Ef f ects of rearing conditions Ef f ects of rearing conditions - - PowerPoint PPT Presentation

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Ef f ects of rearing conditions Ef f ects of rearing conditions on low- - temperature tolerance temperature tolerance on low of Nile tilapia, Oreochromis Oreochromis of Nile tilapia, niloticus, , juveniles juveniles niloticus By By

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SLIDE 1

Ef f ects of rearing conditions Ef f ects of rearing conditions

  • n low
  • n low-
  • temperature tolerance

temperature tolerance

  • f Nile tilapia,
  • f Nile tilapia, Oreochromis

Oreochromis niloticus niloticus, , juveniles juveniles

By By

  • H. Charo
  • H. Charo-
  • Karisa, M. A. Rezk, H. Bovenhuis & H. Komen

Karisa, M. A. Rezk, H. Bovenhuis & H. Komen

From From

Fish Culture and Fisheries & Animal Breeding and Genetics Group, Fish Culture and Fisheries & Animal Breeding and Genetics Group, WI AS, WI AS, Wageningen University, The Netherlands Wageningen University, The Netherlands The World Fish Center, The World Fish Center, Abbasa Abbasa, , Abou Abou Hammad Hammad, Egypt , Egypt Kenya Marine and Fisheries Research I nstitute, Box 136, Pap Kenya Marine and Fisheries Research I nstitute, Box 136, Pap-

  • Onditi

Onditi, Kenya , Kenya

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SLIDE 2

Background information Background information

! ! Global expansion of tilapia farming

Global expansion of tilapia farming constrained by sensitivity to low temperature constrained by sensitivity to low temperature

! ! Optimal growth temperature: 25

Optimal growth temperature: 25-

  • 28°C

28°C

! ! Over

Over-

  • wintering mortalities common

wintering mortalities common

! ! Cold tolerance in fish dependent on

Cold tolerance in fish dependent on

  • Environment

Environment

  • Health and nutrition

Health and nutrition

  • Genetic effects

Genetic effects

! ! Selection for growth in low input

Selection for growth in low input environments at environments at Abbasa Abbasa, Egypt , Egypt

! ! Improvement of trait important for extension

Improvement of trait important for extension

  • f grow
  • f grow-
  • out period
  • ut period
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SLIDE 3

Objectives Objectives

! ! Investigate the effect of age, genotype and

Investigate the effect of age, genotype and body size on cold tolerance (Experiment 1) body size on cold tolerance (Experiment 1)

! ! Investigate effect of diet on cold tolerance

Investigate effect of diet on cold tolerance (Experiment 2) (Experiment 2)

! ! Determine low lethal temperature for

Determine low lethal temperature for O. O. niloticus niloticus reared under low reared under low-

  • input

input environments (Experiment 1 and 2) environments (Experiment 1 and 2)

! ! Determine the effect of acclimatization on

Determine the effect of acclimatization on cold tolerance (Experiment 1 and 2) cold tolerance (Experiment 1 and 2)

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SLIDE 4

Experiment 1 Experiment 1

! ! Fry families produced and

Fry families produced and grown in separate 2x3 m grown in separate 2x3 m hapas in pond until tagging hapas in pond until tagging

! ! Pond received 50kg/ ha

Pond received 50kg/ ha chicken manure per day chicken manure per day

! ! Carried out in summer

Carried out in summer

! ! 10 fry/ family from 80

10 fry/ family from 80 families tagged families tagged

! ! Age range from 41

Age range from 41-

  • 90 days

90 days

! ! Weight: 1

Weight: 1-

  • 20g

20g

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SLIDE 5

Cold tolerance test Cold tolerance test

! ! Experiment in cold room and

Experiment in cold room and 5 aquaria 5 aquaria

! Water temperature lowered

from 16 °C at the rate of 1°C/day

! ! Fry not fed

Fry not fed

! ! Hourly measurements of

Hourly measurements of temperature and mortality temperature and mortality

! ! Trait description:

Trait description: Temperature at Death (TAD) Temperature at Death (TAD)

  • r Cooling Degree hours
  • r Cooling Degree hours

(CDH) (CDH)

Chiller

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SLIDE 6

Experiment 2 Experiment 2

! ! Carried out in Fall

Carried out in Fall

! ! 20 full

20 full-

  • sib families produced using

sib families produced using brooders in first experiment brooders in first experiment

! ! Each family divided in two groups

Each family divided in two groups

  • f 30 swim
  • f 30 swim -
  • up fry

up fry

! ! Assigned to two treatments:

Assigned to two treatments: pellet and natural pellet and natural-

  • fed

fed

! ! Reared for 42 days

Reared for 42 days

! ! 10 fish per treatment per family

10 fish per treatment per family tagged for cold tolerance tagged for cold tolerance

! ! Cold tolerance measured as in

Cold tolerance measured as in experiment 1 experiment 1

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SLIDE 7

Data analysis Data analysis

! ! Genotype, aquarium, age, size analyzed

Genotype, aquarium, age, size analyzed in experiment 1 in experiment 1

! ! Model 1:

