Food, water and NaCl consumption by 14 strains of rats

We measured the voluntary intake of food, water, and NaCl by 8 male and 8 female rats from each of 3 outbred strains (Crl:CD(SD) IGS, LE, and Wistar) and 11 inbred strains (BN/SsNHsdMcwiCrl, BUF/CrCrl, COP/CrCrl, DA/OlaHsd, DahlSS/JrHsdMcwi, F344/NTac, FHH/EurMcwi, LEW/NHsd, Noble/CrCrl, PVG/OlaHsd, and SHR/NCrl). At 8-week old when tests began, there was a 182-g range in body weight (PVG-female=121±2 g, LE-male=303±4 g), a 17-g range in food intake (BN-female=11±1 g/d, SHR-male=28±2 g/d of AIN-76A diet), and a 34-mL range in water intake (BN-female=15±1 mL/d, FHH-male=49±4 mL/d of deionized water). In a series of 48-h two-bottle tests with a choice between water and progressively increasing concentrations of NaCl, all rat strains strongly preferred 3.16, 10, 31.6, and 100 mM NaCl relative to water. All except BUF, Noble and PVG preferred 178 mM NaCl relative to water. All except LEW, SHR, and DA avoided 316 mM NaCl, and all avoided 562 mM NaCl. There were few differences in NaCl preference between the sexes at any concentration. These results illustrate the substantial diversity of voluntary ingestive behavior in rats and set the stage for future genetic analyses.