Cardiac transcriptome study of the effect of heat stress in yellow-feather broilers

Abstract

The yellow-feather broiler is a popular poultry breed in Asia, particularly in China. In this study, we performed RNA-seq analysis to identify differentially expressed genes (DEGs) in the heart of yellow-feather broilers that had been subjected to heat stress treatment (38 ± 1 C for 8 h, over 7 d) and determine the response of the heart to high temperature and its effects on yellowfeather broiler physiology. We found that body weight (BW) of the heat stress treatment group (BW 28 ¼ 354.8 ± 34.8 g) was significantly decreased (p ¼ .033) compared with that of the control group (BW 28 ¼ 384.8 ± 58.9 g). However, there was no significant reduction in the heart relative weight (HRW) (p ¼ .538). A total of 37 DEGs related to energy metabolism responded to heat stress in the heart of yellow-feather broiler. The results of KEGG pathways analysis indicated that these genes are involved in oxidative phosphorylation (KO: 00190), cardiac muscle contraction (KO: 04260) and carbon metabolism (KO: 01200). Analysis of the cardiac transcriptome of yellowfeather broilers subjected to heat stress indicated that the heart of these birds has specific physiological mechanisms for regulating body growth in response to high-temperature environments. HIGHLIGHTS Yellow-feather broilers, a popular poultry breed in Asia, were used to determine how the heart responds to heat stress. A total of 37 genes in the heart of yellow-feather broilers showed differential expression in response to heat stress. The differentially expressed genes (DEGs) are associated with oxidative phosphorylation, cardiac muscle contraction and carbon metabolism pathways.

Effects of heat stress on the hepatic transcriptome of yellow-feathered chickens

“…In poultry, relative weights of tissue are usually assessed as indicators of physiological development ( Van et al, 2013). Previous studies have shown that the heat stress-driven decline in the growth performance of fast-growing broilers has varying effects on organs, including the relative weight reduction of the spleen, thymus, bursa, and heart (Quinteirofilho et al, 2010;Zhang et al, 2017), but no significant difference in relative heart weight was found in slow-growing chickens and YFC under chronic heat stress (Zhang et al, 2017;Zhang et al, 2019). In the present study, the authors found that HWI was not affected significantly by chronic heat stress, and they observed normal physiological development of the liver in the treatment group YFC ( Van et al, 2013).…”

“…The control group was kept at 25 ± 1 °C, 24 hours a day. Bodyweight (BW) and cloacal temperature (CT) were measured according to (Zhang et al, 2020;Zhang et al, 2019). All 28-day-old YFC from the treatment and control groups were euthanized at the end of the final day of the heat stress treatment, and their livers were removed.…”

“…Yellow-feathered chickens are less affected by heat stress than commercial broilers, especially for its effect on weight gain (Azad et al, 2010;Zhang et al, 2019). Transcriptome studies are an effective method of analysing tissue gene expression and can be used to study the effect of heat stress on poultry.…”

“…Transcriptome studies are an effective method of analysing tissue gene expression and can be used to study the effect of heat stress on poultry. At a phenotypic level, the decreased growth performance that is observed in poultry exposed to heat stress affects the relative weights of various tissues (Quinteirofilho et al, 2010;Zhang et al, 2017;Zhang et al, 2019). This might be interpreted to indicate that heat stress can suppress tissue cell proliferation at various rates depending on the organ.…”

“…A parallel study by the same group analysed the transcriptome of YFC liver tissue exposed to acute heat stress, and found 834 DEG, almost half of which were involved in lipid and energy metabolism (Zhang et al, 2020). In YFC that were exposed to chronic heat stress, an RNA-seq analysis of heart tissue revealed 37 DEG that were involved in oxidative phosphorylation and cardiac muscle contraction pathways (Zhang et al, 2019). However, to the authors' knowledge, a transcriptomic study has not been undertaken on livers of YFC exposed to chronic heat stress.…”