Department of Animal Science and Aquaculture, Faculty of Agriculture, Dalhousie University, Truro, NS, B2N 5E3, Canada.
Department of Engineering, Faculty of Agriculture, Dalhousie University, Truro, NS, B2N 5E3, Canada.
Animal. 2020 Feb;14(2):353-359. doi: 10.1017/S1751731119002039. Epub 2019 Sep 26.
Implementing a photoperiod during incubation has been shown to be a potential next step to removing one more stressor for newly hatched poultry species. The distribution of hatch over time is a parameter that may be influenced by photoperiod that could benefit from a photoperiod but has not been studied at this time and is the objective of this paper. The impact on hatch rate for three strains of chicken, Barred Plymouth Rock (BR), Lohmann Brown (LB) and Lohmann Lite (LL), was measured following the provision of a 12L : 12D (12 h light : 12 h dark) photoperiod starting at 0, 9 or 17 days of incubation and compared with incubation in the dark. The cumulative number of chicks hatched eggs at four points in time (489, 498, 507 and 516 h of incubation) was analysed using repeated measures analysis in a 3 × 4 factorial arrangement of treatments. Repeated measures analysis was done to determine the main and interaction effects of photoperiod and bird strain, and a regression analysis was used to determine how these effects evolved over time. Lohmann Brown embryos provided a 12L : 12D photoperiod throughout incubation were first to reach 50% of total chicks hatched and rate of hatch from 50% to 75% of total chicks hatched as well. As the LB chicks did not begin to hatch earlier or finish later, the LB strain was the most synchronised when provided a 12L : 12D photoperiod from the beginning of incubation. Similar results were found for LL, but no difference on the percentage hatched over time was found when provided the 12L : 12D photoperiod at the beginning of incubation or at day 9. The BR strain only showed a significant difference in hatch window synchronisation when provided a 12L : 12D photoperiod at day 9 of incubation. These results indicate that the strain of chicken impacts the hatch window, and each strain responds to a photoperiod during incubation differently. This information could be useful for hatchery managers to deal with different strains of chicken for incubation.
在孵化期间实施光周期已被证明是去除新孵化家禽物种另一个应激源的潜在下一步措施。孵化时间的分布是一个可能受光周期影响的参数，光周期可能会从中受益，但目前尚未对此进行研究，这也是本文的研究目的。本研究旨在测量三种鸡品系（巴德·普利茅斯洛克（BR）、洛曼褐（LB）和洛曼莱特（LL））在孵化期间提供 12L:12D（12 小时光照：12 小时黑暗）光周期后的孵化率的影响，该光周期从孵化 0、9 或 17 天开始，并与黑暗孵化进行比较。在孵化的四个时间点（489、498、507 和 516 小时）孵化的雏鸡数量使用重复测量分析在 3×4 因子处理排列中进行分析。重复测量分析用于确定光周期和鸡品系的主要和相互作用效应，回归分析用于确定这些效应随时间的演变。在整个孵化期间，洛曼褐鸡胚胎提供 12L:12D 光周期的孵化率最早达到总孵化雏鸡的 50%，从 50%到 75%的孵化率也最高。由于 LB 雏鸡孵化时间不会更早或更晚，因此当从孵化开始就提供 12L:12D 光周期时，LB 品系是最同步的。对于 LL 也发现了类似的结果，但当在孵化开始或第 9 天提供 12L:12D 光周期时，孵化率随时间的变化没有差异。BR 品系只有在孵化第 9 天提供 12L:12D 光周期时，孵化窗口同步性才有显著差异。这些结果表明，鸡的品系会影响孵化窗口，每个品系对孵化期间的光周期的反应不同。这些信息对于孵化场管理人员来说可能是有用的，因为他们可以根据不同的鸡品系进行孵化。
