Wistar rats do not show preference for either of two commonly used nutritionally sound food rewards in a T-maze

By Cathalijn H.C. Leenaars - Elmar G.M. Pels - Ruud N.J.M.A. Joosten - Merel Ritskes-Hoitinga

Food rewards are commonly used as positive reinforcement in rodent behavioral experiments. Bioserv dustless precision pellets and Noyes formula P precision pellets are both used for this purpose in behavioral experiments in multiple laboratories, as they are nutritionally consistent with standard laboratory diets. Because of the nutritional value, they are superior to other positive food rewards such as chocolate. Whether male Wistar rats prefer either of these pellets was tested with a T-maze choice test, because Noyes formula P precision pellets could no longer easily be purchased in Europe. Rats did not show preference for either Bioserv dustless precision pellets or Noyes formula P precision pellets. Concluding, both pellet types can be used reliably as positive reinforcement in behavioral experiments. We advise against repeating of experiments replacing one of these pellet types with the other, to reduce the number of experimental animals needed.