Department of Poultry Science, University of Georgia, Athens, GA, USA.
Department of Poultry Science, University of Georgia, Athens, GA, USA.
Poult Sci. 2024 Jan;103(1):103174. doi: 10.1016/j.psj.2023.103174. Epub 2023 Oct 10.
The aim of this experiment was to investigate how different levels of Eimeria infection affect the performance, intestinal health, oxidative status, and egg production of Hy-Line W-36 pullets and laying hens. Three hundred and sixty Hy-Line W-36 pullets, aged 15 wk, were randomly distributed into 5 treatment groups, each comprising 6 replicates and a nonchallenged control. At 15 wk, pullets were inoculated with different levels of mixed Eimeria species as high-dose, medium-high, medium-low, and low-dose treatments. The growth performance and average daily feed intake (ADFI) were measured from 0- to 18-days postinoculation (DPI), whereas hen day egg production (HDEP) was recorded from wk 19. The markers of gastrointestinal health and oxidative status were measured at 6 DPI, 14 DPI, and 23 wk of age. The findings revealed a significant linear reduction in growth performance in response to increased Eimeria challenge dosage on 6 and 14 DPI (P < 0.0001, P-L < 0.0001). An interaction between the graded level of Eimeria infection and DPI was observed for ADFI. The challenged pullets showed a reduction in ADFI starting at 4 DPI, which persisted until 14 DPI, when ADFI recovered back to normal. The most significant drop in feed intake was observed in 6 DPI in all the Eimeria-infected groups. The markers of gastrointestinal health (gastrointestinal permeability and tight junction proteins) were upregulated in challenged pullets because of infection, whereas the relative mRNA expression of key nutrient transporters was downregulated following infection on 6 and 14 DPI (P < 0.05). As a result of an infection on 6 DPI, the oxidative equilibrium was shifted toward the oxidative stress, and at the same time, upregulation of proinflammatory and inflammatory cytokines was observed (P < 0.05). An interaction between the Eimeria challenge dosage and bird age was observed for HDEP (P = 0.0427). The pullets infected with Eimeria started to lay eggs later than the Control birds. However, the HDEP of the challenged groups became similar to Control only at wk 22, 3 wk after laying eggs. In conclusion, coccidiosis reduced growth performance, altered gastrointestinal health, induced oxidative stress, and delayed egg production when infected at the prelay stage of pullets and negatively impacted the laying hens' overall performance.
本实验旨在研究不同水平的艾美耳球虫感染对海兰 W-36 后备母鸡和产蛋鸡的生产性能、肠道健康、氧化状态和产蛋性能的影响。将 360 只 15 周龄的海兰 W-36 后备母鸡随机分为 5 个处理组，每组 6 个重复，设不感染对照组。在 15 周龄时，后备母鸡接种不同剂量的混合艾美耳球虫感染，设高剂量、中高剂量、中低剂量和低剂量处理。从接种后 0-18 天（DPI）测量生长性能和平均日采食量（ADFI），从第 19 周开始记录母鸡周产蛋数（HDEP）。在 6、14 和 23 周龄时测量胃肠道健康和氧化状态标志物。结果表明，随着艾美耳球虫感染剂量的增加，后备母鸡的生长性能在 6 和 14 DPI 时呈显著线性下降（P<0.0001，P-L<0.0001）。在 ADFI 方面，观察到艾美耳球虫感染程度的分级水平与 DPI 之间存在交互作用。感染组后备母鸡的 ADFI 从 4 DPI 开始下降，持续到 14 DPI，此时 ADFI 恢复正常。所有感染组在 6 DPI 时的采食量下降最明显。感染后，胃肠道健康标志物（胃肠道通透性和紧密连接蛋白）上调，而关键营养素转运体的相对 mRNA 表达在 6 和 14 DPI 时下调（P<0.05）。由于 6 DPI 的感染，氧化平衡向氧化应激倾斜，同时观察到促炎和炎症细胞因子的上调（P<0.05）。在 HDEP 方面观察到艾美耳球虫挑战剂量和鸡龄之间的交互作用（P=0.0427）。感染艾美耳球虫的后备母鸡比对照组母鸡产蛋时间晚。然而，仅在 22 周，即产蛋后 3 周，感染组的 HDEP 才与对照组相似。综上所述，在后备母鸡产蛋前感染球虫会降低生产性能，改变肠道健康，诱导氧化应激，延迟产蛋，并对产蛋母鸡的整体性能产生负面影响。
