OBJECTIVES/GOALS: Dietary fiber has been used in other clinical populations to improve mineral disorders, but there is limited data in chronic kidney disease, despite the high prevalence of mineral and bone disorder (known as CKD-MBD). Our objective was to evaluate the effect of dietary fiber based on viscosity and fermentability on CKD-MBD outcomes. METHODS/STUDY POPULATION: 22-week-old male CKD rats (mild-to-moderate CKD) were randomly assigned to receive one of four fiber treatments (10% w/w each) based on fermentability and viscosity: 1) Cellulose (-fermentability, -viscosity), 2) Inulin (+fermentability, -viscosity), 3) Psyllium husk (-fermentability, +viscosity), or 4) Pectin (+ fermentability, +viscosity). Treatments lasted 10 weeks, and rats were euthanized at 32 weeks of age (kidney failure). Rats were placed in metabolic cages for 3 consecutive days the last week before euthanasia for mineral balance. At euthanasia, blood, tibia, heart, and aorta were collected for CKD-MBD assessment. Additional tissues collected included kidneys and all intestinal segments. RESULTS/ANTICIPATED RESULTS: Our preliminary data indicates that weight trajectories and survival were similar between treatment groups. At 33 weeks of age, kidney weight index (an indirect measurement of kidney function as this animal model develops polycystic kidneys) was lower in the psyllium-treated rats compared to all of the other treatments. Plasma phosphorus was lower with Psyllium and Pectin compared to Cellulose-treated rats. Left ventricular mass index was lower in the Inulin, Psyllium, and Pectin-treated rats compared to the Cellulose-treated rats. Ongoing tissue analyses include biochemical markers of mineral and bone metabolism (parathyroid hormone, fibroblast growth factor-23, and phosphorus balance), bone parameters (dynamic histomorphometry and microCT), and cardiovascular calcification. DISCUSSION/SIGNIFICANCE: Our preliminary data indicate that dietary fiber based on fermentability and viscosity impacts CKD-MBD outcomes and may be an innovative, low-cost intervention that can be trialed in people with CKD for the prevention and treatment of CKD-MBD.