Daily rhythms of serum and salivary parameters in goats.
OBJECTIVE
Determine the daily rhythms of urea, bicarbonate, sodium, potassium, chloride, calcium, magnesium and inorganic phosphorus secretion in the serum and saliva of goats and whether there is a relationship between them.


METHODS
Ten non-gravid, non-lactating does underwent a 30-day preconditioning period (natural 24-h photoperiod, environmental temperature 19-21 degrees C, relative humidity 40-50%, the same feeding regimen, offered as a single meal at 07:00 hours, and water ad libitum), following which saliva and blood samples were collected from each subject every 4 h for 2 days (starting at 08:00 hours) for measurement of urea and electrolytes.


RESULTS
Data analysis was conducted by one-way repeated measures analysis of variance (ANOVA) and by the single cosinor method. ANOVA showed a significant effect of time (0.001 < P < 0.01) on all the studied parameters in saliva and serum on both days. Cosinor analysis identified the periodic parameters and their acrophases (expressed in hours) during the 2 days of monitoring. Serum and salivary acrophases were all diurnal and were observed between 11:40 and 16:24 hours. No circadian rhythmicity was found for bicarbonate, magnesium or potassium in either saliva or serum.


CONCLUSIONS
There was a daily rhythm of secretion for the majority of the measured parameters, suggesting the potential role of saliva as an additional, reliable index for physiological, clinical, nutritional and chronophysiological studies.
Laboratory of Veterinary Chronophysiology, Department of Experimental Science and Applied Biotechnology, Faculty of Veterinary Medicine. University of Messina-Polo Universitario dell'Annunziata, Italy.
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D000818:Animals; D001639:Bicarbonates / Q000097:blood; D002712:Chlorides / Q000097:blood; D002940:Circadian Rhythm / Q000502:physiology*; D004573:Electrolytes / Q000097:blood*; D005260:Female; D006041:Goats / Q000097:blood / Q000378:metabolism / Q000502:physiology*; D008274:Magnesium / Q000097:blood; D010758:Phosphorus / Q000097:blood; D017440:Photoperiod; D011188:Potassium / Q000097:blood; D012463:Saliva / Q000378:metabolism*; D012964:Sodium / Q000097:blood; D014508:Urea / Q000097:blood
D001639:Bicarbonates; D002712:Chlorides; D004573:Electrolytes; D010758:Phosphorus; D014508:Urea; D012964:Sodium; D008274:Magnesium; D011188:Potassium