Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
Department of Animal Hygiene, Faculty of Veterinary Medicine, Assiut University, Assiut 71526, Egypt.
Poult Sci. 2019 Oct 1;98(10):4408-4415. doi: 10.3382/ps/pez246.
The aim of this study was to examine the effect of a dietary synbiotic supplement on the cecal microflora, antioxidant status, and immune response of broiler chickens under heat stress (HS). A total of 360 one-day-old male Ross 708 broiler chicks were randomly distributed among 3 dietary treatments containing a synbiotic (PoultryStar consists of Bifidobacterium animalis, Enterococcus faecium, Lactobacillus reuteri, Pediococcus acidilactici, and fructooligosaccharides) at 0 (control), 0.5 (0.5X), and 1.0 (1.0X) g/kg. Each treatment contained 8 replicates of 15 birds each housed in floor pens. Heat stimulation was at 32°C for 9 h daily from day 15 to 42. Heat stress-induced changes of cecal bacteria were detected using bacteria-specific agars, and spleen protein concentration and mRNA expression of interleukins and antioxidants were examined using ELISA and real-time PCR, respectively. Under the HS condition, synbiotic fed broilers regardless of dose had lower cecal enumerations of Escherichia coli and coliforms, and a lower heterophil/lymphocyte (H/L) ratio (P < 0.05) compared to controls. 1.0X group also had higher cecal enumerations of Bifidobacterium spp. and Lactobacillus spp., spleen glutathione peroxidase (GPx), and plasma nuclear factor erythroid 2-related factor 2 (Nrf-2), and a lower H/L ratio compared to both control and 0.5X groups (P < 0.05). However, there were no treatment effects on the levels of Enterococcus spp., the circulating monocytes, eosinophils, and basophils, Toll like receptor-4 (TLR-4), interleukin-6 (IL-6), interlukin-10 (IL-10), and their mRNA expression, as well as plasma Kelch-like ECH-associated protein 1 (Keap-1) (P > 0.05). These results suggest that the synbiotic could inhibit the negative effects of HS on broiler health through the reduction of cecal pathogens, regulation of stress reactions, and improvement of antioxidant status.
本研究旨在探讨日粮合生元补充剂对热应激（HS）下肉鸡盲肠微生物群、抗氧化状态和免疫反应的影响。将 360 只 1 日龄雄性罗斯 708 肉鸡随机分为 3 种日粮处理组，分别添加 0（对照组）、0.5（0.5X）和 1.0（1.0X）g/kg 的合生元（PoultryStar 由双歧杆菌、屎肠球菌、鼠李糖乳杆菌、嗜酸乳杆菌和低聚果糖组成）。每个处理组包含 8 个重复，每个重复包含 15 只鸡，饲养在地板笼中。从第 15 天到第 42 天，每天对鸡进行 9 小时 32°C 的热刺激。使用细菌特异性琼脂检测盲肠细菌的变化，使用 ELISA 和实时 PCR 分别检测脾脏蛋白浓度和白细胞介素和抗氧化剂的 mRNA 表达。在 HS 条件下，无论剂量如何，添加合生元的肉鸡盲肠中大肠杆菌和大肠菌群的计数较低，异嗜性粒细胞/淋巴细胞（H/L）比值较低（P<0.05）。与对照组相比，1.0X 组盲肠双歧杆菌和乳酸杆菌的计数较高，脾脏谷胱甘肽过氧化物酶（GPx）和血浆核因子红细胞 2 相关因子 2（Nrf-2）较高，H/L 比值较低（P<0.05）。然而，处理对肠球菌、循环单核细胞、嗜酸性粒细胞和嗜碱性粒细胞、Toll 样受体 4（TLR-4）、白细胞介素 6（IL-6）、白细胞介素 10（IL-10）及其 mRNA 表达以及血浆 Kelch 样 ECH 相关蛋白 1（Keap-1）水平没有影响（P>0.05）。这些结果表明，合生元可以通过减少盲肠病原体、调节应激反应和改善抗氧化状态来抑制 HS 对肉鸡健康的负面影响。
