Energy utilization and requirement of broiler breeders during the production phase.

This study aimed to evaluate energy utilization and propose models for metabolizable and net energy requirements in broiler breeders during the egg production phase. Sixty Cobb500 broiler breeders aged between 29 and 65 wk were randomly assigned to 3 feeding levels. At each age, 6 birds were adapted for 8 d to 3 levels of metabolizable energy intake (MEi), established based on the amount of feed allocated: 1) the amount of feed recommended in the guideline, 2) 25% above, and 3) 25% below.

Heat stress affects breathing and metabolism of chicks incubated at high temperature.

Global warming poses serious implications to animal physiology and a gradual increase in ambient temperature affects all living organisms, particularly fast-growing selected species. We recorded ventilation (V̇), body temperature (T), oxygen consumption (V̇O) and respiratory equivalent (V̇/V̇O) of 14-day-old (14d) male and female chicks at room air conditions, hypercapnia and hypoxia at heat stress (HS, 32 °C). These chicks had previously been exposed to control (CI, 37.

Energy cost of physical activities in growing broilers.

1. The time-energy budget method estimates the energy used for physical activity (PA) by integrating behaviour PA patterns with energy cost for specific PAs. Nevertheless, information about individual energy cost by type of PA are not available and so this study estimated the energy cost of PA for growing broilers.

Dynamic of heat production partitioning in rooster by indirect calorimetry.

Objective: The objective of this study was to describe a methodological procedure to quantify the heat production (HP) partitioning in basal metabolism or fasting heat production (FHP), heat production due to physical activity (HPA), and the thermic effect of feeding (TEF) in roosters.

Methods: Eighteen 54-wk-old Hy Line Brown roosters (2.916±0.

Composition of feathers and pulp of two broiler genotypes.

1. Cobb and Ross broilers (200 of each sex and breed) were fed four phases of diets formulated with balanced protein to match their amino acid requirements throughout growth. Ten birds per genotype were sampled and euthanised at two-weekly intervals from 14 to 112 d of age.