Skip to Main content Skip to Navigation
Theses

Genotype by environment interactions in meat-type chickens and laying hens

Aya Lydie N'Dri
Abstract : Interactions between genotype and environment have been neglected in selection, as rearing conditions were standardised, so that interactions were of limited importance. Nowadays, selection firms are concentrated, which leads to a reduction in the number of available lines and to more standardized selection conditions in selection. Simultaneously, poultry production is developing in an increasing number of environments (rearing conditions and climates). This work therefore aimed at answering to several questions posed to poultry breeders: which line has to be chosen for a specific rearing condition, in which environment and on which criterion have animals to be selected? In order to answer the first question, we compared growth, carcass composition, meat technological and organoleptic quality of standard and label meat-type chickens, reared either in temperate climate or under hot conditions. Label chickens presented the three possible genotypes to the naked neck gene Na. Our study showed that the label chickens were more resistant to hot temperature than broilers. However, the "Na" gene did not bring any additional advantage in terms of heat resistance. Finally, we also found several triple genotype by temperature by sex interactions, which showed that results found in one sex cannot be easily extrapolated to the other sex. In a second part, we were in the situation in which the genotype was already chosen, as we worked on traditional laying hens, the la Gauloise Noire and the Gauloise Dorée. These breeds are to be reared in traditional conditions, outside, where they are under natural photoperiodic variations. In this part, the question was therefore to determine whether the best selection environment was claustration with a fixed light program or with a light program simulating natural diurnal variations. We did not find much significant genotype by environment interactions. However, in the Gauloise Dorée, sires ranked very differently in both environments, which implied that selecting candidates in claustration environment would lead no to keep the best males. For some traits showing crossed interactions, the selected candidates would even be the worse in natural conditions. In the last part, we studied the interaction between rearing system and genotype in label chickens. These animals are selected in claustration but are production in an environment with access to open-air. Genetic correlations estimated between both environments showed the presence of genotype by environment interactions on growth and carcass composition. However, there were of sufficiently limited importance to justify the selection in claustration. Moreover, we evaluated the possibilities of selection of feed conversion ratio in this genotype. Direct selection is possible from heritability estimate, but it implies to rear animals in cage. Ignoring interaction leads to choose fatness as the best indirect selection criterion of feed conversion ratio, in cage. At the opposite, taking interactions into account leads to choose growth
Document type :
Theses
Complete list of metadatas

https://pastel.archives-ouvertes.fr/pastel-00002277
Contributor : Ecole Agroparistech <>
Submitted on : Thursday, March 22, 2007 - 8:00:00 AM
Last modification on : Thursday, March 22, 2007 - 8:00:00 AM
Long-term archiving on: : Thursday, September 30, 2010 - 8:10:35 PM

Identifiers

  • HAL Id : pastel-00002277, version 1

Collections

Citation

Aya Lydie N'Dri. Genotype by environment interactions in meat-type chickens and laying hens. Life Sciences [q-bio]. INAPG (AgroParisTech), 2006. English. ⟨NNT : 2006INAP0017⟩. ⟨pastel-00002277⟩

Share

Metrics

Record views

613

Files downloads

2781