A titanium dioxide tracer (E171 titanium dioxide, IMCD Benelux N.V., Mechelen, Belgium) was added as an indigestible marker at an inclusion rate of 3 g/kg. Next,
the feed was divided into 2 batches. In a horizontal mixer either the soybean oil (5.30%) or pig lard (5.81%) was added and the contents were homogenized to finalize both basal grower diets (Table 1).