Circadian rhythm of biochemical parameters and H/L ratio in Passer domesticus


ARIAS R; PADRONES N; RONCHI GD; CID, F.D.; CAVIEDES VIDAL, E; CHEDIACK JG

San Luis

Congreso; XXX Reunion anual de la Sociedad de Biologia de Cuyo; 2012

Sociedad de Biologia de Cuyo

Vertebrate use different mechanisms to optimize their physiological functions that copes environmental changes. In mammals, it has been described circadian rhythms in biochemical parameters, however literature about passerine birds is scarce. Our objective was to determine if the profiles of biochemical parameters and leukocytes display circadian rhythm variations in Passer domesticus. To achieve our goal, thirty six birds were acclimated to laboratory conditions, 14L:10D photoperiod and water and food ad libitum. Because repeated blood sampling affects hematological parameters we established six independents groups of six birds for different times of the day (01:00; 06:00; 08:00; 12:00; 16:00; 20:00 hs). Blood samples were collected from brachial vein for smears and used to determine glucose, triglycerides, uric acid and total protein concentration in plasma. We used a multivariate ANOVA with Tukey post-hoc to compare biochemical parameters and an ANOVA repeated measures for H/L index. We found circadian variation in glucose, triglycerides, uric acid and H/L ratio; but not in total proteins. Plasma parameters increase during the afternoon and decrease at night. On the other hand, H/L index, which indicates stress, shows a peak at 6hs. These results are according to a natural overnight fasting rhythm that maintains the energy balance of the bird