Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt.
Polymers and Pigments Department, National Research Centre, 33 El-Buhouth St, Dokki, Cairo, Egypt.
BMC Vet Res. 2023 Aug 1;19(1):103. doi: 10.1186/s12917-023-03632-1.
Salmonella Enteritidis (SE) propagates in chickens' gastrointestinal surfaces and is transmitted to humans, causing food poisoning. Oral supplementation with natural nanoparticles can overcome the harsh gastrointestinal conditions facing oral vaccines and requires no antibiotic administration to protect against microbial infection. This study was designed to study Nigella sativa-chitosan nanoparticles (CNP-NS) prophylactic immunomodulatory efficacy against SE infection in broiler chicks. The CNP-NS was prepared and characterized, and its in vivo immunomodulatory activities against an avian virulent-MDR SE-induced challenge in chicks were investigated.
To verify the immune-protective activities of the CNP-NS, colony forming units (CFU) in the liver and fecal droppings; intestinal histopathological alterations and immune cell recruitment; MUC-2, TLR-4, cecal cytokines, and specific IgA gene expression levels were assessed. On the 7th and 12th days after the SE challenge, the CNP-NS supplemented chicks showed complete clearance of SE CFU in livers and fecal droppings, as well as an improvement in food conversion rate compared to non-supplemented CNP-NS that revealed the presence of the challenge SE CFU on the same days. A prominent influx of antigen presenting cells and lymphoid aggregates into the intestinal wall, spleen, and liver was detected with improvements in the intestinal villi morphometry of the CNP-NS-supplemented chicks. The changes of INF-γ, IL-1β, and IL-4 cecal cytokines, as well as TLR-4, MUC-2, and IgA mRNA expression levels, confirm CNP-NS immunomodulatory activities and provide a mechanism(s) for its protective actions against the induced SE challenge of the tested chickens.
These findings suggest promising useful insights into CNP-NS supplementation as a safe food additive for poultry meat consumers' and a protective immunomodulator of the chickens' mucosal immune systems. It could be recommended for epidemiological purposes to reduce the risk of SE food poisoning and transmission to humans.
肠炎沙门氏菌（SE）在鸡的胃肠道表面繁殖，并传播给人类，导致食物中毒。口服补充天然纳米颗粒可以克服口服疫苗面临的恶劣胃肠道条件，并且不需要抗生素管理来预防微生物感染。本研究旨在研究黑种草-壳聚糖纳米颗粒（CNP-NS）对肉鸡沙门氏菌感染的预防免疫调节功效。制备并表征 CNP-NS，并研究其对鸡中禽毒力-MDR SE 诱导的攻毒的体内免疫调节活性。
为了验证 CNP-NS 的免疫保护活性，评估了肝和粪便中的菌落形成单位（CFU）；肠道组织病理学改变和免疫细胞募集；MUC-2、TLR-4、盲肠细胞因子和特异性 IgA 基因表达水平。在 SE 攻毒后的第 7 天和第 12 天，补充 CNP-NS 的鸡清除了肝脏和粪便中的 SE CFU，与未补充 CNP-NS 的鸡相比，饲料转化率得到了提高，而未补充 CNP-NS 的鸡在同一时间显示出攻毒 SE CFU 的存在。在补充 CNP-NS 的鸡中，肠壁、脾脏和肝脏中抗原呈递细胞和淋巴样聚集物的明显涌入，以及肠绒毛形态计量学的改善。补充 CNP-NS 的鸡盲肠细胞因子 INF-γ、IL-1β 和 IL-4 以及 TLR-4、MUC-2 和 IgA mRNA 表达水平的变化，证实了 CNP-NS 的免疫调节活性，并为其对试验鸡 SE 诱导攻毒的保护作用提供了机制。
这些发现为 CNP-NS 作为家禽肉消费者的安全食品添加剂和鸡黏膜免疫系统的保护性免疫调节剂提供了有希望的有用见解。它可以推荐用于流行病学目的，以降低 SE 食物中毒和向人类传播的风险。
