UWU Repository :: Browsing by Author "Coswatte, A.C.W.W.M.C.L.K."

Browsing by Author "Coswatte, A.C.W.W.M.C.L.K."

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Breeding performance of Pterophyllum scalare (Angelfish) fed with enriched Daphnia magna
(Uva Wellassa University of Sri Lanka, 2018) Mohamed Rashath, M.R.; Coswatte, A.C.W.W.M.C.L.K.; Withanage, P.M.; Liyanage, N.P.P.
Ornamental fish industry is a popular and profitable trade in the world. The production cost of ornamental fish varies with the cost of fish feed. The objective of the study was to investigate the breeding performance of Pterophyllum scalare fed with enriched Daphnia magna. The live feed of Daphnia magna was enriched with culture media, contained 58% crude protein and artificial feed with 40% crude protein were used to feed Pterophyllum scalare brooders (body weight l0g - 27g) as treatment I and II respectively. Square cement tanks with a size of 0.45 x 0.45 m2 were used for each treatment with 4 replicates for 80 days experimental period. Average Temperature, pH, Dissolved Oxygen, and Alkalinity in the two treatments were maintained at 28 °C, 7.4, 6.9 ppm and 560 mg 1-1 respectively. Although the brooders spawned in both treatments, the relative fecundity was not significantly different (P>0.05). Other breeding performances such as fertilization rate, spawn recovery and spawning period have shown significant differences (P<0.05) between Treatment-1 and Treatment-11. Comparatively highest fertilization rate (93.19%) and survival rate (70.87%) were observed in the Treatment-1, whereas lowest (fertilization rate: 67.31%) (survival rate: 50.55%) in Treatment-11. Most of the eggs in the Treatment-11 remained immature. Highest breeding performance was resulted with enriched Daphnia magna when compared to artificial feed in Pterophyllum scalare. The results revealed that the nutritional quality of the live feed considerably influenced on the breeding performance of Pterophyllum scalare.
Development of Explant Sterilization Protocol for In-vitro Propagation of Hydrocera triflora (Marsh Henna)
(Uva Wellassa University of Sri Lanka, 2019) Nuwarage, N.G.D.S.; Senarathne, M.M.D.J.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
Hydrocera triflora is a demanded, commercially valuable, perennial, ornamental aquatic plant, distributed within the Indo-Malaysian region and still not developed some in-vitro sterilization protocol for this species. This study was conducted to analyze the effect of surface sterilization treatments on H. triflora explants for development of in-vitro explant’s surface sterilization protocol. Explants (shoot tip, node, and Internode) were cultured in full strength Murashige and Skooge (MS) medium, supplemented with 3% sucrose level and 3:1 BAP (6-Benzylaminopurine): NAA (Naphthalene Acetic Acid) concentration at 5.70 pH. Effect of sterilization treatments with factorial combinations; 15% to 30% Sodium hypochlorite (NaOCl) (1 to 5 minutes), 70% Ethanol (30 s) on explant surface sterilization with pre-treatment (Topsin fungicide, Teepol detergent and Tween 20) and without pre-treatment for each explants were determined after 10 days. All the explant types’ sterilized without pre-treatment indicated 100% contamination by fungal infection within 2 days. In 20% to 30% NaOCl with 70% Ethanol (pre-treated) indicated that there was no significant difference with the number of contaminants and the treatments for all explant types. All the explant types in this treatment were contaminated by bleaching effects. In 15% to 20% NaOCl with 70% Ethanol (pre-treated) indicated that there was a significant difference between treatments for the average number of contaminants (fungal infection). Lowest average number of contaminants for shoot tips (0.00), nodes (0.16) and internodes (0.16) represented the best treatment for explant sterilization, which was provided by 18%, 19% and 18% NaOCl and 70% Ethanol (pre-treated) respectively. The most effective explant sterilization protocol (pre-treatment, 18 to 19% NaOCl and 70% Ethanol) developed from this study can achieve the highest number of healthy explants for in-vitro propagation of Hydrocera triflora.
Development of Fish Feed Using Marigold Petals and Banana Peel to Enhance the Coloration of Koi Carp (Cyprinus carpio)
(Uva Wellassa University of Sri Lanka, 2020) Sachintha, S.L.; Coswatte, A.C.W.W.M.C.L.K.; Bambaranda, B.V.A.S.M.
Koi is an economically important fish variety because of the wide diversity of skin color patterns. Fishes are unable to synthesis carotenoids in their body. The culture of ornamental fish without supplementation of dietary carotenoids leads to fade coloration. But synthetic carotenoids are expensive. Marigold petals (Tagetes erecta) and banana peels (Musa acuminata) are inexpensive, abundant, rich in carotenoids, and discarded as wastes. The objective of this study was to develop a suitable color enhancing fish feed and enhance the skin color of Koi carp by using natural color pigments. An experiment was carried out for nine weeks to enhance the body coloration of Koi carp under laboratory conditions. Four weeks old, 252 Kohaku fish were randomly introduced into seven treatments with triplicates. Marigold petals and banana peels were sundried, ground into fine particles, and sieved. Color enhancing diets were prepared with different concentrations (5, 10, 15%) of sun-dried marigold petal powder and banana peel powder; with the control treatment; commercial fish feed. All seven feed types were analysed for crude protein, crude lipid, ash, and moisture. Feed samples were checked for changes in physical properties at room temperature and refrigerated conditions (4 ºC) for one month. The total carotenoid concentration of all diets was measured using a UV spectrophotometer. The color analysis of the fish skin was done by a photographic method using Image J software. After 9 weeks from feeding, maximum skin coloration of Kohaku fish was achieved by the feed incorporated with 15% Marigold petal powder and 15% banana peel powder with significantly different. (p<0.005). Marigold petal incorporated feed obtained high skin coloration than banana peels. The lowest skin coloration was achieved in commercial fish feed. The growth rate of fish did not show any significant difference among prepared feeds during the trial. This study showed that prepared diets using Marigold petals and banana peel with different concentrations provide adequate enhancement of coloration for Kohaku fish with a short time. Keywords: Kohaku Carp, Fish feed, Skin coloration, Marigold petals, Banana peels
Development of Low Cost Mass Culture Media for Spirulina platensis
(Uva Wellassa University of Sri Lanka, 2019-02) Munirathna, K.S.P.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
Spirulina platensis is an algae popular as a food supplement with high protein content. The pure cultures of Spirulina are maintained using Zarrouk medium, which cannot be used for mass culture as the medium is highly expensive. The present study aims to develop a low cost mass culture media suitable for commercial scale culture of S. platensis in Sri Lanka. Three culture media [T1 (w/w)-NaHCO3:73.68%, NaCl:8.77%, Urea :10.96%, Albert solution:4.38%, T2 (w/w)-NaHCO3:75.4%, NaCl:7.18%, Muriate of Potash:4.39%, Triple Supper Phosphate:1.79%, Urea:11.22%, T3 (w/w) -Triple Supper Phosphate:0.95%, NaNO3:7.18%, Muriate of Potash:4.96%, NaCl:47.91%, MgSO4 :0.71%, CaCl2:0.19%, NaHCO3:38.33%] were formulated by incorporating selected fertilizers and other cost-effective alternative chemicals, while Zarrouk medium was used as the control. Three media were tested in triplicates for growth performance of Spirulina. One-unit volume was used from a pure culture with 1100 cells ml-1 and inoculated in to all the treatments. Cultures were initiated in an axenic batch culture method in the formulated media and maintained under the illumination of 4000 lux and at 35oC temperature. The growth rate of culture was measured by counting the number of cells under light microscope and cell ratio was calculated. Data were collected once in three days for 15 days and data were statistically analyzed by one-way analysis of variance (ANOVA) Results revealed the significantly high numbers of cells (186.24±25.76 cells ml-1) in T3 followed by control 123.21±3.10 cells ml-1, T1 114.80±27.97 cells ml-1, T2 96.92±3.69 cells ml-1 (P<0.05). Hence, T3 medium was identified as the most favorable media for the growth of S. platensis. The highest growth rate was also observed in T3 medium during the 15 days culture period. According to the cost analysis, T3 medium was three times cheaper than the Zarrouk’s medium and can be recommended for initiating mass culture of S. platensis in Sri Lanka.
Development of Micro-Propagation Protocol for Aponogeton dassanayakei
(Uva Wellassa University of Sri Lanka, 2018) Hettiarachchi, H.D.B.K.; Coswatte, A.C.W.W.M.C.L.K.; Senaratne, M.M.D.J.; Krishnarajah, S.A.; Kaliyadasa, P.E.
