Department of Animal Science and Aquaculture, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada.
Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada.
Poult Sci. 2023 Aug;102(8):102723. doi: 10.1016/j.psj.2023.102723. Epub 2023 Apr 15.
The poultry industry has not been spared from the prevalent incidence of diseases caused by invasive pathogens, especially Salmonella. Due to the pressing need to identify a suitable antibiotic alternative for use in poultry production, this study investigated the efficacy of red osier dogwood (ROD) extract on the growth, blood parameters, gut morphology, and Salmonella excretion in broiler chickens orally challenged with Salmonella Enteritidis (SE). A 4 × 2 factorial experiment was conducted based on 2 main factors, namely dietary treatments, and SE challenge. A total of 404, one-day-old male Ross broiler chicks were randomly assigned to 4 dietary treatments; 1) Negative control (NC), 2) NC + 0.075 ppm of Trimethoprim-sulfadiazine (TMP/SDZ)/kg of diet, 3) NC + 0.3% ROD extract, and 4) NC + 0.5% ROD extract. The absence of SE in the fecal samples obtained from chick delivery boxes was confirmed on d 0. On d 1, half of the birds were orally gavaged with 0.5 mL of phosphate-buffered saline each (noninfected group) and the remaining with 0.5 mL of 3.1 × 10 CFU/mL SE (infected group) in all treatment groups. Dietary treatments were randomly assigned to 8 replicate cages at 6 birds/cage. On 1-, 5-, 12-, and 18-day postinfection (DPI), cloacal fecal samples were collected on the 6 birds/cage to assess SE excretion. Average weight gain (AWG), average feed intake (AFI), feed conversion ratio (FCR), and mortality were determined weekly. On d 21, 10 chickens/treatment were euthanized to perform hematology, gut histomorphometry, serum immunoglobulins G and M (IgG and IgM), and superoxide dismutase measurements. Both ROD extract levels did not affect (P > 0.05) growth performance; however, the SE-infected birds showed increased (P < 0.05) AFI and FCR throughout the experimental period. Regardless of the SE-infection, both ROD extract levels improved (P < 0.05) duodenal villus height: crypt depth compared to other treatments. 0.5% ROD extract improved (P < 0.05) ileal villus width (VW) of noninfected birds and ileal crypt depth of infected birds, but it decreased (P < 0.05) the ileal VW of infected birds, compared to other treatments. The SE-infected birds showed lower (P < 0.05) lymphocytes (L) but increased (P < 0.05) heterophils (H), H:L, and monocytes (MON). Both ROD extract levels did not affect (P > 0.05) white blood cell differential, while dietary 0.3% ROD extract increased (P < 0.05) MON of the birds, regardless of infection model. Regardless of infection model, both TMP/SDZ and 0.5% ROD extract reduced the concentration of IgM in the serum, compared to the control and 0.3% ROD (P = 0.006). Conclusively, both ROD extract levels improved duodenal histomorphology and body defense against SE infection in broiler chickens; however, the 0.3% ROD extract was better.
家禽业也未能幸免于由入侵病原体引起的疾病的普遍发生，特别是沙门氏菌。由于迫切需要确定一种适合家禽生产的替代抗生素，本研究调查了红瑞木（ROD）提取物对经口感染肠炎沙门氏菌（SE）的肉鸡生长、血液参数、肠道形态和 SE 排泄的影响。本研究基于 2 个主要因素，即饮食处理和 SE 挑战，进行了 4×2 因子实验。总共将 404 只 1 日龄雄性罗斯肉鸡随机分配到 4 种饮食处理中；1）阴性对照（NC），2）NC+0.075 ppm 甲氧苄啶-磺胺嘧啶（TMP/SDZ）/kg 日粮，3）NC+0.3% ROD 提取物，和 4）NC+0.5% ROD 提取物。在 d 0 时，从雏鸡交付箱中获得的粪便样本中确认无 SE。在 d 1 时，一半的鸡用 0.5 mL 磷酸盐缓冲盐水（非感染组），其余的鸡用 0.5 mL 3.1×10 CFU/mL SE（感染组）经口灌胃。所有处理组的饮食处理均随机分配到 8 个重复笼中，每笼 6 只鸡。在感染后 1、5、12 和 18 天（dpi），对每笼 6 只鸡进行直肠粪便采样，以评估 SE 的排泄量。每周测定平均增重（AWG）、平均采食量（AFI）、饲料转化率（FCR）和死亡率。在 d 21，10 只鸡/处理被安乐死，以进行血液学、肠道组织形态学、血清免疫球蛋白 G 和 M（IgG 和 IgM）和超氧化物歧化酶的测量。两种 ROD 提取物水平均不影响（P>0.05）生长性能；然而，感染 SE 的鸡在整个实验期间表现出增加的（P<0.05）AFI 和 FCR。无论 SE 是否感染，两种 ROD 提取物水平均改善（P<0.05）十二指肠绒毛高度：与其他处理相比，隐窝深度。0.5%ROD 提取物提高了（P<0.05）非感染鸡的回肠绒毛宽度（VW）和感染鸡的回肠隐窝深度，但降低了（P<0.05）感染鸡的回肠 VW，与其他处理相比。感染 SE 的鸡表现出较低的（P<0.05）淋巴细胞（L），但增加的（P<0.05）异嗜性白细胞（H）、H：L 和单核细胞（MON）。两种 ROD 提取物水平均不影响（P>0.05）白细胞分类，而日粮 0.3%ROD 提取物增加了（P<0.05）感染模型中鸡的 MON。无论感染模型如何，TMP/SDZ 和 0.5%ROD 提取物均降低了血清中 IgM 的浓度，与对照组和 0.3%ROD 相比（P=0.006）。综上所述，两种 ROD 提取物水平均改善了肉鸡的十二指肠组织形态学和对 SE 感染的机体防御；然而，0.3%ROD 提取物的效果更好。
