www.iaard.net IAARD Journals eISSN:2456-009X International Journal of Agriculture And Veterinary Sciences IAARD-International Journal of Agriculture and Veterinary Sciences, 2018, 4(2),11-15 Occurrence and prevalence of Metazoan Parasites in farmed Nile tilapia (Oreochromusniloticus) and Commoncarp (Cyprinuscarpio) in Sebeta fish farm, Sebeta, *Marshet Adugna Mitiku *EthiopianInstitute of Agricultural Research, National Fishery and Aquatic Life Research Center, Sebeta, Ethiopia P. O. Box 64, Sebeta, Ethiopia Email: [email protected] ………………………………………………………………………………………………………………………………………………………….. Abstract: Fish farming is the fastest growing sector of agriculture worldwide but many factors affect its development including fish parasites. A cross sectional study was conducted from November, 2016 to April, 2017 with the objective of identifying and determining the prevalence of internal parasites of fish from Nile tilapia and Common carp in Sebeta fish farm.Parasite identification was done based on the standard protocols and available manuals. The overall prevalence of internal parasites infection in the two species of fish was 46.67%. The risk factors considered in this study including sex and size of fish for the prevalence of internal parasite infestation showed statistically significant difference (P< 0.05). However, there was no statistically significant difference (p>0.05) in the prevalence of the parasite between the two species of fish. The highest prevalent parasite was the trematode Clinostomum species(13.6%) followed by Cestode Botherocephalus species and Nematode Contracaeum species. The lager sized fish are found highly infested than smaller sized fish. It is therefore important to control intermediate host, washing and disinfecting of ponds regularly and keeping good quality water as a means of prevention of the occurrence of internal parasites.

Key words: Occurrence; Nile tilapia; Common carp; Parasites; Prevalence; Sebeta ………………………………………………………………………………………………………………………………………… Introduction diseases have been described from fish of Ethiopian waters so Fish farming is a means of improving food security far, although their pathogenic significance is well recognized and supplementing income for families at subsistence level and [5]. Study on disease of fish in general and metazoan parasites the little surplus produced is sold in the local markets in particularly in culture condition are not well studied in the developing countries [1]. It has recently received increasing country. Previous studies in the country by Florio et al. [3]was attention among governments due to rapid increase in human based on same tilapia breeding farm, a dam, caged and riverine population, increasing need for inexpensive sources of protein fish. This study therefore aimed at investigating and and the stagnating or declining catches of fish from inland determining the prevalence of metazoan fish parasites infesting natural lakes have justified[1,2]. Nile tilapia farmed tilapia and common carp and associated risk factors in (Oreochromisniloticus) accounts the highest culture Sebeta fish farm. production, followed by African catfish (Clariasgariepinus), common carp (Cyprinuscarpio) and goldfish Material and Methods (Carassiusauratus) in Ethiopia. Nile tilapia and Common carp Study Area are the main species farmed and all of fish farming system is The study was conducted in Sebeta fish farm which under semi-intensive system. Some of the common challenges serves as spawning and research purpose for the National Fish of fish farming in the Ethiopia has challenged by predators, and Aquatic Life Research Center, Sebeta, Ethiopia. Sebeta lack of feeds, high mortality of fingerlings, lack of fish Farm is located in regional state in Sebeta city management information and availability of pathogen free administration. It is 24 km far from the capital city Addis fingerlings and environmental pollution, biosecurity and spread Ababa. It is situated at 2200m above sea level and an altitude of fish diseases including metazoan parasites [3]. of 8°55′N 38°37′E covering a total area of 16 hectare. The area Fish metazoan parasitic infestations in cultured fish is characterized by a moderately warm climate with annual farms can cause epizootics and mass mortality and the fish mean temperature of about 21OC. The area gets annual rainfall deaths may go unnoticed particularly when the few dead fishes of about 866–1200 millimetres. The annual minimum and are immediately consumed by piscivorous birds[4]. Fish maximum temperature is 18 oC to 25 oC respectively. metazoan parasites are a key constraint to production, sustainability and economic viability in aquaculture but little Study Population has been documented on fish parasites and their associated risk Nile tilapia and common carp were selected to be factors in small scale fish farms in Ethiopia well. The experimental animals. These fish species are the commercially occurrences of metazoan parasites and losses due to parasitic important fish species in the country and best candidate infestations have not been investigated in Ethiopia. Very few

