Phosphate‐dependent physiological changes during short‐term dietary phosphorus deficiency with or without a dietary phosphorus binder

Patients with end‐stage renal failure are susceptible to increased plasma phosphate; hence, animal models to rapidly screen strategies to prevent dietary phosphate absorption are needed. The objective of this experiment was to evaluate a short‐term animal feeding model for estimating the effectiveness of a phosphate binder to limit dietary phosphate absorption. Nutrient‐adequate chicks (10 days of age) were either maintained on a phosphorus (P) adequate diet (0.70% total P, or 0.45% available P) or switched to a P deficient (0.35% total P) diet with or without 1% inclusion of the phosphate binder sevelamer hydrochloride (Sev) (n=15/trt). Body weight gain from 10–13d of age, plasma phosphate, and dry fat‐free tibiotarsus ash were determined on day 13. When chicks were placed on the P deficient diet, bone ash and plasma phosphate, but not body weight, were reduced (9% and 26%, respectively) within 3 days (p<0.05, main effect of P). The addition of Sev to the diet (main effect) had no effect on plasma phosphate or ash, but reduced body weight 22%. Since there was no interaction between P and Sev, these data would suggest, within the limits of this model, that Sev was unable to interfere with phosphate absorption even when animals were clearly deficient. These data also suggest body weight was reduced through a mechanism other than phosphate deficiency. This work was supported by the Wisconsin Alumni Research Foundation (WARF). Grant Funding Source : WARF