Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", University of Murcia, 30100, Murcia, Spain.
Institute of Microbiology and Parasitology, Universidad Autónoma de Santo Domingo (IMPA-UASD), Alma Máter, Santo Domingo, 10103, Dominican Republic.
J Ethnopharmacol. 2020 Sep 15;259:112838. doi: 10.1016/j.jep.2020.112838. Epub 2020 May 6.
Due to the intensification practices in global aquaculture, fish are often confined in small volumes, which can results in outbreak diseases. In this context, the use of antibiotics is very usual. Thus, looking for natural substance able to reduce the use of the antibiotics is imperative. Among them, there is a great interest at present in the study of medicinal plants such as guava (Psidium guajava L.). These plants could help to develop a more sustainable aquaculture all over the world. The application of guava in traditional medicine dates for centuries and it is widely used in tropical countries for the treatment of diseases in human and animals.
The purpose of this work was to study the effects of the dietary administration of dried leaves of Psidium guajava on the skin mucosal immunity of hybrid tilapia (Oreochromis niloticus × O. mossambicus). Furthermore, the ability of this plant to inhibit the bacterial load in different tissues after an experimental infection with Vibrio harveyi was studied.
P. guajava leaves collection and the experimentation was carried out in Dominican Republic. Fish were fed with a commercial diet supplemented with guava leaf at different concentrations (0%, 1.5% and 3%) for 21 days before being intraperitoneally injected with V. harveyi (1 × 10 cells mL). Thereafter, several immune activities were measured in fish skin mucus and after 48 h of injection, the skin, spleen and liver were collected to analyse the bactericidal activity of guava leaf and the gene expression of some immune related genes.
The administration of P. guajava leaves significantly modulated some immune-related enzymes (protease, antiprotease and peroxidase) in the skin mucus of hybrid tilapia. In addition, the bacterial load after V. harveyi infection in skin, spleen and liver significantly reduced in fish supplemented with guava leaves. Finally, the expression profile of hepcidin gene in skin and liver was modulated in fish feed with control diet after V. harveyi infection.
These results demonstrate that the dietary intake of guava leaves increases the skin mucosal barrier defences of hybrid tilapia and confers protection against V. harveyi colonization.
由于全球水产养殖集约化实践的加强，鱼类经常被限制在小体积中，这可能导致爆发疾病。在这种情况下，抗生素的使用非常普遍。因此，寻找能够减少抗生素使用的天然物质是当务之急。其中，目前人们对番石榴（Psidium guajava L.）等药用植物的研究非常感兴趣。这些植物可以帮助在全世界发展更可持续的水产养殖。番石榴在传统医学中的应用已有几个世纪的历史，在热带国家被广泛用于治疗人类和动物的疾病。
本研究的目的是研究日粮中添加番石榴干叶对杂交罗非鱼（奥利亚罗非鱼×奥利亚莫桑比克罗非鱼）皮肤粘膜免疫的影响。此外，还研究了这种植物在经哈维弧菌实验感染后抑制不同组织中细菌负荷的能力。
番石榴叶的采集和实验在多米尼加共和国进行。鱼用商业饲料喂养，饲料中添加不同浓度（0%、1.5%和 3%）的番石榴叶喂养 21 天，然后用哈维弧菌（1×10 个细胞 mL）经腹腔注射。此后，测量鱼皮粘液中的几种免疫活性，注射后 48 小时，采集皮肤、脾脏和肝脏，分析番石榴叶的杀菌活性和一些免疫相关基因的表达。
番石榴叶的给药显著调节了杂交罗非鱼皮肤粘液中的一些免疫相关酶（蛋白酶、抗蛋白酶和过氧化物酶）。此外，在感染哈维弧菌后，添加番石榴叶的鱼的皮肤、脾脏和肝脏中的细菌负荷显著减少。最后，在感染哈维弧菌后，对照组鱼的皮肤和肝脏中的铁调素基因表达谱发生了调节。
这些结果表明，日粮中摄入番石榴叶可增强杂交罗非鱼的皮肤粘膜屏障防御能力，并赋予其抵抗哈维弧菌定植的保护作用。
