Abstract：
Heat stress (HS) is a global serious issue in the poultry industry with numerous adverse effects, including increased stress, depressed feed intake (FI), poor growth performance and higher mortality. Herbal adaptogens, plant extracts considered as stress response modifiers, are metabolic regulators that improve an organism\'s ability to adapt to and minimize damage from environmental stresses. Previously, we showed that herbal adaptogen supplementation increased FI and body weight (BW) of broiler (meat-type) chickens reared under HS conditions. Therefore, we hypothesized that these effects may be mediated through modulation of hypothalamic feeding-related neuropeptides. Male Cobb 500 chicks were reared in 12 environmental chambers with three diets: a corn-soybean-based diet (C) and two herbal adaptogen-supplemented diets at 500 g/1000 kg (NR-PHY-500) and 1 kg/1000 kg (NR-PHY-1000). Broilers in 9 chambers were exposed to chronic cyclic HS (35 °C for 8 h/day) from d29 to d42, while 3 chambers were maintained at 24 °C (thermoneutral, TN) for all 42 days. Hypothalamic samples were collected on d42 from each group, both before the onset of HS (Pre-HS) that day and after 3 h of HS (post-HS). Hypothalamic expressions of neuropeptide Y (NPY) receptors Y4 and Y7, Corticotropin-releasing hormone (CRH), orexin receptor 1 (ORXR1), melanocortin receptors (MC1R, MC4R, and MC5R), visfatin and neurosecretory protein GL (NPGL) genes were significantly upregulated by adaptogen supplementation. The hypothalamic expression of MC2R was affect by period, with a significant upregulation during post-HS phase. There was a significant period by treatment interaction for hypothalamic orexin and adiponectin expression. The hypothalamic expression of NPY, Y1, Y2, Y5, Y6, proopiomelanocortin (POMC), cocaine and amphetamine regulated transcript (CART), agouti-related peptide (AgRP), ORXR2, AdipR1/2, MC3R, and ghrelin was not affected by diet supplementation nor by HS exposure. In conclusion, these findings suggest that in-feed supplementation of adaptogen might improve FI and growth via modulation of hypothalamic feeding-related neuropeptides in heat-stressed broilers.
摘要：
热应激（HS）是家禽业中的一个全球性的严重问题，具有许多不利影响，包括增加的压力，降低采食量（FI），增长表现不佳，死亡率较高。草药适应原，被认为是胁迫响应调节剂的植物提取物，是代谢调节剂，可以提高生物体适应环境压力的能力，并将环境压力的损害降至最低。以前,我们表明，在HS条件下饲养的肉鸡（肉型）的FI和体重（BW）增加。因此,我们假设这些作用可能是通过调节下丘脑摄食相关神经肽介导的。雄性Cobb500雏鸡在12个环境室中饲养，采用三种饮食：以玉米大豆为基础的饮食（C）和两种补充草药适应原的饮食，分别为500g/1000kg（NR-PHY-500）和1kg/1000kg（NR-PHY-1000）。从d29到d42，将9个小室的肉鸡暴露于慢性循环HS（35°C，8小时/天），同时将3个小室保持在24°C（热中性，TN)为所有42天。在d42从每组收集下丘脑样本，在当天发生HS之前（Pre-HS）和HS后3小时（Post-HS）。神经肽Y(NPY)受体Y4和Y7、促肾上腺皮质激素释放激素(CRH)、食欲素受体1（ORXR1），黑皮质素受体（MC1R，MC4R,和MC5R），通过补充适应原，内脂素和神经分泌蛋白GL（NPGL）基因显着上调。MC2R的下丘脑表达受周期影响,在HS后阶段显着上调。通过治疗，下丘脑食欲素和脂联素表达存在明显的相互作用。下丘脑NPY的表达,Y1，Y2，Y5，Y6，原黑皮质素（POMC），可卡因和苯丙胺调节转录本（CART），agouti相关肽(AgRP)，ORXR2,AdipR1/2,MC3R,ghrelin不受饮食补充或HS暴露的影响。总之,这些发现表明，在热应激肉鸡中，饲料中补充适应原可能通过调节下丘脑摄食相关神经肽来改善FI和生长。
