oocysts of Eimeria species. The double oocyst-walls were undamaged and internal structures were well enough preserved and e sporocysts and sporozoites can be seen in detailed description. Sporulation rates of oocysts obtained from different condition temperatures were given in Figure-2. Eimeria oocysts sporulated most efficiently under e different temperature conditions studied, and at e lowest sporulation was observed in e samples wi e highest temperature condition (Figure-2). On 6 day, e mean sporulation rate of 35 C was significantly lower an at of 2 C, 25 C and 3 C. The best temperature for complete sporulation was found to be 25 C, sporulation rate was 88.91%, while 2 C sporulated 88.3%, and 3 C sporulated 82.%. Oocyst count: More irregular courses of oocyst excretion were observed wi E. tenella, E. maxima and E. acervulima (Figure-3). Mean oocyst counts of ese species increased more quickly on e day of 5 to 6 PI. E. acervulina reached its highest infection level on e 6 day while bo E. tenella and E. maxima reached a maximum infection peak on e 7 day. The prepatent period of oocyst output in e E. acervulina Veterinary World, EISSN:

3 Available at Figure-1: Oocysts morphological feature: (A) Photomicrograph of freshly shed unsporulated oocyst (Z-zygote); in e ovoidal was shown. Two layers of e oocyst wall (OL-outward, IL-inward). x.; (B) Photomicrograph of e sporulated spherical oocyst wi four sporocysts (SPC) each containing two sporozoites (SPO); e stieda body (St). x. Figure-2: Mean sporulation rate of Eimeria in water ba wi different temperature. started 12 h after oocyst inoculation and ended on e 1 day after inoculation, whereas e E. maxima started oocyst output at 1 h and E. tenella oocyst output at 168 h, respectively. On e oer hand, chickens from infected group 3 showed higher E. acervulina oocyst 6 shedding (2.32 x 1 /g faeces) an infected E. tenella 6 from group 1 (. 7 x 1 /g faeces) and group 2 ( E. maxima) 6 (.3 x 1 /g faeces), (Figure-3). After it reached its peak, e number of oocysts gradually reduced and a small number of remained on e 8 day PI. Histopaological observations of chickens infected wi e Eimeria tenella, E. acervulina and E. maxima during e course of infection: Histopaological examination of tissue sections at e 72, 96, 12 and 1 h PI (Figure-, 5, and 6) revealed e detection of developmental Eimerial stages in duodenum, jejunum and cecum, respectively. In e chicken inoculated wi E. tenella, gametocytes were observed wiin crypt epielial cells of e cecum at 72 h PI (Figure-.B), en were observed numerous intracellular schizonts containing merozoites and immature macrogametocytes in e border epielial cells of cecum at 12 and 1 h PI (Figure -C and D). So, after 72 and 12 h of E. tenella infection in chickens, severe inflammatory process was observed in e lamina propria and Figure-3: Fecal oocysts shedding in chickens infected wi Eimeria tenella, E. acervulina and E. maxima. Each data point shows e average oocysts of four counts. among crypts. From 96 h PI, increasing number of second mature schizonts of E. maxima was present wiin border cells of villi of e jejunum. Four generation schizonts, oocysts, zygotes and gametocytes were seen from 1 h PI present wiin e submucosa cells of e mid-jejunum (Figure-5). Sections from e duodenum at 72 and 96 h PI, increased numbers of second schizonts, young macrogametocyte and immature gametocytes in e intestine cells(figure-6). Infected E. acervulina at at 12 h, great multiplication of four-generation schizonts and sexual stages in e middle and near e lumen of e crypts were also observed wi hyperplasia of e villi. The schizont was observed 1-2 days beforeemaximum oocyst output. Discussion In all experiments, ere was a successful infection wi Eimeria species as indicated by e intestinal lesions and e shedding of e oocysts. The experimental infection of chickens by Eimeria species isolates is aimed to study e biological characters of each isolate and confirming e diagnosis of each species of Eimeria. The protocol was also followed by Amer [8] and Kucera [1]. The histopaolological lesions, mean OPG of e infected groups of chickens at day 7 PI were consistent wi findings of Jordan and Veterinary World, EISSN:

