To prepare the carotenoid-enriched diets, each carotenoid
source was weighed, dissolved in water at 35 C, and
added to the diet according to each tested level [24]. All the
diets were prepared with fish oil and water and processed
in a California Pelleting Machine at a final pellet size of 2 3 mm in diameter. Next, the pellets were dried in a
drying machine (Hobart manufacturing Company Ltd.,
London, UK) for 24 hours at 50 C. The amount of total
protein, fat, carbohydrates, ash, and moisture in each diet
was measured according to the Association of Official
Analytical Chemists [25] (Table 1).