Apparent metabolizable energy determination of fat and formulated to diets broiler chicken.

Author(s)

Juliano Benedito Gaiotto

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2004-09-24

Examining board members

Jose Fernando Machado Menten; Antonio Augusto Domingos Coelho; Valdomiro Shigueru Miyada; Antonio Celso Pezzato; José Roberto Sartori

• Advisor: Jose Fernando Machado Menten

Abstract

Two metabolism trials were carried out to determine the apparent metabolizable energy (AME) and nitrogen-corrected apparent metabolizable energy (AMEn) of fats and their mixtures. In trial 1 the treatments consisted of a basal diet and 5 diets obtained by substituting, weight by weight, 10% of the basal diets with the fat sources: soybean oil (SO), acidulated soapstock (AS), poultry offal fat (PF), 50% soybean oil and 50% acidulated soapstock (SO50/AS50), 50% soybean oil and 50% poultry offal fat (SO50/PF50). In trial 2, the following mixtures were fed: 75% poultry offal fat and 25% soybean oil (PF75/SO25), 75% poultry offal fat and 25% acidulated soapstock (PF75/AS25), 50% soapstock and 50% poultry offal fat (AS50/PF50), 75% acidulated soapstock and 25% poultry offal fat (AS75/PF25) and 75% acidulated soapstock and 25% soybean oil (AS75/SO25). The basal diet was based on corn and soybean meal, formulated with no added fat. Each treatment was replicated 4 times in a completely randomized design. In each trial there were 4 assays corresponding to the pre-starter (0-10 days), starter (11-21 days), grower (22-35 days) and finisher (36-42 days) phases. In trial 1, AME and AMEn values for AS were lower (p<0.05) than those for the other fats in all phases; this can be due to the elevated level of free fatty acids in AS. AME and AMEn of the mixture SO50/AS50, as well as the mixture (SO50/PF50), were not different from those of SO and PF in the pre-starter, starter and grower phases; however, in the finisher phase these mixtures resulted in metabolizable energy similar to PF (p>0.05), lower than SO and higher than AS (p<0.05). In trial 2, AME and AMEn values were lower in the pre-starter, starter and grower phases for the mixtures AS75/PF25, AS75/SO25 and AS50/SO50 (p<0.05). AME and AMEn were higher for PF75/SO25 in the pre-starter, starter and grower phases (p<0.05). In both trials the metabolizable energy was lower for birds in the pre-starter phase than in the other phases. In a performance trial diets were formulated using the AMEn of fats previously determined for pre-starter, starter, grower and finisher phases. Selected treatments were AS, SO, PF, AS75/SO25, AS50/SO50 and PF50/SO50 with 6 replicates and 40 birds per pen. Diets were isoproteic and isoenergetic. Growth performance and carcass and parts yield were determined. Treatments did not result in significant differences (p>0.05), except for SO which was inferior to the other treatments. (AU)