(P11-006-20) High Protein Food with Similar Phosphorus Content as Lower Protein Foods Increases Levels of Uremic Toxins
Objectives: The aim of this study was to determine the effect of feeding cats with reduced renal function a high protein food while maintaining phosphorus concentration across foods containing varying protein levels.
Methods: The study was conducted using 23 cats of 5-13 years of age with chronic kidney disease. After a 1 month washout period, cats were randomly assigned to one of the 6 groups of approximately 4 cats to receive 3 treatment foods, each for 111 days, in a sequence following the William’s Latin Square design. The treatment foods contained on a dry matter basis, low (25.94%), medium (31.91%) or high (36.77%) protein and had similar other nutrient levels including Phosphorus. Average body weights were determined after each treatment period. Blood and urine samples were collected at the end of each treatment period to compare changes in levels of metabolites associated with progression of kidney disease.
Results: The consumption of the foods with different protein levels did not have an effect on body weight. Urine pH was significantly higher after cats were fed high protein food (P=0.0003). Blood chemistry results showed that cats had significantly increased level of blood urea nitrogen (BUN) after the consumption of the high protein food compared with the low protein food (P=0.005). Increased urea levels were also confirmed from results of plasma metabolomics. Levels of microbial uremic toxins such as 3-indoxyl sulfate, 5-hydroxyindole sulfate, 6-hydroxyindole sulfate and 3-hydroxyindoline-one sulfate were significantly elevated after cats were fed high protein compared to both medium and low protein foods (P< 0.05). The glycine conjugate of butyric acid (butyrylglycine) was significantly lower in the plasma of cats fed the high protein compared to low protein food (P=0.004). Levels of betaine were lower after feeding high protein compared to low (P=0.001) and medium protein (P=0.046) foods. Furthermore, cats had the lowest level of gamma-tocopherol/beta-tocopherol with high protein food compared to medium and low protein foods (P< 0.001).
Conclusions: Feeding high protein food to cats with chronic kidney disease leads to higher concentrations of uremic toxins in the blood.
Funding Sources: The study was funded by Hill's Pet Nutrition, Topeka, Kansas, USA.
Hill's Pet Nutrition Topeka, Kansas
Dennis E. Jewell
Adjunct Faculty Kansas State University Lawrence, Kansas