Research Department, Hatchtech BV, 3900 AG Veenendaal, The Netherlands; Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, 6700 AH Wageningen, The Netherlands.
Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, 6700 AH Wageningen, The Netherlands.
Poult Sci. 2020 Dec;99(12):6619-6629. doi: 10.1016/j.psj.2020.09.088. Epub 2020 Oct 9.
Eggshell temperature (EST) during incubation greatly affects embryo development, chick quality at hatch, and subsequently various broiler physiological systems. Until now, a constant EST of 37.8°C seems optimal. Data on effects of EST patterns on immune organ development and subsequent broiler immune response are, however, scarce. A higher EST of 38.9°C in week 2 and/or a lower EST of 36.7°C in week 3 of incubation potentially positively affect embryo immune organ development and broiler immune response post hatch. Broiler eggs (n = 468) were incubated at 4 different EST patterns (n = 117 eggs/treatment) from week 2 of incubation onward. Week 1 (embryonic age (E)0 < E7) EST was 37.8°C for all eggs. Week 2 (E7 < E14) EST was either 37.8°C (Control) or 38.9°C (Higher), and week 3 (E14 - /hatch) EST was either Control or 36.7°C (Lower). At hatch, histology of bursal follicles and jejunum villi and crypts were determined as well as heterophil to lymphocyte ratio (H:L) (n = 49). Posthatch, both sexes were grown in 8 pens/treatment for 6 wk (n = 320). Natural antibodies (NAb) were determined at day 14, 22, and slaughter (day 41 or 42) as an indicator of immunocompetence and response to a Newcastle disease (NCD) vaccination was determined by antibody levels at day 22 and slaughter (n = 128). Results showed no interaction EST week 2 × EST week 3, except for jejunum histology. Higher EST in week 2 resulted in lower cell density within bursal follicles (P = 0.02) and a tendency for lower H:L (P = 0.07) at hatch, and higher NCD titers at slaughter (P = 0.02) than Control EST. Lower EST in week 3 resulted at hatch in higher cell density within bursal follicles, higher H:L (both P < 0.05), and a tendency for a higher posthatch mortality rate than control EST (P = 0.10). In conclusion, higher EST in week 2 during incubation may benefit embryonic immune organ development and posthatch broiler immunocompetence, while lower EST in week 3 showed opposite indications.
孵化过程中的蛋壳温度（EST）对胚胎发育、孵化小鸡质量以及随后的各种肉鸡生理系统有很大影响。到目前为止，37.8°C 的恒定 EST 似乎是最佳的。然而，关于 EST 模式对免疫器官发育和随后肉鸡免疫反应的影响的数据却很少。孵化第 2 周 EST 升高至 38.9°C 和/或第 3 周 EST 降低至 36.7°C 可能会对胚胎免疫器官发育和孵化后肉鸡免疫反应产生积极影响。将 468 枚肉鸡种蛋（n = 468）分别在孵化的第 2 周开始进行 4 种不同的 EST 模式（n = 117 枚/处理）孵化。第 1 周（胚胎龄（E）0 < E7）所有种蛋的 EST 均为 37.8°C。第 2 周（E7 < E14）EST 要么为 37.8°C（对照），要么为 38.9°C（升高），第 3 周（E14 - /出雏）EST 要么为对照，要么为 36.7°C（降低）。出雏时，确定了法氏囊滤泡和空肠绒毛及隐窝的组织学以及异嗜性白细胞与淋巴细胞比值（H:L）（n = 49）。出雏后，雌雄各半在 8 个栏位/处理中饲养 6 周（n = 320）。14 日龄、22 日龄和屠宰时（41 日龄或 42 日龄）测定天然抗体（NAb），以作为免疫能力的指标，22 日龄和屠宰时的抗体水平（n = 128）用于测定对新城疫（NCD）疫苗接种的反应。结果显示，除了空肠组织学外，EST 第 2 周×EST 第 3 周之间没有相互作用。EST 第 2 周升高会导致出雏时法氏囊滤泡内细胞密度降低（P = 0.02）和 H:L 降低的趋势（P = 0.07），并导致屠宰时 NCD 滴度升高（P = 0.02），而对照 EST 则没有。EST 第 3 周降低会导致出雏时法氏囊滤泡内细胞密度升高、H:L 升高（均 P < 0.05），以及出雏后死亡率升高的趋势，高于对照 EST（P = 0.10）。总之，孵化第 2 周 EST 升高可能有利于胚胎免疫器官发育和出雏后肉鸡的免疫能力，而第 3 周 EST 降低则显示出相反的迹象。
