Assessment of the effects of early life exposure to triphenyl phosphate on fear, boldness, aggression, and activity in Japanese quail (Coturnix japonica) chicks

Early life exposure to TPHP increases measures of boldness and aggression, but not fear and activity in Japanese quail chicks.Triphenyl phosphate (TPHP) is an organophosphate ester (OPE) used as a flame retardant (FR) and plasticizer. TPHP has previously been shown to disrupt behaviour in fish and mammals, but to our knowledge, this is the first study on the behavioural effects of TPHP in birds. Early life stage Japanese quail (Coturnix japonica) were exposed to nominal doses of 0 ng/g (vehicle-control), 5 ng/g (low dose), 50 ng/g (mid dose), and 100 ng/g (high dose) TPHP, both as embryos (via air cell injection prior to incubation) and as chicks (via daily gavage until 5 days post-hatch). The low dose reflects TPHP levels recorded in wild avian eggs, but actual environmental exposure levels may be higher given that TPHP is known to be rapidly metabolized in birds. We previously reported that the chicks exposed to TPHP in this study experienced reduced growth and resting metabolic rate, and sex-specific changes in thyroid function. The current study focuses on behavioural endpoints. We found that high-TPHP chicks exhibited less neophobia than vehicle-controls, and low-TPHP chicks exhibited more aggression towards conspecifics. No differences were observed in the responses of Japanese quail chicks to activity or tonic immobility (fear response) tests. These data add weight of evidence t

Transfer of hexabromocyclododecane flame retardant isomers from captive American kestrel eggs to feathers and their association with thyroid hormones and growth

Feathers are useful for monitoring contaminants in wild birds and are increasingly used to determine persistent organic pollutants. However, few studies have been conducted on birds with known exposure levels. We aimed to determine how well nestling feather concentrations reflect in ovo exposure to hexabromocyclododecane (α-, β- and γ-HBCDD), and to determine if feather concentrations are related to physiological biomarkers. Captive kestrels (n = 11) were exposed in ovo to maternally transferred HBCDD-isomers at concentrations of 127, 12 and 2 ng/g wet weight of α-, β- and γ-HBCDD (measured in sibling eggs), respectively, and compared to controls (n = 6). Nestling growth was monitored at 5 d intervals and circulating thyroid hormone concentrations assessed at d 20. Tail feathers were collected prior to the first molt and analyzed for HBCDD isomers. The mean ΣHBCDD concentration in feathers was 2405 pg/g dry weight (in exposed birds) and α-, β- and γ-HBCDD made up 32%, 13%, and 55%, respectively of the ΣHBCDD concentrations. This isomer distribution deviated from the typical dominance of α-HBCDD reported in vertebrate samples. Exposed chicks had significantly higher feather concentrations of β- and γ-HBCDD compared with controls (p = 0.007 and p = 0.001 respectively), while α-HBCDD concentrations did not differ between the two groups. Feather concentrations of α-HBCDD were best explained by egg concentrations of β- or γ-HBCDD concentrations (wi = 0.50, 0.30 respectively), while feather concentrations of β- and γ-HBCDD were influenced by growth parameters (rectrix length: wi = 0.61; tibiotarsus length: wi = 0.28). These results suggest that feather α-HBCDD concentrations may reflect internal body burdens, whereas β- and γ-HBCDD may be subject to selective uptake. The α-HBCDD concentrations in the feathers were negatively associated with the ratio of plasma free triiodothyronine to free thyroxine (T3:T4; p = 0.020), demonstrating for the first time that feather concentrations may be used to model the effect of body burdens on physiological endpoints

Sex-specific responses in neuroanatomy of hatchling American kestrels in response to embryonic exposure to the flame retardants bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate

Bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), flame retardant components of FireMaster 550® and 600® have been detected in tissues of wild birds. To address the paucity of information regarding potential impacts of flame retardants on the brain, brain volume regions of hatchling American kestrels (Falco sparverius) were evaluated following in ovo injection at embryonic day 5 with safflower oil or to 1 of 3 doses of either BEH-TEBP (13, 64, or 116 μg/g egg) or EH-TBB (12, 60, or 149 μg/g egg). The doses for both chemicals reflected concentrations reported in wild birds. The volumes of the hippocampus and telencephalon and volumetric differences between left and right hemispheres were measured in hatchlings (embryonic day 28). A sex-specific effect of BEH-TEBP on relative hippocampus volume was evident: the hippocampus was significantly enlarged in high-dose females compared to control females but smaller in low-dose f