The effects of polychlorinated biphenyls (Aroclor 1242) on thyroxine, estradiol, molt, and plumage characteristics in the American kestrel (Falco sparverius).
The purpose of this experiment was to determine the effects of Aroclor 1242, a mixture of polychlorinated biphenyls (PCBs), on plumage characteristics and molt in the American kestrel, Falco sparverius. Several characteristics of plumage, including color and molt schedule, are modulated by hormonal signals and hence may be modified by endocrine-active contaminants. If so, the functions of plumage (e.g., communication for mating or territorial defense) may be compromised by exposure to such compounds. Captive American kestrels were fed Aroclor 1242 at 0, 6.0, and 60.0 ppm (n = 6 males and 6 females per treatment) mixed in their normal diet. Concentrations of plasma estradiol and thyroxine were measured weekly from the beginning of treatment. Measured plumage characteristics included width of the black subterminal band on the tail, color (a composite index of hue and saturation), reflectance from 230 to 800 nm. pattern of feather loss and regrowth on the tail and wing, and timing of onset and duration of molt. Aroclor 1242 depressed plasma thyroxine. Plasma estradiol levels remained low due to the phase of the breeding cycle. Treatments did not disrupt the measured plumage characteristics. This may be due to timing or dose of exposure or to genetic factors.
Quinn
Michael J
MJ
Department of Animal and Avian Sciences, University of Maryland, College Park 20742, USA. mq15@umail.umd.edu
French
John B
JB
McNabb
F M Anne
FM
Ottinger
Mary Ann
MA
D000284:Administration, Oral; D000818:Animals; D001140:Aroclors / Q000633:toxicity*; D004703:Endocrine System / Q000187:drug effects; D004785:Environmental Pollutants / Q000633:toxicity*; D004958:Estradiol / Q000097:blood; D005241:Feathers / Q000254:growth & development*; D005260:Female; D006728:Hormones / Q000097:blood*; D008297:Male; D018978:Molting / Q000187:drug effects*; D020304:Raptors; D013974:Thyroxine / Q000097:blood
D001140:Aroclors; D004785:Environmental Pollutants; D006728:Hormones; D004958:Estradiol; C027423:aroclor 1242; D013974:Thyroxine