Brickett K E, Dahiya J P, Classen H L, Annett C B, Gomis S
Department of Animal and Poultry Science, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B4.
Poult Sci. 2007 Oct;86(10):2117-25. doi: 10.1093/ps/86.10.2117.
The aim of this study was to examine the main and interaction effects of 3 dietary nutrient densities (low-, medium-, high-density), 2 feed forms (mash, pellet), and 2 lighting programs (20L:4D, 12L:12D) on the walking ability and skeletal quality of broiler chickens raised to a young age (35 d). Forty-eight birds per treatment (nutrient density x feed form x lighting program subclass) were randomly selected (0 d) for assessment of their gait score (GS) and BW at 11, 18, 25, and 32 d. Samples of birds from various GS classifications were selected at 32 d for radiographs and histology of the femur and tibiotarsus. Bone ash (BA) content was evaluated at 35 d from the right tibiotarsus to assess bone quality. Overall, the mean GS values were low (GS <1). An interaction existed between lighting and sex. Males provided with 20L:4D had a higher GS (0.74) than females (0.45), and this score was greater than for broilers provided with 12L:12D (0.34 and 0.26 for males and females, respectively). Feeding mash reduced the GS (0.29) compared with pellet rations (0.62). The GS increased with age, and by 32 d 2.43% of birds had a GS >/=3. Broilers fed mash had a higher BA content (50.6%) than birds fed pellet diets (49.8%), and the 12L:12D value (50.5%) was greater than for 20L:4D (48.9%). Last, males had a lower BA content (49.8%) than females (50.6%). A positive correlation existed between BW and GS based on sex, where BW at 11, 18, and 25 d affected bird mobility at 32 d (r(2) = 0.39, 0.49, and 0.50 for males; r(2) = 0.34, 0.37, and 0.36 for females, respectively). Radiography and histology were unaffected by GS. This study confirmed that a reduced growth rate improved GS but also demonstrated that overall bird mobility was good and the incidence of skeletal disease was low.
本研究旨在考察3种日粮营养密度（低密度、中密度、高密度）、2种饲料形态（粉料、颗粒料）和2种光照程序（20小时光照：4小时黑暗、12小时光照：12小时黑暗）对幼龄（35日龄）饲养的肉鸡行走能力和骨骼质量的主要及交互作用。每个处理组（营养密度×饲料形态×光照程序亚组）随机选取48只鸡（0日龄），在11、18、25和32日龄时评估其步态评分（GS）和体重。在32日龄时，从不同GS分类的鸡中选取样本，对股骨和胫跗骨进行X光摄影和组织学检查。在35日龄时，从右侧胫跗骨评估骨灰（BA）含量以评估骨骼质量。总体而言，GS平均值较低（GS<1）。光照和性别之间存在交互作用。接受20小时光照：4小时黑暗的雄性鸡GS（0.74）高于雌性鸡（0.45），且该评分高于接受12小时光照：12小时黑暗的肉鸡（雄性和雌性分别为0.34和0.26）。与颗粒料日粮（0.62）相比，饲喂粉料可降低GS（0.29）。GS随年龄增加，到32日龄时，2.43%的鸡GS≥3。饲喂粉料的肉鸡BA含量（50.6%）高于饲喂颗粒料日粮的鸡（49.8%），12小时光照：12小时黑暗组的值（50.5%）高于20小时光照：4小时黑暗组（48.9%）。最后，雄性鸡的BA含量（49.8%）低于雌性鸡（50.6%）。基于性别，体重与GS之间存在正相关，11、18和25日龄时的体重影响32日龄时鸡的活动能力（雄性的r²分别为0.39、0.49和0.50；雌性的r²分别为0.34、0.37和0.36）。X光摄影和组织学不受GS影响。本研究证实生长速率降低可改善GS，但也表明鸡的总体活动能力良好且骨骼疾病发病率较低。
