Department of Animal Sciences, The Ohio State University, Columbus.
Poult Sci. 2019 Nov 1;98(11):5488-5496. doi: 10.3382/ps/pez405.
Necrotic enteritis (NE) is a disease that has gained relevance in the poultry industry with both immediate and sustained effects on BW of broilers. The objective of the 3 experiments was to evaluate the impact of NE, induced by methods that reflect common broiler production systems, on the growth curve throughout the growth period. In addition, the impact of Eimeria maxima (EM) on NE, as well as the long-term impact of Clostridium perfringens (CP) on BW, were analyzed. In experiment 1, a dual infection model of EM and CP was compared to a non-challenged control, while experiment 2 evaluated 2 different strains of EM dual infection, as well as 6 CP-only groups. Similarly, experiment 3 tested dual infection and both high and low dose CP-only groups. Both NetB and non-NetB strains of CP were used to evaluate whether NetB toxin may potentially play a role in NE induction. In all 3 experiments, BW was measured immediately before infection on day 16, then weekly through the end of the test period. In all 3 experiments, a decrease (p < 0.05) in BW was observed immediately following the acute NE disease period of day 21 to day 23, with a negative impact also observed of BW gain during NE disease period (p < 0.05). A long-term effect on BW was most clearly detected in the EM + CP dual infection models, as well as when high levels of CP-only were administered. In these cases, BW was impacted long-term, with a requisite week or more to return to a BW similar to the non-challenged control. The separation in BW, though not significant, was nearly parallel with the non-challenged control throughout the growth period, indicating a shift in the growth curve. In addition to showing the long-term impact of various forms of NE on broiler growth, these shifts in the growth curve can be used to measure the effects of treatments on prevention and recovery of broilers impacted by NE.
坏死性肠炎（NE）是一种在禽类养殖业中具有重要意义的疾病，对肉鸡的体重（BW）具有直接和持续的影响。这 3 个实验的目的是评估通过反映常见肉鸡生产系统的方法诱导的 NE 对整个生长期间的生长曲线的影响。此外，还分析了最大艾美耳球虫（EM）对 NE 的影响，以及产气荚膜梭菌（CP）对 BW 的长期影响。在实验 1 中，将 EM 和 CP 的双重感染模型与未感染对照进行了比较，而实验 2 则评估了 2 种不同株系的 EM 双重感染，以及 6 个仅 CP 组。同样，实验 3 测试了双重感染以及高剂量和低剂量 CP 仅感染组。实验使用了 NetB 和非 NetB 株系的 CP，以评估 NetB 毒素是否可能在 NE 诱导中发挥作用。在所有 3 个实验中，在感染前第 16 天立即测量 BW，然后每周测量一次，直至试验结束。在所有 3 个实验中，在第 21 天至第 23 天急性 NE 疾病期间观察到 BW 下降（p<0.05），并且还观察到在 NE 疾病期间 BW 增益受到负面影响（p<0.05）。EM+CP 双重感染模型以及高剂量 CP 仅感染组中最明显地检测到对 BW 的长期影响。在这些情况下，BW 受到长期影响，需要一周或更长时间才能恢复到与未感染对照相似的 BW。BW 的分离虽然不显著，但在整个生长期间几乎与未感染对照平行，表明生长曲线发生了变化。除了显示各种形式的 NE 对肉鸡生长的长期影响外，这些生长曲线的变化还可以用于衡量处理措施对受 NE 影响的肉鸡的预防和恢复效果。
