<div ng-controller="CesansCtrl">
  <div id='conteudo' class="margB40">
     <table>
         <thead>
            <tr>
               <th>#</th>
               <th>Firstname</th>
               <th>Lastname</th>
               <th>Age</th>
               <th>City</th>
               <th>Country</th>
            </tr>
         </thead>
             <tbody>
                <tr>
                  <td>1</td>
                  <td>Anna</td>
                  <td>Pitt</td>
                  <td>35</td>
                  <td>New York</td>
                  <td>USA</td>
                </tr>
             </tbody>
      </table>
  </div>

  <script type="text/javascript" src="/scripts/jquery-1.10.2.min.js"></script>
  <script src="/scripts/bootstrap.min.js"></script>

    <script type="text/javascript">
        $(function () {

            if ($("#conteudo").find("table").val() != " ") {

                // Rolou, mas quero deixa com o addClass
                //$("table").css("color", "red");
                //$("table").css("border", "1px solid #ddd");

                // Não rolou
                $("table").addClass('table table-responsible');
                $("table").addClass('table table-bordered');
            }
        });
    </script>

</div>