Research Symposium-2013
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Browsing Research Symposium-2013 by Subject "Aquatic Products"
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Item Antimicrobial Activity of Seagrss (Cymodocea serrulata) from South West Coast of Sri Lanka(Uva Wellassa University of Sri Lanka, 2013) Arulananthan, A.; De Silva, D. P. N.; Jayamanne, S. C.; Dalpatadu, S.L.; Senaratne, S. G.Sri Lanka has rich oceanic vegetation along its coastal water bodies. However, utilization of them is limited when compared to terrestrial plants which are used as natural alternatives especially in Ayurveda remedy. It is expected that marine vegetation also ensure the potential bioactivity. Marine plants derived natural products are known as secondary metabolites which are bioactive compounds responsible for antimicrobial activities. Documented results from most of the Atlantic, Pacific, and Indian Ocean resultant macro algae exhibits broad range of biological activities. Some of these are antibacterial, antifungal, antiviral etc. On the other hand, few literature are available on the therapeutic values of seagrasses in Sri Lanka. Therefore, the objective of this study was to test the antimicrobial activity of some selected seagrass species collected from the Beruwela beach rocky platforms and Hikkaduwa coast of Sri Lanka. Methodology Collection and preparation of samples - The fresh seagrass species (Cymodocea serrulata) was collected by hand picking during the low tidal conditions from the submerged rocky platforms of Barberrian reef and in Hikkaduwa coast. The collected vegetation was cleaned well with tap water and distilled water. Then the samples were drained and spread on the filter paper to remove excess water. Samples were chopped into nearly 1cm length pieces prior to grinding using liquid nitrogen. Solvent extraction - Coarsely powdered samples were subjected to solvent extraction by using chloroform, methanol and water solvents. The powdered form of samples and solvents were taken (1:10 w/v) and kept for 24 hours at room temperature (27 °C) in the orbital shaker at 150 rpm. Later, the extracts were filtered through a Buchner funnel with muslin cloth followed by Whatman number 1 filter paper. The resulting filtrates were concentrated by using rotary evaporator. Test microorganism - Human pathogenic Gram positive bacteria Staphylococcus aureus, Gram negative bacteria- Escherichia coli, and a fungal species Candida albicans were used to defeat the antimicrobial activity of C. serrulata. Antimicrobial susceptibility test - Antimicrobial activity of extracts was performed by using the disc diffusion method and agar well diffusion method. The stock solution was prepared with extract of 100 mg/ ml concentration of respective solvents. Sterile discs of 6 mm diameter were prepared in three different quantities (1 mg, 2 mg, and 5 mg). Each plate contained discs with three different quantities and negative control. Agar well diffusion method was carried with all extracts in same concentration as 100 mg/ ml in three different quantities (5 mg, 10 mg and 20 mg). In positive control Kanamycin 10 µl (3µg/ µl) was used for bacterial species and Flucanozole (1.25 µg/ µl) was used as antifungal agent. The plates were incubated overnight.Item Distribution and Abundance of Seaweeds at Polhena Reef-Matara(Uva Wellassa University of Sri Lanka, 2013) Ediriweera, A.N.; Jayamanne, S.C.Polhena reef is among the most valuable marine ecosystems existing along the southern coastal belt of Sri Lanka. The reef is a fringing coral reef and is highly diverse both in flora and fauna. It is well known as an ecosystem that has significant ecological and economical value. Senaratne et al. (2013) has indicated that the reef is exposed to anthropogenic activities and is disturbed to some extent. Coral reef is covered with seaweeds that belong to categories of green, brown and red. Seaweeds also play a major role as live feed, breeding grounds and as habitats for marine fauna existing in coral reef. It is also economically important as human food, animal feed, pharmaceutical, fodder, stationary and cosmetic production. Growth, distribution and abundance of seaweeds vary spatially, seasonally and with other external factors of the environment. This study was focused on the identification of seaweed species, distribution and their abundance within a selected area of Polhena coral