Browsing by Author "Mahaliyana, A.S."

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    Balancing the benefits of protein content and the risks of trace metal toxicity exposure from Skipjack tuna (Katsuwonus pelamis) consumption in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2015) Mahaliyana, A.S.; Liyanage, N.P.P.; Jayamanne, S.C.
    Fish is considered as an excellent source of protein that can provide immense health benefits to human being. Protein is the major nutrient in fish consumption and it is highly digestible and consist all the essential amino acids. However, recent claims that marine fish are contaminated with trace metals exceeding the recommended maximum allowable limits have raised concerns among consumers regarding fish consumption. This may lead to rejection of marine fish both by local and export markets (Liyanage, 2009) as fish contaminated with toxic trace metal can lead to acute and chronic effects in human being. In the present study, protein content and major toxic trace metal concentrations in skipjack tuna (Katsuwonus pelamis) which is a major commercial marine fish species were studied with the aim of assessing benefits and risks in consumption of skipjack tuna in Sri Lanka. Materials and Methods Samples of skipjack tuna fish (n = 44) were collected to represent all fish landing site areas around Sri Lanka during April-July, 2014. Concentrations of toxic trace metals Hg, Cd, Pb and As were analysed individually for all the samples while the protein content analysis was carried out for composite samples that were prepared based on gender and standard length of each fish. Crude protein content was analysed according to 928.08, AOAC 2000 standard method. Crude protein content was determined using UDK 132 (VELP Scientifica, Usmate, Italy) semi-automated Kjeltec system. All composite samples were analysed in triplicates. Hg, Cd, Pb and As trace metal concentrations were analysed by Atomic Absorption Spectrophotometer (AAS; Varian240 FS, Varian Inc., Australia) following the standard method in AOAC 1998. All analyses were strictly adhered with quality control procedures. Protein content of skipjack tuna was assessed in terms of benefits with reference to its Recommended Dietary Allowance (RDA) value whereas the toxicity of each trace metal was assessed based on the stipulated Provisional Tolerable Weekly Intake (PTWI) with the Probable Weekly Intake (PWI) values. Average consumption of skipjack tuna flesh in Sri Lanka was considered as 2.8 g/person/day (MFARD, 2013) and the average body weight of a Sri Lankan adult person was assumed as 55 kg. In addition, resulted mean toxic trace metal concentrations were compared with the established maximum allowable limits for toxic trace metals in Sri Lanka and European Union standards for skipjack tuna. Results and Discussion In order to determine the recovery percentage in crude protein analysis, spiked samples with (NH4)2SO4 were used and the recovery values were maintained within the acceptable range of 90- 110%. The method of trace metal analysis was evaluated for its suitability in terms of their respective Limit Of Detection (LOD) and recovery levels using spiked samples and certified quality control materials. Calculated recovery values for all the trace metals were within the expected recovery range of 80%-120%. The mean standard length of the analysed skipjack tuna fish was 47.4±3.9 cm and the range was 36- 56 cm whereas the mean total weight was 2.2±0.5 kg and it had a variation of 1.1 - 4.2 kg. Among the analysed specimens 24 were males and 20 were females.
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    Determination of Suitable Breeding Substrate for Redside Barb (Puntius bitnaculatus) in Captive Conditions
    (Uva Wellassa University of Sri Lanka, 2018) Wajiramala, G.K.Y.; Mahaliyana, A.S.; Chandrarathna, W.P.R.; Jayamanne, S.C.
    Redside barb (Puntius biniaculatus) is one of the most popular indigenous ornamental fish species, which commonly found in Sri Lanka. This species has been heavily collected from wild for aquarium trade and have a severe influence on the reduction of naturally available stocks. Development of captive breeding and larval rearing techniques are found as an effective strategy to increase commercially available stocks, which will also lead to ensure the sustainable utilization as a valuable resource. Hence, the objective of this study was to determine the suitable substrate for successful breeding of Redside barb in captivity. Three types of breeding conditions; gravels with aquatic plants, sand with aquatic plants, only aquatic plants were provided with stilled water in 60 cm x 30 cm x 30 cm size indoor glass tanks and three replicates for each treatment were used. Mature males with bright red colour stripe on their body and females which released yolked eggs, when slight pressure is applied on their abdominal region were selected as brooders for the experiment. Selected individuals were introduced into each tank at 2:1 male to female ratio. Completely Randomized Design was used as the experimental design and produced fry number was counted. Data were analyzed using one way ANOVA. Spawning was observed in all conditions and fry number varied significantly among three different substrates (p<0.05). The highest mean fry number was observed in the substrate of gravel with aquatic plants (195±20) compared to other 2 (fry number in the substrate which contain sand with aquatic plants: 77±39 and only aquatic plants: 33+33). Results of this study revealed that the most suitable breeding substrate for the Redside barb in indoor glass tanks was the substrate with a gravel bottom and aquatic plants.
