The Impact of Intensive Genetic Selection for Improved Performance in the Broiler Chicken on Metabolic Rate, Morphology and Body Composition

Gavin, Amanda Jane (2001) The Impact of Intensive Genetic Selection for Improved Performance in the Broiler Chicken on Metabolic Rate, Morphology and Body Composition. PhD thesis, University of Glasgow.

Abstract

The intensive genetic selection for fast growth rate, improved feed conversion ratio and increased breast meat yield that broilers have undergone has resulted in an increased incidence of metabolic disorders. It has been hypothesised that this is due to an imbalance in form and function between supply and demand tissues, known as symmorphosis. Such a breakdown in symmorphosis may also have consequences in limiting future performance. The effects of genetic selection on the gross morphology (organ mass), metabolic rates and carcass composition of three genotypes of chicken, which have undergone selection on different criteria, were examined. In addition, the use of near-infrared spectroscopy (NIRS) was investigated as an alternative technique for assessing the chemical composition of chicken carcasses. The experimental studies described within this thesis investigated the effects of the intensive genetic selection in the modem broiler by comparing it with two other genotypes of chicken that have undergone different levels of selection. These included: a modem commercial broiler (Ross 308, FB), a broiler that has not been selected for fast growth since 1972 (Ross 1972, SB) and a layer chicken which has never been selected for fast growth rate (Euribrid HISEX, L). A thermal load was placed on the birds to evaluate the effects of genetic selection on metabolic rate. Metabolic rate was determined using open-circuit indirect calorimetry to measure oxygen consumption (VO2). Resting (RMR) and peak metabolic rate (PMR) were measured in each individual bird on the same day during the first 2 weeks of life. Resting metabolic rate was determined by measuring VO, of the birds at thermoneutrality (28-32

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Regina McDevitt
• Keywords: Animal sciences, Genetics, Physiology
• Date of Award: 2001
• Depositing User: Enlighten Team
• Unique ID: glathesis:2001-76268
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 16:12
• Last Modified: 19 Nov 2019 16:12
• URI: https://theses.gla.ac.uk/id/eprint/76268