Effects of dietary stinging nettle (Urtica dioica) on hormone stress and selected serum biochemical parameters of broilers subjected to chronic heat stress

Abstract

Background: Heat stress is one of the most critical problems confronting the poultry industry. Stinging nettle (SN) is a medicinal plant with potent antioxidant properties. Objective:The goal of this study was to evaluate the effects of dietary SN at two different levels (2 and 4%) on the serum levels of cortisol and some selected parameters of broilers exposed to chronic heat stress.Methods: A total of 240 broiler chickens were randomly assigned to six dietary groups as follows: (1) control: fed the basal diet; (2) HS: heat-stressed broiler fed the basal diet; (3) HS-SN2: heat-stressed broiler fed 2% dietary SN; (4) HS-SN4: heat-stressed broilers fed 4% SN; (5) SN2: no heat-stressed broilers fed the basal diet supplemented with 2% SN; (6) SN4: no heat-stressed broilers fed the basal diet supplemented with 4% SN. Diet supplementation with SN was performed from days 14 to 35 and chronic heat stress was induced from days 22 to 29. The serum parameters were evaluated on days 14, 21, 29 and 35.Results: HS had higher serum levels of cortisol, total cholesterol (TC), aspartate aminotransferase, alanine aminotransferase and creatine kinase (CK) compared to the other treatments. HS-SN4 had significantly lower cortisol, TC, alanine aminotransferase and CK compared to HS and HS-SN2. Conclusions:The inclusion of 4% SN powder in the broilers' diet alleviated the negative effects of heat stress by decreasing cortisol, TC and tissue damage indices. It seems that dietary SN could be used as a feed additive in the poultry diet for improving the health status and defence mechanisms of the birds under stressful conditions.

Chicken pituitary transcriptomic responses to acute heat stress

“…While not reaching our FDR < 0.05, cutoff, the transcript levels encoding three other enzymes critical to cholesterol synthesis were elevated under heat stress including: 3-Hydroxy-3-Methylglutaryl-CoA Reductase (HMGCR; HS mean FPKM = 191.4, TN FPKM mean = 122.9); 24-Dehydrocholesterol Reductase (DHCR24; HS mean FPKM = 54.1, TN FPKM mean = 39.7) and 7-Dehydrocholesterol Reductase (DHCR7; HS mean FPKM = 136.2, TN FPKM mean = 97.7). The increase in the transcripts encoding these genes is consistent with reports of cholesterol levels increasing during heat stress [ 56 – 58 ]. As mentioned above, DNAJA4 also affects cholesterol metabolism by increasing HMGCR protein levels [ 20 ].…”

Heat stress and poultry production: a comprehensive review

“…The physiological response to HS in poultry involves the activation of the sympathetic adreno-medullary ( SAM ) pathway that results in the release of catecholamines, such as epinephrine and norepinephrine, and then activation of the hypothalamic–pituitary–adrenal ( HPA ) axis that results in the secretion of glucocorticoids ( GC ) ( Li et al, 2022 ; Mirsaiidi Farahani and Hosseinian, 2022 ; Oluwagbenga et al, 2022 ). Several studies have reported the detrimental effect of prolonged exposure to GC resulting from HS on production, performance, egg quality and welfare of the exposed animal ( Mashaly et al, 2004 ; Ebeid et al, 2012 ; Ma et al, 2014 ; Mehaisen et al, 2019 ; Qin et al, 2023 ; Welay et al, 2023 ).…”

“…The physiological responses to stress in poultry involve the activation of the SAM pathway that results in the release of catecholamines such as epinephrine ( EP ) and norepinephrine ( NE ) from the adrenal medulla ( Li et al, 2022 ). After the SAM, the HPA axis is activated which results in the release of GC, such as cortisol and corticosterone from the adrenal cortex ( Li et al, 2022 ; Mirsaiidi Farahani and Hosseinian, 2022 ; Oluwagbenga et al, 2022 ). Historically, cortisol and corticosterone were believed to be the major stress hormones in birds; however, over the past 20 years cortisol has been given considerably less attention in birds with corticosterone being the focus of research.…”

“…Glucocorticoids can be measured in the blood, feces, egg, and feather ( Weimer et al, 2018 ; Bartels et al, 2021 ; Kim et al, 2021 ; Lee et al, 2022 ; Oluwagbenga et al, 2022 , 2023b ). Although measurement of cortisol as biomarker of stress has been ignored for over 2 decades, recent studies reported an increase in circulating cortisol following exposure to HS or ACTH in poultry thereby showing its importance as an index of stress ( Sohail et al, 2010 ; Kim et al, 2022b ; Mirsaiidi Farahani and Hosseinian, 2022 ; Oluwagbenga et al, 2022 ; Tetel et al, 2022a , b ). ACTH is secreted by the anterior pituitary during stress response therefore it can also be measured as a biomarker of HS ( Contarteze et al, 2008 ; Li et al, 2022 ).…”

Whole Transcriptome Analysis of Differentially Expressed Genes in Cultured Nile Tilapia (O. niloticus) Subjected to Chronic Stress Reveals Signaling Pathways Associated with Depressed Growth

“…The HPI axis, on the other hand, is involved in the reallocation of resources to increase the supply of glucose in the blood by increasing catabolic pathways and depressing other energetically costly processes such as immune responses and reproduction. The HPI axis activation culminates in the release of glucocorticoids from internal cells located in the head kidney [ 27 ], leading to production of corticosteroids, primarily cortisol [ 24 , 28 ].…”