The Influence of Diets Differing in Polyunsaturated Fatty Acids on Renal Function in Female Rats

Abstract

Renal tissue is influenced by dietary composition in rodents. Evidence suggests that renal diseases may be modulated by dietary polyunsaturated fatty acids (PUFAs). Therefore, the objective of our study was to evaluate kidney function in rats fed diets differing in PUFAs. Young (28 d) female Sprague‐Dawley rats (n=10/group) were individually housed in metabolic cages to collect urine. Rats were pair‐fed high fat diets (12% by weight) consisting of corn oil (CO) rich in n‐6 PUFAs, or flax (FO), menhaden (MO), or krill (KO) oils rich in n‐3 PUFA. After 8 weeks rats were euthanized and serum and both kidneys were collected. Kidney function was assessed by measuring serum total protein, albumin, blood urea nitrogen (BUN), creatinine, calcium (Ca), and phosphorus (P) by colorimetric reactions. Urinary protein was determined by colorimetric assay. Kidney tissue and urinary mineral content was determined by inductively‐coupled plasma spectrometry. Rats fed KO had heavier (P<0.01) kidney weights than rats fed FO or MO. No differences were found in serum measurements of kidney function. However, urinary protein was higher (P=0.03) in rats fed KO compared to rats fed MO. Rats fed KO also had the highest (P<0.001) urinary P content. The data suggests that different dietary PUFAs influence urinary protein and mineral content, conditions associated with the development of kidney diseases. Funding NRI Grant #1004489R USDA‐NIFA.