json response

  public function executeIndex(sfWebRequest $request)
  {
    
      $this->mouses = Doctrine::getTable('Mouse')
      ->createQuery('m')
      ->leftJoin('m.LabStrain s')
      ->leftJoin('m.MouseCage j')
      ->leftJoin('j.Cage c')
      ->where('j.dateout = ?', "0000-00-00")
      ->execute();
			
      return $this->renderText(json_encode($this->mouses));
					
  }