*Marshet Adugna Mitiku Page No.11 IAARD-International Journal of Agriculture and Veterinary Sciences, 2018, 4(2),11-15 aquaculture fish species cultured in many small scale fish farms Results in Ethiopia. In the present study, one genus of cestode (Bothriocephalus spp.), one genus of nematode Study Design and Sample size (Contracaecumspp.) and three genera of trematode The study designewas across sectional study and the (Clinostomumspp, Euclinostomum spp. and Dactylogyrus spp.) fish selected for this study include Orechromisniloticus and parasites have been identified. The total prevalence of internal cyprinuscarpio. The factors considered were species of the parasites of O. niloticus and C. carpio in this study was found animal, sex, size and parasite type.The sample size wad to be 46.7% among which 50.00% and 45.6% of the C. carpio determined based on the tabulated value at 5% desired level of and O. niloticuswas infected by different genera of internal accuracy and at an estimate prevalence rate of 50% are most parasites respectively. The prevalence of internal parasites commonly used for presumed pathogenic agent with a 95% between the species of O. niloticus and C.capriofish were confidence limit [6]. Sample size needed to detect at least one compared (Table 1).The result showed that both species are infected host in fish population is 150, which represent greater susceptible to internal helminth parasites and C. carpio was the than 10,000 fish population however for better precision value highest prevalent (50%) and followed by O. niloticus with 180 fish sample size were taken. 45.58%. However there were no statistically significant difference in the prevalence of the helminth parasite between Fish Sampling the two species(x2<3.84, p>0.05). Both Nile tilapia and Common carp fish species were selected for this study as they are the most common cultured With regard to the size of the fish, comparative fish species in the farm. A total of 180 fish sample of two analysis of the prevalence was done (Table.2) and hence the species was caught using scoop nets. The fish specimen was prevalence has been observed to be higher in bigger sized fish transported to the laboratory live in water containing bucket. than smaller sized fish. There was statistically significant difference in the prevalence of the internal parasites among Morphometric measurements different sized fish(x2>3.84, p<0.05). The prevalence was also The sampled fish were killed humanely by dislocating compared between the two sexes of fish (Table.3). The the spinal cord using surgical blade. The morphometric prevalence was higher in female than male fish and showed parameters including total length (cm) and total weight statistically significant difference(x2 >3.84, p<0.05) in (gm)were measured with the aid of measuring board and prevalence of internal parasite among the sex. From the result weighing balance respectively. nematodes all are localized in the pericardial cavity (Table 4). The prevalence of Contracecum species in the O.niloticuswas Parasite examination found to be 9.55% and the prevalence of Contracecumspp. in External examination of the fish was made by the C.carpiowas found to be 9.09%. There is no statistically observing the skin and fins using naked eye and magnifying significant deference in the prevalence of the Contracecum glass. Mucus sample was then taken from the body surface parasite between the two species of fish(X2<3.83, P>0.05). especially from pectoral and ventral fish and direct smear was made on a slide and examined using compound The cestode parasite Bothriocephalus spp. was the only microscope.The abdominal wall was opened by inserting a cestode parasite recorded in this study found located in sharp end of scissor through the vent. The alimentary canal intestine as their predilection sites (Table 5). The relative were there after removed sectioned in to its parts; esophagus, prevalence of Bothrocephalus spp. in O.niloticus and C.carpio stomach, intestine and rectum and each section was separated was found to be 11.02% and 9.09% respectively. There is no in to Petri dish containing normal pond water, incised and statistically significant difference(X2<3.84, P>0.05) between examined for parasite by naked eye and under microscope. the two species with regard to the prevalence of Bothroephalus Other organs such as gas bladder, liver, spleen, heart, gill eye spp. The site of localization of the Trematode Clinostomum, pericardial cavity, kidney. Brachial cavity was examined Euolinostomum and Gyrodactlus was found to be brachial thoroughly. Parasites collected from each fish were examined cavity, kidney and gill respectively. The prevalence of under the microscope to identify each parasite to the lowest Clinostomumspp., Euolinostomum spp. and Gyrodactlus spp. in possible tax using standard procedures [7]. O.niloticuswas found to be 11.02%, 3.67%, 2.94% respectively. (Table 6). There is no statistically significant Data Analysis difference (x2<3.84, P>0.05) between the two species of fish The data was entered and managed in MS excel work with respect of the prevalence of Clinostomum spp. sheet and the analysis was conducted using SPSS version 21. Euclinostomum spp. and Gyrodactlus spp. Prevalence of helminthes parasites was expressed as percentage, with 95% confidence interval and is calculated Discussion based on Bush et. al., [8]. The study showed that the overall prevalence of 푇표푡푎푙 푛푢푚푏푒푟 표푓 푓𝑖푠ℎ 𝑖푛푓푒푐푡푑 helimenth parasites infection in O.niloticus and C.carpio is 푃푟푒푣푎푙푒푛푐푒 = ∗ 100 푇표푡푎푙 푁푢푚푏푒푟 표푓 푓𝑖푠ℎ 푒푥푎푚𝑖푛푒푑 found to be 46.7%. The most prevalent helminth parasites were The significance of differences between the prevalence of Clinostomumspecies followed by Botherocephalus spp. and helminthes was determined using Chi- square test. Contracecum spp. The less prevalent helminth parasites were

