Clarias batrachus (Linn) is a species of catfish of the family claridae. Pathogenecity of Aeromonas salmonicida was studied in healthy fish. The inoculum was injected into healthy fingerlings through intramuscular injection and immersion challenge. Histopathological investigation of the infected organs was also studied. The bacterial infection was treated using neem nanoemulsion by in vitro and in vivo analysis and was found to be effective. © 2013 Elsevier B.V.

John Thomas

Centre for Nanobiotechnology

Vellore Campus

Chandra Sekaran N

Amitava Mukherjee

Jerobin J

Seelan T.S.J

Thanigaivel S

Vijayakumar S

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

Aquaculture

Sea weeds are valuable natural assets in aquaculture due to the presence of various bioactive active metabolites in them. Successful fish production and maintenance of disease free culturing systems in aquaculture with environment friendly practices is often affected by various environmental factors. Disease causing pathogens is one of the major factors. These can be controlled by the emerging technologies such as biopolymer based drug delivery systems, feed encapsulations processes and immersions of active ingredients which can possibly facilitate sustainable production by enhancing growth and immune responses in aquaculture animals. The focus of our study is on the identification of antibacterial and antioxidant compounds from two brown seaweeds, Gracilaria foliifera and Sargassum longifolium which have proven bioactive compounds. By a process of microencapsulation these bioactive compounds were encapsulated in the form of beads. Sodium caseinate and xanthan gum were mixed together to form the beads. This process helps to retain and protect the bio active ingredients from adverse reactions such as oxidation and nutritional deterioration. These microencapsulated beads were administered orally to 10 Oreochromis mossambicus the experimental fishes, with average body weight of 10-12 g and challenged against the pathogenic bacteria Aeromonas salmonicida to assess their antibacterial efficacy to control this bacterial pathogen. Microencapsulated bio active compounds were further characterized by FT-Raman, GC-MS, NMR, HPLC and SEM analysis. In this study, the effects of combined formulations of the different bioactive compounds were determined. Data obtained from the treatment of A. salmonicida infection in O. mossambicus using formulated bioactive compounds obtained from these seaweeds showed very high survival percentage in this species of fish.

Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology

Protective efficacy of microencapsulated seaweed extracts for preventing Aeromonas infections in Oreochromis mossambicus

The present study deals with the preparation and optimisation of neem oil nanoemulsion by microfluidization process and its application for the bacterial infection management in aquaculture. The effect of process parameters like surfactant concentration (Tween 20, Tween 80), homogenisation pressure and the number of cycles on the droplet size of neem oil nanoemulsion was investigated. The optimized pressure and number of cycles for the neem oil nanoemulsion preparation was found to be 20,000 psi and 25 cycles respectively. A significant decrease (p &lt; 0.05) in the particle size of neem oil nanoemulsion was observed as the pressure, number of cycles and concentration of surfactant increase. The neem oil nanoemulsion prepared using 1:3 ratio of neem oil and Tween 80 surfactant showed a good stability with a mean droplet size of 24.5 ± 1.33 nm. The concentration of Azadiractin, an active ingredient in neem oil nanoemulsion was found to be 21.187 ± 1.01 μg/mL. The 1:3 ratio of neem oil - Tween 80 formulated nanoemulsion showed good antibacterial activity against the fish pathogen, Aeromonas culicicola (MIC of 0.93 μl/mL). The morphological changes inflicted by the neem nanoemulsion treatment on bacterial cells were evident from the scanning electron microscopy and membrane integrity analysis. Further, the In-vivo bactericidal efficacy of the neem oil nanoemulsion was tested on Common carp (Cyprinus carpio). The neem oil nanoemulsion treatment exhibited protective action against Aeromonas culicicola infection and it improved the antioxidant defence system of fish. The above results envisage the use of neem oil nanoemulsion as a potential alternative for synthetic antibiotics in treatment of bacterial infection of the fish. Copyright © 2018 John Wiley &amp; Sons, Ltd.

Flavour and Fragrance Journal

Nanometric neem oil emulsification through microfluidization, and its therapeutic potential againstAeromonas culicicolainfection inCyprinus carpio

