I use the zinc in the wort, half a 15 mg diet supplement tablet is in the recommended range for 10 gallons.
The starters get a little nutrient, I use one of the blends, i think the bag says LD Carlson. These have vitamins, minerals and FAN. DAP is a good source of Nitrogen so you have that covered. You might think about what other things the yeast need. From a couple of presentations at the NHC, I picked up the fact that the one thing wort lacks is zinc, so that is why I add it. Trace levels of copper are good too, but there is some copper in my mash tun, boil kettle, and the imersion chiller so I don't add any additional copper. If you don't have any copper in your system, a length of copper pipe in the boil would give you trace amounts.