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EFFECTS OF MEDICATIONS ON THE SURVIVAL OF
WILD CAUGHT SNAKEHEAD (Channa striatus) FRY
DURING WEANING TO PELLETED FEED
Presented by -Wahida Haque (st105569)
AARM, SERD
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Introduction
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Problem Statement
 Mortality of Snakehead fry during weaning to artificial or pelleted
feed
Overall objective
 To develop a suitable weaning method by using feed combinations
along with medication to ensure high survival rate
Specific objectives
 To improve the survival by application of three medications during
weaning
 To quantify the effect of medication on survival rate
 To evaluate the effectiveness of three medications used by some
farmers during weaning
 To provide some preliminary scientific information about snakehead
fry weaning
 Scopes
 Improvement of weaning method and survival rate
 Identification and Reduction of the factors responsible for mortality
 Determine suitable medication
 Limitations
 Limited experimental units and supporting literatures
 Supply of quality and same aged seed, Timing and unavailability of
raw materials supply, Cost of feed and drug
 Maintaining water quality, Environmental fluctuation
 Microbiological infection and identification, Cannibalism ,stress
 Specific drug for specific pathogenic infestation
 Budget shortage, wastage of time, money and labour due to
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dependency on others
 Language and communication
Experiment-1
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Materials and Methods
 Experimental fish
 Wild caught Snakehead fry about 1-2.5 inch size
 Age of about 1 month (Marimuthu, 2007)
 Collected from Suphanburi fishers
 Initially held in big hapa for acclimatization of 5 days
 Stocking density
 65 fry/ hapa
 Experimental units
 Hapa of 1 m2 size, 3 earthen ponds of 200 m2
 Water depth about 30-40 cm inside hapa
 Hapa covered with net to avoid predation and escaping
Materials and Methods cont’d
 Experimental indicator
 Survival rate
 Experimental drugs/medicines
 Formalin bath- 37% formaldehyde solution ; dose as
35ppm for 30 min with continuous aeration
 Oxytetracycline- 25mg/kg of body weight/day in feed
for 10 days
 Rotab- 0.1% of Piperazine citrate /kg of feed fed at a
rate of 1% of body weight/day, twice in three weeks
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Ref: FDA 1992, Boonyaratpalin,1985, Yolande,2005, Noga,2000
Materials and Methods cont’d
 Experimental feed
 Trash fish and frog feed (40% protein) in feed combination as
100: 00, 80:20, 60:40, 50:50, 40:60, 20:80 and 00:100
 Each feed combination used for 3 days
 Feeding protocol
 Fed 3 times/day (7 am, 12.00 & 5 pm)until satiation (Wee 1982)
 Management
 Weekly water filling
 Dead fish removal
 Checking of hapa and covers
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Materials and Methods
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Materials and Methods
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Materials and Methods cont’d
 Size Grading
 By 0.75 and 1 cm grading net at the beginning and after10
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days
 Length and weight measurement
 Randomly initial and final length of 20 fry was measured
 Water quality measurement
 Temperature, DO, pH measured daily
 NH3 and NO2 measured weekly
 Estimation of survival rate
 SR%= (No of final harvest x100)/No of initial stocking
 Data analysis by -Microsoft Excel, SPSS 16.0
 One way ANOVA and Tukey’s HSD Post Hoc
Experimental design-1
CRD with 3 replicate of each treatment
Duration 3 weeks
Initial fry
stock
Formalin
Formalin +
antibiotic
Antibiotic
Rotab
No drug
(control)
Formalin + antibiotic +
Rotab
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Formalin +
Rotab
Rotab +
antibiotic
Experimental hapa Setup
Chemicals/drugs
Formalin (T1)
Antibiotic (T2)
Rotab (T3)
Formalin + Antibiotic (T4)
Formalin + Rotab (T5)
Rotab + Antibiotic (T6)
Formalin + Antibiotic + Rotab (T7)
Control –no drug (T8)
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All with same feed combination
All size graded
Pond-1
Pond-2
Pond-3
R1
R2
R3
1(8)
1(6)
1(2)
2(6)
2(8)
2(1)
3(7)
3(5)
3(3)
4(4)
4(1)
4(4)
5(1)
5(2)
5(7)
6(2)
6(4)
