Water intake of the rat with food present following different durations of water deprivation.

Abstract

burk, & Rollins, 1966), the intake function might be different when food is present during the drinking period. The experiment reported here explored this possibility. The procedure followed that of the previous study, with the exception that food was present during the drinking period. Briefly, 60 naive male albino rats were matched into 10 water-deprivation conditions on the basis of mean daily water intake during an ad Libitum base period. The deprivation conditions were: 0, 12, 24, 36, 48, 72, 96, 120, 144, and 168 hr. A 2-hr. drinking period for all Ss was set from 7:00 AM to 9:00 AM on the last day of an %day deprivation period. Water was removed from the 6 Ss in each group at the appropriate number of hours before the common drinking period. All Ss had access to food during deprivation; food also was available during the drinking period. The water-intake function obtained was similar in shape to the function reported earlier (Dufort & Abrahamson, 1966); intake increased up co 48 hr. deprivation and was stable thereafter with only minor upward fluctuations at 96 hr. and 168 hr. Analysis of variance yielded an effect of length of deprivation (P < .001). Duncan's test showed that intake did not vary significantly for groups deprived for 48 hr. or longer, but significant differences (P < .05) were found among groups deprived for 0, 12, 24, and 36 hr. and those deprived for 48 hr. or longer. The results also showed an approximately 20% greater intake than was found earlier. Thus, while the asymptote of the intake function was reached at 26 to 27 ml. in the earlier srudy, the asymptotic intake was in the 30 to 31 ml. range in this study. These resulcs support other evidence showing greater water intake in the presence of food; the shape of the intake-deprivation function is not affected by presence or absence of food.