The Antler Cycle and Fecal Testosterone of Male Sambar Deer Rusa unicolor unicolor at the Horton Plains National Park in Sri Lanka

This study is aimed at evaluating the relationship between endogenous testosterone levels and antler development in male sambar deer (Rusa unicolor unicolor) inhabiting the Horton Plains National Park, Sri Lanka. Seven antler growth stages of sambar were documented based on phenotypic observations for the first time in Sri Lanka as (a) cast, (b) growing 1—single spike, (c) growing 2—antler fork into a Y as the second tine appears, (d) growing 3—velvet begins to harden as the third tine appears, (e) growth completed—velvet shedding begins, (f) hard antler, and (g) casting. Fecal samples were collected every month for a period of eighteen months from male sambar deer in different stages of the antler growth cycle, feeding in the wet patana grasslands of the park, and the fecal testosterone level was estimated by radioimmunoassay. Ten animals were randomly selected from each antler stage for the experiment. The results disclose that the highest concentrations of testosterone were recorded in the hard antler stage. Velvet shedding was preceded by an increase in the testosterone level, and it is the sudden drop in the testosterone concentration which triggers the antler casting. The casting stage corresponded with the lowest mean testosterone concentration. Although the study was able to conclude a clear relationship between the fecal testosterone levels of the male sambar deer in the Horton Plains National Park and their antler stages, there is no clear seasonality for the antler cycle.

Measurement of Fecal Testosterone Metabolites in Mice: Replacement of Invasive Techniques

Testosterone is the main reproductive hormone in male vertebrates and conventional methods to measure testosterone rely on invasive blood sampling procedures. Here, we aimed to establish a non-invasive alternative by assessing testosterone metabolites (TMs) in fecal and urinary samples in mice. We performed a radiometabolism study to determine the effects of daytime and sex on the metabolism and excretion pattern of radiolabeled TMs. We performed physiological and biological validations of the applied EIA to measure TMs and assessed diurnal fluctuations in TM excretions in male and female mice and across strains. We found that males excreted significantly more radiolabeled TMs via the feces (59%) compared to females (49.5%). TM excretion patterns differed significantly between urinary and fecal samples and were affected by the daytime of ³H-testosterone injection. Overall, TM excretion occurred faster in urinary than fecal samples. Peak excretion of fecal TMs occurred after 8 h when animals received the 3H-testosterone in the morning, or after 4 h when they received the 3H-testosterone injection in the evening. Daytime had no effect on the formed TMs; however, males and females formed different types of TMs. As expected, males showed higher fecal TM levels than females. Males also showed diurnal fluctuations in their TM levels but we found no differences in the TM levels of C57BL/6J and B6D2F1 hybrid males. Finally, we successfully validated our applied EIA (measuring 17β-hydroxyandrostane) by showing that hCG (human chorionic gonadotropin) administration increased TM levels, whereas castration reduced them. In conclusion, our EIA proved suitable for measuring fecal TMs in mice. Our non-invasive method to assess fecal TMs can be widely used in various research disciplines like animal behavior, reproduction, animal welfare, ecology, conservation, and biomedicine.

Effect of Testosterone on Antler Growth in Male Sambar Deer (Rusaunicolor unicolor) in Horton Plains National Park, Sri Lanka

