I think it might be 2000, I'm not sure. Your best bet of getting platinum is just to not use warp gates. You're not going to get extra points for playing later levels, unless they have a lot of fruit to grab.
If you really need to endure as many gates as possible, you can cheat a bit by grabbing your wii remote, and pointing at any fruit you miss (or are too much of a pain to grab). You can zap a single fruit per attempt. The only penalty is not getting the 10 points for that potential egg, MUCH better than losing a life.
DK's Crash Course - First Stage in 38.9 seconds http://www.youtube.com/watch?v=wRW9wR2VzDQ
That being said, I'm not sure it's actually possible to not get Platinum when getting the trophy for doing all 50 day gates without using warps.
I bet it is, but you would really have to go out of your way to do it. It would be an interesting challenge run to try to get the lowest possible score while completing all 50 levels. You'd have to intentionally avoid getting eggs by making lines longer than necessary.
Just by avoiding all eggs you could really lower your score, and should also get lower per-level scores. You just have to average less than 40 points per level to avoid platinum.
"Impossible is just a word people use to make themselves feel better when they quit." -Skies of Arcadia