How can you fill your feed with more professional content? Easy! Share articles relevant to your industry. Personally I use Google reader to manage all the websites I read regularly for industry information.
Ive even added an add-in called Google2Tweet to make sharing easier.
You can also simply Google for terms popular in your industry and share those you think others would find interesting. Just be careful sharing old links. If you only read an article that was published three years ago, youll appear to be out of date.