<?php
$db = JFactory::getDBO();
$db->setQuery('SELECT category_name FROM '.hikashop_table('category').'
WHERE category_id='.(int)$this->row->product_manufacturer_id);
$brandName = $db->loadResult();
?>
<?php
if (!empty($brandName)) {
echo JText::_('MANUFACTURER').': '. $brandName;
} else { echo " ";}
?>

<?php
$db = JFactory::getDBO();
$db->setQuery('SELECT category_name FROM '.hikashop_table('category').' AS c
LEFT JOIN '.hikashop_table('product_category').' AS pc ON c.category_id = pc.category_id
WHERE pc.product_id='.(int)$this->row->product_id);
$categoryName = $db->loadResult();
echo categoryName;
?>