The spontaneously hypertensive rat's preference for salted foods

Sprague-Dawley rats drink mild salt (NaCl) solutions in preference to plain water. In contrast, rats of this strain are less likely to show preferences when salt is tested in food. Others have established that rats of the spontaneously hypertensive strain (SHR) have greater preferences for salt water than do their normotensive counterparts (WKY). The question addressed in the present research was whether SHR rats would show an enhanced salted food preference when compared with WKY rats. SHR and WKY rats were given choices between a variety of salted and unsalted foods. When tested with potato chips, no major strain differences in salt preferences were observed; depending on concentrations, rats ate either equal amounts of salted and unsalted chips or avoided salted chips. However, when tested with liquid milk products (heavy cream and half & half), SHR rats showed both higher salt preferences and consumed more salt. The SHR actually preferred these products salted, whereas the WKY rats, like Sprague-Dawley rats, never ate more salted milk than plain milk. When tested with skim milk, SHR and WKY did not differ; both preferred the milk salted. In order to test the effect of physical state (or texture) upon salt preference, the skim milk was gelled. Salt preferences of the SHR rats fell to 50% whereas the salt preferences of the WKY rats remained unchanged.