To
examine whether age influences taste solution preferences we measured intakes of
C57BL/6J and 129X1/SvJ mice given a series of 48-h two-bottle tests with a
choice between water and one of the following seven taste solutions: 2 mM
saccharin, 5 mM citric acid, 30 µM quinine hydrochloride, 75 mM sodium
chloride (NaCl), 10 mM inosine monophosphate (IMP), 50 mM calcium chloride
(CaCl2), and 10% ethanol. We tested
separate groups of male mice fed Teklad 8604 chow at ages 4, 6, 9, 12, 15, 20,
25, 30, 40, and 50 wk, and retested some of these mice at 54, 75, 100, and 125
wk. Additional groups of female mice fed
chow were tested at ages 4, 8, 12, 25, 50, 54, 75, 100 and 125 wk, and male
mice fed a semisynthetic diet (AIN-93G) were tested at ages 4, 12, 25, 50, 54,
75, and 100 wk. Concentration-response
functions for each taste solution were collected from male and female mice fed
chow and aged 8 or 125 wk. In general,
the results showed that age had little effect on taste preferences. Exceptions included (1) a gradual but progressive
reduction in IMP preference between 4 – 125 wk in male and female 129 mice, (2)
a marked reduction in CaCl2 preference between 54 – 125 wk in male
and female 129 mice, (3) a marked increase in NaCl preference between 4 - 12 wk
in female but not male B6 mice, and (4) a marked reduction in ethanol
preference between 4 - 12 wk in male B6 mice fed AIN-76A diet but not chow. These results show that over a wide range and
with the exceptions noted, age contributes little to the variation in taste
preferences observed in C57BL/6J and 129X1/SvJ mice.
(Paper
submitted to Chemical Senses, Dec 18th
2006; contact the PI for a preprint)
Schematic
of the design
There
were ~16 B6 and ~16 129 mice tested at each age listed with an x in the table
below.
|
Age at start of tests |
Part of |
Males fed Teklad 8604 chow |
Females fed Teklad
8604 chow |
Males fed AIN-96G diet |
|
4 |
1 |
x |
x |
x |
|
6 |
1 |
x |
|
|
|
8 |
3 |
x |
x |
|
|
9 |
1 |
x |
|
|
|
12 |
1 |
x |
x |
x |
|
15 |
1 |
x |
|
|
|
20 |
1 |
x |
|
|
|
25 |
1 |
x |
x |
x |
|
30 |
1 |
x |
|
|
|
40 |
1 |
x |
|
|
|
50 |
1 |
x |
x |
x |
|
54 |
2 |
x |
x |
x |
|
75 |
2 |
x |
x |
x |
|
100 |
2 |
x |
x |
x |
|
125 |
3 |
x |
x |
|
x = mice of this age and sex were tested
The
experiment involved four large series of analyses, which are provided, along
with raw data, in the following Excel 2003 files.
1. B6 and 129 males fed chow at 4, 6,
9, 12, 15, 20, 25, 30, 40, 50, 54, 75, 100, and 125 wk
2. B6 and 129 males fed chow and
females fed chow at 4, 8, 12, 25, 50, 54, 75, 100 and 125 wk
3. B6 and 129 males fed chow with
males fed AIN-93G diet at 4, 12, 25, 50, 54, 75, and 100 wk
4. Concentration-response
functions of B6 and 129 males and females fed chow at 8 and 125 wk
The following describes the methods and
results of Part I of the experiment (naïve mice tested at ages between 4 and 50
wk):
Groups
of ~16 mice were tested. All were shipped from the vendor, Jackson
Laboratories, at the age of 3 wk, and then individually housed until the
appropriate age for testing. The main
experiment involved groups of male B6 and 129 mice fed chow. There were cohorts at 4, 6, 9, 12, 15, 20,
25, 30, 40, and 50 wk old. Smaller
experiments examined the effect of sex and age.
The male mice fed chow at 4, 12, 25, and 50 wk were compared with female
mice fed chow and male mice fed AIN93G diet (since 3 wk old) of the same age.
The
mice were tested simultaneously, in two replications of ~288 mice, conducted
one day apart. They received 48-hr
two-bottle choice tests of the solutions listed below, in the order given.
Note: All values
are intakes during a 48 h test.
Comparison of males fed chow at 4, 6, 9, 12, 15, 20, 25,
30, 40, and 50 wk
Comparison of male and females at 4, 12, 25 and 50 wk
Comparison of males fed chow with males fed AIN93G diet at
4, 12, 25 and 50 wk