Metabolizable energy in energy food for growing pigs and crossvalidation regression models

Newton Tavares Escocard De Oliveira,Leandro Dalcin Castilha,Carolina Natali Langer,Tiago Junior Pasquetti,Paulo Cesar Pozza

doi:10.5935/1806-6690.20180017

Abstract

The present study aimed to determine the apparent metabolizable energy (AME) of six corn cultivars, two sorghum cultivars and two wheat brans and to evaluate the cross-validation of predictive models of AME for corn, sorghum and wheat bran for growing pigs, as estimated from the data of chemical composition. Forty-four pigs, with an average initial weight of 24.3 kg, were distributed in a randomized block design, with 11 treatments (ten food treatments and the reference diet), four replicates and one pig per experimental unit. The reference diet was replaced by 30% for the ground corn and sorghum conditions and 20% for the wheat bran condition. The values of AME for corn, sorghum and wheat meal for pigs ranged from 3161 to 3275, 3317 to 3457 and 2767 to 2842 kcal kg-1 as a feed basis, respectively. The average metabolizability of the gross energy did not differ between the corn and sorghum cultivars, which formed a homogeneous group of food. Next, linear regression models were fitted to the 1st degree of the observed values as a function of the predicted AME, to test the hypothesis β0 = 0 and β1 = 1 in an experimental sample and 200 bootstrap samples. Fourteen predictive models had low percentages of cross-validation, ranging from 0-29.5%. The AME1A = 2.547 + 0.969ADE model was validated in experimental sample and 68% of bootstrap samples, proving its accuracy in estimating the AME of corn and sorghum from national data for growing pigs.

Highlights

The precise quantification of energy that pigs can digest and metabolize from eating a food is essential for the formulation of balanced diets (SAKOMURA; ROSTAGNO, 2016) because protein, amino acid and other nutrient requirements are expressed in terms of energy levels of diets
This research was conducted in order to determine the apparent metabolizable energy (AME) of six corn cultivars, two sorghum cultivars and two wheat brans for growing pigs and evaluates the cross-validation of the 15 predictive models of energia metabolizável aparente (EMA) in experimental sample and 200 bootstrap samples
In the evaluation phase of model validation, chemical and energetic composition values for corn, sorghum and wheat bran, as obtained in the laboratory, and apparent digestible energy (ADE) measurements obtained experimentally were replaced in 15 regression models estimated from the chemical and energetic composition of these foods, as reported in the national and international scientific literature, via meta-analysis, to obtain the predicted values of apparent metabolizable energy (PAME)

Summary

INTRODUCTION

The precise quantification of energy that pigs can digest and metabolize from eating a food is essential for the formulation of balanced diets (SAKOMURA; ROSTAGNO, 2016) because protein, amino acid and other nutrient requirements are expressed in terms of energy levels of diets. In the evaluation of the validity of regression models, the use of the bootstrap method is advantageous because from the original database, it is possible to increase the number of samples and tests to evaluate the joint null hypothesis β0 = 0 and β1 = 1 upon linear regression parameters (MONTGOMERY; PECK; VINING, 2006). In this context, this research was conducted in order to determine the AME of six corn cultivars, two sorghum cultivars and two wheat brans for growing pigs and evaluates the cross-validation of the 15 predictive models of EMA in experimental sample and 200 bootstrap samples

MATERIAL AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS