  We present a comprehensive transport investigation of the itinerant
antiferromagnet Mn3Si which undergoes a spin density wave (SDW) order below
T_N~21.3K. The electrical resistivity, the Hall-, Seebeck and Nernst effects
exhibit pronounced anomalies at the SDW transition, while the heat conductivity
is phonon dominated and therefore is insensitive to the intrinsic electronic
ordering in this compound. At temperatures higher than T_N our data provide
strong evidence for a large fluctuation regime which extends up to ~200K in the
resistivity, the Seebeck effect and the Nernst effect. From the comparison of
our results with other prototype SDW materials, viz. LaFeAsO and Chromium, we
conclude that many of the observed features are of generic character.