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Gyrodoctlusspecies and followed by Euclinostomum spp. this feeding of any type of feed, rest at one place until the larvae parasite recovered from brachial cavity, intestine mesentery, emerged. And also after this period the female fish able to feed pericardial cavity, gill and kidney of the fish respectively. This whatever in the surrounded and some of this was probably finding was lower than the one reported 59.8% by Yimer and intermediate hosts for metazoan parasites. Enyew[5] at Lake Tana. The variation in prevalence could be The current study has recorded no statistically associated with variation in distribution of definitive host significant difference is susceptibility of the two species of fish commonly the fish eating birds and the primary intermediate for all five parasites taxa. This finding was agreed with host’s copepods as well as on the season on which the studies Shelemo[10] which was reported from NFALRC. This might be are conducted and probably high level of immunity built up in due to the fact that parasitism is much more diversified in the fish sample that were sampled and examined during the study wild than in the farm, ponds and hatcheries where there is period. relatively the same environments, the same biotic condition and diversity of intermediate hosts [11]. Parasitic infection rates and The percentage parasite infection is higher in female diversities are expected to vary greatly from one area to another than male. There were statistically significant difference and this depends on a number of factors which includes among (p<0.05) in the prevalence of the parasite between the sex. The other things, the nature of water and the endemicity of infection finding agrees with Mgbemena[9] that report high percentage of in the area where the study was conducted[12].For the current infection in females.The variation may be due to female fish study sampling was done in rather one station. Other places has over stressed during reproduction time that is incubate their were not used for sampling and hence diversity and difference egg within the its own mouth special O.niloticus fish without in prevalence was not reflected in between two species.

