S. Augustine B.Gagnaire C. Adam-Guillermin S. A. L. M. Kooijman

Mechanistic modeling of zebrafish Mechanistic modeling of zebrafish metabolism in relationship to food metabolism in relationship to food level and the presence of a toxicant level and the presence of a toxicant

(uranium)(uranium)

S. AugustineB.Gagnaire

C. Adam-GuillerminS. A. L. M. Kooijman

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Processes at different levels of biological organisation

Space

Time

molecules

cells

populations

ecosystems

Individuals

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To what extent does a single combination of parameters capture all aspects of metabolism for each life stage for a

particular animal?

Estimation of a single set of parameters for zebrafish, Danio rerio based on observations of:

- Embryonic development - Growth - Reproduction - Survival

Dynamic Energy Budget (DEB) Theory (Kooijman 2010)

Specifies uptake and use of substrate by all organisms

Standard DEB model

Mechanistic parameter sparse model which specifies individual mass and energy fluxes for all animals over a whole lifecycle

Augustine et al. subm. 2011

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DEB model applied to the whole lifecycle of Danio rerio

FoodReserve

Structure

Somatic Maintenance

Maturity

Maturity MaintenanceқX

қG

(0.67)

қR (0.95)

Eggs

Reproduction Buffer

Қ (0.44)

1 – қ

BIRTH METAMORPHOSIS PUBERTY

EMBRYO JUV I J II ADULTAGE

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age

size

Developmental milestone quantified as cumulated energy invested in maturity

(J)

Effects of feeding history accumulate over time

Maturity is a good quantifier for developmental stage

The value of қ is close to the one that maximises reproduction

High variability in reproduction buffer handling rules combines with low variability of cumulated reproductive output

Surface area-specific assimilation and reserve mobilization rates are higher for adults than for embryos

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1 J

Relationships between egg size, and cumulated energy invested in the different metabolic processes at birth

Relationship between egg size and resistance to starvation?

1.67 J

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Effects of compounds: URANIUM

Internalised U

Effects

Internalised U

Exposure to contaminants induces physiological deviations from the blank

No Internal Effect Concentration

Uranium is toxic for organisms (Canadian law on environmental protection 1999)

-Modified growth-Modified reproductive output

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FoodReserve

Structure

Somatic Maintenance

Maturity

Maturity Maintenance

MaturityReproduction Buffer

Scenario 1 : Bring up the cost for a unit of structureScenario 2 : Bring up the volume linked somatic maintenance costsScenario 3 : Bring up maturity maintenance costs

Effects are translated as the modification of a parameter value

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Length (mm) Maturation (kJ) Cumulated # eggs

2000

40

Age, day Age, day Age, day

5

Scenario 1 : Bring up the cost for a unit of structureScenario 2 : Bring up the volume linked somatic maintenance costsScenario 3 : Bring up maturity maintenance costs

0

8.104

0

3

BLANK

5 200 5 200

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Conclusions

Food

Compounds

Metabolic performance of an individual over a whole life cycle

For effects of compounds the predictive power of the model is linked to the quality of parameter values of the blank

The model can be applied to data to determine the mode action of substances on the metabolism and so contributes analysis of chemically induced environmental risks

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Thank you for your attention …