Replication data for: In pursuit of a better broiler: carcass traits and muscle myopathies in conventional and slower-growing strains of broiler chickens

Selection for accelerated growth rate and high breast yield in broiler chickens have been associated with an increase in myopathies, including wooden breast (WB) and white striping (WS). To investigate effects of growth rate on carcass traits and incidence of myopathies, 14 strains were evaluated, encompassing 2 conventional(CONV; strains B and C: ADG0-48 > 60 g/d)and 12 slower-growing (SL) strains. The latter were categorized based on growth rate: FAST (strains F, G, I and M; ADG0-62=53−55 g/d), MOD (strains E, H, O and S; ADG0-62=50-51 g/d), and SLOW (strains D, J, K and N; ADG0-62<50 g/d). In a randomized incomplete block design, 7,216 mixed-sex birds were equally allocated into 164 pens (44 birds/pen; 30 kg/m2), with each strain represented in 8 to 12 pens over 2 to 3 production cycles. From each pen, 4 males and 4 females were processed at 2 Target Weights (TWs) based on their expected time to reach 2.1 kg BW (TW 1: 34 d for CONV; 48 d for SL strains) and 3.2 kg BW (TW 2: 48 d for CONV; 62 d for SL strains). Weights and yields for the carcass, breast, drumsticks, thighs, and wings were obtained; breast fillets were assessed to determine the presence and severity of WB and WS. At both TWs, breast yield was higher as growth rate increased (P < 0.001), with CONV having greater breast yield than other categories. Strain F had the greatest breast yield at both TWs (P < 0.001) within the FAST category. At TW 2, CONV had the greatest incidence of WB and WS (P < 0.001). However, within FAST, strain F had the greatest incidence of myopathies (P < 0.001) at both TWs, exhibiting values as high or as greater than CONV birds. The incidence of WB and WS in strains with differing growth rates but high breast meat yield suggests that the latter may play a major role in the occurrence of these myopathies.

肉鸡的加速生长选育与高胸肉产量选育，已被证实与包括木质胸（wooden breast, WB）和白条纹病（white striping, WS）在内的肌肉病变发生率升高相关。为探究生长速率对屠体性状及肌肉病变发生率的影响，本研究共评估14个品系，包含2个常规品系（conventional, CONV；品系B与C：0~48日龄平均日增重（average daily gain, ADG）>60 g/d）与12个慢生长品系（slower-growing, SL）。后者按生长速率划分为三类：快长型（FAST：品系F、G、I与M；0~62日龄ADG为53~55 g/d）、中速型（MOD：品系E、H、O与S；0~62日龄ADG为50~51 g/d）以及慢长型（SLOW：品系D、J、K与N；0~62日龄ADG<50 g/d）。本研究采用随机不完全区组设计，将7216只混合性别的肉鸡均等分配至164个栏舍（每栏44只，饲养密度30 kg/m²），每个品系在2~3个生产周期内设置8~12个重复栏舍。从每个栏舍选取4只公雏与4只母雏，分别在两个目标体重（Target Weights, TWs）下进行屠宰：基于预期达到2.1 kg活体重的时间（TW1：常规品系为34日龄，慢生长品系为48日龄），以及达到3.2 kg活体重的时间（TW2：常规品系为48日龄，慢生长品系为62日龄）。研究人员测定了屠体、胸肉、鸡腿、大腿以及翅膀的重量与产率；对胸大肌进行评估，以确定木质胸与白条纹病的发生情况与严重程度。在两个目标体重下，胸肉产率均随生长速率提升而显著升高（P < 0.001），常规品系的胸肉产率高于其余品系类别。在快长型品系中，品系F在两个目标体重下均表现出最高的胸肉产率（P < 0.001）。在TW2下，常规品系的木质胸与白条纹病发生率最高（P < 0.001）。但在快长型品系中，品系F在两个目标体重下的肌肉病变发生率均为最高（P < 0.001），其病变数值达到甚至超过常规品系肉鸡。不同生长速率但胸肉产率较高的品系中，木质胸与白条纹病的发生率提示，胸肉产率可能是引发此类肌肉病变的主要影响因素。