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PH25 Wildlife Ecotoxicology II
(PH285) Trenbolone acetate suppresses vocalization in Japanese quail chicks.
Quinn, Jr., M1, Lavoie, E1, Ottinger, M1, 1 University of Maryland, College Park, MD, USA
ABSTRACT- Japanese quail (Coturnix japonica) are precocial birds, being able to leave the nest and find their own food at day of hatch. It is necessary for chicks to remain with the brood after hatch for protection from predators and for thermoregulation. If a chick becomes separated from its brood, it calls to its conspecifics. Siblings vocally respond to the chick′s separation call, which helps the separated individual to locate and return to the rest of the brood. In birds, androgens are necessary for development of areas of the brain responsible for vocalization and are known to influence motor activity in Japanese quail. The objective of this experiment was to determine if embryonic exposure to the endocrine disrupting chemical trenbolone acetate, a synthetic androgen, would disrupt this early survival behavior in Japanese quail. Sesame oil (vehicle control) or 0.05, 0.5, 5.0, or 50.0 g trenbolone was injected into the yolk of quail eggs at day 4 of incubation. Motor and calling behavior were assessed in a modified open field runway test at weeks 1 and 2 posthatch. Individuals were separated from their conspecifics and allowed to call and return to the group at the opposite end of the runway (182 cm long). Vocalization, motor behavior (time to reach conspecifics and direction of locomotion), and stress (defecation) were measured. Vocalization and defecation were significantly reduced in chicks that were exposed to higher concentrations of trenbolone. No differences were observed in motor behavior. Reductions in defecation were most likely due to disrupted development of the gastrointestinal tract rather than differences in stress responses. Vocalization was completely abolished in chicks from the 50.0 g group; individuals simulated calling, but no noise was made by either the individual or the group of conspecifics. Since individuals from this group were able to return to their conspecifics similarly to controls, these individuals must have used cues other than vocalization to locate and return to the group. Partially funded by Battelle Labs in support of a U.S. EPA contract.
Key words: vocalization, trenbolone, motor behavior, androgen
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