4 Available at Figure-: Comparative histopaological observations of chicken intestine post infection (PI) wi E. tenella (1.x1 sporulated oocyst/chick): oocyst's developmental stages in e cecum cells (AXIO ZEISS Imager M2 microscope, using AxioCam HRc). (A) Photomicrograph of a cecum from broiler chicken of e control. Cecum of non infected: normal tissues can be seen (H & E, bar=2 μm) x2; (B) Photomicrograph of a cecum from a broiler chicken inoculated wi E. tenella at 72 h PI: gametocytes in e cecum cells (H&E) x2; (C) Photomicrograph of a cecum from a broiler chicken inoculated wi E. tenella at 12 h PI: Numerous intracellular schizonts containing merozoites (arrow) can be seen wi severe submucosal hemorrhage. (H&E). x; (D) Photomicrograph of a cecum from a broiler chicken inoculated wi E. tenella at 1 h PI: infected cells wi immature macrogametocytes in e border epielial cells of cecum. (H&E). x. Arrow indicates different forms of e intracellular parasite. Figure-5: Jejunum sections of chicken infected wi oocysts E. maxima (1.x1 sporulated oocyst/chick) showing: oocyst's developmental stages in e jejunum cells. (A) Photomicrograph of a jejunum from broiler chicken of e control. Normal jejunum can be seen. (H&E) x8; (B) Photomicrograph of a jejunum from a broiler chicken inoculated wi E. maxima at 96 h PI: presence of second mature schizonts in e border cells of villi. (H&E) x; (C) Photomicrograph of a jejunum from a broiler chicken inoculated wi E. maxima at 12 h PI: zygotes and oocysts in e cells. (H&E) x; (D) Photomicrograph of a jejunum from a broiler chicken inoculated wi E. maxima at 1 h PI: four generation schizonts, oocysts, zygotes, gametocytes in submucosa cells. (H&E). x. Arrow indicates different forms of e intracellular parasite. Figure-6: Chicken duodenal sections stained wi H&E of birds infected wi oocysts E. acervulina (1.x1 sporulated oocyst/chick) showing: oocyst's developmental stages in e duodenum cells. (A) Photomicrograph of a duodenum from broiler chicken of e control. Normal duodenum can be seen. (H&E) x2; (B) Photomicrograph of a duodenum from a broiler chicken inoculated wi E. acervulina at 72 h PI: presence of second schizonts and young macrogametocyte in e striated border cells of villi. (H&E, bar=1 μm), x; (C) Photomicrograph of a duodenum from a broiler chicken inoculated wi E. acervulina at 96 h PI: presence of immature gametocytes in intestine cells. (H&E) x; (D) Photomicrograph of a duodenum from a broiler chicken inoculated wi E. acervulina at 12 h PI: great multiplication of micro and macrogametocytes, oocysts, zygotes, four generation schizonts in e middle and beginning of crypts and hyperplasia up to e tip level of villi. (H&E), x. (E) Photomicrograph of a duodenum inoculated wi E. acervulina at 12 h PI: x extension (x). Arrow indicates different forms of e intracellular parasite. Pattison in chickens infected wi coccidian [11]. Prepatent periods may generally range from to 5 days post infection. Maximum oocyst output ranges from 6 to 9 days PI. Edgar [12] reported at 29 C±1 C (8 F) was optimum for most rapid sporulation of E. tenella and at some oocysts reached e infective stage between 15 and 18 h. In e present study, at e first observations e more high temperature samples had a much lower sporulation rate, and Figure-2 indicate at sporulation started later in high temperature conditions an in low temperature conditions. Veterinary World, EISSN:

5 Available at The use of 2-3% potassium dichromate for sporulation at room temperature has been documented in many reports. Under is condition, at least 95% of e oocysts sporulate in 7-1 days. In our study, e best temperature for complete sporulation was found to be 25 C in 6 days. The sporulation time may decrease in crowds of oocysts or depend on contamination. This may support e opinion at different sporulation times may be related to different experimental factors or laboratory techniques or to e lack of adequate oxygen. Once sporulation started, ere were no differences in e rate of sporulation up to e maximum sporulation proportion obtained at different moisture contents. Tierney et al. [13] reported at e development of E. tenella continued to immature and mature schizonts in MDBK cells. These stages were observed in e present study at 8 and 6 h respectively. This sporulation time also support e study of Al-Quraishy et al [1]. But in our histopaological study, observed at 12 h PI in broiler chickens. Researchers used different criteria to evaluate coccidial infections. Some suggested at oocyst production might be a very unreliable quantitative criterion [15] as e number of oocysts produced is affected by factors such as e inherent potential of each species to reproduce in a non-immune host; immunity or resistance developed by e host; e 'crowding' factor; competition wi oer species of coccidia or oer infectious agents; nutrition of e host; and strain differences of e host. The inherent difference in reproductive potential is high for E. tenella, and E. acervulina, and low for E. maxima. Immunity, which is specific to each coccidian species, results in decreased production of oocysts after ingestion of infective oocysts [16]. The histopaological analyses confirmed more extensive presence of lesions, observed wi e light microscope, where more inflammatory cells occur in chickens infected wi E. tenella an in E. maxima, suggesting a low paogenicity of E. acervulina. This