Evonik Corporation, 1701 Barrett Lakes Blvd., Kennesaw, GA, 30144.
Evonik Nutrition & Care GmbH, Rodenbacher Chaussee 4, 63457 Hanau-Wolfgang, Germany.
Avian Dis. 2020 Sep 1;64(3):379-385. doi: 10.1637/aviandiseases-D-19-00116.
Challenge models are needed to understand the pathogenesis of necrotic enteritis (NE) and provide the basis of evaluating nonantibiotic feed-additive interventions. In the category of nonantibiotic feed additives, the application of probiotics to improve intestinal health and growth performance of broiler chickens in the face of an NE challenge has been well described. However, it is crucial to evaluate the consistency of specific probiotics for mitigating the disease challenge and improving performance. Therefore, a meta-analysis of five independent research trials was conducted with the objective of evaluating the effect of Bacillus subtilis DSM 32315 (probiotic) on body weight gain (BWG), feed conversion ratio (FCR), NE mortality, and lesion score (LS) of broiler chickens challenged with NE. These independent studies were conducted in three countries (the United States, Thailand, and Finland). The statistical analysis used fixed and random effects to estimate the mean effect size (MES) of the difference between NE-challenged birds (control) and NE-challenged probiotic-fed birds and the 95% confidence interval of MES. A meta-regression was performed to evaluate heterogeneity (MES variance) among studies. The statistical analysis was performed using a robust variance estimation strategy with a SAS macro. Probiotic-supplemented birds had a significantly higher BWG (MES = 1.04, P = 0.009) and a significantly lower FCR (MES = -1.39, P = 0.020), NE mortality (MES = -1.15, P = 0.012), and LS (MES = -1.29, P = 0.045). Response variables of BWG (Q = 2.81, P = 0.560) and NE mortality (Q = 5.60, P = 0.354) did not present heterogeneity. Heterogeneity was found for FCR (Q = 10.34, P = 0.035) and LS (Q = 16.13, P = 0.001). Overall, dietary supplementation of B. subtilis DSM 32315 significantly improved BWG and reduced FCR, mortality, and LS in a repeatable large-scale manner.
需要建立模型来理解坏死性肠炎（NE）的发病机制，并为评估非抗生素饲料添加剂干预措施提供依据。在非抗生素饲料添加剂类别中，益生菌的应用已被很好地描述为改善肉鸡的肠道健康和生长性能，以应对 NE 挑战。然而，评估特定益生菌减轻疾病挑战和提高性能的一致性至关重要。因此，进行了五项独立研究试验的荟萃分析，目的是评估枯草芽孢杆菌 DSM 32315（益生菌）对遭受 NE 挑战的肉鸡的体重增加（BWG）、饲料转化率（FCR）、NE 死亡率和病变评分（LS）的影响。这些独立的研究在美国、泰国和芬兰三个国家进行。统计分析采用固定和随机效应来估计 NE 挑战鸟类（对照）和 NE 挑战益生菌喂养鸟类之间差异的平均效应大小（MES）和 MES 的 95%置信区间。进行了荟萃回归分析以评估研究之间的异质性（MES 方差）。统计分析使用带有 SAS 宏的稳健方差估计策略进行。补充益生菌的鸟类的 BWG 显著增加（MES = 1.04，P = 0.009），FCR 显著降低（MES = -1.39，P = 0.020），NE 死亡率（MES = -1.15，P = 0.012）和 LS（MES = -1.29，P = 0.045）。BWG（Q = 2.81，P = 0.560）和 NE 死亡率（Q = 5.60，P = 0.354）的响应变量没有表现出异质性。FCR（Q = 10.34，P = 0.035）和 LS（Q = 16.13，P = 0.001）存在异质性。总的来说，枯草芽孢杆菌 DSM 32315 的日粮补充以可重复的大规模方式显著提高了 BWG，降低了 FCR、死亡率和 LS。
