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SVILUPPO ZOOMETRICO DI GIOVANI OVINI GENTILE DI PUGLIA SOTTOPOSTI A DIFFERENTI LIVELLI NUTRITIVI
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Optimal control theory and the reelection problem: The rise of a political business cycle
No full textPolitical Business Cycle, Optimal Control, JEL (1991) C61, E32, MSC (1991) 49N10, 90A16, 90A70,
NON-INVASIVE MONITORING OF HORMONAL PROFILE IN TWO PUBERTAL CAPTIVE POLAR BEARS (URSUS MARITIMUS): THYROID HORMONES
No full textLittle research have been published concerning endocrine profiles in bears, the existing literature mainly focusing on sun (Ursus malayanus) and Formosan bear (Ursus thibetanus formosanus). Almost no information is available on the endocrine profile of polar bears (Ursus maritimus). Our present research aims at evaluating thyroid hormones profile in captive pubertal polar bears through the non-invasive measurement of thyroid hormones in feces.
Samples were collected from two juvenile polar bear, one male and one female, and stored frozen until analysis. Hormone extraction was performed on 0.3 g homogenized feces with a double ethanol extraction and analyzed with commercial ELISA kits for thyroxine (T4) and triiodothyronine (T3). In all samples T4 presented higher concentrations than T3. The female bear showed higher level of fecal T3 than the male (40.67 ± 55.49 ng/g vs 25.87 ± 4.78 ng/g
respectively). Similarly, a higher variation in T3 and T4 excretion was observed in the female bear with respect to male. Finally, a decrease in T4 excretion was observed in both bears in summer months.
Our preliminary results strongly suggest that feces can be used as tool for monitoring thyroid function in bears. This is also the first study presenting data concerning thyroid hormones from non-invasive, fecal samples in bears
PRELIMINARY RESULTS OF METAL CONTAMINATION IN CAPTIVE KILLER WHALES (ORCINUS ORCA)
No full textMost studies conducted on toxicology of killer whales (Orcinus orca) focus on the accumulation of organochlorine compounds. Few heavy metals studies have been published on stranded individuals. The aim of this work is to monitor the accumulation of inorganic compounds in live captive orcas, using non-invasive methods and the periodical veterinary blood sampling in animals kept in a controlled environment. Metal and metalloid contamination has been
evaluated in four captive killer whales: one adult and one sub-adult male, and two adult females. Low levels of contaminants were found in all of the animals, with the exception of lead, showing higher levels than observed in wild bottlenose dolphins. One female gave birth during the period of study and showed a decrease in Pb and Fe concentrations and an increase in Zn levels after parturition (0.7 μg/ml vs 0.4 μg/ml; 303.6 μg/ml vs 273.90 μg/ml; 2.92 μg/ml
vs 3.121 μg/ml respectively) These changes can be partially ascribed to lactation, as already found in humans and domestic animals.
This study is the first step for the definition of reference baseline values for hematic metals in killer whales, to be applied in the future in the study of wild animals
L'influenza del livello nutritivo sulla crescita relativa in giovani ovini "Gentile di Puglia".
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