Model 1:

  • Y

Yijkl

ijkl = µ +

= µ + a ai

i +

+ β β1* 1*AGE AGEijkl

ijkl +

+ β β2* 2*ln(w) ln(w)ijkl

ijkl +

+s sj

j +

+ d dk

k(s

(sj

j) +

) + e eijkl

ijkl

! ! Effect of diet, genotype, aquarium,

Effect of diet, genotype, aquarium, specific growth rate, condition factor specific growth rate, condition factor and and genotype X diet effects genotype X diet effects analyzed in analyzed in second experiment second experiment

! ! Correlation of size and cold tolerance

Correlation of size and cold tolerance

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SLIDE 8

Results Results

Fish that lost balance (arrows) considered dead

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SLIDE 9

Results Results

! ! Mortality in experiment 1 from 13.6°C to 8.6 °C

Mortality in experiment 1 from 13.6°C to 8.6 °C

! ! Experiment 2: from 11.7 °C to 7.5 °C

Experiment 2: from 11.7 °C to 7.5 °C

10 20 30 40 50 60 70 80 90 100 1 4 1 3 . 5 1 3 1 2 . 5 1 2 1 1 . 5 1 1 1 . 5 1 9 . 5 9 8 . 5 8 7 . 5 7 Temperature (°C) Cumulative percent mortality Experiment 1 Experiment 2

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SLIDE 10

Size and cold tolerance parameters Size and cold tolerance parameters

  • f pellet and natural
  • f pellet and natural-
  • fed tilapia fry

fed tilapia fry

  • 0.4771

0.2239 0.8659 0.0002 0.0348 0.0414 0.045 (0.03) 1.92 (0.61) 37.58 (3.81) 9.34 (1.29) 3.71 (0.37) 9.0 (0.64) 530.56 (99.80) 0.045(0.03) 1.97 (0.65) 38.05 (3.99) 9.37 (1.21) 3.86 (0.40) 8.9 (0.67) 551.66 (104.53) Initial weight (g) Final weight (g) Standard length (mm) Specific growth rate (%/day) Condition factor Temperature at death (ºC) Cooling degree hours P-value Natural-fed Pellet-fed Diet Parameter

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SLIDE 11

Tendency for smaller fish to have lower Tendency for smaller fish to have lower cold tolerance cold tolerance

y = 86.662Ln(x) + 165.31 R2 = 0.3365 50 100 150 200 250 300 350 400 450 500 5 10 15 20 25

Body weight (g) Cooling Degree Hours

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SLIDE 12

Presence of genotype environment Presence of genotype environment interaction interaction

0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Family Cooling Degree Hours

Pellets Manure

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SLIDE 13

Results and Discussion Results and Discussion

! ! Significant effect of aquarium,

Significant effect of aquarium, genotype, fish size in both genotype, fish size in both experiments experiments

! ! Age does not affect tolerance

Age does not affect tolerance

! ! Pellet

Pellet -

  • fed fish significantly more cold

fed fish significantly more cold tolerant than natural (phytoplankton) tolerant than natural (phytoplankton) fed fish fed fish

! ! Fish reared in autumn more cold

Fish reared in autumn more cold tolerant tolerant

  • Acclimatization effect ?

Acclimatization effect ?

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SLIDE 14

Acclimatization Acclimatization

! ! Mortality in experiment 1 from 13.6°C to 8.6 °C

Mortality in experiment 1 from 13.6°C to 8.6 °C

! ! Experiment 2: from 11.7 °C to 7.5 °C

Experiment 2: from 11.7 °C to 7.5 °C

10 20 30 40 50 60 70 80 90 100 1 4 1 3 . 5 1 3 1 2 . 5 1 2 1 1 . 5 1 1 1 . 5 1 9 . 5 9 8 . 5 8 7 . 5 7 Temperature (°C) Cumulative percent mortality Experiment 1 Experiment 2

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SLIDE 15

Temperature regimes during fry Temperature regimes during fry rearing in the two experiments rearing in the two experiments

15 17 19 21 23 25 27 29 31 Time (days) Temperature (ºC)

  • Min. Experiment 1
  • Min. Experiment 2

(a) 15 17 19 21 23 25 27 29 31 33 35 Time (days) T em p eratu re (°C )

  • Max. Experiment 1
  • Max. Experiment 2

(b)

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SLIDE 16

Conclusions Conclusions

! Smaller (< 5g) fish are less tolerant

to lower temperatures

! ! Potential for manipulation of

Potential for manipulation of environment and diet for improved environment and diet for improved cold tolerance cold tolerance

! ! Genotype x diet interactions should

Genotype x diet interactions should be further studied be further studied

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SLIDE 17

Acknowledgements Acknowledgements

! ! INREF

INREF-

  • POND

POND

! ! World Fish Center

World Fish Center

! ! Tilapia International Foundation (TIF)

Tilapia International Foundation (TIF)

Thank You All! Thank You All!