Maybe the errata changes something (like it changed the turn undead uses burned), but in the book you don't get to keep the spells...
Complete Champion: (emphasis mine)
In addition, you can choose to give up access to a domain in exchange for the corresponding domain feat. Doing so allows you to select up to three domain feats, but you cannot prepare domain spells or use the granted power of the sacrificed
domain. In essence, you trade in a domain for an extra feat slot that you can spend only on a specific domain feat. For example, the above cleric of Pelor could choose to give up the granted power and spells of the Good domain for the Good Devotion feat.
Edit: I see where you might have gotten confused. The paragraph above the one I quoted mentions that you can take 2 domains of a deity and cast spells/use powers from them normally, and then take domain feats (ie with character levels, not trading in) without taking the same domains, so a cleric of nature could have the nature and animal domains, and still take the earth and fire domain feats later.