Enzymes produced by agro-industrial co-products enhance digestible values for Nile tilapia (Oreochromis niloticus): A significant animal feeding alternative

The use of enzymes in animal feed is common practice nowadays and its utilization has shown good results for improving the efficiency of nutrient utilization. In this sense, the goal of this work was to add low cost fungal phytases and proteases, with promising biological characteristics, produced by Solid State Fermentation using agro-industrial co-products to improve nutritional availability of plant based diets for Nile tilapia. Considering the enzymes chosen for the digestibility trail, Aspergillus niger produced acid phytases, as A. oryzae, produced proteases withoptimum pH over 8. The enzymes were stable at high temperatures (90 degrees C for phytase and 50 degrees C for protease) and showed very distinct behavior when different substrates were tested. Subsequently, the upscale production of A. niger phytase and A. oryzae protease with 7000 U g(-1) and 2500 U g(-1), respectively, were applied as additive in a plant protein based fish diet. They increased protein, mineral, energy and lipids availability (P < 0.05), showing that these new enzymes can improve animal production and performance. Additionally, these low cost enzymes are an alternative as additives to improve soybean meal digestibility in fish plant based diets.