reef with an aim of finding their value as an ecological resource. Methodology The study was carried out during the period May, 2013 to July, 2013. An area with a length of 3 km parallel to the shore was selected for the study and five parallel transect lines (T1-T5) were laid across the coral reef perpendicular to shore up to the sea end of the reef using colour coded nylon ropes. An equal distance was maintained between every adjacent two transect lines by using a GPS (Garmin GPS 72). Each rope was marked at each 4 m. Triplicate samples of seaweeds were collected between each and every two marks using a 50 cm x50 cm quadrat and photographs were taken at each quadrat using an underwater camera (Panasonic-Lumix FT-20). Data on species composition and percent cover of the seaweeds that were collected from each quadrat. Species were identified at the laboratory using hand lenses and a binocular microscope (SN090933909 labomed binonular) (Coppejans et al., 2009). Species of seaweeds recorded in five transects during the study period was entered to a table created in Minitab-15 data sheet and Microsoft Excel data sheet. Statistical analysis was done using a Two-way ANOVA, One-way ANOVA and Turkey’s Test in Minitab 15 statistical software.Item Production of Imitation Caviar Using Yellow Fin Tuna Fish Species: Thunnus albacares – A Novel product using Fish Roe in Sri Lanka(Uva Wellassa University of Sri Lanka, 2013) Abeyrathna, I.G.S.N.K.; Liyanage, N.P.P.; Thushari, G.G.N.; Jayamanne, C.Caviar is defined as salted fish roe that basically prepared with eggs or roe of sturgeon fish. Imitation caviar is defined as roe that comes from a fish other than the sturgeon, and it can be classified as a caviar substitute. This product is not so popular among Sri Lankans, because of lack of knowledge regarding processing of caviar and its cost. In Sri Lanka, fish roe is discarded from processing plants and sold in the local market. Therefore it is important to add value to fish roe and make them a high demanded product. Since discarded fish roe is used for this product, there will be no threat of over exploitation by production of imitation caviar. Local people can acquire nutritional benefits from the imitation caviar due to high nutritional quality. Yellow fin tuna: (Thunnus albacares) was selected as the resource fish species for the present study. T. albacares is a species in family Scombridae found in pelagic water of tropical and subtropical oceans waters. In Sri Lanka, it is considered as a commercially important food fish that represent considerable portion of tuna fishery. Therefore, main objective of present study is to develop proper methodology and select suitable maturity stage of fish roe for production of imitation caviar. Methodology Roe samples of T. albacares were collected from Ceylon Fresh sea food (Pvt) Ltd. and Jay sea food (Pvt) Ltd. in Ja-Ela, Sri Lanka. Then collected samples were transported to the Animal Science laboratory of Uva Wellassa University using cooler boxes with ice. First, ovary sacks with fish roe were separated according to maturity stage as immature roe, half mature roe and mature roe using external features of ovary sac. Then fish roe were separated from the ovary sac using manual screening method. Blood and other connective tissue on the roe were removed by rinsing with 5 % brine solution and fish roe were sieved using the sieve set. Prepared roe samples were subjected to “dry salting method” separately. Surface moisture of the roe samples were removed using clean cloth and arranged in plastic boxes with one layer of powder form Iodized salt and one layer of roe alternatively. Three different salt (g): fish roe (g) ratios as 0.05:1, 0.25:1 and 0.45:1 were used to determine the best ratio/s of each maturity stage after preliminary experimental trials (S:immature roe : S1 -0.05:1, S2-0.25:1 S3-0.45:1/ X:half mature roe: X1-0.05:1, X2- 0.25:1, X3-0.45:1, Y: mature roe: Y1- 0.05:1, Y2- 0.25:1, Y3- 0.45:1). Three replicates were used for each treatment. Salted roe samples were kept for two and half hours. During this period they were pressed gently by fingers for five minutes for effective absorption of salt. Afterwards they were dipped in tap water bath to remove excess salt and then covered with a wet cloth for 4-4.5 hours. Then the caviar were placed in a dry cool place (approximately 20 C) to be dried (Celic et al., 2012). Final products were filled into glass jars manually and pasteurized using hot water bath at 68 C for 45 minutes. Final products were analyzed for different parameters. Protein and fat contents were determined using Kjeldahl method (6.25×N) and Soxhlet method respectively (AOAC, 1990). Moisture content was determined by drying the sample at 105 C to a constant weight (AOAC, 1990). The pH values of the samples were determined with a pH meter and microbial Count (TPC) of the final products was determined. pH and TPC values were recorded once in 07 days for 02 months of storage period (0, 07, 14, 21, 28 days). All final products were evaluated using 30 untrained panelists in terms of color, texture, aroma, salty taste, mouth feel and overall acceptability on a 5 point hedonic scale to identify the organoleptic properties. Differences between mean values of proximate composition, pH values and microbiological factors were analyzed using ANOVA. Friedman non parametric test was used to analyze the results of sensory evaluation. MINITAB statistical package (16 Version) was used for analysis of results at 0.05 probability level. Results and Discussion Based on the results obtained from protein level, lipid content, sensory evaluation and microbial count studies, three samples (Salt: Fish roe by weight) 0.05:1 g, 0.25:1 g and 0.45:1 g of each maturity stage were separately compared to select best sample. Treatment that shows highest protein level, lowest lipid content, greatest consumer preference and lowest microbiological content was selected as the best sample for each maturity stage. S1 (0.05:1; salt: fish roe) was selected for immature stage, whilst X1 (0.05:1; salt: fish roe) and Y2 (0.25:1; salt: fish roe) were selected for half mature stage and mature stage respectively. The ratio of 0.45: 1 (salt: fish roe) was recorded having lowest nutritional quality, unsatisfactory consumer preference and greater microbial count for each maturity stages compared to other two treatments.Item A Study on Extracting Gelatin from Bigeye Tuna (Thunnus Obesus) Skin: An Alternative to Mammalian Gelatin(Uva Wellassa University of Sri Lanka, 2013) Azhar, A.M.; Thushari, G.G.N.; Jayamanne, S.C.; Asoka, M.D.C.Gelatin is not a naturally occurring protein, obtained by partially hydrolysis of native collagen (Karim, and Bhat, 2009). It is a colorless or slightly yellow, nearly tasteless and odorless compound with translucent property. Gelatin is widely used in food, pharmaceutical, photographic and cosmetic industries (Karim and Bhat, 2009). Currently, gelatin is produced using beef bone, hide, and pig skin and pig bone. However, Bovine spongiform encephalopathy (BSE) disease as well as religious concerns is negatively affecting the gelatin market. There is also a high competition for this kind of mammalian sources among producers. Therefore, it is important to introduce alternative sources rich in collagen for production of gelatin. Fish skin, which is enriched with collagen, has a potential to be used for extraction of gelatin (Badii and Howell, 2006). Furthermore, fish skin is concerned as a major byproduct of the fish-processing industry, causing waste accumulation and pollution. Utilization of this collagenous fish waste minimizes environmental pollution, while it adds value to fish based by-product sector. For the present study, Bigeye tuna (Thunnus obesus) skin was used, since Bigeye tuna is one of the most commercially important tuna fishery resource in Sri Lanka. The study aims to extract fish methodology characterization of physical, chemical and functional properties of extracted gelatin. The cleaned fish skin samples were chopped in to small pieces and washed with running tap water for about 10 minutes. Six treatments with three different NaOH and H 2SO4 concentrations at two different time combinations were selected for final experiment after conducting preliminary experimental trials. First 30 g each of six samples were soaked in different concentrations of Sodium Hydroxide (w/v) for two different time combinations (S1- 0.1 % for 24 hrs, S2- 0.2 % for 24 hrs, S3 -0.3 % for 24 hrs,S4- 0.1 % for 36 hrs, S5-0.2 % for 36 hrs, S6- 0.3 % for 36 hrs) separately. Then each pretreated skin samples were rinsed with running tap water and allowed to drain using muslin cloth. Each partially treated sample was again treated with different diluted H2SO4 concentrations (w/v) for two different time combinations (S1-0.1 % for 24hrs, S2-0.2 % for 24 hrs, S3-0.3 % for 24 hrs, S4-0.1 % for 36 hrs, S5-0.2 % for 36 hrs, S6-0.3 % for 36 hrs) separately. Each treated skin samples were again rinsed with tap water and allowed to drain using muslin cloth separately. Treated samples with different acid, alkaline time combinations were performed using distilled water (1:2 w/v) in a water bath at 60 C for 05 hours for gelatin extraction separately. Finally, differently treated gelatin solutions were filtered through 2 layers of muslin cloth to remove residual skin parts and final products were oven dried at 90 C for 06 hrs. Then the final products were analyzed for different parameters. Yield was expressed as a percentage (%) of the wet weight of the fish skin used. Gel strength was determined by using a Texture Analyzer (53205 Digital fruit firmness tester). The melting point was determined by preparing 6.67 % (w/v) gelatin solutions and maturating in a refrigeration temperature at 07 C for 16-18 hrs. Then melting points of final products were recorded by increasing the temperature in a water bath until the gelatin samples are dissolved (Karim and Bhat, 2009).Item Use of Side Scan Sonar in identification of submerged objects in the shallow sea area(Uva Wellassa University of Sri Lanka, 2013) Illangasinghe, M.J.B.; Liyanage, N.P.P.; Thushari, G.G.N.; Jinadasa, S.U.P.North east coast is playing a significant role in economy of the country via fishery. Beach seine fishery has been initiated in this area after 30 years of civil war. Under water war remnants buried in the bottom of the north east shallow sea acts as a major impediment in improving of beach seine fishery in the area. Generally, unidentified buried objects are discovered with the help of divers and underwater cameras. However, this technique is ineffective, due to absurd searching in the sea bottom, time consuming and high cost. So survey becomes unsuccessful, most of the time. In this study, Side Scan Sonar (SSS) survey technique which has been developed using medical ultrasound technology was used to detect the specific objects that affect the beach seine fishery, their exact location and distribution on the seafloor. North east coast of Mullaithivu area in Northern Province was selected as the study area for four waypoints / 80°49'15.06"E, Z-9°17'30.00"N/80°48'30.00"E) using the Integrated Global Positioning System (inbuilt GPS or DGPS Garmin Colorado 300 handheld GPS). Survey was carried out by towing vessel along predetermined survey lines just above the bottom of the seafloor depending upon the water depth. Data was collected using Imaginex Model 872 “YellowFin” side scan sonar combination with data acquisition using “YellowFin version 2.0.1.4” software. Image processing techniques of “sonarWiz” 5 and “ArcGIS” software was used to detect and classify buried objects in side-scan sonar images. According to the results, three objects were identified in three different locations. Object 01was at 09˚ 17.97244’ N/080˚ 48.66892’E with 85 m length and 21 m width, while object 02 was at 09˚ 18.71599’ N/080˚ 48.02634’E with 55 m length and 15 m width at the widest point. Location of object 03 was at 09˚ 18.87650’ N/080˚ 47.48114’E with 120 m length and 25 m width at its widest point. Highest coverage (with greatest length and width), was recorded for object three (3000 m ) which was distributed over a larger area of sea bed. Distance from coastal area to object one, two and three are reported as 400 m, 575 m and 200 m respectively. Third object is in close proximity to beach environment compared to other two. Average depth of the studied area was recorded as 10 -12 m. Sharp edges and curvy features of first and second objects indicated that these two objects are ship wrecks. Images show vast amounts of ship debris around these identified ship wrecks. Since these two artificial objects were identified within boundary of coastal area, there is a high potential to damage coastal fishing gears, especially beach seines by entangling and will waste time and money in repairing the damaged nets. Third object exhibits blunt edges with smooth curvatures and can be a natural structure such as a bed rock or a sand bar. The identified objects can be marked as the objects that directly influence on commercial beach seine industry. Side Scan Sonar can be recommended as a modern technique useful in detection of underwater objects with their precise location.