Characterizing endocrine profiles in birds can assist in non-invasive sex differentiation and in the facilitation of aviculture breeding programs. Often times, however, the stress and volume of blood involved in serum hormonal assays limits their use in avian species. By measuring these hormones in feces, levels can be measured frequently and easily without stress to the bird. Characterization of thick-billed parrot ovarian activity through noninvasive fecal monitoring would enable us to better facilitate the captive breeding of this endangered species.
To determine conjugated estradiol, progesterone, and testosterone levels, feces were collected from eight individually housed birds and one breeding pair, four times per week for 52 weeks. The samples were divided, with one-half of each sample being frozen, and the other half being dried in a drying oven until a constant weight was achieved. The dried feces was weighed and then solubilized at a 1:10 (weight:volume) ratio in a solubilizer solution. Samples were vortexed briefly, then shaken for 24 hours. The samples were then centrifuged for 10 minutes at 3,000 rpm and the supernatant was removed, aliquoted, and stored frozen.
To establish a standard concentration range, samples were used to make serial dilutions in distilled water. This also provided the final dilution factor for the samples. Dilutions to the experimental samples were then made using these values. Each sample was run in duplicate at two different dilutions, using only one bird per plate to minimize interassay variation. Plates were read on a Spectramax 340 spectrophotometer at 405 nm and 650 nm. SoftMax Pro, SAS 612, and Microsoft Excel were utilized to analyze the resulting data.
The findings of this study led to preliminary conclusions about the characterization of the progesterone profiles of thick-billed parrots using enzyme immunoassay (EIA) techniques. Future characterization and analysis of fecal hormone levels for estradiol and testosterone conjugates will be performed. The characterization of the hormone profile in thick-billed parrots should greatly enhance opportunities to utilize reproductive technology in this species.