Escribano Damián, Contreras-Jodar Alexandra, López-Arjona Marina, Cerón José Joaquín, Fàbrega Emma, Aymerich Pau, Dalmau Antoni
Interdisciplinary Laboratory of Clinical Analysis, Interlab-UMU, Regional Campus of International Excellence Campus Mare Nostrum, University of Murcia, Murcia, Spain.
Department of Animal Production, Veterinary School, Regional Campus of International Excellence Campus Mare Nostrum, University of Murcia, Murcia, Spain.
Front Vet Sci. 2023 Jul 18;10:1156480. doi: 10.3389/fvets.2023.1156480. eCollection 2023.
Heat stress accounts for millions of dollars in losses for swine producers worldwide. The aim of the present study was to determine and evaluate cortisol and cortisone in hair as indicators of thermal stress in growing pigs reared under high environmental temperatures. The study was carried out in two independent batches of commercial crosses of Lean Duroc and Pietrain in trials 1 and 2, respectively, during the growing period (from 40 to 100 kg; 81 days in trial 1 and 77 days in trial 2) in the same commercial farm in Spain during the summers of 2020 and 2021. In both cases, four rooms were used. In Trial 1, Room 1 had cooling and 11 pigs per pen; Room 2 had no cooling and 13 pigs per pen; Room 3 had no cooling and 11 pigs per pen, and Room 4 had cooling and 13 pigs per pen. In Trial 2, Rooms 2 and 3 had cooling and rooms 1 and 4 had no cooling, and all of them had 13 pigs per pen. Mean THI value was higher ( < 0.0001) in rooms without cooling systems (75.0 trial 1; 74.9 trial 2) than with them (71.3 trial 1; 71.7 trial 2). A total of four pens per room (16 in total) was selected for analysis of hair corticoids and all pigs inside were sampled at the end of the study. Fifty percent of the pigs were males (castrated and intact in trial 1 and 2, respectively) and 50% females. In total, 44, 52, 44, and 52 pigs, respectively, were sampled in four rooms from the first trial and 52 for each of four rooms in Trial 2. Cortisol concentrations in hair did not show any significant change in relation to cooling-non-cooling in any trial. However, hair cortisone concentration was 172.3 pg./mg and 105.8 pg./mg less ( < 0.001) in pigs housed with cooling systems compared to those without them in Trial 1 and 2, respectively. In addition, the cortisone/cortisol ratio, which is an estimator of the activity of 11β-hydroxysteroid dehydrogenase (11β-HSD) type 2, was also greater in rooms without cooling than in rooms with cooling in both trials ( < 0.0001 and = 0.0105 for Trials 1 and 2, respectively). In relation to the sex effect, the results showed greater levels in females than in castrated males both in cortisone and the cortisol/cortisone ratio while cortisol hair levels were greater in intact males than in females. Therefore, the use of cortisone and the estimation of 11β-HSD type 2 activity in hair is recommended to evaluate the chronic stress produced by high environmental conditions in pigs instead of using hair cortisol concentrations alone.
热应激给全球养猪生产者造成了数百万美元的损失。本研究的目的是测定和评估猪毛中的皮质醇和可的松，作为在高温环境下饲养的生长猪热应激的指标。该研究在2020年和2021年夏季于西班牙同一个商业农场进行，分别在试验1和试验2的生长阶段（体重从40公斤增长到100公斤；试验1为81天，试验2为77天），对两个独立批次的杜洛克和皮特兰商业杂交猪进行。两种情况下均使用了四个猪舍。在试验1中，1号猪舍有降温设备，每栏饲养11头猪；2号猪舍没有降温设备，每栏饲养13头猪；3号猪舍没有降温设备，每栏饲养11头猪，4号猪舍有降温设备，每栏饲养13头猪。在试验2中，2号和3号猪舍有降温设备，1号和4号猪舍没有降温设备，所有猪舍每栏均饲养13头猪。没有降温系统的猪舍平均温湿指数值更高（P<0.0001）（试验1中为75.0；试验2中为74.9），而有降温系统的猪舍平均温湿指数值分别为试验1中的71.3和试验2中的71.7。每个猪舍总共选择四栏（共16栏）用于分析猪毛中的皮质类固醇，并且在研究结束时对栏内所有猪进行采样。50%的猪为雄性（试验1和试验2中分别为去势公猪和未去势公猪），50%为雌性。试验1中四个猪舍分别总共采样44头、52头、44头和52头猪，试验2中四个猪舍每个猪舍采样52头猪。在任何试验中，猪毛中的皮质醇浓度与是否有降温设备无关，均未显示出任何显著变化。然而，在试验1和试验2中，与没有降温设备的猪相比，有降温设备的猪的猪毛可的松浓度分别低172.3 pg./mg和105.8 pg./mg（P<0.001）。此外，作为2型11β-羟基类固醇脱氢酶（11β-HSD）活性指标的可的松/皮质醇比值，在两个试验中没有降温设备的猪舍中也均高于有降温设备的猪舍（试验1中P<0.0001，试验2中P = 0.0105）。关于性别效应，结果显示，无论是可的松还是皮质醇/可的松比值，雌性猪的水平均高于去势雄性猪，而未去势雄性猪的猪毛皮质醇水平高于雌性猪。因此推荐使用可的松以及评估猪毛中2型11β-HSD的活性，以评估高温环境给猪造成的慢性应激，而不是仅使用猪毛皮质醇浓度。
