Fig. 2

Water intake and dehydration markers. a Water intake by young and older adult rabbits during the baseline period where animals were given water ad libitum. Older adult rabbits consumed ~ 30% less water than young rabbits. b Comparison of water intake by young and older adult rabbits between the control and dehydrated groups during the experiment’s baseline and water restriction periods. During the water restriction period, both young and older adult rabbits in the control group received water ad libitum, while those in the dehydrated group received a restricted volume of water. c, d Percentage body weight loss. Both young and older adult rabbits in the dehydrated group had an average body weight loss of − 5.4% and − 4.6%, respectively, at the end of the water restriction period compared to the control rabbits. e, f Percentage change in packed cell volume (PCV) and total solids (TS) after the water restriction period. Water restriction did not alter the PCV or TS of rabbits in the dehydrated group in either young or older adult rabbits. g, h Kidney renin gene expression. The expression level of renin was increased in the young water restriction-dehydrated rabbits but not in the older-dehydrated rabbits compared to their respective controls. W-ad lib: control groups that received water ad libitum throughout the study. WR-dehy: dehydrated groups that received water restricted volume during the water restriction period of the study. All bars show average values ± SEM. *p ≤ 0.05, **p ≤ 0.01, ****p ≤ 0.0001. ns: non-significant