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Tilapia genetic improvement:

achievements and future directions

Hans Komen & Trịnh Quốc Trọng

Animal breeding and genomics group, wageningen university

GIFT – a brief history

2002G6 to G14

RIA1

1988Base to G5

Bangladesh, Côte d’Ivoire, Egypt, Fiji Islands,

India, Indonesia, Kenya, Laos, Malaysia, Papua

New Guinea, China, Thailand, and Viet Nam

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Examples of commercial strains with

ancient GIFT ‘heritage’

� Genomar supreme tilapia

� Spring genetics

� ProGift Hainan

Realized genetic gains & inbreeding

Strain Avg Gain %/gen

∆F%/gen

reference

GIFT Base to G91) 7 (9) 1.4**) Khaw, 2008

GIFT G6 to G14 2) 12.5 >5* 0.37 Khaw, 2010

ProGift Hainan G2 to G6 2) 13.2 >5.3* 0.8 Thodesen, 2011

Nicanor G0-G3 2) 3.5 - Gjerde, 2012

FaST G0 to G12 2) 12.9 0.53 Bolivar and Newkirk, 2002

1) Relative to unselected base (cryopreserved sperm)

2) Regression on EBV

*) reduction due to decreased selection intensity in later generations

**) GIFT base to G5; cf Ponzoni, 2010

Harvest weight

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“Is this the best you can do?”

h2 CVResponse

i = 1 - 1.5

Maximum R

i =2.35♂ 2.06♀

0.41 40 16.0 – 23.8 35.2

0.24 34 8.2 – 12.2 18.0

0.16 25 4.3 – 7.6 9.5

Gain (%) = i * h2 * CV (Sae Lim, 2012)

No, single trait (2 at most)

No, low selection intensities (for fish)

Harvest weight

Yes, look at Livestock!

Harvest weight and growth rate

Growth models describe growth over a range of weights and

ages:

� TGC = [(HW)1-b – (TW)1-b / (days x T)] *100 (e.g. Dumas, 2007)

● 1-b =species dependent, from Length Weight relationship W≈ Lb

● Growth in length is constant over production time

� Corrects for heterogeneity of variance in TW and HW,

� Corrects for differences in stocking weight and grow-out period

� Corrects for differences in rearing temperature

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Effects of temperature on growth of NT

6.5

14.1

19.2

10.6

5.4

7.2

6.26.7

0.0

5.0

10.0

15.0

20.0

25.0

22 26 30 34

Me

an

we

igh

t (g

)

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

9.5

10.0

SG

R (

%/d

ay

)

FBW after 60day growth (g) SGR (%)

Krishen Rana

Growth rate

Trong, 2013

DGC = [(HW)3 – (TW)3 / days] *100

i.e. W≈ L3

DGC can be used to predict weight at given age and temperature

DGC can be used to compare performance across strains and environments

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A comparison across strains and test

environments

environment DGC Origin/reference

Pond, G3*) 3.23ProGIFT, Hainan;

Thodesen, 2011

Cage, G6 5.05

Pond, G6 4.67

VAC 2.20GIFT G13, RIA-2

Trong, 2013

Pond 3.11

River cage 3.85

RAS, base (♀♀) 2.29 Crossbred AIT/GIFT/IDRCRutten, 2005;

Unpublished results

RAS, base (♂♂) 3.00

RAS, G6 (all) 4.46

Correlated responses to selection

● Growth rate

● Fillet weight and fillet yield

● Shape

Reproduction

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DGC: h2 and genetic correlations between 2

environments

Trait Cage – VAC

HW rg0.94

DGC rg0.77

h2 nucleus 0.47, rg with HW: 0.94

(Trong, Aquaculture 384-387, 119

Fillet weight and Fillet %

Fillet Weight Fillet-% ∆G F-% reference

h2 rg HW h2 rg HW

0.24 0.99 0.12 0.74 - Rutten, 2005

0.33 0.96 0.25 0.44 Noreps.

Nguyen, 2010

0.16 0.99 0.06 0.21 0.28% units

Gjerde, 2012

0.30 - 0.17-0.23

0.09 0.3%units

Thodesen, 2012

selection for harvest weight will increase fillet yield by correlated response

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width reference

h2 rg HW

0.25 0.92 Rutten, 2005

0.58 0.99 Charo-Karisa, 2007

0.20 0.82 Nguyen, 2010

0.23 (?) Khaw, 2012

0.27 0.89 Trong, 2013

Correlated responses in thickness

Effects of age and body weight on fillet yield

Thodesen, Aquaculture 366-367, 67.

