Desert Research Center, Mataria, Cairo, Egypt.
Biological Applications Department, Nuclear Research Center, Egyptian Atomic Energy Authority, Abu-Zaabal, 13759, Egypt.
Trop Anim Health Prod. 2021 Jan 12;53(1):115. doi: 10.1007/s11250-021-02554-0.
Heat stress, one of the critical obstacles to poultry sector in subtropical and tropical countries, reduces performance, immune response, and animal welfare. This study examined the effect of dietary inclusion of probiotic (PRO), citric acid (CIT), garlic powder (GAR) or their combinations on growth, blood constituents, ileal microflora and morphology and humoral immunity of broiler chickens subjected to cyclic heat stress. Four hundred ninety one-day-old Ross-308 broiler chicks were randomly allocated to 7 groups with 7 replicates of 10 birds each as follows: control (C) group received the basal diet without supplements, PRO, CIT and GAR groups supplemented with 0.5 g kg multi-strain probiotic mixture (MPM), citric acid and garlic powder, respectively. PRO-CIT and PRO-GAR groups treated with 0.5 g kg MPM, and 0.5 g kg citric acid and garlic powder, while CIT-GAR group fed diet with 0.5 g kg of citric acid and garlic powder. Results revealed that dietary supplements and their combinations improved (P < 0.001) growth performance and decreased abdominal fat of heat-stressed birds. Dietary supplements decreased (P < 0.01) serum concentrations of cholesterol, triglycerides and LDL, while HDL was elevated (P < 0.05). Feed additives reduced (P < 0.01) ileal enumeration of Escherichia coli and total coliform while Lactobacillus count was increased (P < 0.05) only in MPM-enriched groups. Supplementation of these natural products improved (P < 0.01) ileal architecture while humoral immune response was not significantly influenced except antibody titre against Newcastle disease virus which was increased (P < 0.05) in MPM-supplemented groups. Conclusively, addition of the dietary supplements and their combinations, particularly, probiotic and citric acid combination can improve productive performance, and intestinal flora and histomorphometry of broilers exposed to cyclic heat stress.
热应激是亚热带和热带国家家禽业的主要障碍之一，它会降低家禽的生产性能、免疫反应和动物福利。本研究探讨了在周期性热应激条件下，日粮中添加益生菌（PRO）、柠檬酸（CIT）、大蒜粉（GAR）或它们的组合对肉鸡生长性能、血液成分、回肠微生物区系和形态以及体液免疫的影响。将 491 日龄罗斯 308 肉鸡随机分为 7 组，每组 7 个重复，每个重复 10 只鸡，如下所示：对照组（C）饲喂基础日粮，不添加任何补充剂；PRO、CIT 和 GAR 组分别在基础日粮中添加 0.5 g/kg 多菌株益生菌混合物（MPM）、柠檬酸和大蒜粉；PRO-CIT 和 PRO-GAR 组在基础日粮中添加 0.5 g/kg MPM 和 0.5 g/kg 柠檬酸和大蒜粉；CIT-GAR 组在基础日粮中添加 0.5 g/kg 柠檬酸和大蒜粉。结果表明，日粮补充剂及其组合提高了（P<0.001）热应激鸡的生长性能，降低了腹部脂肪含量。日粮补充剂降低了（P<0.01）血清胆固醇、甘油三酯和 LDL 浓度，而高密度脂蛋白（HDL）升高（P<0.05）。饲料添加剂降低了（P<0.01）回肠大肠杆菌和总大肠菌群的计数，而仅在 MPM 富集组中乳酸杆菌的计数增加（P<0.05）。这些天然产物的添加改善了（P<0.01）回肠形态结构，而体液免疫反应除了新城疫病毒抗体滴度增加（P<0.05）外，没有显著影响，仅在添加 MPM 的组中增加。总之，添加日粮补充剂及其组合，特别是益生菌和柠檬酸组合，可以提高处于周期性热应激下的肉鸡的生产性能、肠道菌群和组织形态学。
