Digestibility of vegetal energetic ingredients supplemented with phytase for silver catfish (Rhamdia voulezi)

- 1500 FTU Kg-1 in the diet improves the coefficients of nutrient digestibility for oat, rice grits and wheat middlings by silver catfish (R. voulezi).
- The rice grits and wheat middlings have higher values of use of its nutrients, and can be used more efficiently in feeding silver catfish (R. voulezi).
- The phytase supplementation don't is necessary when want higher use of the nutrients of wheat middlings by the catfish (R. voulezi).

The aim of this study was to evaluate the digestibility of nutrients in oats, rice grits and wheat middlings by the silver catfish (Rhamdia voulezi), with and without phytase. Two hundred eighty-eight fish were distributed in 24 tanks of 500 L with tapered conical bottoms. The experimental design was completely randomized, represented by eight treatments and three replications. The treatments consisted of the development of eight diets (reference with and without phytase, oats with or without phytase, rice grits with or without phytase and wheat middlings with or without phytase) in a factorial scheme. The diets using the ingredients were composed of 70% of the reference diet and 30% of the ingredient. In the supplemented diets, we used 1500 FTU Kg− 1 of phytase. We performed physico-chemical and mineral analyses of the ingredients, diets and feces and performed the reading of chromium oxide in the diets and feces. The supplement of 1500 FTU Kg− 1 in the diet improves the coefficients of nutrient digestibility, mainly for oats and rice grits. Considering the feeds supplemented or not with 1500 FTU Kg− 1 in the diet, the rice grits and wheat middlings have higher values of use of their nutrients and can be used more efficiently in feeding catfish (R. voulezi).