Water balance of Graomys griseoflavus (2n=37)

RODRIGO POL; NOEMÍ RODRIGUEZ; C. ALMEIDA; ENRIQUE CAVIEDES-VIDAL; ENRIQUE CAVIEDES-CODELIA; CARLOS ZULETA

Mendoza

Congreso; XV Reunion Anual de la Sociedad de Biologia de Cuyo; 1998

Sociedad de Biologia de Cuyo

G. griseoflavus is a rodent species with a wide geographical distribution in Argentina, including areas with extreme climatic conditions (i.e. annual rainfall<300mm, seasonal temperature range >40°C). Maintenance of the water balance may represents a challenge for surviving in these harsh environments. The aim of this study was to evaluate the water balance and water intake of G. griseoflavus (2n=37). We captured in the Desierto del Monte (32°43´S, 66°45´W, San Luis Argentina) six adult individuals captured with a mean body mass of 62,08±4,33g were used in our trials. They were maintained in our laboratory at 21 ± 2C°, a photoperiod of 12:12 and, food and water ad libitum. There were carried out 3 trials of 3 days each one, in which we daily measured for each animal: food consumption (Fi), water intake (Wi), urine production (OR), feces production (Mf), and body mass changes during the trail period (DBM). Data, expressed mass-specifically as the mean ± 1 SEM, were: a) Fi =0,10±0,003 g food g-1 day-1, b) Wi = 0,068±0,004g water g-1 day-1, c) Mf = 0,019±0,0011 g feces g-1 day-1, d) OR = 0,027±0.01 g urine g-1 day-1, and DBM = -1,62±1,08%. We estimated an apparent coefficient of mass assimilation (AMC*) of 0,85 ± 0,01. These results show that water intake of G. griseoflavus (2n=37) was at least 25.8 % less than the other dessert dwelling sigmodontine rodents and may support the hypothesis of a water economical adaptation to xeric environments. Supported by an UNSL grant.