6(5)
7(3)
7(7)
7(8)
8(5)
8(3)
8(6)
Inside parenthesis is the Position of hapa and outside the hapa number. Hapa= 24+24=48,
grading in 10 days
Results:
Graph showing the survival rate of eight
treatments in experiment 1
Survival rate%
100
c
80
b
60
40
bc
bc
c
b
a
a
20
0
F
A
R
F+A
F+R
R+A F+A+R
C
Treatments
 Survival rate of T1,T2, T3, T4,T5,T6, T7 and (T8) are 43.59±2.35,
61.03±3.88,71.28±6.41, 59.49±3.88,73.84±4.07, 84.62±10.09,
80.00±4.62,42.56±6.41 respectively
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 The bars with different superscript are significantly different (P<0.05)
Water Quality parameters in experiment 1
Parameters
Pond-1
Pond-2
Pond-3
Temperature C
28.02 ± 0.64a
27.95 ± 0.63a 27.69 ± 0.81a
DO mg/l
4.65 ± 0.64a
5.51 ± 0.85b
5.57 ± 0.73b
pH
7.76 ± 0.10ab
7.85 ± 0.18a
7.71 ± 0.20b
NH3mg/l
0.04 ± 0.01a
0.12 ± 0.07a
0.06 ± 0.03a
NO2 mg/l
0.02 ± 00ab
0.04 ± 0.01a
0.01 ± 0.00b
 Values with same superscript in a same row are not significantly
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different (P<0.05)
Experiment - 2
Materials and Methods is same as experiment 1 except Stocking density- 58 fry/ hapa
 Experimental drugs- only Oxytetracycline and Rotab
 Parasites count : Gross examination of the intestine by
wet mount microscopy for the presence of Nematodes,
Cestodes and Acanthocephalans (Kabata,1985). Sample
size 25 fish/group (randomly selected) assuming parasitic
carrier prevalence more than 10% (Kabata, 1985). The
parasites were identified as Kabata (1985), Ribelin (1975),
Roberts (1978 and 1974).
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Experimental design-2
CRD with 3 replicate of each treatment
Duration 3 weeks
Initial fry stock
Antibiotic
No drug (control)
Rotab
Rotab + Antibiotic
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Experimental hapa setup in four treatments
Chemicals/drugs
Feed combination
All size graded
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Pond-1
Pond-2
Pond-3
R1
R2
R3
Rotab (T1)
1(3)
1(4)
1(1)
Antibiotic(T2)
2(2)
2(2)
2(2)
Rotab + Antibiotic(T3)
3(1)
3(1)
3(4)
Control –no drug(T4)
4(4)
4(3)
4(3)
Inside parenthesis is the Position of hapa and outside the hapa number. Hapa=12+12=24,
grading in 10 days
Results:
Survival rate %
100
80
Graph showing the survival rate of
four treatments in experiment 2
a
a
b
c
60
40
20
0
R (T1)
A (T2)
R+A (T3)
C (T4)
Treatments
 Survival rate of Rotab (T1), Antibiotic (T2), Rotab+ Antibiotic (T3)
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and Control -No drug (T4) are 93.11± 2.98,84.48 ±1.73,94.25 ± 2.63
and 72.99 ± 6.06 respectively with stocking density 58 fry/hapa
 The bars with different superscript are significantly different (P<0.05)
Water Quality parameters in experiment 2
Parameters
Pond-1
Pond-2
Pond-3
Temperature C
33.17±1.33a
32.77±1.29a
32.38±1.29a
DO mg/L
5.15±1.60a
5.28±1.34a
4.31±1.53a
pH
7.24±0.47a
7.23±0.35a
7.31±0.26a
NH3mg/L
0.05±0.01a
0.15±0.08a
0.06±0.01a
NO2 mg/L
0.03±0.01a
0.03±0.01a
0.03±0.01a
 No parameter showed significant difference among ponds ; Values
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with same superscript in a same row are not significantly different
(P<0.05)
Parasites density
Mean number of parasite per fish
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5
a
a
a
b
4
c
3
b
2
1
0
a
a
Initial Stock
Control
Sample group
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a
Rotab treated
Nematode
Cestode
Acanthocephala
Healthy , infected dead & moribund fishes
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Parasites in
experimental
fishes
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Discussions
 Carnivore, surface feeder (Sampath, 1979) Cannibalism obvious,
(Qin, 1996) reduced
by size grading and satiation feeding
 Fed as protein requirement,35-40% (Samantaray et al.,1997) and at
5% of body wt./day for juveniles for optimum growth (Qin,
1996,1997)
 Stocking density was appropriate (75-400/m2 Wee, 1982, Aonanong, 2008)
 Fry survival low, 7-24%, if stocked immediately in pond
after collection from wild then survival is only 13-15%
(Boonyarapatlin, 1985)
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Discussions
 3 major groups of pathogens found in snakehead Bacteria: Aeromonas sp. Flavobacterium sp., Pseudomonas sp., Haemophilus sp.
