Effects of pre-hatch thermal manipulation and post-hatch acute heat stress on the mRNA expression of interleukin-6 and genes involved in its induction pathways in 2 broiler chicken breeds

2020

Veterinary Sciences

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Decades of selective breeding for commercial purposes have rendered the broiler chicken (Gallus gallus domesticus) highly susceptible to heat and cold stress. A multitude of studies have documented the effects of thermal manipulation (TM) on broiler thermotolerance during periods of post-hatch heat stress, but very few have focused on the effect of TM on a broiler’s ability to withstand cold stress. Therefore, the primary objective of the current study is to determine the effects of TM on the acquisition of thermotolerance in broilers via their expression of the stress-associated 70 kilodalton heat shock protein (Hsp70) gene and heat shock factor 3 (HSF3) gene. Briefly, Hubbard broiler embryos were subject to TM by increasing the incubation temperature to 39 °C and 65% relative humidity (RH) for 18 h daily, from embryonic days (ED) 10 to 18. Broilers were then exposed to cold stress by decreasing the room temperature to 16 °C during post-hatch days 32 to 37. After thermal challenge, broilers were euthanized and hepatic and splenic tissues were collected. Our results showed that TM decreased the hatchability rate and body temperature but improved the body weight gain. TM generally decreased the hepatic expression but did not change the splenic expression of HSF3 during cold stress. In contrast, both hepatic and splenic Hsp70 expression decreased during cold stress. The results of the present study may suggest that TM significantly affects a broiler’s genetic response to cold stress.

Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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HSF3 and Hsp70 Expression during Post-Hatch Cold Stress in Broiler Chickens Subjected to Embryonic Thermal Manipulation

Tarkhan

2020

Veterinary Sciences

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“…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 ). During chronic heat stress, chickens subjected to TM had higher SOD activity and glutathione levels and lower levels of lipid peroxidation ( Vinoth et al., 2015 ).…”

Section: Introductionmentioning

confidence: 97%

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

2020

Poultry Science

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In this study, the aim was to investigate effects of chronic heat stress ( CHS ) on the mRNA levels of proinflammatory cytokines (interleukin [ IL ]-6, IL-8, IL-1β, and tumor necrosis factor alpha [ TNF-α ]), toll-like receptors (TLR2 and TLR4), heat shock proteins (Hsp70, heat shock transcription factor [ HSF ]-1, and HSF3) and antioxidant enzymes (catalase, glutathione peroxidase, NADPH oxidase, and superoxide-dismutase) in the jejunal mucosae of broiler chickens subjected to thermal manipulation ( TM ) during embryogenesis. TM was carried out at 39°C and 65% relative humidity ( RH ) for 18 h daily from embryonic days 10 to 18. Control group was incubated at 37.8°C and 56% RH. CHS was induced by raising the temperature to 35°C for 7 D throughout posthatch days 28 to 35. On post-hatch-day 28 (day zero of CHS) and after 1, 3, 5, and 7 D of CHS, the jejunal mucosae were collected from both groups to evaluate the mRNA levels by real-time reverse transcription-PCR analysis. On day zero of CHS, the mRNA levels of antioxidant enzymes, TLRs, HSF3, IL-1β, and TNF-α were not significantly different between TM and control groups, while the levels of IL-6, IL-8, and HSF1 were lower and the level of Hsp70 was higher in TM. However, during CHS, the mRNA levels of antioxidant enzymes, IL-1β, TNF-α, TLR4, and HSF1 were significantly lower in TM than in controls, while the levels of TLR2 and IL-8 were significantly higher in TM than in controls. In addition, TM led to significant increase of mRNA levels of IL-6 and HSF3 after 1 D and Hsp70 after 3 D of CHS and to significant decrease of mRNA levels of IL-6 after 3 and 5 D, HSF3 after 7 D, and Hsp70 after 5 D of CHS. Results of this study suggest that TM led to altered posthatch antioxidant, immunological, and Hsp response to CHS in the jejunal mucosae of broiler chickens, probably indicating that TM may mitigate the adverse effects of CHS.

“…To mitigate the damage caused by heat and cold stress, thermal manipulation (TM), which involves embryonic exposure to high or low temperatures, has been found to improve thermotolerance and enhance physiological parameters of broilers [13,[29][30][31][32][33]. However, further research needs to be carried out in order to understand the effects of heat-and cold-induced oxidative stress in thermally manipulated broilers.…”

Section: Introductionmentioning

confidence: 99%

Embryonic Thermal Manipulation Affects the Antioxidant Response to Post-Hatch Thermal Exposure in Broiler Chickens

Tarkhan

2020

Animals

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Thermal stress is a major source of oxidative damage in the broiler chicken (Gallus gallus domesticus) due to the latter’s impaired metabolic function. While heat stress has been extensively studied in broilers, the effects of cold stress on broiler physiologic and oxidative function are still relatively unknown. The present study aimed to understand how thermal manipulation (TM) might affect a broiler’s oxidative response to post-hatch thermal stress in terms of the mRNA expression of the catalase, NADPH oxidase 4 (NOX4), and superoxide dismutase 2 (SOD2) genes. During embryonic days 10 to 18, TM was carried out by raising the temperature to 39 °C at 65% relative humidity for 18 h/day. To induce heat stress, room temperature was raised from 21 to 35 °C during post-hatch days (PD) 28 to 35, while cold stress was induced during PD 32 to 37 by lowering the room temperature from 21 to 16 °C. At the end of the thermal stress periods, a number of chickens were euthanized to extract hepatic and splenic tissue from the heat-stressed group and cardiac, hepatic, muscular, and splenic tissue from the cold-stressed group. Catalase, NOX4, and SOD2 expression in the heart, liver, and spleen were decreased in TM chickens compared to controls after both cold and heat stress. In contrast, the expression levels of these genes in the breast muscles of the TM group were increased or not affected. Moreover, TM chicks possessed an increased body weight (BW) and decreased cloacal temperature (TC) compared to controls on PD 37. In addition, TM led to increased BW and lower TC after both cold and heat stress. Conclusively, our findings suggest that TM has a significant effect on the oxidative function of thermally stressed broilers.