Bertino M, Beauchamp G K
Appetite. 1987 Feb;8(1):55-66. doi: 10.1016/s0195-6663(87)80027-2.
Sprague-Dawley rats do not prefer salted (NaCl) solid food when it is presented with its unsalted counterpart but prefer isotonic saline when it is presented with plain water. Preferences in liquid foods were examined by giving rats one-hour choices between various salted liquid milk products and their unsalted counterparts. When heavy cream and half and half were tested, rats consumed either equal amounts of the salted and unsalted food, or more of the unsalted food. The absence of salt preference in heavy cream and half and half was evident using other testing procedures and, with heavy cream, additional salt concentrations. In contrast, rats consumed more skin milk containing 0.150 M NaCl than plain skim milk. The role of fat content in modulating the expression of these salt preferences was examined in tests using whole milk and low-fat milk, both of which have water, protein and carbohydrate contents similar to skim milk, but a greater fat content. Unlike skim milk, preferences for 0.150 M NaCl in whole milk and low-fat milk were approximately 50%. The role of solidity in salted food preferences was also investigated by adding gelatin to salted (0.150 M NaCl) and unsalted skim milk. Whereas the rats ate equal quantities of salted and unsalted gelled skim milk, they preferred salted skim milk when it was a liquid. Results from these experiments suggest that several cues contained within food influence the expression of rats' salt preferences.
当给斯普拉格-道利大鼠提供未加盐的固体食物时，它们并不偏好加盐（氯化钠）的固体食物，但当给它们提供等渗盐水而非普通水时，它们会表现出偏好。通过让大鼠在各种加盐的液态奶制品及其未加盐的对应产品之间进行一小时的选择，来研究它们对液态食物的偏好。在测试重奶油和半脱脂奶时，大鼠对加盐和未加盐食物的摄入量要么相等，要么更多地选择未加盐食物。使用其他测试程序以及不同盐浓度测试重奶油时，重奶油和半脱脂奶中不存在盐偏好这一点很明显。相比之下，大鼠摄入含0.150 M氯化钠的脱脂奶比普通脱脂奶更多。在使用全脂奶和低脂奶的测试中研究了脂肪含量在调节这些盐偏好表达中的作用，这两种奶的水、蛋白质和碳水化合物含量与脱脂奶相似，但脂肪含量更高。与脱脂奶不同，大鼠对全脂奶和低脂奶中0.150 M氯化钠的偏好约为50%。还通过向加盐（0.150 M氯化钠）和未加盐的脱脂奶中添加明胶来研究食物的固态性在盐偏好中的作用。虽然大鼠食用加盐和未加盐的胶状脱脂奶的量相等，但当脱脂奶是液态时，它们更喜欢加盐的脱脂奶。这些实验结果表明，食物中包含的几种线索会影响大鼠盐偏好的表达。