 External parasites: Protozoa and Fungi, monogeneans
 Internal parasites: Helminthes- cestodes, nematodes and
Acanthocephalus
(Ref: Boonyaratpalin ,1985, Areerat ,1981, Nash ,1988, Chinabut, 1983, Kaewpaitoon, 1992)
 Nematodes (Camallanus spp. and Spinitectus spp), cestodes (Senga spp) and
acanthocephalans (Acanthocephalus spp., Gorgorhynchus spp. and Pallisentis
spp.) have been found in our experimental fishes
 The average nematode and acanthocephalan number of initial stock
(4.52/fish &5.32/fish) didn’t show significant difference with control
treatment (4.24/fish and 4.24/fish) but showed significant reduction in
Rotab treated (1.84/fish and 2.88/fish) fish sample.

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Discussions
In first experiment,
 Higher survival in Rotab +OTC combination treatment
 Rotab alone and in combination with OTC showed better survival than
formalin and control treatments
 Formalin found non-effective to improve SR as formalin treatment had no
variation with control indicate no significant presence of external
pathogen
 The potentiality of endoparasites and bacterial pathogens assumed
Second experiment was conducted to confirm the previous result
 Higher survival in Rotab + OTC treatment. Rotab alone and OTC+
Rotab combination has significant variation with control
 No significant difference (P > 0.05) of survival rate Rotab (93.11 ± 2.98)
and combination of Rotab + OTC (94.25 ± 2.63) treatments. This
confirms that Rotab is effective and the use of Rotab as a feed additive is
sufficient to maintain relatively high survival during the weaning
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Discussions
 In china, OTC used in feed as 50-80 mg/kg body wt./day for 4-6 days
as “non-pollution fishery drug” and not different among species
(Wang,2004)
 OTC depletion occur in fish tissue (Meinertz,2001) though it may present
for 4-6 weeks in tissues after administration (Heijden 1995)
 Microbial control has greater influence on the survival and growth of
fish larvae during the transitional feeding stage and addition of OTC in
feed improves survival (Battaglene, 2006).
 OTC in food improved survival during weaning and caused less grey gut
disease in striped trumpeter fish (Battaglene, 2006).
