how to display only the “user-supplied excerpt” if it found

Hi,,
I searched alot to know the code of user-supplied excerpt excerpt but i didn’t find any thing ,,,
I want to display only “user-supplied excerpt” if it found ,
I tried to make the excerpt lenght (zero) ,, it display my need but the page loads very slowly specially the number of posts on on cat. page is 50 post.
I am using dynamic news lite theme , and this is a part of my content-excerpt.php

<div class="entry clearfix">
            <?php the_excerpt(); ?>
            <a href="<?php esc_url(the_permalink()) ?>" class="more-link"><?php _e('Read more', 'dynamicnewslite'); ?></a>
        </div>

I want to change the_excerpt(); function by another function or code that directly display the “user-supplied excerpt” only.

Thanx