EFFECT OF 5 PERCENT DEHYDRATION ON BREATH HYDROGEN CONCENTRATIONS IN DOGS

Objective-To determine the effect of mild dehydration (5%) on expired breath H-2 concentrations in dogs. Animals-10 healthy, colony-source d ogs. Procedure-Expired breath samples were collected at baseline, and every 90 minutes for 18 hours after ingestion of a test meal (commerci al dog food and kibbled wheat) in fully hydrated dogs and in the same dogs when they had lost 5% of their body weight after food and water d eprivation. The areas under the breath H-2 concentration versus time c urves (AUC) for the dehydrated and nondehydrated states were compared, using a two-stage, balanced, crossover, repeated measures technique. The number of breath samples considered to be contaminated by flatus w ere compared by use of a one-sided sign test. Results-Expired breath H -2 concentration of dogs during the dehydration lest period was signif icantly (P < 0.02) greater than that during the nondehydration test pe riod. In addition, flatulence was significantly (P < 0.033) more frequ ent in dogs during the dehydration period. Conclusions-Dehydrated dogs have greater expired breath H-2 concentration and produce more flatus after ingestion of a carbohydrate-containing meal. Considered togethe r, these findings suggest that dehydration results in an increase in t he net amount of H-2 produced in the gastrointestinal tract. Clinical Relevance-Care should be taken to assess the hydration status, and to correct hydration deficits of dogs prior to breath H-2 testing.