Dietary net energy levels for growing barrows from 30 to 70 kg

Gabriela Puhl Rodrigues,Alexandre Pereira Dos Santos,Danilo Alves Marçal,Marina De Nadai Bonin,Luana Cristiane Dos Santos,Charles Kiefer,Anderson Corassa,Karina Márcia Ribeiro De Souza Nascimento

doi:10.1590/0103-8478cr20201033

Gabriela Puhl Rodrigues, Alexandre Pereira Dos Santos + Show 6 more

Open Access

https://doi.org/10.1590/0103-8478cr20201033

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Abstract

ABSTRACT: This study evaluated the effect of dietary net energy (NE) levels on growth performance and carcass characteristics of barrows from 30 to 70 kg of body weight (BW). Sixty barrows with initial body weight (IBW) of 31.94 ± 3.54 kg and final body weight (FBW) of 71.98 ± 5.99 kg were allotted to one of five dietary NE levels (2.40, 2.45, 2.50, 2.55, and 2.60 Mcal kg-1), using a completely randomized block design with six replicates and two barrows per replicate. The experimental period was divided into phase I: 30 to 50 kg and phase II: 50 to 70 kg. The variables analyzed were average daily feed intake (ADFI), net energy intake (NEI), digestible lysine intake (LysI), average daily gain (ADG), feed conversion (FC), FBW, digestible lysine conversion:gain (LysI:G), Cost:Gain (C:G), loin eye area (LEA), muscle depth (MD), first backfat layer (BF1), second backfat layer (BF2), total backfat (BFt), lean meat percentage, and carcass bonus index (BI). In phase I, there was a linear increase (P < 0.05) in FBW, ADG, NEI, and LysI with increasing NE levels in the diet. In phase II, increasing dietary NE levels also increased (P < 0.05) FBW, ADG, NEI, LysI, and FC linearly. Overall, there was a linear increase (P < 0.05) in ADG, NEI, LysI, and FC with increasing NE levels in the diet. The other performance variables were not affected (P > 0.05) by the NE levels. There was an increase (P < 0.05) in BF2 with increasing NE levels, but the other carcass characteristics were not altered (P > 0.05). We recommended 2.60 Mcal of NE kg-1 in the diet for growing barrows from 30 to 70 kg.

Highlights

Considering the important relationships that dietary energy has with costs (NOBLET, 2007), growth performance, and carcass characteristics (QUINIOU & NOBLET, 2012), several studies were developed to establish the ideal level of dietary energy for pigs (QUINIOU & NOBLET, 2012; NITIKANCHANA et al, 2015; SMITH et al, 2017; MARÇAL et al, 2018a, b; MARÇAL et al, 2019)
Considering the average daily feed intake (ADFI) and average daily gain (ADG) observed in the present study, when compared to the standards for high genetic potential barrows with medium-superior growth performance, established by ROSTAGNO et al (2017), it can be inferred that the thermal conditions did not influence the growth performance of the pigs
Considering the evaluated net energy (NE) levels, it was expected that the difference of 0.20 Mcal kg-1 between the minimum and maximum levels that were studied (2.40 and 2.60 Mcal kg-1, respectively) would provide an effect on the ADFI, as studies indicate that pigs are able to adjust their voluntary feed intake in response to changes in the nutritional density of the diet (NYACHOTI et al, 2004; LI & PATIENCE, 2017)

Summary

Introduction

Considering the important relationships that dietary energy has with costs (NOBLET, 2007), growth performance, and carcass characteristics (QUINIOU & NOBLET, 2012), several studies were developed to establish the ideal level of dietary energy for pigs (QUINIOU & NOBLET, 2012; NITIKANCHANA et al, 2015; SMITH et al, 2017; MARÇAL et al, 2018a, b; MARÇAL et al, 2019). In the growing and finishing phases, studies indicated that increasing the dietary energy level decreases the average daily feed intake (ADFI) and improves feed conversion of the pigs (CÁMARA et al, 2014, 2016; GONÇALVES et al, 2015; MARÇAL et al, 2018a,b). Increasing the dietary energy density without maintaining a constant energy:nutrient ratio may not simultaneously improve the average daily gain (ADG) and increase carcass fat deposition, since the availability of essential amino acids may not be sufficient for protein synthesis. This would limit both the ADG and the extent to which excess energy consumed can be deposited as fat in the carcass (MARÇAL et al, 2019)

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