Potential use of corn co-products in fishmeal-free diets for juvenile Nile tilapia Oreochromis niloticus

We conducted a 12-week feeding trial to evaluate the effects of total fishmeal replacement with different corn co-products on growth performance, feed utilization efficiency, and body composition in juvenile Nile tilapia Oreochromis niloticus. Five isonitrogenous diets were prepared. Fifty percent of the dietary protein was obtained from fishmeal (control diet) or from one of four corn co-products (experimental diets), namely corn protein concentrate, corn gluten meal, high-protein distillers' dried grains (HPDDG), or distillers' dried grains with solubles (DDGS). Fish with an initial mean weight of 4.5 g were fed one of the five diets twice a day to near satiety. Significantly higher (P < 0.05) specific growth rates and survival occurred in the fish fed the control diet or DDGS, followed by those fed the HPDDG; mean feed intakes by fish in these three groups were significantly greater than those in the others. Food conversion ratio, protein efficiency ratio, and total amino acid content of the whole body were not affected by changes in dietary ingredients. Whole-body and fillet protein contents were highest in the HPDDG group, whereas the lipid content was highest in those fed DDGS. DDGS can be used to fully replace the fishmeal components of Nile tilapia diets.