If the engine is running OE bores and its not been rebored & honed you can fill with the oil that you intend to run for the life of the engine, as Ellie Boon posted.
Modern engines have such a good finish on the bores that it is no longer necessary to go through the process of running in with mineral oil to bed in the rings.
However I choose to run with semi syth for a few hundred miles and then do an oil and filter change just to ensure that any unwanted particles that may be in the engine are removed.
It horrifies me to think of modern cars going for 20,000 miles before the first service.
Rob