Parasites Found Associated with Wild Giant Freshwater Prawn,

Macrobrachium rosenbergii (de Man, 1879) in Peninsula Malaysia:

Occurrence, Prevalence & Morphology

By

CHOONG, F. C.1, KUA, B. C.2, HAZREEN NITA, M. K.2, FAIZAH, S.1 & GLENN, A. B.3

1Institute of Tropical Aquaculture (AKUATROP), Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu.

2National Fish Health Research Centre, Fisheries Research Institute, 11960 Batu Maung, Penang, Malaysia

3 Institute of Biology, University of Bergen, Postboks 7800 5020 Bergen.

Giant Freshwater Prawn, Macrobrachium rosenbergii (De Man, 1879)

• Common name: Malaysian prawn(http://en.wikipedia.org/wiki/Macrobrachium_rosenbergii)

• Largest Palaemonid (New, 2002)

– 33 cm (male)– 29 cm (female)

• Production in Malaysia 2007 (http://www.fao.org/fishery/statistics/en)

– 246 ton– RM 40 – RM 54/kg

Introduction

• Culturing of M. rosenbergii in M’sia– Source from wild

• Prawn from natural habitat:– Serve as host for various parasites.

• Parasites: – Affecting growth & reproductive performance.– Causes stress, lead to secondary viral or bacterial infection

Introduction

• Baseline study on the list of parasites from wild M. rosenbergii.

• Farmers & hatchery operators:– Recognize the pathogenic & non-pathogenic

parasites– Determine the pre-caution steps

Objectives

• Examine on the monthly occurrence & prevalence of parasites found on M. rosenbergii.

• Examine on the morphology of parasites found on wild M. rosenbergii

Materials & Methods

Materials & Methods• Site selection

– Timun River (N. Sembilan)– Perak River (Perak)

• Sampling period– Monthly sampling (1 year)

• Sources– Wild caught from rivers

• Average size – N. Sembilan,

28.70 ±29.74 g

– Perak, 35.42±21.05 g

Collected from the fishermen at sampling

site

Transported alive to laboratory

Wet mount of pleopods, gills & intestine

Examined under LM & SEM

Results & Discussion

Occurrence & Prevalence

Parasites found in wild M. rosenbergii

Parasite Sites of InfectionParasites Prevalence (%)

Negeri Sembilan PerakEpibiont protozoan

Zoothamnium sp. Gills Pleopods 1.5 10.5 33.6 8.2Epistylis sp. Gills Pleopods 1.5 28.9 21.6 66.6Acineta sp. Gills - 19.0Lagenophrys sp. Gills Pleopods 38.4 23.9 42.4 7.2

Apostome ciliate cysts Gills Pleopods 14.7 24.3 5.0 28.6

GregarinesNematopsis sp. Intestine 11.2 16.8

DigeneaMetacercariae stage Intestine 0.2 2.0

IsopodProbopyrus buitendijki Branchial chamber 0.2 -

Leech cocoons Exoskeleton 4.6 3.2

Parasites Prevalence of N. Sembilan

Parasites Prevalence of Perak

1. Diversification– Higher in Perak

2. Leech cocoons– Early of the year

Results & Discussion

Morphological Study

Lagenophrys sp.

• Measurement:– Length: 48.66 ± 2.88 μm– Width: 44.31 ± 2.32 μm

(n =30)

• Site of Infection: Gill & Pleopods

• Effect:– interfere with respiration and results

suffocation

Jan '09 Feb '09 Mar '09 Apr '09 May '09 Jun '09 Jul '09 Aug '09 Sep '09 Oct '090

0.10.20.30.40.50.60.70.8

Monthly Prevalence

N. Sembilan Perak

Lagenophrys sp.

Nematopsis sp.

Jan '09 Feb '09 Mar '09 Apr '09 May '09 Jun '09 Jul '09 Aug '09 Sep '09 Oct '090

0.1

0.2

0.3

0.4

0.5

0.6

Monthly Prevalence

N. Sembilan Perak

Nematopsis sp.• Apicomplexan protozoan

• Measurement:– Length: 517.13± 158.47 μm– Width: 75.17 ± 38.19 μm

(n =12)

• Effect:– Growth retardation &

mortalities

Image Reference Species Host of infection

Shanavas et al., 1989

Nematopsis rosenbergii M. rosenbergii

Prasadan & Janardanan, 1996

Nematopsis idella M. idella

Present study Species A M. rosenbergii

Present study Species B M. rosenbergii

Present study Species C M. rosenbergii

Present study Species D M. rosenbergii

Apostome ciliate cysts

Cysts found on the pleopods

SEM image of apostome ciliate cysts

• Found frequently on the gills & pleopods.

• Measurement:– Length: 35.47 ± 5.67 μm– Width: 15.01 ± 1.89 μm

(n =30)

Jan '09 Feb '09 Mar '09 Apr '09 May '09 Jun '09 Jul '09 Aug '09 Sep '09 Oct '090

0.1

0.2

0.3

0.4

0.5

0.6

Monthly Prevalence

N. Sembilan Perak

• Species– Probopyrus buitendijki

(Horst, 1910)

• Measurement: – Length = 1.8 cm – Width = 1.5 cm Gill chamber deformities due to isopod infection

Gill chamber structure of a healthy prawn

Bopyrid Isopod

Female bopyrid isopod, Probopyrus buitendijki

A B

Unidentified Digenea,(A) metacercariae found in the intestine of prawn; (B) A close-up image on the sucker of metacercariae.

A

B

• Stage:– Metacercariae

• M. rosenbergii served as intermediate host

Digenea

Jan '09 Feb '09 Mar '09 Apr '09 May '09 Jun '09 Jul '09 Aug '09 Sep '09 Oct '090

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

Monthly Prevalence

N. Sembilan Perak

Conclusion

Conclusion

• Wild M. rosenbergii serve as host for wide range of parasites in both location.– Epibionts protozoan infections are common– Metacercariae, isopod & leech cocoons are less

frequent.

• Different abundance of parasite in both collection sites– Ecology, water quality, seasonal changes

Parasite Effects ReferenceEpibionts protozoan

Zoothamnium sp.Epistylis sp.Acineta sp.Lagenophrys sp.

Heavy infestation: Interfere with physiological activities Cause mortalities

Johnson, 1977; Villareal & Hutching, 1986;

Brown et al., 1993;Jayasress et al., 2001

Apostome ciliate cysts Causing stress, possibly pathogenic to the prawn Jayasree et al., 2001

Apicomplexan protozoanNematopsis sp. Heavy infections

Growth retardation & mortalities in culture system Causes mortality & lesion

Lightner, 1993; Lightner, 1996

DigeneaMetacercariae stage

Microphallus brevis in Macrobrachium sp. has zoonotic significance Nash, 1989

IsopodProbopyrus buitendijki Carapace deformities Owens & Mendelin, 1989

Future Study

1. Relationship between the seasonal changes with the abundance of parasites.

2. Life cycle of Nematopsis sp.

3. The species and risks of Lagenophrys sp.

4. The roles and specific status of apostome ciliate cysts.

Thank you for your attention