Thermal manipulation during late embryogenesis: Effect on body weight and temperature, thyroid hormones, and differential white blood cell counts in broiler chickens

Abstract

The effects of thermal manipulation (TM) at 38.5°C and 40°C for 6 h at embryonic day (ED) 16, 9 h at ED 17, and 12 h at ED 18 on body weight (BW) and cloacal body temperature (T) during the first wk and later at post-hatch d 10, 14, 21, 28, and 42 were evaluated. Furthermore, chicks' ability to cope with a thermal challenge (TC; 41°C for 6 h) at post-hatch d 14 and 42 was also evaluated. A chick's response to TC was measured by determining the cloacal body temperature; the plasma thyroid hormones (thyroxin (T) and triiodothyronine (T)); the packed cell volume (PCV); the heterophil (H), lymphocyte (L), monocyte, basophil, and eosinophil percentages; and the heterophil-to-lymphocyte ratios (H/L). Thermal manipulation did not affect the hatchability. However, the body weight of TM chicken was higher compared with controls at marketing age (post-hatch d 42). At post-hatch d 14 and 42, no significant changes in T were observed among the different treatment groups. However, during TC at d 14 and 42, the T of TM chicks was lower compared with the controls. During TC, a significant increase in plasma T and a significant decrease in plasma T of TM chicks compared with controls were reported. Furthermore, during TC, a significant increase in the PCV and heterophil, monocyte, and H/L ratios, and a reduction in the lymphocyte percentages also were observed in TM chicks compared with the controls. Results of this study showed that chicks subjected to heat manipulation during late embryogenesis respond better to heat stress later in the growth and development period.

Evaluation of DNA methylation and mRNA expression of heat shock proteins in thermal manipulated chicken

“…Furthermore, to reduce metabolic heat production, peripheral T 3 is maintained low during high ambient temperature (Melesse et al 2011). Other reports have also described a significant drop in levels of T 3 and decreased metabolic rate in thermally conditioned chicken (Piestun et al 2011;Al-Zghoul et al 2015;Al-Rukibat et al 2017). The present observations differ from that of Rajkumar et al (2015a) where thermal manipulation did not alter the T 3 level chicken.…”

Positive Impact of Thermal Manipulation During Embryogenesis on Foie Gras Production in Mule Ducks

“…Several studies have previously shown that embryonic thermal manipulation (TM) could enhance adult poultry performance characteristics, such as thermoregulation during acute heat stress and breast muscle yield (Piestun et al, 2011(Piestun et al, , 2013Al-Rukibat et al, 2017). For the first time, we have shown that a moderate increase in incubation temperature during the second half of embryogenesis could improve foie gras production (by up to 15%) in adult male mule ducks.…”

“…the temperature variation, period and duration of the treatment (Collin et al, 2005;Piestun et al, 2008a;Loyau et al, 2013;Narinç et al, 2016;Al-Rukibat et al, 2017). Furthermore, most of the previous studies were conducted on chicken, raising the possibility that different species could respond differently to TM.…”

Effects of thermal manipulation of eggs on the response of jejunal mucosae to posthatch chronic heat stress in broiler chickens

“…Thermal manipulation ( TM ) during broiler embryogenesis, by increasing or decreasing the incubation temperature, was suggested to enhance heat tolerance during posthatch life ( Piestun et al., 2008 , Molenaar et al., 2010 , Al-Zghoul et al., 2013 , Al-Zghoul et al., 2015b , Al-Rukibat et al., 2017 ). Heat-tolerance improvement was achieved by the modulation of thyroid hormones, which are major players in the basal metabolic rate regulation, and HSP levels ( Al-Zghoul et al., 2013 , Al-Zghoul et al., 2015a , Al-Zghoul et al., 2015b , Al-Zghoul et al., 2015c , Al-Rukibat et al., 2017 ). Previously, TM was reported to increase Hsp70, HSF3, IL-1β, TNF-α, IL-6, TLR2, and TLR4 and to decrease catalase, GPX, SOD, and NOX expression in broiler chickens during acute heat stress ( Al-Zghoul et al., 2018 , Al-Zghoul et al., 2019 ).…”