title: Assessment of neuroanatomical and behavioural effects of in ovo methylmercury exposure in zebra finches (Taeniopygia guttata).
abstract: Methylmercury (MeHg) readily crosses the blood brain barrier and is a known neuro-toxicant. MeHg accumulation in the brain causes histopathological alterations, neurobehavioral changes, and impairments to cognitive motor functions in mammalian models. However, in birds the neurotoxic effects of MeHg on the developing pre-hatching brain and consequent behavioral alterations in adult birds have not received much attention. Moreover, passerine birds are poorly represented in MeHg neurotoxicology studies in comparison to other avian orders. Hence in this study, we used the egg injection method to investigate the long term effects of in ovo MeHg exposure on brain histopathology and courtship behavior in a model songbird species, the zebra finch (Taeniopygia guttata). Egg treatment groups included: a low MeHg dose of 0.2μg Hg g-1egg, a high MeHg dose of 3.2μg Hg g-1egg, and a vehicle control (water). No adverse effects of in ovo MeHg treatment were detected on courtship song quality or on mating behavior in experimental males at sexually maturity which would suggest that observable neurobehavioral effects of MeHg exposure may depend on the timing of exposure during offspring development. However, neuroanatomical analysis indicated an increase in telencephalon volume with increased MeHg concentrations which may suggest a prolonged inflammatory response in this region of the brain.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada. Electronic address: mariay@sfu.ca.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Yu
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada; Environment and Climate Change Canada, Science & Technology Branch, Pacific Wildlife Research Centre, Delta, British Columbia, Canada.
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Eng
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Tony D
authors.initials: TD
authors.lastname: Williams
authors.affiliation: Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada.
authors.forename: Mélanie F
authors.initials: MF
authors.lastname: Guigueno
authors.affiliation: Environment and Climate Change Canada, Science & Technology Branch, Pacific Wildlife Research Centre, Delta, British Columbia, Canada. Electronic address: john.elliott@canada.ca.
authors.forename: John E
authors.initials: JE
authors.lastname: Elliott
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D005260:Female; D046369:Finches / Q000196:embryology / Q000254:growth & development; D008297:Male; D008767:Methylmercury Compounds / Q000633:toxicity*; D009498:Neurotoxins / Q000633:toxicity*; D010063:Ovum / Q000187:drug effects / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000187:drug effects; D014828:Vocalization, Animal / Q000187:drug effects
chemical_list: D008767:Methylmercury Compounds; D009498:Neurotoxins
keywords: Courtship behavior; Developmental neurotoxicity; In ovo exposure; Methylmercury; Passerines