Equações de predição para estimar os valores energéticos de alimentos concentrados de origem vegetal para aves utilizando a metanálise

Abstract

The present study was carried out to obtain prediction equations to estimate the metabolizable energy values (AMEn) of concentrate feeds of plant origin commonly used in poultry diets, using the meta-analysis principle. A data collection review was made of the studies carried out in Brazil to catalogue information on the metabolizable energy values and chemical composition of the feeds (CP - crude protein; EE - ether extract; ash; CF - crude fiber; NDF - neutral detergent fiber; ADF - acid detergent fiber), to obtain the prediction equations to estimate the metabolizable energy of these feeds, using their chemical composition. The following effects were considered: sex at three levels (male; female and mixed); age at four levels (1st and 2nd week of life; 3rd and 4th week; 5th and 6th seek; above or indefinite) and the methodology used in the metabolism assay at two levels (total collection of excreta - TC and forced fed plus TC). The factorial arrangement among the effects (3 × 4 × 2), totaling up to 24 groups, was submitted to the weighed least squares analysis. The Stepwise procedure was adopted to study the association among the variables, and then, the Proc Reg (SAS) as used to fit the multiple linear regression model. Two equations were a better fit to estimate the metabolizable energy of the concentrate feeds, metabolizable energy = 4101.33 + 56.28EE – 232.97ash – 28.86NDF + 10.42ADF (R² = 0.84) and metabolizable energy = 4095.41 + 56.84EE – 225,26ash – 22.24NDF (R² = 0.83). It was observed that the variables neutral detergent fiber and acid detergent fiber were important and that they cannot be disregarded, since their removal from the model reduced the determination coefficient from 84% and 83% to 70%.