Evaluation nutritional of acid silage of Nile tilapia (Oreochromis niloticus), whole fish discarded, farmed in Indaiatuba – SP

Abstract

The continental aquaculture with a production of 210,644,500 thousand tonnes produces a volume of solid waste causing a serious environmental problem, where 20% of the fish caught gets lost for lack of storage. The ideal would be to use raw materials and to recover byproducts as ingredients for animal feed. Aiming to increase the income and the capacity of production and, thus, to minimize environmental and health problems, deriving from fish waste, it was prepared the acid silage of the whole fish discarded from Nile tilapia ( Oreocrhromis niloticus ) after acidification and homogenisation of the biomass with 3% of formic acid and maintaining the pH around 3.7. Analyses were conducted to determine the humidity, protein, lipids and ash. Amino acids were examined in an auto-analyzer after acid hydrolysis, except for tryptophan determined by colorimetry. The new silage of Nile tilapia showed values higher than FAO standards for all essential amino acids, except for tryptophan. The highest values ​​were found for glutamic acid, aspartic acid, lysine, leucine and glycine. The results indicate the potential use of the acid silage, prepared from the whole fish discarded from Nile tilapia, as a protein source in the formulation of animal feed, turning it into an excellent alternative for adding value to biowaste deriving from solid fish waste.