Genetic analysis of production, physiological, and egg quality traits in heat-challenged commercial white egg-laying hens using 600k SNP array data

Abstract

Background Heat stress negatively affects the welfare and production of chickens. High ambient temperature is considered one of the most ubiquitous abiotic environmental challenges to laying hens around the world. In this study, we recorded several production traits, feed intake, body weight, digestibility, and egg quality of 400 commercial white egg-laying hens before and during a 4-week heat treatment. For the phenotypes that had estimated heritabilities (using 600k SNP chip data) higher than 0, SNP associations were tested using the same 600k genotype data. Results Seventeen phenotypes had heritability estimates higher than 0, including measurements at various time points for feed intake, feed efficiency, body weight, albumen weight, egg quality expressed in Haugh units, egg mass, and also for change in egg mass from prior to heat exposure to various time points during the 4-week heat treatment. Quantitative trait loci (QTL) were identified for 10 of these 17 phenotypes. Some of the phenotypes shared QTL including Haugh units before heat exposure and after 4 weeks of heat treatment. Conclusions Estimated heritabilities differed from 0 for 17 traits, which indicates that they are under genetic control and that there is potential for improving these traits through selective breeding. The association of different QTL with the same phenotypes before heat exposure and during heat treatment indicates that genomic control of traits under heat stress is distinct from that under thermoneutral conditions. This study contributes to the knowledge on the genomic control of response to heat stress in laying hens. Electronic supplementary material The online version of this article (10.1186/s12711-019-0474-6) contains supplementary material, which is available to authorized users.

Transcriptome Response of Liver and Muscle in Heat-Stressed Laying Hens

“…Analysis of the dataset with PCA suggested that heat stress induced only moderate gene expression changes compared to the control group because the heat and control samples did not form tight clusters based on two principal components. Yet heat exposure using this 4-week protocol was shown to have a strong negative impact on egg production for heat-treated layers in a parallel heat stress experiment [ 7 , 8 ].…”

“…The detrimental effects of heat stress on broilers and laying hens ranges from reduced growth and egg production to decreased meat and egg quality and food safety [ 4 ]. In layers, heat stress negatively affects feed intake, endocrine function, acid-base balance, and organ functions; this can result in lower egg production and decreased welfare for laying hens [ 5 , 6 , 7 , 8 ]. Genetic influence on response to heat stress in layer chickens has been shown by different survivability of two layer populations divergently selected for heat tolerance [ 9 ].…”

Genetic parameters for residual feed intake, methane emissions, and body composition in New Zealand maternal sheep

“…Bivariate models were used to estimate the genetic and phenotypic correlations between RFI and the gas traits and between these and all other traits. Genetic parameter estimates were considered to be different from zero when they were more than two times the standard error estimates ( Rowland et al, 2019 ).…”

“…Significant effects (p < 0.05) Frontiers in Genetics frontiersin.org were considered to be different from zero when they were more than two times the standard error estimates (Rowland et al, 2019).…”

Morphometric measurements and carcass characteristics of Black Australorp, Naked Neck, and Rhode Island Red crossbreds under alternative production systems

“…Crossing the indigenous germplasm with exotic breeds can result in the improvement of production performance, carcass and reproductive traits and better acclimatization to local environment (Adebambo et al, 2011;Khawaja et al, 2013). Genetic manipulations for enhanced production may result in modification of overall physiology of chicken's body as observed in commercial broilers (Tallentire et al, 2016;Hartcher and Lum, 2020) and layers (Rowland et al, 2019). To maintain the physiological status of genetically selected birds, one should also make suitable changes to the rearing system that can help the birds to perform according to the genetic potential by maintaining their metabolic physiology (Preisinger, 2005).…”