P7516

By detaching the femoral arterial catheter from the swivel, 1 mL of arterial blood was collected the morning of the diet change and at every subsequent 7th day. Twenty‐four hour urine was collected with the metabolic cage apparatus on the same day as blood collections. Whole blood and urine electrolytes were measured with a blood gas and electrolyte analyzer (ABL system 800 Flex; Radiometer, Copenhagen, Denmark). Albumin was measured using a fluorescent assay (Albumin Blue 580 dye; Molecular Probes, Eugene, OR), read by a fluorescent plate reader (FL600; Bio‐Tek, Winooski, VT), and creatinine using a Jaffé reaction‐assay using an autoanalyzer (ACE; Alfa Wasserman, West Caldwell, NJ). Inorganic phosphorus was measured by chemical reduction to form a phosphomolybdate complex (P7516; Pointe Scientific, Canton, MI) and read by a fluorescent plate reader (SpectraFluor Plus; Tecan). Ammonia was quantified using an enzymatic reagent kit (A7553; Pointe Scientific) and read by a fluorescent plate reader (SpectraFluor Plus; Tecan, Männedorf, Switzerland).