USDA, Agricultural Research Service, Poultry Research Unit, PO Box 5367, Mississippi State, MS 39762-5367
Advanced Animal Eye Care, 1067 Old West Point Road, Starkville, MS 39759.
Poult Sci. 2014 Aug;93(8):1890-9. doi: 10.3382/ps.2013-03806. Epub 2014 Jun 3.
Effects of genetic strain and light intensity on growth performance and carcass characteristics of broilers grown to heavy weights were investigated. The experimental design was a randomized complete block design. Treatment structure was a 2 × 5 factorial arrangement with the main factors being strain (Ross × Ross 308, Ross × Ross 708) and light intensity (25, 10, 5, 2.5, and 0.2 lx) with trial as replicates. In each of the 5 trials, chicks of 2 different strains of the same commercial hatchery were equally and randomly distributed into 10 environmentally controlled rooms (5 rooms/strain) at 1 d of age at 50% RH. Each room was randomly assigned 1 of 5 light intensities from 22 to 56 d of age. Feed and water were provided ad libitum. Birds and feed were weighed on 0, 14, 28, 42, and 56 d of age for growth performance. Humoral immune response was determined on d 28, whereas ocular and blood samples were performed on d 42 and 55, respectively. On d 56, 20 (10 males and 10 females) birds/strain from each room were processed to determine weights and yields. Genetic strain was significant (P ≤ 0.05) for most of the examined variables, where Ross × Ross 308 had better growth performance and meat yield in comparison with Ross × Ross 708. Although, there was no main effect of light intensity on growth performance and meat yield, results indicated that birds under 10 and 5 lx intensities showed slightly better growth performance and meat yield compared with birds under 25, 2.5, and 0.2 lx in both strains. There was no effect of strain and light intensity on ocular indices, immune response, plasma corticosterone levels, and mortality. This study shows the positive influence on profits to commercial poultry facilities that are using a low lighting environment to reduce energy cost, optimize feed conversion, and maximize production without compromising the welfare of the broilers.
本研究旨在探讨遗传品系和光照强度对育至大体重肉鸡生长性能和胴体特征的影响。采用完全随机区组设计，处理结构为 2×5 因子排列，主因子为品系（罗斯 308 品系×罗斯 708 品系、罗斯 308 品系×罗斯 708 品系）和光照强度（25、10、5、2.5 和 0.2 lx），试验为重复。在每个 5 次试验中，同一商业孵化场的 2 个不同品系的雏鸡在 1 日龄、相对湿度为 50%时，等比例、随机分配到 10 个环境控制室内（每个品系 5 个室内）。从 22 日龄至 56 日龄，每个室内随机分配 5 种光照强度中的 1 种。自由采食和饮水。在 0、14、28、42 和 56 日龄时对鸡和饲料进行称重，以评估生长性能。在 28 日龄时测定体液免疫反应，在 42 日龄和 55 日龄时分别进行眼部和血液取样。在 56 日龄时，从每个室内随机选择 20 只（10 只雄性和 10 只雌性）鸡进行屠宰，以确定体重和产肉量。遗传品系对大多数检测变量均有显著影响（P≤0.05），与罗斯 708 品系相比，罗斯 308 品系的生长性能和产肉量更好。尽管光照强度对生长性能和产肉量没有主要影响，但结果表明，在两种品系中，10 和 5 lx 光照强度下的鸡只生长性能和产肉量略优于 25、2.5 和 0.2 lx 光照强度下的鸡只。光照强度和遗传品系对眼部指数、免疫反应、血浆皮质酮水平和死亡率没有影响。本研究表明，商业家禽养殖场采用低光照环境来降低能源成本、优化饲料转化率和最大限度地提高生产效率，而不会损害肉鸡的福利，这对其产生了积极的影响。