Table1: Prevalence of internal parasites in relation to fish species (O.niloticus and C.carpio). Species Number of examined Positive Prevalence P value (%) O. niloticus 136 62 45.58 C. carpio 44 22 50.00 Total 180 84 46.7 P=0.77

Table 2: Prevalence of internal parasite of O. niloticus and C. carpioin relation to size Size (cm) Number of Positive Prevalence P value examined 1-10 88 31 35.22 11-20 78 46 60.52 21-30 16 11 68.75 P = 0.00 31-40 5 4 80.00

Table 3: Overall prevalence and prevalence of internal parasites in relation to sex of O.niloticus and C.carpio Sex Number of examined Positive Prevalence (%) P value Male 85 26 30.58 Female 95 58 61.05 P=0.001 Total 180 84 46.7

Table 4: Prevalence of the Nematode Contraceacum spp. O. niloticus and C. carpio Species Parasite species Site of Number Positive Prevalence P value of fishes localization examined (%) O. Contracecumspp Pericardial 136 13 9.55 niloticus cavity C. ContracecumSpp 44 4 9.0 P=0.437 carpio

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Table 5: Prevalence of Bothriocephalusspp in O. niloticusand C. carpio Species of fish Parasite Site of Number Positiv Prevalence P value species . examined e (%) O. niloticus Bothroceph Intestine 136 15 11.02 X2=0.71 alusspp. 0 C. carpio Botheroceph Intestine 44 4 9.09 P=0.399 alusspp.

Table 6: Prevalence of the Digenetic trematode Clinostomunspp, Euclinostomum spp. and the Monogenetic Trematode Gyrodactylus spp. in the study site Species Parasite species Site of No. Positive Prevalence P value of fish localization examined (%) O. Clinostomumspp. Brachial cavity 136 15 11.02 niloticus P=0.374 Euclinostomumspp. kidney 136 5 3.67

Gyrodactlusspp. Skin 136 4 2.94 C. Clinostomumspp Brachial cavity 44 6 13.63 carpio Gyrodactlusspp. Skin 44 4 9.09

Regarding the size of fish, the prevalence has been management of the lake, water quality, feeding habits and observed to be higher in bigger fish. There is statistically overcrowding of fishes, presence of aquatic birds that significant difference (p<0.05) in the prevalence of the contribute to the exposure of fish to the parasite [18]. The parasites among the different sized fish. This finding agree with metazoan infection is reported to interfere with the absorption a report of Wundem[13] that metazoan infection increase with of nutrients in the intestine of the fish and may reduce food length of fish and Paperna[14] reported that the prevalence of intake. The metabolites produced by some of these parasites metazoan parasite increased in large sized fish. The increased could adversely affect vital system of the fish. Further number of helminth parasite per host and the rate of infection pathological effects due to the parasites can be attributed to the with increasing length were attributed to number factors. Some abrasions and lesions caused during attachment and may be of these included the bigger quality of food consumed by larger accompanied by secondary bacterial infection [11] . fish and fact that they preyed on other organisms [15]. Some of these were probably intermediate hosts for the helminth Conclusion parasite because the fish preyed up on bigger food item The present work which was conducted in Sebeta fish carrying the infective stages. farm revealed that the prevalence of the parasites that affect fish were high.During the study period an overall prevalence The nematode Contracecum was found 9.55% and rate of helminth parasite is 46.66%. Clinostomum spp., 9.09% on O.niloticusand C.caripo fish species respectively in Botherocephulus spp. and Contracecum spp. were the most the present study at the sebeta fish farm ponds. The result of frequently occurrence of the parasite. The high prevalence of current study agrees with the Senas[16] and Shelemo[10] and is helminth parasite in these ponds may be due to the lack good reported from fresh water fishes in Japan and is reported from management of the ponds, distribution of intermediate hosts many countries and from Sebeta fish farm respectively. The and shortage of educational back ground. Female fish were Cestod Bothriocephalus spp. was also found 11.02% and more infected than male fishes and there were statistically 9.09% on the O.niloticus and C.carpio fish species significant among sex of fish. Both of fish were susceptible for respectively. This finding is higher than 1.33 recorded by helminth parasite. Therefore, based on the above conclusion the Yemer[17] at Lake Ziway.This variation may be due to the lack following recommendationsare forwarded:Ponds and cages of regular clearing and disinfecting of the pond, distribution of should be regularly washed to decrease the snail population; intermediate host snail and feeding habits of fish’s species. Water quality of the ponds and its stocking density should be Infection by the trematodes digenea, stage of metacercariae managed regularly; and further fish parasite researches should Clinostomum recorded an infection rate of 11.02% and 13.63% be conducted to assess the prevalence of parasites and its in Oreochromusniloticus and Cyprinuscarpio fish species economic importance to increase productivity in culture respectively. The finding is lower than 74.3% reported by conditions. Wundem (1990) at Lake Tana. The prevalence of Euclinostomum and Gyrodactlus species (6.81% and 9.09% Acknowledgment respectively) agrees with the Yimer[17]and is reported from The author would like to acknowledgment the Lake Ziway. This difference in prevalence rate may be due to Ethiopian Institute of Agricultural Research for funding this

