in response of https://gist.github.com/3275979

gistfile1.php

<?php

use Symfony\Component\HttpFoundation\Response;	

    public function showAction($id)
    {
            $repository = $this->getDoctrine()->getRepository('AcmeHelloBundle:Product');
            $product = $repository->find($id);
            if (!$product) {
                throw $this->createNotFoundException('Nessun prodotto trovato per num id: '.$id);
            }

            return new Response($product->getQualcosa());

            oppure

            return $this->render('AcmeHelloBundle:Hello:show.html.twig', array('product' => $product));

    }

http://symfony.com/it/doc/current/book/controller.html