Sapid solutions and food intake in repeated dehydration and rehydration periods in rats.

Abstract

Experiments were performed to ascertain whether food intake in thirsty rats is influenced by palatability of solutions and whether the availability of food during tests influences taste preference, acceptance, and total fluid intake. In five groups of rats, 2-bottle preference (Experiment 1) and 1-bottle acceptance tests (Experiment 2) in either 12, 24, 36, 48 h water deprived rats were performed; food was available during tests. Results showed that food availability during tests did not affect taste preference and acceptance. In Experiment1, after 36, 48 h water deprivation, rats drinking either NaCl or sucrose, they ate less food than rats drinking either HCl, quinine, or water. In Experiment 2, rats drinking NaCl as the only source of fluid ate significantly less food than all other groups. Two different post-ingestive effects (energetic; osmotic) may explain the same behavior for intake of sucrose or NaCl solutions. Since rats drinking either sucrose or NaCl ate less food but drank more fluid, they had a fluid/food ratio significantly higher than that of rats drinking either water, quinine, or HCl; these latters ate more food but drank less fluid. Taste, together with other factors, might inhibit or enhance the amount of fluid and food intake required to restore body weight and body fluid osmolality at the end of dehydration. During recovery periods, overeating is necessary to restore body mass, Na + and electrolytes; overdrinking corrects imbalance produced by excessive eating. In conclusion, food and fluid intake appears significantly related each other, even in dehydrated rats.