Transcriptome analysis reveals potential mechanisms underlying differential heart development in fast- and slow-growing broilers under heat stress

Abstract

Background: Modern fast-growing broilers are susceptible to heart failure under heat stress because their relatively small hearts cannot meet increased need of blood pumping. To improve the cardiac tolerance to heat stress in modern broilers through breeding, we need to find the important genes and pathways that contribute to imbalanced cardiac development and frequent occurrence of heat-related heart dysfunction. Two broiler linesRoss 708 and Illinois -were included in this study as a fast-growing model and a slow-growing model respectively. Each broiler line was separated to two groups at 21 days posthatch. One group was subjected to heat stress treatment in the range of 35-37°C for 8 h per day, and the other was kept in thermoneutral condition. Body and heart weights were measured at 42 days posthatch, and gene expression in left ventricles were compared between treatments and broiler lines through RNA-seq analysis.

Ecological genomics predicts climate vulnerability in an endangered southwestern songbird

“…300 genes found to be differentially expressed in an RNA‐seq analysis of thermal tolerance in chickens (Zhang et al . ), two of which were physically linked (BRACA1 and RND2), and an additional five genes (Ecel1, SLC23A2, NOX4, PIRT and GR1N1) with GO terms related to other aspects of thermal tolerance, including respiratory system process, oxidative stress and response to heat (Rimoldi et al . ) (Table ).…”

“…; Zhang et al . ). As a first step towards understanding the genomic basis of adaptation to temperature in the willow flycatcher, we identify genes within 25KB of our top ranking climate‐associated SNPs (Table ).…”

“…Our strongest evidence for genes and gene regions that may be important to climate adaptation in this species comes from the overlap between five genes in our panel (BRACA1, RND2, CIITA, ICOS and UBE2C) and those that were also found to be differentially expressed in a thermal tolerance study in poultry (Zhang et al . ). More specifically, Zhang et al .…”

“…In addition, work in poultry has shown that high temperatures can cause heart strain, or in some cases heart failure, as birds attempt to dissipate heat through increased blood circulation. Furthermore, this work has shown that such stress is not just physiological in nature, but is associated with differential expression in a suite of c. 300 genes (Zhang et al 2017). Based on these studies, we predict that genes important to thermal cooling will be under strong selection in small desert passerines as the frequency of heat waves increases.…”

“…300 genes (Zhang et al . ). Based on these studies, we predict that genes important to thermal cooling will be under strong selection in small desert passerines as the frequency of heat waves increases.…”