Evaluation of medicinal plants and colloidal silver efficiency against Vibrio parahaemolyticus infection in Litopenaeus vannamei cultured at low salinity

Abstract

In shrimp aquaculture, reduction in the use of synthetic antibiotics is a priority due to the high incidence of resistant bacteria (Vibrio) in the white shrimp Litopenaeus vannamei. An increasing number of studies show bactericidal activity of natural treatments in aquaculture. The effectiveness of neem (Azadirachta indica) and oregano (Lippia berlandieri) aqueous extracts and colloidal silver against V. parahaemolyticus were evaluated in low salinity shrimp culture. Results show that aqueous extracts of oregano and neem each present a minimum inhibitory concentration (MIC) of 62.50 mg ml −1 and inhibitory halos of 12.0 to 19.0 mm. Colloidal silver gave a MIC of 2 mg ml −1 , and the inhibitory halos were found to be between 11.8 and 18.8 mm, depending on treatment concentrations. An in vivo challenge test was conducted on white shrimp postlarvae cultured at low salinity (5 practical salinity units, PSU), and a significant increase (p < 0.05) in survival was demonstrated in the presence of the aqueous extracts (oregano 64%, neem 76% and colloidal silver 90%), when compared to the control (0%) in the challenge test. However, no significant differences were ob served between treatments, suggesting that they all act as alternative bactericidal source agents against V. parahaemolyticus infections for L. vannamei postlarvae when cultured at 5 PSU.KEY WORDS: Neem · Oregano · Colloidal silver · Vibrio parahaemolyticus · White shrimp · EMS · Acute hepatopancreatic necrosis syndrome · AHPNS Resale or republication not permitted without written consent of the publisherDis Aquat Org 122: [57][58][59][60][61][62][63][64][65] 2016 organisms for human consumption (Mioso et al. 2014).For over 2000 yr, medicinal plants have been used to combat pathogenic agents, and within the last decades, studies have focused on natural alternatives that can be employed as bactericidal treatment in aquaculture (Torres et al. 2007, Ramírez & Marín-Castaño 2009, García-Aguilar 2013.To transform a medicinal plant for conventional medical use, the most common procedures are infusion and decoction to extract the active substances from the vegetable tissues. When the water ebullition point (100°C) is reached and the water makes contact with fresh or dry plants, the vegetable cells explode and discharge active substances. The scientific term for this is 'aqueous extracts', and the principal advantage of using this preparation method is provision of easy and fast in situ preparations (Citarasu 2010).One plant considered an alternative medicine in aquaculture is neem Azadirachta indica; its principal active metabolite is nortriterpenoide (also known as azadiractine) with the presence of limonoides, which are structurally related and are biologically active (Hammer et al. 1999, López-Pantoja et al. 2007, Banerjee et al. 2013, Dhama et al. 2013a,b, Peña-Navarro et al. 2013. Another plant for consideration is oregano Lippia berlandieri Schauer, which possesses thymol and carvacrol as its bio active substances, which both show significant b...

The Potential Pharmacological and Medicinal Properties of Neem (Azadirachta indica A. Juss) in the Drug Development of Phytomedicine

“…Neem leaf extract is reported for a long term oral use for the treatment of malaria in India [4,11]. Clinical trials are in progress to investigate the efficacy of neem extract in the control of hyperlipidemia in a cohort of malarial patients severely infected with P. falciparum [4,17]. The cholesterol level in this study was found to be lower during therapy when compared to non-malaria patients [10].…”

“…They are effectively use in the treatment of fungal, bacterial, and in a lesser extend viral infections. Uses as anti-malaria, treatment for fever, arthritis, rheumatism, and many more is also common in India [7,16,17]. Neem bioactive molecules have also been used as a good protective substance for pests, as insect repellant and insecticide environmentally friendly, safe and harmless to humans [17].…”

“…Uses as anti-malaria, treatment for fever, arthritis, rheumatism, and many more is also common in India [7,16,17]. Neem bioactive molecules have also been used as a good protective substance for pests, as insect repellant and insecticide environmentally friendly, safe and harmless to humans [17]. Neem oil is effective when externally applied to the hair, scalp, and skin as anti-parasites and as an insect repellant [17].…”

“…Neem bioactive molecules have also been used as a good protective substance for pests, as insect repellant and insecticide environmentally friendly, safe and harmless to humans [17]. Neem oil is effective when externally applied to the hair, scalp, and skin as anti-parasites and as an insect repellant [17]. It is also used in most situation in Africa for aromatherapy, massage on rheumatoid arthritis pain relieve and other inflammations [3,19].…”

Evaluation of a new Argovit as an antiviral agent included in feed to protect the shrimpLitopenaeus vannameiagainst White Spot Syndrome Virus infection

“…Several studies have evaluated the effectiveness of AgNPs in aquatic diseases control because to their antimicrobial potential against bacteria, virus and parasites (Barakat, El-Sayed & Gohar, 2016;Morales-Covarrubias et al, 2016;Acedo-Valdez et al, 2017;Pimentel-Acosta et al, 2019). However, this is the first work that examine the efficacy of Argovit-4 (AgNPsbased formulation) as a potential antiviral additive in feed to protect the health of shrimp L. vannamei against WSSV.…”