1 EFFECTS OF DIFFERENT FEEDING REGIM EFFECTS OF DIFFERENT FEEDING REGIM E E , , WEANING PERIOD AND STOCKING DENSIT WEANING PERIOD AND STOCKING DENSIT Y Y ON ON THE THE SURVIVAL AND GROWTH SURVIVAL AND GROWTH OF OF STINGING STINGING CATFISH FRY CATFISH FRY ( ( Heteropneustes fos Heteropneustes fos si si lis lis , Bloch) , Bloch) THEERAWAT SAMPHAWAMANA st 105453
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1 EFFECTS OF DIFFERENT FEEDING REGIME, WEANING PERIOD AND STOCKING DENSITY ON THE SURVIVAL AND GROWTH OF STINGING CATFISH FRY (Heteropneustes fossilis,
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EFFECTS OF DIFFERENT FEEDING REGI EFFECTS OF DIFFERENT FEEDING REGIMMEE,,
WEANING PERIOD AND STOCKING DENS WEANING PERIOD AND STOCKING DENSITITYY
ON ON THE THE SURVIVAL AND GROWTH SURVIVAL AND GROWTH OF OF STINGINGSTINGING CATFISH FRY CATFISH FRY
Major constraints of H. fossilis larvae rearing is
the high rate of mortality.
How to improve the survival?
1. Feeding regime
2. Weaning period
3. Stocking density
Reported studies Feeding regime
Live-feeds are essential for carnivorous fish at the first stage (Dabrowski and Culver, 1991).
Weaning periodCo-feeding live-feed and artificial diets provided higher growth and survival than feeding either live-feeds or micro-diets alone (Giri et al., 2002).
Stocking densityOver-stocking has consequently slow growth and low survival (Shepherd and Bromage, 1992)
.
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Experimental
design
Determine the proper stocking density
Rearing weaned fry with different stocking densities
Select the best weaning procedure
Weaning fish fry onto artificial diets with different acclimation schedules
Select the best live-feed
Experiment 1
Nursing fry with different live-feeds
Recommend the suitable nursing protocols
Experiment 2
Experiment 3
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Experiment 1
To evaluate the effect of different live feeds on the growth and survival of H. fossilis fry at the first stage.
Null hypothesis: There is no effect of different live feeds on the survival and growth of H. fossilis fry.
Experiment period: 21 days
4 treatments and 4 replications.
Two days-old fry were reared with 3 different types of live feeds.
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Design of Experiment 1
Trt Feed SD REP
1A Rotifer 8 fry/L 4
2A Artemia 8 fry/L 4
3A Moina
1st week: small-size Moina
After 1st week: ungraded Moina
8 fry/L 4
4A 1st week: Rotifer
2nd week: Artemia
3rd week: Moina
8 fry/L 4
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Artemia : 0.5+ 0.06 mm
Small-size Moina : 0.36+ 0.04 mmRotifer: 0.15+ 0.03 mm
Ungraded Moina : 0.84+ 0.15 mm
Live-feeds
Rotifer
Ungraded MoinaArtemia
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Treatment3:Moina were graded by sieving through 400 micron seine net during the first week.
400 micron
69 micron
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Fish sample (2 day-old)
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Maintenance of experiment tanks
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Length and weight measurement
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Fish mouth measurement
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Results of experiment 1
Parameters1A
Fed Rotifer
2A
Fed Artemia
3A
Fed Moina
4A
Combination
Mean final weight
FMW (mg)
27.47c
± 7
51.27b
± 14
81.78a
± 29
63.54b
± 21
Daily weight gain
DWG (mg/day)
1.27c
± 1.3
2.6b
± 2.6
3.61a
± 3.6
2.93ab
± 3.0
Specific growth rate
SGR (%)
26.95c
± 0.4
30.0b
± 1.0
31.63a
± 1.0
30.65ab
± 0.5
Mean final length
FML (%)
13.41c
± 0.12
18.09b
± 0.23
20.03a
± 0.3
19.3ab
± 7
Survival (%)63.25b
± 3.3
84.06a
± 3.1
86.87a
± 1.8
83.81a
± 3.0
Fry fed Moina showed the best growth
Supporting literature
species Protein % Fibre % Fat % Ash %
Moina 71.6 7.4 20.6 11.8
Artemia 61.6 2.7 19.4 10.1
Rotifer 66.7 2.7 24.1 4.3
Source of data: Watanabe (1994)
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This might have resulted from the higher nutritive value.
Discussion Optimum stocking density of H. fossilis is
8 fry/L.
Over-stocking has negative impact on growth and survival rate due to the competition for space. This might be due to stress.
Low temperature might have caused low
survival in all treatments.
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Comparison between water quality parameters during experiment
periods and optimum levelparameters Experiment 1 Experiment 2 Experiment 3
optimum level
DO 5.04-7.95 5.7-7.44 5.86-7.18 > 5
Temp 25.2-31.9 26.0-30.5 22.0-28.9 25-30
pH 7.3-7.94 7.3-7.68 7.3-7.89 6.5-8.5
TAN 0.00-0.17 0.00-0.18 0.00-0.09 < 0.1
NO2 0.00-0.03 0.00-0.06 0.00-0.04 < 0.1
Source of optimum level data: (Boyd,1990) 38
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Experimental
design
Determine the proper stocking density
Rearing weaned fry with different stocking densities
15 day weaning schedules
Weaning fish fry onto artificial diets with different acclimation schedules
Moina
Experiment 1
Nursing fry with different live-feeds
Recommend the suitable nursing protocols
Experiment 2
Experiment 3
8 fry / L
Conclusions
Hypothesis 1: Moina is the most suitable live-feed for H. fossilis larval rearing at the first 3 weeks.
Hypothesis 2: H. fossilis fry can be completely weaned from Moina to artificial-feeds within 15 days with 3 gradually acclimatization per each live-feed to artificial-feeds combination.
Hypothesis 3: 8 fry/L is optimum stocking density of post-weaned H. fossilis fry rearing until achieving the fingerling size (3 month-old).
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Recommendation
Comparison between H. fossilis fed small-size Moina and ungraded Moina at the first week should be done to evaluate the effect of different size, in term of growth and survival.
The development of suitable growth-out system for achieving the marketable size should be conducted.
During the experiment periods, affected should be paid for maintain optimum environment parameters, such as water temperature.