A technical note on sex determination in monomorphic birds using faecal steroid analysis

Excretion and metabolic fate of radiolabeled estradiol and testosterone in the cockatiel (Nymphicus hollandicus)

“…In our study, halving dilutions of aliquots from at least four peaks from the aqueous phase HPLC demonstrated parallelism on both the C-21/C-19 conjugate enzyme immunoassay and dpm radiometric counts, suggesting that these group of conjugates had androsterone-like immunoreactivity. In contrast to previous bird studies [Czekala and Lasley, 1977;Bercovitz et al, 1978;Lee et al, 1995], these peaks did not show any immunoreactivity when assayed by testosterone enzyme or radioimmunoassays. This observation may provide an important clue in the development of simple assays for the androgen metabolites of parrots and other birds in general.…”

“…The failure of the polar testosterone metabolites to be detected by either testosterone immunoassay (enzyme or radio) rules out the possibility that testosterone immunoreactivity was the result of testosterone conjugates, which retain immunoreactivity to testosterone antisera. This immunoreactivity has been previously reported for other bird species [Czekala and Lasley, 1977;Bercovitz et al, 1978;Lee et al, 1995]; however, it was not identified in this study. This lack of testosterone immunoreactivity was supported by the absence of a radiolabel peak consistent with testosterone elution when the hydrolyzed testosterone samples were analyzed by HPLC.…”

“…Estrogen profiles have been documented to reflect ovarian activity accurately [Cockrem and Rounce, 1994], and a pre-ovulatory androgen rise Farner, 1978, 1980;Kofuji et al, 1993;Lee et al, 1995] confirms the previously described fact that testosterone is a precursor of estradiol [Tanabe et al, 1981]. In earlier studies, testosterone immunoreactivity has been the predominant end point for androgen measurements in feces from avian species [Czekala and Lasley, 1977;Bercovitz et al, 1978;Lee et al, 1995]; however, other work has demonstrated that free steroids may be only a small component of the excreta, and conjugated polar androgen metabolites dominate [Bishop and Hall, 1991].…”

A comparison of sex steroid hormone excretion and metabolism by psittacine species

“…The majority of available data is primarily in the form of fecal steroid metabolites that were measured to identify gender [Czekala and Lasley, 1977;Bercovitz et al, 1979]. One study characterized seasonal changes in the gonadal activity of a parrot; however, this investigation was mostly informative for the male bird cycle [Cockrem and Rounce, 1995].…”

Introduction to the European Science Foundation Technical Meeting: Analysis of Hormones in Droppings and Egg Yolk of Birds

“…Starting in the late 1970s and early 1980s with pioneering studies in birds1,2 and mammals,3 noninvasive methods to measure steroid hormone levels in feces have been developed for an increasing number of species 4. In birds, the term “fecal analysis” is a bit problematic, because feces and urine are excreted together in the form of droppings and in general, a complete separation of the fecal and urine fraction is not possible 5.…”