Abstract
This project aims to study protein and amino acids requirements, as well as the genetic potential of poultry and fishes, to update the Avinesp software with results generated with poultry, and to those generated with fishes, to develop an electronic spreadsheet to calculate their nutritional requirements. To meet these objectives, trials will be carried out to characterize the productive genetic potential of poultry and fish; to evaluate the responses of poultry and fishes to amino acid and protein intake; to standardize a method to determine amino acids optimum ratio for poultry and fish; to standardize the use of dual X-ray absorptiometry (DXA) to determine the body composition of birds; and to study the efficiency of 15nitrogen and N15amino acid use for poultry. The trials to characterize the genetic potential will be divided into growth assays for broilers, pullets and fishes and production assays for commercial laying hens and breeders. The growth will be modeled by Gompertz function and egg production parameters of a mechanistic model will be determined. The trials of protein balance for poultry and fishes will be outlined to study the responses of performance, carcass yield, body composition and cost analysis of protein intake. For each amino acid, valine, isoleucine and tryptophan seven dietary levels will be studied, obtained by dilution technique. Amino acids utilization efficiency will be determined considering only the linear response phase. The optimal intake of amino acids will be estimated based on responses from all dietary levels by deterministic and stochastic models. For broiler chickens different methodologies will be studied to determine the ideal amino acid: lysine, and then will be applied to determine the optimum ratio for the essential amino acids: lysine for laying hens and fishes. A method to determine the ideal amino acid: lysine for maintenance will also be studied, with roosters. DXA technique will be standardized comparing to comparative slaughter technique. One trial will be conducted with broiler chickens, energy levels and sex effects will be used in order to modify the body composition of birds. Other trials will be carried out to study the efficiency of utilization of 15nitrogen and N15amino acid marked with broilers. The stable isotope technique will be used to determine the efficiency of utilization of nitrogen and amino acids for deposition in muscle, viscera and feathers. The results of this project will allow theoretical and practical advances in protein and amino acid nutrition of poultry and fishes, which will improve the nutrition of these animals minimizing nitrogen excretion into the environment. This project will enable to standardization of methods that will minimize further research costs, and also will allow the expansion of Avinesp software and the development of a spreadsheet to calculate the nutritional requirements for fishes. (AU)