Effect of chronic heat stress on some physiological and immunological parameters in different breed of broilers

Abstract

The differences in physiological and immunological parameters and pathological damage to organ tissues exposed to chronic heat stress provide the basis for evaluating heat resistance of different chicken breeds (white recessive rock [WRR] and The Lingshan [LS]). Ninety broilers of each breed were divided equally into a chronic heat stress group and a no heat stress group. The effects of chronic heat stress on the physiological and immunological parameters of broilers were analyzed using flow cytometry, ELISA, RT-qPCR, etc. Under heat stress conditions: (1) H and H/L values were significantly increased (P < 0.01) in the 2 breeds, and were higher in the WRR broilers than in the LS broilers at a late stage (P < 0.05). Although the corticosterone levels were also significantly increased (P < 0.01) in both breeds, they were lower in the 49 d WRR broilers than in the LS broilers (P < 0.01). The number of leukocytes were significantly increased in the 49 d WRR broilers (P < 0.01), whereas the number of CD3+, CD8+ cells, and erythrocytes were significantly reduced (P < 0.05). A significantly (P < 0.01) lower number of CD3+, CD4+ T-lymphocytes, and CD4+/CD8+ were present in WRR compared to that in the LS broilers. (2) The HSP70 transcript was significantly increased in the WRR broilers (P < 0.01), and was higher than the level in the LS broilers. The expression level of HSP70 protein was significantly (P < 0.05) increased in WRR broilers. (3) The WRR broilers developed cardiac and leg muscle inflammatory cellular hyperplasia and local inflammatory lesions, as well as cerebral meningitis and inflammatory hyperplasia of the brain tissue. The LS broilers developed mild cerebral inflammatory hyperplasia and mild inflammatory cellular proliferation in the leg muscle. In conclusion, under heat stress conditions, the relative physiological and immunological parameters were worse in the WRR broilers than in the LS broilers. The WRR broilers showed poor heat tolerance as evidenced from the expression of HSP70 and the extent of histopathological damages.

Protective Effects of 1,8-Cineole Microcapsules Against Inflammation and Gut Microbiota Imbalance Associated Weight Loss Induced by Heat Stress in Broiler Chicken

“…Stress injury intestinal barrier integrity plays an important role in the pathogenesis of low-grade inflammation in chickens and is a potential factor in weight loss and related health complications ( Alhenaky et al, 2017 ; Xu et al, 2018 ). To prevent and treat stress induced pathological symptoms, there is a need to find a safe and novel way to limit its development.…”

Effects of heat stress on performance, blood chemistry, and hypothalamic and pituitary mRNA expression in broiler chickens

“…Combined, these results serve as an indication that HS resulted in a cascade of downstream stress-related events. The secretion of CORT has been shown to induce the breakdown of muscle protein and adipose tissue, promoting gluconeogenesis and improving resistance to stress ( Xu et al., 2018 ). Hence the increase in glucose could be a result of increased hepatic gluconeogenesis, in which lactate is partly converted to glucose ( Willemsen et al., 2011 ).…”

Oxidative Stress and Endoplasmic Reticulum Stress Are Involved in the Protective Effect of Alpha Lipoic Acid Against Heat Damage in Chicken Testes

“…Following solidification, paraffin-embedded tissue samples were cut into a series of 5 µm sections using a rotary microtome (RM2235, Leica Biosystems, Buffalo Grove, IL, USA). Hematoxylin and eosin staining was performed as previously described [21]. In brief, the sections were treated with xylene and ethanol, washed with water, and then stained with hematoxylin for 10 min.…”