Circadian rhythm of salivary cortisol secretion in female zoo-kept African elephants (Loxodonta africana).

Salivary samples were collected over a 24-hr period from one group of six juvenile (7-12 years) and one group of three adult (24-25 years) African elephant females, Loxodonta africana, and the cortisol concentration was measured in unextracted samples by EIA. Samples were collected during May, June, and November 2012 (n = 147) using cotton swabs at 4-hr intervals from 20:00 to 20:00 of the next day (seven samples per animal in each trial). The animals are kept under standard zoo management: the herd is maintained in their indoor enclosures until 10:00 and then released into the outdoor enclosures until 21:00-21:30 (May/June) and 18:30-19:00 (November). No adult elephant bull was present at the zoo during this time. The results demonstrate a clear diurnal pattern of cortisol secretion with the lowest concentration observed at 20:00 (2.03 ± 0.08 ng/ml saliva) and the peak concentrations at 08:00 (5.26 ± 0.35 ng/ml saliva). Although the cortisol values were higher in the adult cows compared to the juvenile cows in the May-June period, the differences were not significant. However, the values obtained in November from the juvenile group were significantly higher (P < 0.05) than the concentrations measured in this group in June. In conclusion, salivary cortisol in zoo elephants follows a circadian rhythm (sleep-wake cycle) adapted to daily zoo husbandry routines.

Effects of Dexmedetomidine and Ketamine-Dexmedetomidine with and without Buprenorphine on Corticoadrenal Function in Rabbits.

Anesthetics may influence adrenal function and consequently alter serum glucocorticoid concentrations, leading to erroneous interpretations of results from anesthetized rabbits. However, decreases in glucocorticoid concentrations may be advantageous in protocols designed to minimize the stress response to surgery. This study characterized the variations in adrenocortical function based on changes in corticosterone and cortisol levels after various doses and combinations of dexmedetomidine, ketamine, and buprenorphine. Each rabbit received all treatments with a minimal interexperiment interval of 10 d. Rabbits were allocated to 7 groups (n = 10 per group) and received either 1 mL saline solution; dexmedetomidine at 0.05, 0.15, or 0.25 mg/kg; ketamine (35 mg/kg) and dexmedetomidine (0.25 mg/kg) without or with buprenorphine (0.03 mg/kg); or ketamine (35 mg/kg) and buprenorphine (0.03 mg/kg). Blood was sampled before drug administration and at 10, 30, 60, and 120 min and 24 h afterward. Serum glucocorticoid levels fell in all treatment groups except the one receiving ketamine-dexmedetomidine; in that group, serum glucocorticoids increased. Rabbits that received ketamine-dexmedetomidine-buprenorphine had the lowest serum glucocorticoid levels overall. In conclusion, dexmedetomidine reduces glucocorticoid secretion in rabbits but, when combined with ketamine, increases corticosterone and cortisol levels as well as heart and respiratory rates. The addition of buprenorphine to the ketamine-dexmedetomidine mixture reduces serum glucocorticoid levels. The influence of anesthetic drugs should be considered when designing a protocol to minimize the glucocorticoid response to surgery or when measuring glucocorticoid levels in rabbits.

Assessment of ovarian cycles in the African elephant (Loxodonta africana) by measurement of salivary progesterone metabolites.

Monitoring ovarian cycles through hormonal analysis is important in order to improve breeding management of captive elephants, and non-invasive collection techniques are particularly interesting for this purpose. However, there are some practical difficulties in collecting proper samples, and easier and more practical methods may be an advantage for some institutions and/or some animals. This study describes the development and validation of an enzymeimmunoassay (EIA) for progestins in salivary samples of African elephants, Loxodonta africana. Weekly urinary and salivary samples from five non-pregnant elephant cows aged 7-12 years were obtained for 28 weeks and analyzed using EIA. Both techniques correlated positively (r = 0.799; P < 0.001), and the cycle characteristics obtained were identical. The results clearly show that ovarian cycles can be monitored by measuring progestins from salivary samples in the African elephant. This is a simple and non-invasive method that may be a practical alternative to other sampling methods used in the species.

Physiological stress responses, fecal marking behavior, and reproduction in wild European pine martens (Martes martes).

The relationship among physiological stress responses, fecal marking behavior, and reproduction in male and female European pine martens was investigated. Between July 2004 and June 2007, 145 fresh fecal samples were collected in a protected area of northwest Spain. Fecal DNA was used for specific identification by using the polymerase chain reaction-restriction fragment length polymorphism technique. Glucocorticoids (cortisol) and sex steroid hormones (P, progesterone; E, estradiol; T, testosterone) were quantified by enzyme immunoassays. Sex was assigned according to concentrations of T+P+E and the T/P ratio. Fecal cortisol concentrations were higher in males than in females. Feces with a presumptive marking function (on conspicuous substrates, above ground level, and/or in latrines) had higher mean levels of cortisol than those that were on inconspicuous substrates and/or at ground level, for both males and females. Fecal mark density was highest in spring, when mean levels of fecal cortisol were more elevated. Therefore, the higher physiological stress levels in females could be due to female physiological state (late-term pregnancy and lactation), competition for resources connected to birth, or food resources for offspring rearing. In males, the increase could be due to higher male competition for access to females during pro-estrus and estrus. Our results suggest that scent marking in European pine martens is related to reproduction and is involved in intersexual and intrasexual communication.

Serum biochemical response to inhalant anesthetics in New Zealand white rabbits.

Anesthetics can affect biochemical parameters, complicating the interpretation of laboratory results and perhaps leading to erroneous diagnoses. The present study was performed to characterize variations in selected rabbit biochemical parameters after inhalant anesthetics. Twenty New Zealand White rabbits were allocated to 2 treatment groups (n = 10 animals each), which received either halothane or isoflurane. Anesthesia was induced by using a face-mask, and rabbits were intubated for maintenance of anesthesia for 30 min. Blood samples were obtained before induction and at 1, 10, 30, 60, and 120 min and 24, 48, and 72 h after intubation. Serum cholesterol, triglycerides, albumin, total proteins, total bilirubin, sodium, potassium, chloride, calcium, and phosphorus concentrations were measured by using an autoanalyzer. Administration of halothane significantly increased serum triglyceride levels and decreased serum cholesterol, albumin, total protein, and potassium levels. Isoflurane administration increased serum triglyceride, phosphorus, and chloride concentrations and decreased serum calcium and potassium levels. Caution is required in interpreting data on serum biochemical parameters from rabbits anesthetized with halothane or isoflurane.