Sánchez-Casanova Rubí E, Sarmiento-Franco Luis, Phillips Clive J C
Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carretera Mérida-Xmatkuil, Apdo. 4-116, Itzimná, Mérida, Yucatan 97100, Mexico.
Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia.
Animals (Basel). 2022 Jul 27;12(15):1917. doi: 10.3390/ani12151917.
The effects of outdoor access, stocking density, and age on broiler behavior, stress, and health indicators in a tropical climate were assessed over two seasons, winter and summer. Two hundred and forty Cobb500 male chickens were allocated to one of four treatments, with six replicates of ten birds in each: low stocking density indoors with outdoor access (LO); high stocking density indoors with outdoor access (HO); low stocking density indoors without outdoor access (LI); and high stocking density indoors without outdoor access (HI). Scan sampling was used to record their behavior both indoors and outdoors. At 28 and 42 days old, blood samples were obtained to determine the heterophil to lymphocyte (H/L) ratio. At 42 days old, chickens were culled and inspected for footpad dermatitis (FPD), and bone quality was examined. Their spleens and bursas of Fabricius were collected and weighed, relative to carcass weight (RW). A factorial analysis was used to test the effects of season (winter or summer), outdoor access (with or without), stocking density (low: 5 animals/m or high: 10 animals/m), and age (28 or 42 days) on the behavior and stress and health indicators. There were no major effects of providing outdoor access on behavior, except that resting was reduced by providing outdoor access to older birds and those at low stocking densities inside. Resting was also greater in indoor and high-density treatments during winter. The bursa of Fabricius was heavier in summer in outdoor birds. The tibia bones were shorter in the outdoor birds. Heterophil numbers were greater in the outdoor treatments in summer but not in winter. These results indicate that outdoor access can increase activity in some situations, and potentially increase bone strength, but it may also increase the risk of stress, particularly heat stress in summer.
在冬季和夏季两个季节里，评估了热带气候下户外空间、饲养密度和年龄对肉鸡行为、应激及健康指标的影响。240只科宝500雄性肉鸡被分配到四种处理方式之一，每种处理有六个重复，每个重复十只鸡：室内低密度饲养并可进入户外（LO）；室内高密度饲养并可进入户外（HO）；室内低密度饲养且无户外空间（LI）；室内高密度饲养且无户外空间（HI）。采用扫描取样法记录它们在室内和室外的行为。在28日龄和42日龄时采集血样以测定异嗜性粒细胞与淋巴细胞（H/L）比值。在42日龄时，对鸡进行宰杀并检查脚垫皮炎（FPD）情况，同时检查骨骼质量。收集它们的脾脏和法氏囊并称重，以相对于胴体重（RW）表示。采用析因分析来检验季节（冬季或夏季）、户外空间（有或无）、饲养密度（低：5只/m或高：10只/m）和年龄（28日龄或42日龄）对行为、应激和健康指标的影响。提供户外空间对行为没有重大影响，只是让老龄鸡和室内低密度饲养的鸡进入户外会减少休息时间。冬季时，室内高密度处理组的休息时间也更长。夏季时，户外鸡的法氏囊更重。户外鸡的胫骨较短。夏季户外处理组的异嗜性粒细胞数量更多，但冬季没有这种情况。这些结果表明，在某些情况下户外空间可增加活动量，并可能增强骨骼强度，但也可能增加应激风险，尤其是夏季的热应激风险。