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Shape and ellipticity

Shape and ellipticity

Blonk, Aquaculture 307, 6-10

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Genetic correlations with HW

Trait DGC EL-H EL-T EH-T

HW 0.94 ±

0.02

0.47 ±

0.21

−0.15 ±

0.22

−0.42 ±

0.21

DGC 0.15 ±

0.24

−0.42 ±

0.18

−0.52 ±

0.18

EL-H 0.08 ±±±±

0.04

0.41 ±

0.27

−0.21 ±

0.31

EL-T 0.14 ±±±±

0.04

0.81 ±

0.10

EH-T 0.08 ±±±±

0.04

Trong, Aquaculture 384-387, 119

Ellipticity and Shape

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Shape and ellipticity

� Heavier fish are more rotund,

� no effect of age (200-400 days)

� DGC and Ellipticity: fish selected for high growth rate become more rotund / thicker

Reproductive traits: maturation

� Age at first maturation is a heritable trait

(reviewed in Taranger, 2010)

� In trout, selection for late maturation was successful

(Kause, 2003)

� Fisheries induced mortality of larger fish cause selection

for earlier maturation

TRENDS in Ecology and Evolution Vol.22 No.12

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Maturity: correlations with HW

� Kronert, 1989: zero genetic correlation

� Longalong, 1999 (visual inspection)

� Charo-Karisa, 2007 (dissected gonads): 0.18 ± 0.24

Aquaculture 178:113-12

Reproductive traits: fecundity and fertility

In livestock, genetic correlations with production traits are often negative

Up Down

� Adult body weight

� Feed efficiency

� Carcass fat and moisture level

� Fertility

� Hatchability

� Egg productionMarks, 1996; > 80 generations

� Body weight 8, 20,

24 weeks

� Egg weight

� Hatchability

� Egg production

But also

� Age at first egg

Nestor, 2000; 30 generations

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Genetic correlations with HW

NEGG

0.08

RFEC

0.05

EGGW

0.05

EGGD

0.05

HW0.51

±±±± 0.29

−−−−0.72

±±±± 0.14

−−−−0.48

±±±± 0.41

−−−−0.50

±±±± 0.64

NEGG0.99

±±±± 0.01

−−−−0.74

±±±± 0.50

−−−−0.40

±±±± 0.52

RFEC0.25

±±±± 0.51

−−−−0.07

±±±± 0.81

EGGW0.79

±±±± 0.60

Trong, Aquaculture 416-417, 72

Conclusions

� Selection for improved harvest weight has been successful

� Phenotypic trends suggest considerable improvement in growth rate (DGC)

� Correlated response in

● fillet yield small but positive

● shape might be considerable

● “age at maturity” probably zero

● relative fecundity and egg size negative....

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Future directions: the breeding goal

Future directions: the breeding goal

�Robustness (survival)

� FCR

�Cold tolerance

�Disease resistance

�Carcass quality traits

�Reproductive performance

� Late maturation

porsche toyota

no yes

yes no

no yes

yes yes

yes no

yes no

no yes

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Reproductive performance

August 15 –sept 20, 2013

Total: 108 Fams produced

26 HS-2 families

10 HS-3 families

1 HS-4 family

� Group Mating is fast”: 1 male to 5-10 females

� Reduction of generation interval by two months: + 20% gain /yr!

� Increase of selection intensity (less fish needed to produce fams)

Cold tolerance

h2 0.08 ± 0.17; c2 0.33 ± 0.10 (Charo-karisa, 2005

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Cold tolerance and acclimatization

0

10

20

30

40

50

60

70

80

90

100

14 13.5 13 12

.5 12 11.5 11 10

.5 10 9.5 9

8.5 8

7.5 7

Temperature (°C)

Cum

ulat

ive

perc

ent m

orta

lity

Experiment 1

Experiment 2

Exp 1 from 13.6°C to 8.6 °C

Exp 2 from 11.7 °C to 7.5 °C

Feed efficiency....

Selection for growth (increased harvest weight) should be accompanied by evaluations on realized FCR

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Acknowledgements

� Marc Rutten,

� Carolien Vancoillie

� Yonas Fessehaye

� Harrison Charo-Karisa

� Panya Sae-Lim

� Henk Bovenhuis

Acknowledgements

� Trong and his Tilapia team, Research Institute for Aquaculture No.2 (RIA2)

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Reproductive performance

1:2 mating design: problematic, long time needed to produce HS groups (2-3 months).

� Group mating designs?