 OTC is effective and recommended against some major bacterial
pathogens of snakehead (FDA,1992, Boonyaratpalin, 1985, Chinabut,1990 etc)
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Discussions
 Some Thai farmers use Rotab (Aonanong, 2008 ) and OTC during
weaning to reduce mortality but no scientific literature
available
 Rotab is Anthelmintic for veterinary and key ingredient is
Piperazine which has efficacy to reduce internal helminths and
acanthocephalans (Santamarina,1991, Tojo,1998)
 Piperazine is effective and recommended against nematodes
also effective as antiprotozoal in
fish (Quintela,2003, Parama,2004), so protozoan also might be treated
with Rotab in our study
 Non-toxic to aquatic organisms and environment, no potential
for bioaccumulation, biomagnification or secondary poisoning
(Noga,2000, Fairfield,2000,Youlande,2005)
(CSTEE, 2004, EU report,2005)
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Discussions
 Low quality trash fish increase disease incidence (Wee,1982),pelleted feed is
better due to ensured quality (Kaewpaitoon, 1992, Aononong,2008,Wee,1982)
 Potential pathogen source are trash fish as fishes fed marine trash fish
found to be infected with internal parasites (Chinabut,1990, Limsuwan, 1983,
Kaewpaitoon, 1992) and wild source before collection
 Body symptoms indicate intestinal disease and infestations (Chinabut,1990,
Areerat,1981,Limsuwan, 1983, Kaewpaitoon, 1992)
 In general,2nd experiment showed the better survival -better parents and
source with better immunity, season
 The 1st experiment conducted in cooler months but 2nd experiment in
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summer. Colder temperatures increase disease susceptibility and reduce
growth (Kaewpaitoon,1992, Vivekanandan,1977)
 Water quality didn’t show much fluctuation in each experimental period
and was within tolerable range (Ng, 1990, Qin, 1997, Courtnenay,2004, Rath, 2000) and it
doesn’t cause heavy mortality in snakehead but may affect the growth and
production (Wee,1982)
Conclusions
 Rotab alone or in combination with OTC found to be effective and






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showed higher survival rate but no variation between them
Fishes were infected in wild before collection.
Nematode and acanthocephalan density showed reduction in Rotab treated
sample
Formalin treatment found to be ineffective to improve survival
Both Rotab and OTC used as approved dose so no human health and
environment risk
Rotab used by some farmers is effective and the use of Rotab as a feed
additive is sufficient to maintain relatively high survival during the weaning
phase of wild caught snakehead fry to artificial dry feeds.
Finally can be said that, medications with Rotab and OTC together along
with the size grading can improve the survival rate of snakehead fry during
weaning to pelleted feed and these drugs, used by some farmers is found to
be effective to achieve better survival rate.
Recommendations
 Genetic study of fry
 Study of the source of fry
 Determine and Use of pathogen species specific drugs and
dose
 The quality and shelf life assessment of the fed trash fish
 The microbiological study of the fed trash fish
 Impact assessment of the use of these drugs on other spp
 Effect of these drugs on the physiology of the fishes need
to be assessed
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Few References
 Battaglene, S.C., Morehead, D.T., Cobcroft, J.M., Nichols, P.D., Brown, M.R., Carson,

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


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J. (2006).Combined effects of feeding enriched rotifers and antibiotic addition on
performance of striped trumpeter (Latris lineata) larvae. Aquaculture 251: 456– 471.
Boonyaratpalin, M., McCoy, E. W., Chittapalapong, T, (1985) Snakehead Culture and its
Socio-Economics in Thailand, National Inland Fisheries Institute Kasetsart University and
NACA Head Office, Bangkok, Thailand
Kaewpitoon, K. (1992). Utilization of septage-raised tilapia (Oreochromis niloticus) as feed
for snakehead (Channa striata). AIT Dissertation. 212pp.
Marimuthu, K and Haniffa, M. A., (2007). Embryonic and larval development of the
Striped Snakehead Channa striatus. Taiwania, 52(1):84-92.
Nash, G., R.J. Roberts, S. Chinabut, S. Areerat and C. Limsuwan. 1988. Emaciation of
pond-cultured snakehead, Channa striatus (Fowler). J. Fish. Dis., 11: 215-224.
Noga, E.J (2000). Fish Disease : Diagnosis and Treatment. Wiley –Balckwell publishers.
Book (367 pages). 2nd edition, page 292.
Qin, J., Fast, A. W. (1996). Size and feed dependent cannibalism with juvenile snakehead
Channa striatus. Aquaculture 144: 313-320
Samantaray, K., Mohanty, S.S. (1997) Interactions of dietary levels of protein and energy
on fingerling snakehead, Channa striatus. Aquaculture. 156: 241-249
Wee, K.L (1982). The biology and culture of snakeheads. In: J.F. Muir and R.J. Roberts
(edit) Recent advances in aquaculture. Westview press, Boulder Co. pp180-211.
Thank You
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