SSRS - Sharepoint integration - stored credentials with SQL account

Hi,

I am facing issue on production server. We are using stored credentials for data source of the SSRS reports. When I set the stored credentials to service account for RS web service, it works fine. But in production, we are not allowed to set service account. Is there any other way to do this. e.g. setup SQL account with Read permission on report server database etc.....

Regards,

Pallavi