Effect of Cyclic Heat Stress on Feeding-Related Hypothalamic Neuropeptides of Three Broiler Populations and Their Ancestor Jungle Fowl

Abstract

Heat stress (HS) has been increasingly jeopardizing the sustainability of the poultry production. Moreover, modern high-performing chickens are far less able to withstand HS than their predecessors due to higher growth rate and metabolic rates. Performance losses caused by HS are mainly ascribed to decreases in feed consumption. Since feed intake is tightly controlled by the hypothalamic centers of hunger and satiety, we sought to determine the effect of chronic cyclic HS on the expression of feeding-related hypothalamic neuropeptides (FRHN) in unselected chickens (i.e., the ancestor junglefowl—JF) and three broiler lines from diverse stages of genetic selection (i.e., the slow growing ACRB, the moderate growing 95RN, and the fast growing MRB). From 29 to 56 days, birds (n = 150 birds for each population) were subjected to either thermoneutral (TN, 25°C) or cyclic heat stress (HS, 36°C, 0900–1,800 h) conditions. Molecular data were analyzed by two-way ANOVA with interaction between the main factors, namely environmental temperature and line. The expression of major FHRN, like neuropeptide Y, agouti-related peptide, proopiomelanocortin, and cocaine and amphetamine regulated transcript remained unchanged. However, melanocortin receptor 1 exhibited a line-dependent decreasing trend from JF to MRB under both TN and HS (p = 0.09), adiponectin expression showed a distinct trend toward significance with 95RB exhibiting the highest mRNA level irrespective of the environmental temperature (p = 0.08), and JF had a greater mRNA abundance of visfatin than ACRB under TN (p < 0.05). The hypothalamic integration of circadian information, acclimation to long-lasting HS exposure, stable hypothalamic pathways unaffected by evolution and genetic selection, focus on mRNA abundances, and use of the entire hypothalamus masking gene expression in specific hypothalamic nuclei are all possible explanations for the lack of variations observed in this study. In conclusion, this is the first assessment of the impacts of heat stress on feeding-related hypothalamic neuropeptides of chicken, with a valuable and informative comparison between the ancestor junglefowl and three differently performing broiler lines.

Peripheral and Central Impact of Methionine Source and Level on Growth Performance, Circulating Methionine Levels and Metabolism in Broiler Chickens

“…The control group without methionine from the feeding trial and the aCSF group from the ICV experiment were used as calibrators. The specific oligonucleotide sequences for chicken neuropeptide Y (NPY), agouti-related protein (AgRP), cocaine- and amphetamine-regulated transcript (CART), proopiomelanocortin (POMC), orexin (ORX), orexin receptor 1 and 2 (ORXR1/2), adiponectin (Adip), adiponectin receptor 1 and 2 (Adip-R1/2), adenosine monophosphate (AMP)-activated protein kinase alpha 1 and 2 (AMPKα1/2), mechanistic target of rapamycin (mTOR), neurosecretory protein GL (NPGL), and ribosomal 18S as a housekeeping gene were previously published [ 16 , 17 , 18 ]. The specific oligonucleotide sequences for chicken D-amino acid oxidase (DAO), hydroxyacid oxidase (HAO), and monocarboxylate transporter 1, 2, and 3 (MCT1-3) are summarized in Table 3 .…”

Effect of Cyclic Heat Stress on Hypothalamic Oxygen Homeostasis and Inflammatory State in the Jungle Fowl and Three Broiler-Based Research Lines

“…As previously described ( 17 ), two birds per pen (i.e., six birds/combination of environmental temperature and line) were randomly chosen and euthanized via cervical dislocation. Hypothalamic samples were collected and treated according to the procedures reported by Piekarski and co-workers ( 33 ).…”

“…The environmental temperature was gradually decreased in all chambers as follows: 32°C (0–3 days), 31°C (4–6 days), 29°C (7–10 days), 27°C (11–14 days), and 25°C (15–28 days). From 29 to 56 days, half of the chambers were constantly kept at thermoneutral conditions (TN, 25°C), while the other half subjected to cyclic heat stress (HS, 36°C, 0900–1800 h) as detailed in our recent study ( 17 ). The relative humidity was between 40 and 60% ( 31 ).…”

“…In search for this central model's components and with the advances and revolutions in molecular techniques, subsequent studies over ensuing years have identified numerous (an)orexigenic neuropeptides ( 13 – 16 ). In a recent study, it was reported that chronic cyclic heat stress in broilers did not alter the hypothalamic expression of the classical neuropeptides, namely neuropeptide Y (NPY), agouti-related peptide (AgRP), proopiomelanocortin (POMC), and cocaine- and amphetamine-regulated transcript (CART) ( 17 ), suggesting potential involvement of other central pathways.…”

Effect of heat stress on the hypothalamic expression profile of water homeostasis‐associated genes in low‐ and high‐water efficient chicken lines

“…Of particular interest, and due to their elevated core body temperature compared to mammals (~41°C vs. 37°C), high metabolic rate, feather covering, and lack of sweat glands, chickens (meat and egg types) are very sensitive to high environmental temperatures (Perini, Cendron, Rovelli, Castellini, & Cassandro, 2021 ). The detrimental effects of high environmental temperature on feed intake (Abdelli et al., 2021 ; Brugaletta et al., 2021 ; Tabler et al., 2020 ), growth (He et al., 2018 ; Liu et al., 2020 ; Wasti, Sah, & Mishra, 2020 ), welfare (Sesay, 2022 ; Shields, 2015 ), stress (Greene et al., 2022 ; Lin et al., 2006 ; Mahmoud & Edens, 2003 ), immune system (Jahanian & Rasouli, 2015 ; Liu et al., 2022 ; Molnar, Korosi, Balazs, & Gaspardy, 2021 ; Monson et al., 2018 ), and meat and egg quality (Dai et al., 2009 ; Dai et al., 2012 ; Leishman et al., 2021 ; Maynard et al., 2023 ; Zaboli et al., 2019 ) are well documented. Together, these effects consequently result in significant and heavy economic losses to the industry worldwide (Raspoet & Wang, 2022 ; St Pierre, Cabanov, & Schnitkey, 2003 ), in addition to the add capital investment such as fans, cooler pads, and water sprinklers.…”