Oil capacity - Cars & Trucks

For the 2008 mazda 3 (2004-2008 generation 2.0 to 2.3L)

http://mazda3revolution.com/how-to-guides/how-to-change-oil-mazda-3-23-20/

that link uses 4.25 quarts, to allow some fluid to fill the oil filter
usually, with a canister filter, i pour some inside as well as lubricate the oil ring before spinning it on ~ that way the paper element has been "pre-charged" pre-soaked with oil before you start it up for the first time
if you have the other style filter where the oil filter is just the paper element, i'd make sure to properly torque that cap to specs & not over-tighten it ~ it's made of plastic!

http://www.mazdausa.com/MusaWeb/pdf/manuals/2008_Mazda3_OM.pdf

your owners manual only states the amount of oil needed between the minimum line to the maximum line on the dipstick when just checking the fluid level

page 8-20 says ~ .8 quart when it's low to fill it up to the max ~ line

another site states ~4.5 quarts

as long as it's in between the 2 stated capacities, and you re-check the fluid level, you're good to go ~ just dont put the full 5 quarts in it!