wp_mail: Using file_get_contents to include template in message

$get_file_content = fopen(TEMPLATEPATH . '/mail/create-account-member.php', "r");   

// Lê cada uma das linhas do arquivo
while(!feof($get_file_content)) { 
   $message .= fgets($get_file_content) . "<br/>";
}
fclose($get_file_content);

wp_mail( $user_email, $subject, $message, $headers );