Envigo (Formerly Harlan) Teklad Rat Food Pellets 8604 An Envigo (Formerly Harlan) Teklad Laboratory Diet. Envigo (Formerly Harlan) Teklad 24% Protein Rodent Diet Nutritionally balanced and exceptionally consistent. Repackaged by Nesom Distributing for your companion animals. Globally recognized as one of the best quality rodent diets available.