The maintenance diets of C57BL/6J and 129X1/SvJ mice influence their taste solution preferences: implications for large-scale phenotyping projects.

We examined the extent to which maintenance diet influences the taste preferences of mice. C57BL/6J (B6) and 129X1/SvJ (129) mice were fed one of three standard cereal-based diets (Teklad 8604, Zeigler NIH-07, Purina 5001), a cereal-based diet formulated for breeding (Purina 5015), or two purified diets (AIN-76A or AIN-93G). The mice were given 48-h two-bottle choice tests between water and the following seven taste solutions: 2 mmol/L saccharin, 5 mmol/L citric acid, 50 mmol/L citric acid, 30 micro mol/L quinine hydrochloride (QHCl), 300 micro mol/L QHCl, 75 mmol/L NaCl, and 10% ethanol. There were very few differences in taste solution preference scores among mice of the same strain fed the three different versions of standard cereal-based diet. There were also very few differences in taste solution preference scores between mice of the same strain fed the two purified diets. However, the mice fed standard cereal-based diets generally drank more water and total fluid than did mice fed purified diets. There were larger differences between the B6 and 129 strains in saccharin and ethanol preference scores with mice fed standard cereal-based diets than purified diets. Conversely, there were larger differences between the B6 and 129 strains in citric acid and NaCl preference scores with mice fed purified diets than standard cereal-based diets. These results show that maintenance diet composition can have strain-dependent effects on taste solution preference. They illustrate that attention must be paid to the effects of diet on phenotype in screens of mutagenized mice and other genetic studies.