ABSTRACTThis study establishes the relationship between testosterone concentration with the different antler phases in male sambar deer (Rusa unicolor) inhabiting the Horton plains National Park, Sri Lanka (HPNP). Antler growth of sambar was categorized into seven phases; Cast (C), Growing single spike (GS), Growing into a Y as first tine appears (GIY), Growing Velvet begins to harden as third appears(GVT), Growth completed - velvet shedding begins (VS), Hard antler (HA), Casting (CT) based on phenotypic observations. The fecal samples were collected from 10 male sambar deer in each different phases of the antler growth cycle. Fecal testosterone level was estimated using radioimmunoassay (RIA). The results disclose that the dry feces of sambar deer in hard antler phase have a highest mean testosterone concentration of 18.52± 01.87 ng g−1. In the GVT phase the mean testosterone concentration was 09.50±2.01ng g −1, while in the VS phase the mean testosterone concentration increased to 14 ± 01.89 ng g−1. The study also reveals a declination of the testosterone concentration (06.80± 01.20 ng g-1) in CS phase. The C phase had a mean testosterone concentration of 05.52± 0.84 ng g−1. The fecal testosterone levels of the male sambar deer in HPNP changes according to the phase of the antler cycle.SUMMARY STATEMENTTestosterone concentration in fecal pellets of antler phases of male sambar deer in Horton plains National park, Sri Lanka evaluated by Radioimmunoassay kit. The results obtained in this study were agreement with identical research work carried out in other deer species with temperate ancestry.

TESTOSTERONE AND CORTISOL LEVEL IN FECAL JAVA DEER (Cervus russa timorensis Mul. & Schl 1844) MALE IN CAPTIVITY BUNDER GUNUNG KIDUL YOGYAKARTA

<p>Common reasons for monitoring hormone concentrations in domestic or wild animals, include breeding management, pregnancy diagnosis, stress assessment, and to diagnosed of endocrine illness. The research goal was to develop non invasive analytical techniques of hormone in Java deer (Cervus russa timorensis Mul. &amp; Schl 1844). The non-invasive methods involve the collection of feces, urine, or even saliva in order to measure the metabolites hormones of interest. Samples obtained from either method are most often analyzed with radioimmunoassay (RIA) or enzyme immunoassay (EIA) technology. Both collection and assay methods have advantages and disadvantages. Choice of method depends on the tractability of the species or individual animal in question and the type of question that the data is expected to answer. We are researching basic questions regarding reproductive endocrinology of male Cervus russa timorensis Mul. &amp; Schl 1844. Understanding C timorensis reproductive physiology will help us better address reproductive challenges in both captive and free-ranging populations. Fecal testosterone and cortisol concentrations were measured in captive male C timorensis. As much as five adult male deer were separated into separate cages. Fecal samples were collected in the morning and evening for 30 days. Sample processed through lyophilization stage, pulverization, solvent extraction with methanol and centrifugation to obtain the supernatant for EIA analysis. EIA test results indicated that content of both testosterone and cortisol could be detected, although the levels were still low. This data show that there is a metabolite in-activism in the fecal. With these results through fecal hormone measurement method (non-invasive) it is possible to be developed for observation and research on the reproductive status of the deer.</p><p><br /><strong>Keywords</strong>: Non-invasive, Testosterone, Cortisol, Java deer.</p>

Testosterone, body size, and sexual signals predict parasite load in Yarrow’s Spiny Lizards (Sceloporus jarrovii)

Parasite load significantly impacts host health and fitness and may vary substantially among individuals within a population. The immunocompetence handicap hypothesis posits that sexual signals are honest indicators of male quality because they are maintained by testosterone, an immunosuppressant that yields higher parasite loads. Additionally, testosterone may influence parasite load by increasing activity levels. We examined these two hypotheses in a wild population of Yarrow’s Spiny Lizards (Sceloporus jarrovii Cope, 1875) in Arizona. We (i) compared fecal testosterone levels to ectoparasite and haemoparasite loads, (ii) tested if sexual signals (total coloured area, aggression, and head size), locomotor activity, and body size correlated with testosterone levels, and (iii) compared sexual signals, locomotor activity, and body size to parasite load. Ectoparasite loads increased with total coloured area and tended to increase with testosterone, but this latter relationship was only nearly significant. Parasite loads increased with body size. Thus, we found some support for the immunocompetence handicap hypothesis and none for the activity hypothesis. Our results are consistent with an alternative hypothesis that larger individuals have more parasites because they have more surface area and (or) have had longer to accumulate parasites. Future studies should examine the relative contributions of testosterone and glucocorticoids in driving variation in parasite loads.