The Federal Home Loan Banks shifted further toward holding private label or non-agency mortgage-backed securities in their investment portfolios in the first quarter of 2005 – although their overall appetite for MBS remained flat. According to data obtained by Inside The GSEs, the FHLBank System held a total of $114.37 billion in MBS at the end of the first quarter. That marked a healthy 12 percent increase from a year ago – but that number…