Evaluation of lysine and metabolizable energy in diets for broilers

Two experiments were conducted to evaluate the optimal levels of metabolizable energy and standardized ileal digestible lysine in broiler diets, focusing on performance and body composition. Two chapters were created based on the results of the trials. In the first chapter, a study was conducted to evaluate the optimal levels of metabolizable energy and standardized ileal digestible lysine on the performance, body composition, blood parameters and liver enzyme activity of broilers from 1 to 14 days of age. A total of 768 male broilers were allocated in a completely randomized design in a 3×4 factorial scheme, with 8 replicates. The levels varied in ME (2950, 3050 and 3150 kcal/kg) and digestible lysine (1.30, 1.39, 1.48 and 1.57%). Broilers aged 1 to 14 days receiving a diet with 3150 Kcal/kg of EM and 1.57% of SID Lys, corresponding to a ratio of 4.98 g/Mcal, presented better CA (1.04 g/g). However, the level of 3150 Kcal/kg of EM should be used with caution, as it increases fat deposition in the carcass, leading to changes in the serum biochemical profile and in the activity of liver enzymes. While the best ratio to reduce body fat deposition was 5.32 g/Mcal corresponding to the level of 2950 Kcal/kg of EM and 1.57% of SID Lys. In the second chapter, 1920 male chickens were distributed in a completely randomized design in a 3 (3100, 3200 and 3300 Kcal/kg of energy - ME) x 4 (0.98; 1.07; 1.16 and 1.25% of lysine) factorial scheme, with 8 replicates. Broilers aged 28 to 40 days receiving feed with 3300 Kcal/kg and 1.25% had better CA. However, it increased fat deposition in the carcass. While the best relationship for protein mass deposition, weight gain and carcass and cutting yield was 3.90 g/Mcal corresponding to the level of 3200 Kcal/kg and 1.25%. Keywords: energy; lysine; amino acids; broilers.

Grantor dc:publisher

Universidade Federal de Viçosa

Year dc:date.issued

2025

Author dc:creator

• Farias, Maria Rogervânia Silva de

Advisor dc:contributor.advisor

• Hannas, Melissa Izabel

• Frangos de corte - Alimentação e rações
• Aminoácidos na nutrição animal
• Lisina

Statement dc:rights

• Acesso Aberto

Language dc:language.iso

eng

DOI

https://doi.org/10.47328/ufvbbt.2025.450

OAI identifier oai:identifier

oai:locus.ufv.br:123456789/34471