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    Development of a Value Added Canned Fish Product Using Rough Trigger Fish (Canthidermis inaculatus)
    (Uva Wellassa University of Sri Lanka, 2018) Jeewanthi, J.W.P.C.; Mahaliyana, A.S.; Udayathilaka, K.E.; Abeyrathne, E.D.N.S.
    Fishes are one of the excellent nutrient sources for human. Fish canning is used as preservation technique to reduce spoilage. Improper continuous supply of mackerel to produce canned fish is the main problem in canned fish production. Objective of this research was to develop a value added canned fish product using Rough Trigger fish as an alternative to mackerel. Canning was done under commercial conditions in a fish canning company. Trials were carried out to select the best brine concentration and spices added. Another set of trials were done to compare the brine and oil filling. Based on the sensory evaluation the best treatment was selected using the 30 untrained panelists. Taste, color, aroma, texture, mouth feel and overall acceptability were checked. The final product was subjected to keeping quality analysis by determining the pH, level of oxidation and microbial contamination. According to the trials, 2.5% (w/v) brine solution was selected as the best brine percentage. Aroma and color did not show any significant difference among the treatments (p>0.05) and texture, mouth feel, taste and overall acceptability had significant difference (p<0.05). Similarly 2.5% (w/w) pepper and 0.25% (w/w) cinnamon was selected as the best level of spices to be add in to the final canned fish. According to the sensory data coconut oil was selected as the best oil to be used. Salmonella and E coli were absent in all treatment. pH of the treatment were ranged from 5.79± 0.18 to 6.26±0.18 for 21 days and it was within the acceptable range. Results from TBARS assay showed significantly (p<0.05) low oxidation in brine added canned fish than oil immersed canned fish until 21 days. In conclusion, 2.5% (w/v) brine, 2.5% (w/v) pepper and 0.25% (w/v) cinnamon added canned Rough trigger fish can be a good replacer for mackerel canned fish.
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    Effect of Raw Spirulina platensis Supplement on the Growth Performance of Guppy Fish — Red Blonde (Poecilia reticulata)
    (Uva Wellassa University of Sri Lanka, 2018) Sarathchandra, M.A.D.P.I.; Mahaliyana, A.S.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
    Aquarium fish industry in Sri Lanka has become a valuable source of foreign exchange recently. Guppy fish (Poecilia reticulata) ranks the highest (67%) market of ornamental, fresh water fish export sector in Sri Lanka. Spirulina platensis is one of the commercially important micro algae due to its overall nutritional qualities. The study was investigated the effect of dietary supplementation of different percentages of Spirulina platensis (5%, 10%, 15%, 20%, and 25%) on growth performance, Feed Conversion Rate and survival rate in guppy and were compared with commercial feed as the control treatment. Spirulina platensis were cultured using axenic batch culture method in Zarrouck's medium, under illumination with a photo period of 12 hours light and dark. Glass tanks (0.3 m x 0.15 m x 0.15 in) were used for each treatment with 3 replicates and 21 days old red blond guppy were reared with a stocking density of 10 fish/tank for 30 days. Fish were fed, twice per day at a rate of 10% of body weight for 60 days. Data were collected every 2 weeks interval and analyzed by One Way Analysis Variance (ANOVA). There were significant differences between all the diets in terms of average body weights (p<0.05). Average body weight was highest in treatment with 5% raw Spiruina platensis incorporated feed (0.45±0.090 and lowest in control treatment (0.36±0.13g). No significant differences were observed in weight gain and Specific Growth Rate (SGR) (p>0.05) according to the treatments. There were significant differences of Feed Conversion Ratio (FCR) among all the diets (p<0.05), while it was lowest in 5% raw Spirulina platensis incorporated feed (1.43±0.06) and highest in the control treatment (2.05+0.09). 100% survival rate was observed in all treatments. The study revealed that 5% raw Spirulina platensis dietary supplementation enhances the growth rate in guppy fish.