*Marshet Adugna Mitiku Page No.14 IAARD-International Journal of Agriculture and Veterinary Sciences, 2018, 4(2),11-15 research work and the National Fish and aquatic Life Research 10. Shelemo, T., Prevalence of helminth parasite in center laboratory staff for helping the collection of samples and NFALRC, Ethiopia,Sebeta DVM Thesis, Faculty of analyzingthe research work. Veterinary Medicine, University of , Ethiopia, 2011. References 11. Goselle, O.N., Shir, G.I., Udeh, E.O., Abelau, Mad 1. Musyoki, N, Characterization of fish farming systems in Imandeh, G.N.Helminth parasites of Clariusgariepinus Kiambu and Machakos counties, Kenya. Master of and Tilapia zilli at Lamingodam, Jos, Nigeria. Science thesis, University of Nairobi, Kenya, pp. 1-114., Sci.W.J.3(4): 23-28, 2008. 2014. 12. Edema, C.U., Okaka, C.E., Oboh, I.P. and Okogub, B.O., 2. FAO, Fisheries and Aquaculture Department. Fishery and Inter.J. of Bio.and Hth. Sci.4 (3): 107-112, 2008. Aquaculture Country Profiles. The Republic of Kenya. 13. Wondem, T., Parasites of fish from Lake Tana: DVM pp. 1-28, 2016. Thesis, faculty of VeterinaryMedicine, 3. Florio, D., Gustinelli, A., Caffara, M., Turci, F., Quaglio, University, Ethiopia, 1990. F., et al., Ittiopatologia(6): 51–93, 2009. 14. Paperna, I., Parasites, infection and diseases of fish in 4. Otachi, O., Studies on occurence of protozoan and Africa. An Updated. CIFA Technical paper. No.31.Ro helminth parasites in Nile Tilapia me, FAO.P: 220, 1996. (OreochromisniloticusL.) from Central and Eastern 15. Paperna, I., Parasites, infection and diseases of fish in provinces, Kenya. Thesis for master’s degree, Egerton Africa. CIFATechnical paper. 7.P:216, 1980. University, Kenya, pp.1-78, 2009. 16. Senas, D., Reservoir fisheries of Asia, proceeding of the 5. Eshetu, E. and Enyew, M., Ethiop.J. Of sci.26 (1): 25-32, 2nd Asian Reservoir fisheries workshop held in Hangzhou, 2003. People’s Republic of China, p: 15-19, 1992. 6. Ossiander, F.J. and Wedermeyer G., Journal Fisheries 17. Yimer, E., 2001. Preliminary survey of parasites and Research Board of Canada30:1383-1384. 1993. bacterial pathogens of fish at Lake Ziway. In: SINET: 7. Paperna, I., Annual Review of fish disease1:pp: 155-194, ETHIOP. J.SCI. 23(1): 25-33. Faculty of science, Addis 1991. Ababa University, Ethiopia, 2001. 8. Bush, A. O., Lafferty, K. D., Lotz, J. M., and Shostak, A. 18. Anderson, R.C., Nematode Darasites of Vertebrates and W., The J. of parasito, 575-583, 1997. their Development Transmission. CBA International. P. 9. Mgbemena, I, J.Publ. Health 2001: 30 (3-4): 95-98, 1983. 578, 1992.

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