The development of resistance to antimicrobial agents has been the major concern in the aquaculture industry. Essential oil nanoemulsions can be an effective alternative to the synthetic antimicrobial compounds, as they are efficient and safer to the environment. This study deals with the formulation, characterisation, application and biosafety of the black pepper oil nanoemulsion prepared using high-pressure homogenization method. A stable formulation of black pepper oil nanoemulsion was obtained with the oil and surfactant (Tween 80) ratio of 1:2. The mean droplet size and polydispersity index of the nanoemulsion was found to be 30.3 ± 2 nm and 0.21 respectively. The antibacterial activity of the black pepper oil nanoemulsion against the bacterial pathogen Pseudomonas aeruginosa as studied by microbroth dilution method was found to be 0.234 μl/ml. SEM analysis of the nanoemulsion treated bacterial cells showed significant membrane damage and the results were corroborative with the cell membrane integrity study. The MIC of black pepper oil nanoemulsion was found to be very effective in inhibiting the biofilm formation of P. aeruginosa (0.234 μl/ml) as evident from the Congo red dye reduction assay. Further the in vivo antibacterial efficacy of the black pepper oil nanoemulsion was tested on the shrimp (Penaeus monodon) and the MIC value of (0.234 μl/ml) was found effective in controlling the bacterial infection. Biosafety studies of blackpepper oil nanoemulsion on Artemia salina reveals the nontoxic nature of formulated nanoemulsion. The above findings envisage that black pepper oil nanoemulsion can be used as a potent antimicrobial agent for the control of bacterial infections in aquaculture industry. © 2018 Elsevier B.V.

Antimicrobial potency of high-energy emulsified black pepper oil nanoemulsion against aquaculture pathogen

Indigenous marine seaweeds and their biological activities have played a significant role in aquaculture especially with regard to their antibacterial and antiviral properties. The bioactive compounds and the toxicity profile of aqueous and ethanol extracts of Padina gymnospora and Sargassum cinereum species were assessed for the treatment of bacterial infection. The optimum exposure to seaweed extracts varied with different concentrations, from 100mg/l to 500mg/l of dried solvent extracts dispersed in 10l of water. It was found to be non-toxic up to 250mg/l. Oreochromis mossambicus infected with Pseudomonas aeruginosa showed abnormal activities like hyperactivity, lethargic movements, hemorrhagic lesions and exophthalmia, with LC 50 values of 1.287, 1.634 and 2.021mg/l for 72, 96, 120h respectively. They were exposed to sea weed extracts of different concentrations. Insignificant mortality was seen in the treated group. PCR and histopathological analysis were done. PCR studies were performed to study the distribution of P. aeruginosa in the tissues of different organs. The results revealed that PCR was positive for gills, while skin showed mild positive, which indicates the presence of the bacteria in these organs. The liver and the kidney were found to be negative.Statement of relevanceThe sea weed extracts are excellent source of antimicrobial compounds. These can be used for treating bacterial infection as an alternative to antibiotics which cause resistance. The extracts are found to be nontoxic and can be used in aquaculture industries for treating bacterial infection.

Investigation of seaweed extracts as a source of treatment against bacterial fish pathogen

Neem (Azadirachta indica) is recognized as a medicinal plant well known for its antibacterial, antimalarial, antiviral, and antifungal properties. Neem nanoemulsion (NE) (O/W) is formulated using neem oil, Tween 20, and water by high-energy ultrasonication. The formulated neem NE showed antibacterial activity against the bacterial pathogen Vibrio vulnificus by disrupting the integrity of the bacterial cell membrane. Despite the use of neem NE in various biomedical applications, the toxicity studies on human cells are still lacking. The neem NE showed a decrease in cellular viability in human lymphocytes after 24 hours of exposure. The neem NE at lower concentration (0.7-1 mg/mL) is found to be nontoxic while it is toxic at higher concentrations (1.2-2 mg/mL). The oxidative stress induced by the neem NE is evidenced by the depletion of catalase, SOD, and GSH levels in human lymphocytes. Neem NE showed a significant increase in DNA damage when compared to control in human lymphocytes (P,0.05). The NE is an effective antibacterial agent against the bacterial pathogen V. vulnificus, and it was found to be nontoxic at lower concentrations to human lymphocytes. © 2015 Jerobin et al.

Fulltext

International Journal of Nanomedicine

Antibacterial activity of neem nanoemulsion and its toxicity assessment on human lymphocytes in vitro

Azadirachtin a biological compound found in neem have medicinal and pesticidal properties. The present work reports on the encapsulation of neem oil nanoemulsion using sodium alginate (Na-Alg) by cross linking with glutaraldehyde. Starch and polyethylene glycol (PEG) were used as coating agents for smooth surface of beads. The SEM images showed beads exhibited nearly spherical shape. Swelling of the polymeric beads reduced with coating which in turn decreased the rate of release of Aza-A. Starch coated encapsulation of neem oil nanoemulsion was found to be effective when compared to PEG coated encapsulation of neem oil nanoemulsion. The release rate of neem Aza-A from the beads into an aqueous environment was analyzed by UV-visible spectrophotometer (214 nm). The encapsulated neem oil nanoemulsion have the potential for controlled release of Aza-A. Neem oil nanoemulsion encapsulated beads coated with PEG was found to be toxic in lymphocyte cells. © 2012 Elsevier Ltd. All rights reserved.

Journal	Data powered by TypesetAquaculture
Publisher	Data powered by TypesetElsevier BV
ISSN	0044-8486
Open Access	0