Schothorst Feed Research, PO Box 533, 8200 AM Lelystad, the Netherlands.
Poult Sci. 2012 Mar;91(3):643-52. doi: 10.3382/ps.2011-01923.
The aim of this study was to determine the threonine requirement of broilers during a subclinical Clostridium infection. Three experiments were performed: experiments 1 and 2 to investigate the dose-response of threonine supplementation during infection and experiment 3 to validate the threonine requirement during infection. In each experiment, 1-d-old Ross 308 male broilers were used. An infection model was used with inoculation of Eimeria maxima and Clostridium perfringens at d 9 and 14 of age, respectively. Control birds were inoculated with saline and liver broth at d 9 and 14 of age, respectively. From d 9 of age, infected birds were fed diets differing in the standardized digestible threonine-to-lysine ratio (realized ratios experiment 1: 0.55, 0.58, 0.63, 0.69, and 0.72; realized ratios experiment 2: 0.64, 0.65, 0.67, 0.69, and 0.72; and realized ratios experiment 3: 0.63 and 0.67). Uninfected birds were fed diets with a realized Thr:Lys ratio of 0.63 in experiments 1 and 2 and of 0.63 or 0.67 in experiment 3. The incidence of lesions, lesion severity, and mortality rate of infected birds was not affected by the Thr:Lys ratio. Experiments 1 and 2 showed that the decrease in BW gain and feed intake was less severe in infected birds fed a diet with a Thr:Lys ratio of 0.69 and 0.67, respectively (not significant). Validation of the Thr:Lys ratio in experiment 3 showed that the BW gain and feed intake were higher for infected birds with a Thr:Lys ratio of 0.67 compared with infected birds with a Thr:Lys ratio of 0.63. This resulted in an increased BW gain and feed intake of 129 and 148 g, respectively, with a higher Thr:Lys ratio over a production period of 37 d. This indicates that a higher Thr:Lys ratio in infected birds improved production performance during infection with C. perfringens, although intestinal damage (incidence and lesion severity) was not affected.
本研究旨在确定感染梭菌后肉鸡对苏氨酸的需求。进行了三项实验：实验 1 和 2 研究了感染过程中苏氨酸补充的剂量反应，实验 3 验证了感染过程中的苏氨酸需求。在每个实验中，使用 1 日龄 Ross 308 雄性肉鸡。使用接种柔嫩艾美耳球虫和产气荚膜梭菌的感染模型，分别在 9 日龄和 14 日龄接种。对照组鸡分别在 9 日龄和 14 日龄接种生理盐水和肝肉汤。从 9 日龄开始，感染鸡饲喂不同标准化可消化苏氨酸与赖氨酸比值的日粮（实验 1 的实测比值：0.55、0.58、0.63、0.69 和 0.72；实验 2 的实测比值：0.64、0.65、0.67、0.69 和 0.72；实验 3 的实测比值：0.63 和 0.67）。未感染鸡在实验 1 和 2 中饲喂实测 Thr:Lys 比为 0.63 的日粮，在实验 3 中饲喂实测 Thr:Lys 比为 0.63 或 0.67 的日粮。感染鸡的病变发生率、病变严重程度和死亡率不受 Thr:Lys 比的影响。实验 1 和 2 表明，饲喂 Thr:Lys 比为 0.69 和 0.67 的日粮可降低感染鸡的 BW 增重和采食量下降的严重程度（无显著差异）。实验 3 验证了 Thr:Lys 比，结果表明，与 Thr:Lys 比为 0.63 的感染鸡相比，Thr:Lys 比为 0.67 的感染鸡 BW 增重和采食量更高。在 37 天的生产期内，Thr:Lys 比升高导致 BW 增重和采食量分别增加 129 和 148 g。这表明，感染鸡中较高的 Thr:Lys 比可改善感染产气荚膜梭菌后的生产性能，尽管肠道损伤（发生率和病变严重程度）不受影响。
