Mechanistic modeling of zebrafish metabolism in relationship to food level and the presence of a toxicant (uranium) S. Augustine B.Gagnaire C. Adam-Guillermin S. A. L. M. Kooijman

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ Processes at different levels of biological organisation Space Time molecules cells populations ecosystems Individuals Energy + Mass Balances Role of differences in individuals + selection in evolution Role of behavior on food intake and mate preference Differences between individuals = differences in parameter values

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ 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

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ DEB model applied to the whole lifecycle of Danio rerio Food Reserve Structure Somatic Maintenance Maturity Maturity Maintenance қXқX қ G (0.67) қ R (0.95) Eggs Reproduction Buffer Қ (0.44) 1 – қ BIRTHMETAMORPHOSISPUBERTY EMBRYOJUV IJ IIADULT AGE

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ 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

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ 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

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ 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

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ Food Reserve Structure Somatic Maintenance Maturity Maturity Maintenance Maturity Reproduction Buffer Scenario 1 : Bring up the cost for a unit of structure Scenario 2 : Bring up the volume linked somatic maintenance costs Scenario 3 : Bring up maturity maintenance costs Effects are translated as the modification of a parameter value

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ Length (mm)Maturation (kJ)Cumulated # eggs Age, day 5 Scenario 1 : Bring up the cost for a unit of structure Scenario 2 : Bring up the volume linked somatic maintenance costs Scenario 3 : Bring up maturity maintenance costs BLANK

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ 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

AQUATIC SCIENCES MEETING, ASLO, PR 02/14/ Thank you for your attention …