Aponogeton is a genus of freshwater aquatic plants and there are five Aponogeton species native to Sri Lanka with three endemic members. They have a high demand as an ornamental aquarium plant, food source and medicinal herb. Due to these reasons over exploitation of plants from natural habitats is common with poor attention on conservation. Aponogeton dassanayakei is a newly identified Aponogeton species from Sri Lanka. This study was carried out to develop a micropropagation protocol for newly identified Aponogeton dassanayakei. Treatments included full strength Murashige and Skoog (MS) solid basal media supplemented with combinations of 6-benzylaminopurine (BAP) (0.00, 1.00, 2.00 mg L-1) with 0.10 mg L-1 Indole-3-acetic acid (IAA) and without IAA for both shoot initiation and multiplication in seed culture. Ten replicates obtained per each treatment. During shoot initiation seed germination rate, seedling height and number of leaves per seedling were taken as the response variables and shoot multiplication stage plant height and number of leaves were considered. Application of hormones showed significant effect (p < 0.05) on both number of leaves and seedling height but not on seed germination rate in shoot initiation. Hormones supplemented in solid media during shoot multiplication were shown significance difference (p < 0.05) in plant height but not in number of leaves. According to the study, MS medium supplemented 1.00 mg L-1 BAP is the best for shoot initiation. MS medium containing 2.00 mg L-1 BAP is best for shoot multiplication. The study demonstrated that micro-propagation could be useful for large scale propagation of Aponogeton dassanayakei while conserving the plant in natural habitat.
The Effect of Coriandrum Sativum as Feed Additives on Growth Performance, Immunity and Disease Resistance of Southern Platy Fish (Xiphophorus Maculatus)
(Uva Wellassa University of Sri Lanka, 2021) Bowalage, B.W.G.S. L.; Coswatte, A.C.W.W.M.C.L.K.; De Silva, D.P.N.
Ornamental fish production and trade is a profitable alternative in the aquaculture industry. Nutrition is one of the key factors to obtain a higher productivity while maintain immunity of ornamental fishes. These fishes live in an environment surrounded by stress factors. Increasing immunity via feed additives may help them to thrive such stressors. Therefore, this study was carried out to assess the effect of coriander as feed additives and immune enhancers, on growth performance, immunity and disease resistance of southern platy fish (Xiphophorus maculatus). Sixty healthy platy fish, of 2 months old with an average weight of 0.17 ± 0.01 g were used in the experiment. Fish were fed with coriander incorporated commercially available feed for one month. The experiment was triplicated and controls were also maintained without incorporating coriander to commercially available feed. The weight gain, length and specific growth rate (SGR) were measured. The infection trial was carried out using Aeromonas hydrophila. Immune response and disease resistance of fish were determined by analyzing white blood cell (WBC) count. Results revealed that the, mean length and SGR obtained from coriander fed fish were significantly higher than the control (p<0.05). The fish fed with Coriander incorporated feed obtained 20% of neutrophil count while fish fed without coriander incorporated feed obtained 10% of neutrophil count. In conclusion, there was a positive effect on disease resistance and immunity by the coriander incorporated feed on southern platy fishes and significant length and weight gain indicated the feasibility of using coriander as feed additives and immune enhancers in aquaculture. Keywords: Coriandrum sativum; Disease Resistance; Innate Immunity; Ornamental fish; Specific Growth Rate; White Blood Cell
Effect of Four Formulated Diets on Colour Enhancement of Platy Fish, (Xiphophorus maculates)
(Uva Wellassa University of Sri Lanka, 2018) Premawansha, K. K. K.; Coswatte, A.C.W.W.M.C.L.K.; Liyanage, N. P. P.; de Silva, M. P. K. S. K.
Skin colouration is one of the most important factors which determines the commercial value of ornamental fish. Pigmentation in the skin is responsible for different colouration of fish. Pigment enriched feed is a reliable method, because hazardous effect of fish is considerably reduced. Objective of this study was to determine the colour development of platy fish subjected to four different diets. Four formulated diets were prepared using autolyzed ground shrimp head, autolyzed ground crab shell, dried & ground carrot as supplements and control diet without supplement. Twenty-five percent (25%) supplement was used for each diet preparation and other ingredients were common to all formulated diets consisted of the rest of 75% in the diet. Additional 25% of fish meal was used instead of supplement in the control diet. Experiment was conducted using five-day old platy as 30 individuals /tank and each treatment was triplicated. Laboratory conditions were maintained at 26±1 °C of temperature under natural photo periods for 75 days. Fish were fed two times per day until satiation. Photographs were captured in every 2 week interval by a same person with the same camera (Canon EOS 1300D) at a distance of 5.5 cm and 90° of angle at same condition for colour comparison. Pigmentations in the platy fish of each treatment were compared using a Mathematical language function which is called image analysis. Collected data were statistically analyzed using one-way ANOVA at p<0.05 of significant level by SPSS 24 software. According to the results, colour intensity of the platy fish fed with the feed containing autolyzed ground shrimp shell were significantly different (0.192±0.005) from the other three diets. All three experimental diets with carotenoid pigments at different levels had enhanced the colour of the fish. Present study reveals that the autolyzed shrimp head supplement is a good candidate in improving the colour of the platy fish.
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.
Growth Performances of Tilapia (Oreochromis niloticus) Fed with Duckweed (Lemna minor)
(Uva Wellassa University of Sri Lanka, 2020) Harshani, H.M.D.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
Food fish is the most valuable protein source and highly enriched with many nutrients. The cost of feed is the major reason for decreasing food fish production. The present study was conducted to identify the effect of duckweed on the growth of Tilapia. Five different diets (experiment, 2, 3, 4, 5, 6) were prepared with 40% crude protein while control diet. Experiment 1 contained a 0% duckweed leaf meal. Fish meal in experiment 2-5 was partially replaced with 10, 20, 30, 40, and 50% of dried duckweed leaf meal. Tilapia fry (bodyweight 0.21± 0.007 g and standard length 0.73± 0.005 cm) reared in indoor glass tanks were used for each experiment's diets ensuring three replicates. Daily feed allowance (5% of body weight of fish) was offered at 0900 h. and 1500 h. Results showed that mean weight gain recorded in fish fed with the experimental diets 2, 3, 4, 5, and 6 were significantly different from that of fish fed with the control diet (p< 0.05). There was a significant difference in the Specific Growth Rate of fish fed with the control diet and the experimental diets. Survival Rate of the fish fed with the experimental diets 2, 3, 4 was not significantly different (p> 0.05) with a control diet, when diet 5 and 6 were significantly different (p<0.05) with a control diet at the end of the study period. The highest Feed Conversion Ratio was recorded in fish fed with a control diet (1.28) and the lowest ratio was recorded in diet 4 (0.98). Protein Efficiency Ratio of fish fed with every 5 experimental diets were significantly different from the control diet (p<0.05) at the end of the study period. The cost of production for 1 kg of feed was considerably low for diet 6 compared to the control diet. Present results showed that 30% of dried duckweed leaf meal in a formulated diet for Nile Tilapia fish is very effective and showed the highest growth rate. Keywords: Oreochromis niloticus, Duckweed, Crude protein, Growth performance, Fish feed
Identification of suitable hardening medium for micro-propagated Lagenandra thwaitesii species in the Tilapia based aquaponic system
(Uva Wellassa University of Sri Lanka, 2018) Jayasinghe, J.A.R.A.; Coswatte, A.C.W.W.M.C.L.K.; Senavirathna, J.D.M.; Liyanage, N.P.P.
Lagenandra thwaitesii consider as a threatened endemic ornamental aquatic plant in family Aaraceae. Micro-propagation is a tool for large scale multiplication of these plants. High mortality experienced in transferring of micro-propagated plantlets from the laboratory to the environment is a major limitation in the production of L. thwaitesii at commercial scale. Aquaponic system is used for growing of various plants as a new approach to harden micro-propagated aquatic plantlets. This study focused on examining an effective hardening medium for L. thwaitesii in an aquaponic system. Six weeks aged uniform samples of in-vitro rooted L. thwaitesii plantlets were hardened by 3 different media; coconut husk, clay bricks shards and river gravels. Tilapia fish waste was used as the fertilizer from the aquaponic system, while trickling down to each section with different hardening media. The performance of plantlets in each media were measured using survival and growth parameters (number of leaves, length of roots, shoots and leaves, width of leaves, wet weight of plantlets) during five weeks of hardening period. The collected data were subjected to multivariate analysis at P < 0.05 level. According to the results, characteristics of hardening media significantly affect on growth performance of L. thwaitesii. Highest average leaf length (24.18+0.582), leaf width (10.58+0.250), root length (87.05+5.15) and wet weight (0.83+0.05) were recorded in clay brick shard medium, while maximum average number of leaves (4.05+0.189) was recorded from gravel medium. The 100% survival rate was obtained in all the hardening media. Bricks play a vital role in cation exchange, which enhances the nutrients availability for plants by increasing the growth rate of plants. Hence, clay bricks shards medium was considered as the best substrate for hardening of L. thwaitesii in the Tilapia based aquaponic system. This novel trend in integrated aquaculture system is useful to overcome the practical problems in micropropagation of L. thwaitesii plants, as a valuable asset for ornamental aquatic plant industry.
Impact of Covid-19 Pandemic on Fish Consumption Patterns in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2021) Kapuge, H.K.D.T.; Coswatte, A.C.W.W.M.C.L.K.; Liyanage, N.P.P.; Deyshappriya, N.P.R.
The COVID-19 which was originated in Wuhan, China has been rapidly spreading across the globe and consequently the World Health Organization has announced a global emergency condition. The pandemic has drastically changed the dietary and lifestyle patterns of people and specifically consumption of freshwater fish and sea food has been considerably reduced in terms of frequency and level of consumption. The aim of this study was to examine the food fish consumption patterns, production of inland food fish and price variation of fish before and during the period of the COVID-19 in Sri Lanka. A hybrid survey (both online and physical) was carried out in 13 districts and collected primary data from 711 respondents. The Wilcoxon test was employed to compare the selected variables before and during the COVID-19 using in Statistical Package for the Social Sciences (SPSS, version 25). The study found inland fish consumption has increased by 13.81% as frequently consuming fish type during COVID-19 pandemic when comparing before COVID-19. Moreover, type of fish, processing methods of fish, fish purchasing places, affordability to buy fish per month, fish purchasing frequency, fish consumption frequency and the amount of fish consumed by family per month were also analyzed and there was significant difference (p<0.05) during the pandemic, compared to before 13th march 2020. Moreover, it was examined 78% of the consumers were aware of the process of cleaning, storage and preparation and also 58.74% of them have changed their pre COVID cleaning and storage process during COVID-19 period. The average retail food fish price and inland fish production was increased at the end of the lockdown period after first wave of COVID- 19 pandemic from May 2020 when compared to year 2019. The study identified the differences of the pattern of fish consumption; fish consumption frequency, preference for freshwater food fish during COVID-19 pandemic compared to before COVID-19 pandemic. Keywords: COVID-19; Protein; Dietary pattern; Food price; Fish production
Study of Growth Performance of Oreochromis niloticus (Nile Tilapia) Fed by Formulated Diet Incorporated with Phytase Enzyme
(Uva Wellassa University of Sri Lanka, 2018) Bandara, B.R.M.P.; Withanage, P.M.; Coswatte, A.C.W.W.M.C.L.K.; Athula, J.A.
Fish is highly enriched with nutrients and serve as a valuable source of protein. Major constraints faced by inland aquaculture industry of Sri Lanka are higher feed cost and less growth performance of fish. Nile Tilapia (Oreochroinis niloticus) significantly contributes to the inland aquaculture due to its high adaptability to different environmental conditions and high growth rate. Phytase enzyme incorporated feed increases the release of phosphorus from plant meals and enhance the digestion in fish. Present study was focused to determine the effect of Phytase enzyme incorporated artificial feed on growth performance of Nile Tilapia. Two treatments, Treatment 1 artificial feed with Phytase enzyme and treatment 2 without phytase enzyme were conducted in fiberglass tanks (3.14 m3) with 3 replicates. Artificial feeds were formulated with 39% of protein and 0.2 g kg-1 of Phytase enzyme. Nile Tilapia fingerlings (mean weight 5g±1) were stocked with a stocking density of 5 fish per tank and reared for 10 weeks. They were fed three times per day at 5% of body weight. The live weight and total length of fish were measured within two weeks intervals. The weight gain of treatment 1 (17.25g±4.65) and treatment 2 (15.31g±4.10) were significantly different (p<0.05). Feed Conversion Ratio (FCR) for treatment 1 and 2 were 1.87±0.046 and 2.20+0.241 respectively with no significant difference. There was no significant difference of Specific Growth Rate (SGR) of fish between two treatments. Survival rate of both treatments were 100%. Since Treatment 1 revealed the highest weight gain, Phytase enzyme incorporated feed could be recommended to obtain the high growth performance of Nile tilapia in aquaculture industry.
