![]() Each spout had a 3.175-mm-diameter hole from which the mice could lick fluids. They were constructed from graduated pipette tubes with rubber stoppers and stainless-steel spouts. ![]() The drinking tubes were arranged along the top of the cage at even intervals, with tips approximately 2 cm apart and extending into the cage 2.5 cm ( Fig. During tests, the water bottle was replaced by drinking tubes, and food was scattered on the cage floor (to provide sufficient space to place the drinking tubes). They ate Teklad 8604 diet (Harlan, Madison, WI), which was available from a hopper built into the cage lid. Before tests began, they could drink deionized water from an inverted 300-ml bottle with a stainless-steel spout. ![]() The mice were individually housed in plastic tub cages (26.5 × 17 × 12 cm) with a stainless-steel grid lid and wood shavings scattered on the floor. They were 5 weeks old when they arrived in our facility. Male B6 and 129 mice were purchased from The Jackson Laboratory (catalog Nos. ![]() In experiments 3 and 4, we examined the response of separate groups of B6 mice given various numbers of alcohol and water bottles for 16 or 24 days. In experiments 1 and 2, we examined the behavior of C57BL6/J (B6) and 129X1/SvJ (129) mice and Sprague-Dawley rats given access to various combinations of 10% alcohol and water in short-term tests, using a within-subject design. In the work reported here, we sought to expand our findings with other nutrients by examining the extent to which alcohol intake was influenced by the number of sources available. These experiments indicate that simple manipulations of the availability of nutrients or taste solutions can have profound effects on intake and preference.Īlcohol, of course, is both a nutrient and a taste solution. In another study, we found that mice given any of four archetypical taste solutions (saccharin, citric acid, quinine hydrochloride, or NaCl) drank more of the taste solution when given two bottles of it and one of water than when given either a standard two-bottle test or a test with one bottle of taste solution and two of water ( Tordoff and Bachmanov, 2003). The group with five bottles of sucrose drank approximately twice the volume of sucrose, gained significantly more weight, and accrued significantly more fat than did the group with only one bottle of sucrose. In one study, we compared rats given to drink five bottles of 32% sucrose and one bottle of water with those given one bottle of 32% sucrose and five bottles of water. However, we recently showed that macronutrient selection and intake are strongly dependent on the number of sources of each macronutrient available ( Tordoff, 2002). ![]() This notion, called nutritional wisdom, is based primarily on findings that animals select a balanced diet and grow rapidly when allowed to choose from separate sources of macronutrients (e.g., Richter, 1942–1943– 1956). Intakes during two-bottle choice tests are believed to reflect the physiologic status of the animal. Because the rodent is not forced to drink the alcohol to assuage hunger or thirst, this method provides a measure of “voluntary” or “spontaneous” consumption, and the ratio of alcohol intake to total intake provides a measure of alcohol preference that is relatively free of nonspecific effects, such as body size, customary fluid intake, or minor motor dysfunctions ( Bachmanov et al., 1996a, 2002). It is common practice to assess the alcohol intake of mice and rats by providing them with a choice between a bottle of alcohol and a bottle of water. ![]()
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