Aloui Loujain, Greene Elizabeth S, Tabler Travis, Lassiter Kentu, Thompson Kevin, Bottje Walter G, Orlowski Sara, Dridi Sami
Center of Excellence for Poultry Science, Division of Agriculture, University of Arkansas, Fayetteville, Arkansas, USA.
Higher School of Agriculture of Mograne, University of Carthage, Zaghouan, Tunisia.
Physiol Rep. 2024 Mar;12(5):e15972. doi: 10.14814/phy2.15972.
With climate change, selection for water efficiency and heat resilience are vitally important. We undertook this study to determine the effect of chronic cyclic heat stress (HS) on the hypothalamic expression profile of water homeostasis-associated markers in high (HWE)- and low (LWE)-water efficient chicken lines. HS significantly elevated core body temperatures of both lines. However, the amplitude was higher by 0.5-1°C in HWE compared to their LWE counterparts. HWE line drank significantly less water than LWE during both thermoneutral (TN) and HS conditions, and HS increased water intake in both lines with pronounced magnitude in LWE birds. HWE had better feed conversion ratio (FCR), water conversion ratio (WCR), and water to feed intake ratio. At the molecular level, the overall hypothalamic expression of aquaporins (AQP8 and AQP12), arginine vasopressin (AVP) and its related receptor AVP2R, angiotensinogen (AGT), angiotensin II receptor type 1 (AT1), and calbindin 2 (CALB2) were significantly lower; however, CALB1 mRNA and AQP2 protein levels were higher in HWE compared to LWE line. Compared to TN conditions, HS exposure significantly increased mRNA abundances of AQPs (8, 12), AVPR1a, natriuretic peptide A (NPPA), angiotensin I-converting enzyme (ACE), CALB1 and 2, and transient receptor potential cation channel subfamily V member 1 and 4 (TRPV1 and TRPV4) as well as the protein levels of AQP2, however it decreased that of AQP4 gene expression. A significant line by environment interaction was observed in several hypothalamic genes. Heat stress significantly upregulated AQP2 and SCT at mRNA levels and AQP1 and AQP3 at both mRNA and protein levels, but it downregulated that of AQP4 protein only in LWE birds. In HWE broilers, however, HS upregulated the hypothalamic expression of renin (REN) and AVPR1b genes and AQP5 proteins, but it downregulated that of AQP3 protein. The hypothalamic expression of AQP (5, 7, 10, and 11) genes was increased by HS in both chicken lines. In summary, this is the first report showing improvement of growth performances in HWE birds. The hypothalamic expression of several genes was affected in a line- and/or environment-dependent manner, revealing potential molecular signatures for water efficiency and/or heat tolerance in chickens.
随着气候变化，选择水分利用效率和耐热性至关重要。我们开展这项研究，以确定慢性周期性热应激（HS）对高水分利用效率（HWE）和低水分利用效率（LWE）鸡品系下丘脑与水平衡相关标志物表达谱的影响。热应激显著提高了两个品系的核心体温。然而，HWE品系的体温增幅比LWE品系高0.5 - 1°C。在热中性（TN）和热应激条件下，HWE品系的饮水量均显著低于LWE品系，且热应激使两个品系的饮水量均增加，LWE品系的增幅更为显著。HWE品系具有更好的饲料转化率（FCR）、水分转化率（WCR）以及水与采食量之比。在分子水平上，水通道蛋白（AQP8和AQP12）、精氨酸加压素（AVP）及其相关受体AVP2R、血管紧张素原（AGT）、1型血管紧张素II受体（AT1）和钙结合蛋白2（CALB2）在下丘脑的总体表达显著降低；然而，与LWE品系相比，HWE品系中CALB1 mRNA和AQP2蛋白水平更高。与TN条件相比，热应激暴露显著增加了AQPs（8、12）、AVPR1a、利钠肽A（NPPA）、血管紧张素I转换酶（ACE）、CALB1和2以及瞬时受体电位阳离子通道亚家族V成员1和4（TRPV1和TRPV4）的mRNA丰度以及AQP2的蛋白水平，但降低了AQP4基因的表达。在几个下丘脑基因中观察到显著的品系与环境交互作用。热应激在mRNA水平上显著上调了AQP2和SCT，在mRNA和蛋白水平上均上调了AQP1和AQP3，但仅在LWE品系中下调了AQP4蛋白。然而，在HWE肉鸡中，热应激上调了肾素（REN）和AVPR1b基因以及AQP5蛋白在下丘脑的表达，但下调了AQP3蛋白的表达。热应激使两个鸡品系中AQP（5、7、10和11）基因在下丘脑的表达均增加。总之，这是首份显示HWE品系鸡生长性能得到改善的报告。几个基因在下丘脑的表达受到品系和/或环境依赖性方式的影响，揭示了鸡水分利用效率和/或耐热性的潜在分子特征。