criterion was used previously by Karim et al. [17] who identified 5 Eimeria species; E. acervulina, E.tenella, E. maxima, E. brunette and E. necatrix; based on a lesion seen at post mortem examinations of naturally infected birds, dimensions of oocyst and lesion seen in experimentally infected chicks wi single oocyst. The histological finding in is study confirmed e diagnosis of each species as E. acervulina showed presence of gametocyte wi e characteristic inflammatory cells in duodenal part of intestine. The fact which is agreed wi Hein [18] and Asaduzzaman et al [19]. E. tenella showed considerable numbers of oocyst in lamina propria of coecum beside sever hemorrhage and complete desquamation of epielium and edema of muscular tissue which agreed wi e finding of Levine [2]. The entire lamina propria revealed severe haemorrhages, necrosis and disintegration of glandular epielial cells. Several schizonts were observed in e epielial cells along wi merozoites, infiltrating neutrophils and eosinophils. Conclusion In conclusion, infection rough gavage wi a single high dose of inoculum has no similarity wi e field situation. Infection rough e litter mimics e field situation in combination wi controlled conditions and allowing experimental flexibility and a large number of experimental units wiin e research facility. Acknowledgements This work was supported by e National Research Foundation of Korea (NRF) grant funded by Korea government(mest) (No. KRF E61). Competing interests The auor declare at ey have no competing interests. References 1. Williams, R. B. (22) Anticoccidial vaccines for broiler chickens: paways to success. Avian Paol., 31(): Morris, G. M. and Gasser, R. B. (26) Biotechnological advances in e diagnosis of avian coccidiosis and e analysis of genetic variation in Eimeria. Biotechnol Adv, 2(6): Beraa, A.K., Bhattacharyaa D., Pana, D., Dharab, A., Kumarc, S.and Dasa, S.K. (21) Evaluation of economic losses due to doccidiosis in poultry industry in India. Agri Econ Res Rev, 23 (1): Haug, A., Thebo, P. and Mattsson, J. G. (27) A simplified protocol for molecular identification of Eimeria species in field samples. Vet Parasitol, 16(1-2): Belli, S. I., Ferguson, D. J., Katrib, M., Slapetova, I., Mai, K., Slapeta, J. and Smi, N. C. (29) Conservation of proteins involved in oocyst wall formation in Eimeria maxima, Eimeria tenella and Eimeria acervulina. Int J Parasitol, 39(1): Hadipour, M.M., Olyaie, A., Naderi, M., Azad, F., Nekouie, O. (211) Prevalence of Eimeria species in scavenging native chickens of Shiraz Iran. Afr J Microbiol Res, 5(2): You, M. (21) Detection of four important Eimeria species by multiplex PCR in a single assay. Par Int, 63 (3), Amer, M.M., Awaad, M.H.H., Sherein-Said, A., Ghetas, M. M. and Kutkat, M.A.(21) Isolation and identification of eimeria from field coccidiosis in chickens. J Ame Sci, 6 (1): Long, P. L., Joyner, L. P. Millard, B. J. and Norton, C. C. (1976) A guide to laboratory techniques used in e study and diagnosis of avian coccidiosis. Folia Vet Latina, 6(3): Kucera, J. (199) Identification of Eimeria species in Czechoslovakia. Avian Paol, 19(1): Jordan, F. T. W. and Pattison, M. (28) Protozoal infection. In: McDougald, L.R., editor. Polutry Diseases. 8 edition, Philadelphia, P.A. p Edgar, S. A. (1955) Sporulation of oocysts at specific temperatures and notes on e prepatent period of several species of avian coccidia. J Parasitol, 1(2): Tierney, J. and Mulcahy, G. (23) Comparative development of Eimeria tenella ( Apicomplexa) in host cells in vitro. Parasitol Res, 9(): Al-Quraishya, S., Abdel-Bakia, A.S and Dkhila, M.A. (29) Eimeria tenella infection among broiler chicks Gallus domesticus in Riyadh city, Saudi Arabia. J King Saud Univ Sci, 21( 3): Oikawa, H., Kawaguchi, H., Nakamoto, K. and Tsunoda, K. Veterinary World, EISSN:

6 (1975) Field surveys on coccidial infection in broilers in Japan-results obtained in autumn and winter and summarized in Nihon Juigaku Zasshi, 37(3): Arabkhazaeli, F.,Nabian,S., Modirsaneii, M.,Mansoori,V and Rahbari,S. (211) Biopaologic characterization of ree mixed poultry Eimeria spp. Isolates. Iran J Parasitol, 6 (): Karim, M.J. and Trees, A.J. (199) Isolation of five species of Eimeria from chicken in Bangladesh. Trop Ani Heal Prod, 22 (2): Available at ******** 18. Hein, H. (1971) Paogenic effects of Eimeria necatrix in young chickens. Exp Parasitol, 3(3): Asaduzzaman, M., Miah, M. S., Siddika, A., Popy, N. and Hossain, M. M. (211) Experimental production of necrotic enteritis in broiler chickens. Bangl J Vet Med, 9(1): Levine, N.D. (1985) Erhardorina n. g, Ascogregarina polynesiensis n. spp., Eimeria golemanskii n. spp., Isospora tamariscinin. spp., Gregarina kazumii n. nom., new combinations and emendations in e names of apicomplexan protozoa. J Protozool, 32(3): Veterinary World, EISSN: