Fish diseases caused by Pseudomonas aeruginosa, a known pathogenic organism, is responsible for considerable economic losses in the commercial cultivation of Oreochromis mossambicus (Tilapia). The bacteria were injected into healthy fish through intramuscular injection, oral and immersion challenge. Infection was confirmed by histopathological investigation of the infected organs. Lime nanoemulsion was prepared and the effectiveness of the nanoemulsion was studied both in vitro and invivo by well diffusion assay and invivo in the artificially infected fish. Results showed that the lime nanoemulsion was effective against the P. aeruginosa infection in O. mossambicus both in vitro and in vivo. © 2014 Elsevier B.V.

John Thomas

Centre for Nanobiotechnology

Vellore Campus

Amitava Mukherjee

Chandra Sekaran N

Thanigaivel S

Vijayakumar S

Acharya K

Shinge D

Seelan T.S.J

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.

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VIT University

Colloids and Surfaces B: Biointerfaces

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 aim of the present work was to isolate probiotic bacteria from the intestinal tract of healthy freshwater prawn Macrobrachium rosenbergii and to examine the effect of the isolated probiotic Bacillus vireti 01 in controlling Pseudomonas aeruginosa infection. This is probably the first report on the isolation of probiotic B. vireti 01 from the intestine of M. rosenbergii. The compounds present in B. vireti 01 were identified using GC-MS analysis. The effect of B. vireti 01-incorporated diet on survival and antioxidant enzymes was studied in M. rosenbergii for 2 weeks. Decreased mortality was observed in M. rosenbergii which were administered with the probiotic diet compared to control diet. The antioxidant defence enzymes activities such as SOD, catalase and GSH were analysed in various organs of M. rosenbergii probiotic-treated and control groups. Antioxidant enzyme activities were considerably lowered (p &lt; 0.01) in the muscles, hepatopancreas and gills of prawns infected by P. aeruginosa when compared to that of prawns fed with the probiotic-supplemented diet. The histopathological results suggest that the hepatopancreas, gills and muscles infected with P. aeruginosa were altered structurally. The result of the present work demonstrates that the probiotic B. vireti 01 could be used as a substitute to antibiotics for treating P. aeruginosa infection in prawns. © 2017, Springer Science+Business Media, LLC.

Probiotics and Antimicrobial Proteins

Effect of Dietary Supplementation of Novel Probiotic Bacteria Bacillus vireti 01 on Antioxidant Defence System of Freshwater Prawn Challenged with Pseudomonas aeruginosa

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.

Aquaculture

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

Aquaculture is one of the principal sources to increase the world's fish production. Outbreak of diseases is a major problem in aquaculture. Chemotherapeutic approaches have been used for the treatment and prevention of disease outbreaks. The use of various chemicals has harmful effects on the environment and human health. The prolonged use of antibiotics causes antibiotic resistance. Natural products such as medicinal plants, marine algae, herbs and their extracted compounds are being studied for disease management in fishes and prawns. In this review, the use of seaweeds and their importance in aquaculture health and disease management to control the bacterial infections against the pathogenic bacteria which affect freshwater fishes is explained. Application can either be by a single compound or a combination of two different compounds or as feed additives. Administering the compounds obtained from the extracts in the form of encapsulated beads was found to be more effective. Statement of relevance Seaweeds have good antioxidant capacity and act as a natural medicine. Bacterial fish pathogens affect the health of aquatic organisms. The bioactive compounds from sea weed extracts showed good antibacterial activity. They can be used for treating bacterial infection in aquaculture and as prophylactis. This kind of prophylactic treatment can be used as an alternative to synthetic since they cause resistance. © 2016 Elsevier B.V.

Seaweeds as an alternative therapeutic source for aquatic disease management

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.

Studies on pathogenecity of Aeromonas salmonicida in catfish Clarias batrachus and control measures by neem nanoemulsion

Background: Nanoemulsion composed of neem oil and non-ionic surfactant Tween 20, with a mean droplet size ranging from 31.03 to 251.43 nm, was formulated for various concentrations of the oil and surfactant. The larvicidal effect of the formulated neem oil nanoemulsion was checked against Culex quinquefasciatus. Results: O/W emulsion was prepared using neem oil, Tween 20 and water. Nanoemulsion of 31.03 nm size was obtained at a 1:3 ratio of oil and surfactant, and it was found to be stable. The larger droplet size (251.43 nm) shifted to a smaller size of 31.03 nm with increase in the concentration of Tween 20. The viscosity of the nanoemulsion increased with increasing concentration of Tween 20. The lethal concentration (LC 50) of the nanoemulsion against Cx. quinquefasciatus was checked for 1:0.30, 1:1.5 and 1:3 ratios of oil and surfactant respectively. The LC 50 decreased with droplet size. The LC 50 for the ratio 1:3 nanoemulsions was 11.75 mg L -1. Conclusion: The formulated nanoemulsion of 31.03 nm size was found to be an effective larvicidal agent. This is the first time that a neem oil nanoemulsion of this droplet size has been reported. It may be a good choice as a potent and selective larvicide for Cx. quinquefasciatus. © 2011 Society of Chemical Industry.

Journal	Data powered by TypesetColloids and Surfaces B: Biointerfaces
Publisher	Data powered by TypesetElsevier BV
ISSN	0927-7765
Open Access	0