Lookup NU author(s): Craig Tallentire,
Dr Ilkka Leinonen,
Professor Ilias Kyriazakis
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Artificial selection of broiler chickens for commercial objectives has been employed at an unprecedented magnitude over recent decades. Consequently the number of days, total feed, and in turn energy, required to raise a broiler to slaughter weight have decreased dramatically. Feed provision is the poultry industry's biggest environmental hotspot, hence understanding the interactions between the birds' genetic change and their energy use efficiency forms the necessary starting point for quantifying and predicting, and thereby mitigating, the future environmental impact of the poultry sector. This review assesses the consequences of artificial selection on the following traits: digestive efficiency, body composition and utilization of metabolizable energy for growth and metabolic activity. The main findings were: 1) the digestive system has been subjected to much physical change due to selection in recent decades, but this has not led to any apparent change in digestion efficiency. 2) Both the energy intake per day and the metabolic heat production rate have increased in recent decades whilst 3) the efficiency of utilizing energy for growth has also increased; this is due to an increased growth rate, so that broilers reach slaughter weight more quickly and therefore need to allocate less energy overall to metabolic processes, with the exception of growth. 4) There may have been a reduction in the tendency to waste feed through spillage and carry out energetically expensive behaviors. There is a discrepancy in the literature with regards to the influence of selection on body composition and its contribution to feed efficiency. In this review two scenarios are demonstrated, whereby body composition either has or has not altered via artificial selection. Understanding the effects of artificial selection on the traits that relate to the feed efficiency of the broilers will contribute towards the reduction of the environmental impacts that arise from such systems.
Author(s): Tallentire CW, Leinonen I, Kyriazakis I
Publication type: Review
Publication status: Published
Journal: Agronomy for Sustainable Development
Print publication date: 01/12/2016
Online publication date: 07/11/2016
Acceptance date: 27/09/2016
ISSN (print): 1774-0746
ISSN (electronic): 1773-0155