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    Production of Biodiesel from Yellowfin Tuna (Thunnus albacares) Fish Skin Wastage
    (Uva Wellassa University of Sri Lanka, 2018) Amangilihewa, G.V.; Mahaliyana, A.S.; Kariyawasam, M.G.T.R.; Abeyrathne, E.D.N.S.; Etampawala, T.N.B.
    Yellowfin tuna (Thunnus albacares) is one of the major exporting fish species in Sri Lanka. Approximately 50% of the total large pelagic catch in Sri Lanka constitutes tuna-like fish species and usually fillets, steaks, cubes are exported. The rest, which is approximately 1/3 of the harvest is discarded which contain head, skin, tail, viscera and fins. Roughly 5000 tons of fish waste are generated every year in Sri Lanka. Dumping such waste in to the environment can cause various environmental problems. This study was focused to add value to such waste by producing biodiesel as an alternative energy source for petroleum. Tuna fish skins were collected from local processing factory and brought to the laboratory under 4 °C and cut in to small pieces. Fish oil was extracted using different solvents; absolute ethanol, ether, nhexane and 1:1 mixture of ethanol and water using ultra sonication and soxhlet extraction method. Fatty acid profile, energy and the yield was calculated. Accordingly there were no any significant difference in yield of the extracted oil with single solvents used (p > 0.05). But ether was selected as the best solvent (3.24 g±0.61). Among the two methods, Soxhlet method showed the highest oil yield (20 mL/kg of fish skin). Fish oil profile was obtained by using Thin Layer Chromatography (TLC) and Gas Chromatography-Mass Spectroscopy (GC-MS). The extracted oil was used to produce biodiesel using single step transesterification with potassium methoxide. The percent conversion of oil in to biodiesel was 88%. Fourier Transmission Infrared (FTIR) Spectroscopy method was used to characterize the fish oil as well as the biodiesel. The energy capacity of the synthesized biodiesel was measured using a Differential Scanning Calorimeter. All the test results were benchmarked against the commercially available petrochemical based diesel. Accordingly, ether soxhlet separation can be used as a potential biodiesel production from Yellowfin tuna fish skin.
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    Study on Effects of Substrates for Captive Breeding of Dankolapethiya (Dawkinsia singhala)
    (Uva Wellassa University of Sri Lanka, 2018) Walisundara, W.M.N.K.; Mahaliyana, A.S.; Jayamanne, S.C.; Chandrarathna, W.P.R.
    Dankolapethiya (Dawkinsia singhala) is an endemic freshwater fish in Sri Lanka. This fish species has high ornamental value in export market and their natural stocks are diminishing day by day due to excessive collection by ornamental fish trade, and habitat degradation resulted by anthropogenic activities. Therefore, from the perspectives of the aquarium fish industry and conservation of the endemic fish species, captive breeding of this species is a good remedy. The objective of this study was to identify the ideal substrate under captive breeding environment. Four different substrate conditions created in cement tanks with size of 1.5 m x 0.75 m using coconut coir, sand, gravel and bare bottom and stocked fish at 2:1 male female ratio. Bottoms of the experimental tanks were fully covered with the selected substrates. Each treatment was triplicated. Height of the water column was maintained as 0.20 m. Breeding experiment was started, after 6 weeks of wild caught Dawkinsia singhala brooders' acclimatization period. Experimental tanks were observed closely for 7-14 days after commencement of the experiment and 63 individuals of fry were observed in the tanks with sand substrate condition. Out of four different substrates, captive breeding was only successful in experimental tanks with sandy bottom substrate, while spawning of Dawkinsia singhala was not successful (0%) in other experimental tanks. The study revealed that Dawkinsia singhala can be successfully bred under sand substrate condition in still water. This study will assist researchers to further develop captive breeding techniques for this species.