Tordoff, M.G., and Bachmanov, A.A. Influence of Test Duration on the Sensitivity of the Two-Bottle Choice Test. Chemical Senses, 27: 759-768, 2002.

The long-term two-bottle choice test is commonly used as a simple screen to examine the acceptance of taste solutions by rodents. As part of an investigation of factors influencing the sensitivity of the two-bottle choice test, we determined the extent to which test duration influenced test sensitivity. C57BL6/J and 129X1/SvJ mice received four series of eight two-bottle tests, with each test lasting 1, 2, 4, or 6 days. Each series involved sequential tests with water, 0.2 mM saccharin, 5 and 50 mM citrate, 30 and 300 µM quinine hydrochloride (QHCl), 75 mM NaCl, and 10% ethanol). There were significant differences between the strains in intake of saccharin, 5 and 50 mM citrate, NaCl, and ethanol in 4- and 6-day tests, but only saccharin and ethanol in 2-day tests, and 5 mM citrate and ethanol in 1-day tests. Our results suggest that to discriminate between strains or treatments, 1-day tests are generally inadequate and 2-day tests are useful only if large effects are anticipated. Tests lasting 4 or 6 days are more sensitive, but conducting 6-day tests provides little additional benefit and sometimes is detrimental relative to conducting 4-day tests.

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