Modfiy scriopt to embed txt into body of email

I would like to modify the following script so that it will embed the contents of the source file in the body of the email:

The source file is at:

C:\Users\User\Desktop\File\file.txt


[code][/###PROGRAM START###
      # Invokes the Send-MailMessage function to send notification email
      $splat = @{
            From =                  'email1@email.com'
            To =                  Get-Content -Path ( Join-Path $PSScriptRoot 'DistList..txt')
            SmtpServer =      'smtp.smtp.com'
            Subject =            $subject
            body =                  $MessageBody
            BodyAsHtml =      $true
      }
      Send-MailMessage @splat
###PROGRAM END###code]