Sakkas Panagiotis, Oikeh Idiegberanoise, Blake Damer P, Nolan Matthew J, Bailey Richard A, Oxley Anthony, Rychlik Ivan, Lietz Georg, Kyriazakis Ilias
School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
Vet Parasitol. 2018 Jul 15;258:88-98. doi: 10.1016/j.vetpar.2018.06.014. Epub 2018 Jun 18.
Chickens exhibit varied responses to infection with Eimeria parasites. We hypothesise that broilers selected for increased growth rate will show lower resistance and tolerance to a coccidian challenge. 288 chickens of fast (F) or slow (S) growing lines were inoculated with 0 (control), 2500 (low-dose), or 7000 (high-dose) sporulated E. maxima oocysts at 13 days of age in two consecutive rounds. Gain and Intake were measured daily and their values relative to BW at the point of infection were calculated over the pre-patent (days 1-4 post-infection), acute (d5-8 pi), and recovery (d9-12 pi) phases of infection to assess the impact of infection. Levels of plasma carotenoids, vitamins E and A, long bone mineralisation, caecal microbiota diversity indices, and histological measurements were assessed at the acute (d6 pi) and recovery stage (d13 pi). In addition, we measured the levels of nitric oxide metabolites and the number of parasite genome copies in the jejunumat d6pi. In absolute terms F birds grew 1.42 times faster than S birds when not infected. Infection significantly reduced relative daily gain and intake (P < 0.001), with the effects being most pronounced during the acute phase (P < 0.001). Levels of all metabolites were significantly decreased, apart from NO which increased (P < 0.001) in response to infection on d6pi, and were accompanied by changes in histomorphometric features and the presence of E. maxima genome copies in infected birds, which persisted to d13pi. Furthermore, infection reduced tibia and femur mineralisation, which also persisted to d13pi. Reductions in measured variables were mostly independent of dose size, as was the level of parasite replication. The impact of infection was similar for S and F-line birds for all measured parameters, and there were no significant interactions between line x dose size on any of these parameters. In conclusion, our results suggest that line differences in productive performance do not influence host responses to coccidiosis when offered nutrient adequate diets.
鸡对艾美耳球虫寄生虫感染表现出不同的反应。我们假设，选择生长速度加快的肉鸡对球虫攻击的抵抗力和耐受性会较低。在13日龄时，将288只快长（F）或慢长（S）品系的鸡分两轮接种0（对照）、2500（低剂量）或7000（高剂量）个孢子化的巨型艾美耳球虫卵囊。每天测量增重和采食量，并计算在感染的潜隐期（感染后第1 - 4天）、急性期（感染后第5 - 8天）和恢复期（感染后第9 - 12天）相对于感染时体重的数值，以评估感染的影响。在急性期（感染后第6天）和恢复期（感染后第13天）评估血浆类胡萝卜素、维生素E和A的水平、长骨矿化、盲肠微生物群多样性指数以及组织学测量结果。此外，我们在感染后第6天测量了空肠中一氧化氮代谢物的水平和寄生虫基因组拷贝数。在未感染时，F系鸡的绝对生长速度比S系鸡快1.42倍。感染显著降低了相对日增重和采食量（P < 0.001），在急性期影响最为明显（P < 0.001）。除了一氧化氮在感染后第6天因感染而增加（P < 0.001）外，所有代谢物水平均显著降低，同时感染鸡的组织形态计量学特征发生变化，且存在巨型艾美耳球虫基因组拷贝，这种情况持续到感染后第13天。此外，感染降低了胫骨和股骨的矿化，这种情况也持续到感染后第13天。测量变量的减少大多与剂量大小无关，寄生虫复制水平也是如此。对于所有测量参数，S系和F系鸡感染的影响相似，品系×剂量大小在任何这些参数上均无显著交互作用。总之，我们的结果表明，当提供营养充足的日粮时，生产性能的品系差异不会影响宿主对球虫病的反应。
