Effects of Thermal Manipulation on mRNA Regulation of Response Genes Regarding Improvement of Thermotolerance Adaptation in Chickens during Embryogenesis

Abstract

The phenomenon of increasing heat stress (HS) among animals is of particular significance when it is seen in economically significant industries, such as poultry. Due to the identification of the physiological, molecular, and genetic roots of HS responses in chickens, a substantial number of studies have focused on reducing the effects of HS in poultry through environmental management, dietary manipulation, and genetic alterations. Temperature manipulation (TM) during embryogenesis has been claimed to increase the thermal tolerance and well-being of chickens without affecting their capacity for future growth. There has been little investigation into the vulnerability of the epigenome involving TM during embryogenesis, although the cellular pathways activated by HS have been explored in chickens. Epigenetic changes caused by prenatal TM enhance postnatal temperature adaption and produce physiological memory. This work offers a thorough analysis that explains the cumulative impact of HS response genes, such as genes related to heat shock proteins, antioxidants, and immunological genes, which may aid in the enhanced adaptability of chickens that have undergone thermal manipulation during their embryonic stages.

Effect of thermal manipulation on embryonic development, hatching process, and chick quality under heat-stress conditions

“…Furthermore, the egg weight loss percentages for both studied groups were within the normal range, therefore egg weight loss did not impact embryo mortality and the hatchability percentages ( Tables 1 and 3 ). This finding is consistent with those previously mentioned by Ismail et al (2016) , El-Zeniny et al (2019) , Amjadian and Shahir (2020) , Saleh et al (2020) , and Ramiah et al (2022) .…”

“…Thermal manipulation during egg incubation is considered mild heat shock exposure during embryogenesis, which improves tissue stability, oxidative stress response, and immunological response to heat stress ( Al-Zghoul et al, 2023 ). Different thermal manipulation protocols resulted in a significant increase in heat shock proteins mRNA expression in the pectoral and thigh muscles ( Al-Zghoul et al, 2013 , 2015 ; Ali et al, 2022 ; Ramiah et al, 2022 ), and the same was associated with enhanced thermoregulation and thermotolerance, as previously reported by Al-Aqil and Zulkifli (2009) . Likewise, Li et al (2017) reported that thermal manipulation can promote mRNA and protein expression of growth marker genes and muscle-related genes.…”

“… Yalcin et al (2012) and Liu et al (2015) found that hatch weight can be used as a measure of chick quality. Different thermal manipulation protocols resulted in a significant increase in chick body weight ( Han et al, 2022 ; Ramiah et al, 2022 ). The improvement in embryonic weight during incubation, which was affected by thermal stimulation during embryogenesis, is reflected in the increase in hatch weight.…”

“…By optimizing the temperature conditions during incubation, hatcheries can produce healthier, more robust chicks that are better suited for commercial production. Furthermore, chicks incubated in a manipulating temperature range have a higher growth rate and thermal tolerance, as well as a stronger immune system and a reduced mortality rate ( Liu et al, 2015 ; Ismail et al, 2016 ; Al-Zghoul and El-Bahr, 2019 ; Han et al, 2022 ; Ramiah et al, 2022 ; Rocha et al, 2022 ). Thermal manipulation during chicken egg incubation has been demonstrated to significantly improve birds’ metabolism, posthatch thermoregulation, and reduce the adverse effect of high ambient temperature ( Han et al, 2022 ; Ramiah et al, 2022 ).…”

“…Furthermore, chicks incubated in a manipulating temperature range have a higher growth rate and thermal tolerance, as well as a stronger immune system and a reduced mortality rate ( Liu et al, 2015 ; Ismail et al, 2016 ; Al-Zghoul and El-Bahr, 2019 ; Han et al, 2022 ; Ramiah et al, 2022 ; Rocha et al, 2022 ). Thermal manipulation during chicken egg incubation has been demonstrated to significantly improve birds’ metabolism, posthatch thermoregulation, and reduce the adverse effect of high ambient temperature ( Han et al, 2022 ; Ramiah et al, 2022 ). In addition, it can positively affect birds' development, productivity, and welfare ( Loyau et al, 2016 ; Vinoth et al, 2018 ; Garvalho et al, 2020 ; Al-Zghoul et al, 2023 ).…”