Forty male Sprague–Dawley rats were purchased from Charles River Laboratories (Sulzfeld, Germany). Animals were acclimatized for 2 weeks upon arrival and were 12 weeks old at the beginning of the experiment, weighing approximately 440–460 g. They were housed two per cage with access to non-chlorinated, non-acidific tap-water and with unrestricted access to standard rodent chow (Altromin 1324, Brogaarden, Denmark) until initiation of the experiment. Temperature in the animal rooms was maintained at 20–25 °C with a light/dark cycle of 12/12 h, a relative humidity of 30–70%, and air change 8–15 times/h.