Download SPARUS AURATA (L.) EMBRYOS AS MODEL ORGANISM FOR

Biol. Mar. Mediterr. (2010), 17 (1): 124-125
F. Del Prete1, A.L. Langellotti1, V. Vitiello1, G. Sansone1,2
Università degli Studi di Napoli “Federico II”
CRIAcq (Centro interdipartimentale di ricerche per la gestione delle risorse idrobiologiche e per l’acquacoltura),
Via Università, 100 – 80055 Portici (NA), Italia.
2
Dip. delle Scienze Biologiche, Sez. di Fisiologia ed Igiene, Via Mezzocannone, 16 – 80134 Napoli, Italia.
[email protected]
1
SPARUS AURATA (L.) EMBRYOS AS
MODEL ORGANISM FOR ECOTOXICOLOGICAL STUDIES
EMBRIONI DI SPARUS AURATA (L.) QUALE
ORGANISMO MODELLO PER STUDI ECOTOSSICOLOGICI
Abstract – Sparus aurata (L.) embryos have been proposed as model organism for aquatic
biosciences. Particularly the Authors propose eleutheroembryos for exceeding limitations presented in
European laws for the management of experimental animals; these embryos are year-round available
because this specie is commonly reared; moreover this model showed high sensitivity to xenobiotic
substances in ecotoxicological tests.
Key-words: Sparus aurata, fish embryos, aquatic model, ecotoxicology.
Introduction – The gilthead seabream, Sparus aurata (L.), one of the most
important fish for aquaculture in Mediterranean countries, is becoming a model
organism for marine teleosts as a result of its high commercial value and intensive
research efforts from the European scientific community (Franch et al., 2006), such as
the network of excellence Marine Genomics Europe (MGE) (www.marine-genomicseurope.org) (Rafael et al., 2006). The European Council Directive n. 88/609/EEC,
transposed in Italy by Legislative Decree no. 116/1992, imposes strict rules on use of
acute and chronic toxicity tests performed on teleost fishes.
Recently, attention has focused on the use of fish embryos in ecotoxicological
acute assays (Embry et al., 2010) as alternative method for environmental risk
assessment.
The large availability of seabream embryos is correlated to conditioning of the
reproductive cycle and to the daily spawning, because the asynchronous gonads
maturation. This work suggests the use of sea bream embryos as a model for aquatic
ecotoxicology and more generally for aquatic biosciences.
Materials and methods – Sparus aurata embryos, supplied by Mediterranean
farms, were year-round used in the last ten years. The embryos, obtained from natural
spawning, were collected at 1–2 cell stage and transported into the laboratory. 48h
toxicity tests were performed with growing concentrations of CdCl2 (UNICHIM ring
test reference toxicant) using 24h and 72h embryos post fertilization at the following
conditions: T 19±1 °C, salinity 37±1‰, pH 8±0.5, O2 7±1 ppm, density 25 embryos/
100 ml. Survival was evaluated at the end of the exposure and after 48h from Cd
removal. Statistical analysis was performed by t-Student test (n≥9) and significance
p<0.02.
Results – The embryo survival percentage in the controls, until complete resorption
of the yolk sac, was rarely less than 90% over the past 10 years independently from
sampling season.
Assessing survival 48h post-exposure period, pre-hatched embryos (24 h max
aged) showed LOEL at 0.06 ppm and an EC50 to concentrations more than 0.5 ppm
S. aurata embryos as model organism for ecotoxicological studies
125
Fig. 1 - Survival at endtest and after 48h of S. aurata embryos exposed to Cd.
Sopravvivenza fine test e 48h post fine test degli embrioni di S. aurata esposti al Cd.
Fig. 2 - Survival at endtest and after 48h of S. aurata eleutherioembryos exposed to Cd.
Sopravvivenza fine test e 48h post fine test degli eleuterioembrioni di S. aurata esposti al Cd.
(Fig. 1). Post-hatched embryos (aged between 72h and 120h) showed higher sensitivity
to the reference toxicant; LOEL value was at 0.007 ppm, with an EC50 less than 0.05
ppm (Fig. 2).
Conclusions – The lower sensitivity of pre-hatched embryos is probably due
to the presence of chorion. In relation to the large availability of Sparus aurata
embryos, this model can be proposed for a general tool in aquatic biosciences; posthatched embryos will be interesting model in ecotoxicological researches and related
applications.
References
EMBRY M.R., BELANGER S.E., BRAUNBECK T.A., GALAY-BURGOS M., HALDER M.,
HINTON D.E., LÉONARD M.A., LILLICRAP A., NORBERG-KING T., WHALE G. (2010) The fish embryo toxicity test as an animal alternative method in hazard and risk assessment
and scientific research. Aquat. Toxicol., 97 (2): 79-87.
FRANCH R., LOURO B., TSALAVOUTA M, CHATZIPLIS D., TSIGENOPOULOS C.S.,
SARROPOULOU E., ANTONELLO J., MAGOULAS A., MYLONAS C.C., BABBUCCI M.,
PATARNELLO T., POWER D.M., KOTOULAS G., BARGELLONI L. (2006) - A Genetic
Linkage Map of the Hermaphrodite Teleost Fish Sparus aurata L. Genetics, 174: 851-861.
RAFAEL M.S., LAIZÉ V., LEONOR CANCELA M. (2006). Identification of Sparus aurata bone
morphogenetic protein 2: Molecular cloning, gene expression and in silico analysis of protein
conserved features in vertebrates. Bone, 39: 1373–1381.