presentation AP2009

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
• 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 Infection
Parasites Prevalence (%)
Negeri Sembilan Perak
Epibiont protozoan
Zoothamnium sp. Gills Pleopods 1.5 10.5 33.6 8.2
Epistylis sp. Gills Pleopods 1.5 28.9 21.6 66.6
Acineta sp. Gills - 19.0
Lagenophrys sp. Gills Pleopods 38.4 23.9 42.4 7.2
Apostome ciliate cysts Gills Pleopods 14.7 24.3 5.0 28.6
Gregarines
Nematopsis sp. Intestine 11.2 16.8
Digenea
Metacercariae stage Intestine 0.2 2.0
Isopod
Probopyrus 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

• 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
0
0.2
0.4
0.6
0.8
Jan '09 Feb '09 Mar '09 Apr '09 May '09 Jun '09 Jul '09 Aug '09 Sep '09 Oct '09
Monthly Prevalence
N. Sembilan Perak
Lagenophrys sp.

0
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)
0
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
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
Monthly Prevalence
N. Sembilan Perak

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 Reference
Epibionts 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 protozoan
Nematopsis sp.
Heavy infections
 Growth retardation & mortalities in culture
system
 Causes mortality & lesion
Lightner, 1993;
Lightner, 1996
Digenea
Metacercariae stage
Microphallus brevis in Macrobrachium sp. has
zoonotic significance
Nash, 1989
Isopod
Probopyrus 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.

presentation AP2009

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