Amazon plans to introduce a limited music streaming feature as early as Thursday, according to several people briefed on its plans. The new feature, which has been rumored in the music industry for months, will give subscribers to Amazon’s Prime service access to thousands of songs free and without interruptions from advertising. But it will omit most new releases, and will not include the catalog of the Universal Music Group, the world’s largest music company, according to these people, who spoke on the condition of anonymity. Amazon, already one of the biggest retailers of music downloads, is adding the streaming feature as a sweetener for its Prime customers, whose annual subscription fee was recently raised to $99 from $79. Prime subscribers get free shipping on orders and other perks like free access to some movies and television shows.