Use of oral antibiotics in studies of ingestive behavior in rats.

The occurrence of chronic respiratory disease (CRD) in animal colonies is a problem encountered in many laboratories. Sixteen female albino rats were used to investigate the effects on food and water intake of the oral antibiotics most often used to treat CRD. Four concentrations (0.01, 0.05, 0.25, and 0.50%) of Tetracycline hydrochloride (TH) and Sodium sulfamethazine (SS) were presented at different times mixed with food or water. The animals were permitted to choose between each drugged and normal food or water combination for 4 days. Both drugs seriously affected fluid intake when placed in solution. When mixed with food, only SS produced a preference-aversion function and increased total daily food and water intake regardless of concentration. The presence of TH in the food had no effect on food choice or on total daily food intake at any concentration.