The present study uses two differential extraction methods (sequential, maceration) to identify bioactive compounds present in two seaweeds Gracilaria folifera and Sargassum longifolium. Five different solvents namely Petroleum ether, Dichloromethane, Chloroform, ethanol and water were used. The bioactive compounds present in the extracts showed antioxidant and antibacterial activities against Aeromonas salmonicida. Ethanol and aqueous extracts of these seaweeds were found to have better antibacterial activity against bacterial diseases in fish when compared to the other extracts. Toxicological and in vivo pathogenicity studies were performed with the highest concentration of 250. mg/l of extracts. The compounds identified by GC-MS which were found to have antibacterial activity were prepared in the form of a colloidal suspension for oral treatment. The use of algal extracts in aquaculture disease management is a cost effective and eco-friendly approach. These extracts could be used as prophylactics. © 2015 Elsevier B.V.

Amitava Mukherjee

Centre for Nanobiotechnology

Vellore Campus

John Thomas

Chandra Sekaran N

Thanigaivel S

Vidhya Hindu 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.

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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

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

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

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.

Colloids and Surfaces B: Biointerfaces

Pathogenecity of Pseudomonas aeruginosa in Oreochromis mossambicus and treatment using lime oil nanoemulsion

Antioxidants are increasingly being recommended because they act directly on oxidative processes and may prevent diseases and problems associated with disease control and aging. Therefore, there is a constant search for antioxidants from natural sources for the isolation of antioxidant biomolecules. Seaweeds are an excellent source of natural antioxidant bioactive compounds which can be used as dietary supplements or as antioxidants in controlling bacterial infection in aquaculture farms as well as in the food industry. A great deal of effort has therefore focused on using available techniques to identify natural antioxidants from seaweeds. The aim of the present study was to analyse the bioactive compounds extracted from ethanol extract of the seaweed Chaetomorpha antennina by GC-MS study and to evaluate its antioxidant and antibacterial activities for controlling bacterial infection in shrimp pathogens through immersion and intramuscular infection study. The antioxidant activity of the selected seaweed was estimated in order to evaluate the efficiency of its ethanol extract since this will help in finding novel bioactive compounds with antioxidant & radical scavenging properties, which in turn can reveal the unexploited properties of this seaweed which could be used in the food and pharmaceutical industry. © 2014 Elsevier B.V.

Antioxidant and antibacterial activity of Chaetomorpha antennina against shrimp pathogen Vibrio parahaemolyticus

Use of plant extracts in fish aquaculture as an alternative to chemotherapy: Current status and future perspectives

Electronic Journal of Biotechnology

Novel antimicrobial activity of a dichloromethane extract obtained from red seaweed Ceramium rubrum (Hudson) (Rhodophyta: Florideophyceae) against Yersinia ruckeri and Saprolegnia parasitica, agents that cause diseases in salmonids

Journal of Animal Physiology and Animal Nutrition

Aquaculture and stress management: a review of probiotic intervention

Differential solvent extraction of two seaweeds and their efficacy in controlling Aeromonas salmonicida infection in Oreochromis mossambicus: A novel therapeutic approach

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