Triclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus.
Thyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely employed in consumer personal care products, suggests triclosan can have adverse effects on the thyroid system. The sheepshead minnow, Cyprinodon variegatus, is now used in ecotoxicological studies that have recently begun to focus on potential disruption of the thyroid axis by endocrine disrupting compounds. Here, we investigate the in vivo effects of exposure to triclosan (20, 50, and 100μgL-1) on the thyroid system and the embryonic and larval development of C. variegatus. Triclosan exposure did not affect hatching success, but delayed hatching time by 6-13h compared to control embryos. Triclosan exposure affected the ontogenetic variations of whole body thyroid hormone concentrations during the larval phase. The T3 peak around 12-15 dph, described to be indicative for the metamorphosis climax in C. variegatus, was absent in triclosan-exposed larvae. Triclosan exposure did not produce any deformity or allometric repatterning, but a delayed development of 18-32h was observed. We conclude that the triclosan-induced disruption of the thyroid system delays in vivo the start of metamorphosis in our experimental model. We observed a global developmental delay of 24-45h, equivalent to 4-7% prolongation of the developmental time in C. variegatus. The costs of delayed metamorphosis can lead to reduction of juvenile fitness and could be a determining factor in the outcome of competitive interactions.
Laboratory of Oceanology, MARE, B6c, Liège University, Liège, Belgium. Electronic address: joseph.schnitzler@ulg.ac.be.
Joseph G
JG
Schnitzler
Laboratoire de Morphologie Fonctionnelle et Evolutive, AFFISH Research Center, Liège University, Liège, Belgium. Electronic address: bruno.frederich@ulg.ac.be.
Bruno
B
Frédérich
Laboratory of Oceanology, MARE, B6c, Liège University, Liège, Belgium. Electronic address: melanie_dussenne@hotmail.fr.
Mélanie
M
Dussenne
Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Faculty of Science, Radboud University, Nijmegen, The Netherlands. Electronic address: p.klaren@science.ru.nl.
Peter H M
PH
Klaren
Laboratory of Evolutionary and Adaptive Physiology-URBE, UNamur, B-5000 Namur, Belgium. Electronic address: frederic.silvestre@unamur.be.
Frédéric
F
Silvestre
Laboratory of Oceanology, MARE, B6c, Liège University, Liège, Belgium. Electronic address: krishna.das@ulg.ac.be.
Krishna
K
Das
D000818:Animals; D052244:Endocrine Disruptors / Q000633:toxicity*; D005260:Female; D007695:Killifishes / Q000254:growth & development* / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D008297:Male; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism; D013963:Thyroid Hormones / Q000378:metabolism*; D014260:Triclosan / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
D052244:Endocrine Disruptors; D013963:Thyroid Hormones; D014874:Water Pollutants, Chemical; D014260:Triclosan
Development; Morphometrics; Sheepshead minnow; Thyroid hormone; Triclosan