Study on impacts of shade and substrates on optimum growth of micro- propagated Cryptocoryne wendtii.
(Uva Wellassa University of Sri Lanka, 2018) Lakmali, M.T.R.V.; Coswatte, A.C.W.W.M.C.L.K.; Pahalawattaarachchi, V.; Jayamanne, S.C.
Cryptocoryne wendtii which belongs to the Araceae family play a main role in the ornamental aquatic plant industry of Sri Lanka. Micro-propagation is used as a method for large scale multiplication of this plant. However transferring of micropropagated plants to the outer environment is challenging and needs best hardening substrate to achieve optimum growth. Therefore, this study was focused to determine the best hardening substrate and shade condition. Eight weeks old 45 plants of in-vitro rooted plants were hardened using three different substrates; coir fiber (A), clay pebbles (B), stone wools (C) and three different shades; without shade (1), 80% shade (2), 60% shade (3) for two months. Five replicates were used under different substrates and shade conditions: A(1,2,3) , B(1,2,3) , C(1,2,3). Growth performances of plants were measured using growth rates; stem length (S), root length (R), number of leaves (L) in all treatments at each substrate and shade. Collected data were subjected to statistical analysis at p<0.05. According to the results, characteristics of substrates and shade (fixed factors) significantly affect on the growth performance of C.wendtii (p<0.05). Mean stem length of plants were SA1(10.47cm+.14), SA2(9.78cm±.14), SA3(9.80cm±.14), SB1(9.74cm+.14), SB2(9.72cm+.14), SB3(10.54cm+.14), SC1(10.28cm±.14), SC2(10.10cm +.14) and SC3(10.33cm+.14) in all the treatments. Mean numbers of leaves are; LA1 (10.5±.16), LA2(9.8±.16), LA3(9.9±.16), LB1(9.7±.16), LB2(9.8±.16), LB3 (I0.5±.16), LC1(10.3±.16), LC2(10.1±.16), LC3(10.3±.16) in different treatments, while mean values of root length are recorded as; RA1(3.45cm+.16), RA2 (2.8cm±.16), RA3(2.9cm±.16), RB1(2.7cm±.16), RB2(2.8cm±.16), RB3 (3.5cm±.16), RC1(3.3cm±.16), RC2(3.1cm+.16), RC3(3.2cm±.16). The highest mean values for S, L, R were recorded by stone wool (C) substrate. The results of this study are important to achieve best growth performance of micro-propagated C. wendtii plants for ornamental aquatic plant industry.
A Study on the Potential of Extraction of Roe Oil from Thunnus albacares, Katsuwonus pelamis, Canthidermis maculata and Lepidocybium flavobrunneum
(Uva Wellassa University of Sri Lanka, 2019-02) Shanuke, D.S.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
Fish oil contains essential polyunsaturated long chain fatty acids which are crucial for normal growth and survival of the fish. Food fish roe and fish waste contain oils in different levels. Even though roe of food fish has a lower demand in Sri Lanka, there is a potential of extracting edible fish roe oil and fatty acids. In this study, five different oil producing methods; heat and salt extraction, enzymatic hydrolysis, mechanical pressing and solvent extraction were tested with selected four fish species (Thunnus albacares, Katsuwonus pelamis, Canthidermis maculata and Lepidocybium flavobrunneum) to identify the best method and best fish roe type for edible roe oil production. Solvent extraction with 2-propanol was found to be the best method of producing roe oil considering oil yields (1.48±0.70 g: T. albacares, 1.33±0.10 g: K. pelamis, 1.27±0.25 g: C. maculata and 1.01±0.01 g: F. flavobrunneum). Hence, solvent extraction method was carried out for the selected matured roe of four species using four types of solvents: (50ml) 2-propanol, hexane, acetone and mixture of hexane and 2-propanol (70:30). Oil yields of roe in different maturation stages were (using 2-propanol) measured and compared. Highest oil yields were recorded by matured roe of (K. pelamis: 1.18±0.14 g, T. albacares: 1.03±0.32 g, L. flavobrunneum: 1.01±0.01 g and C. maculata: 0.94±0.52 g). Oil yields of immature roe in all four fish species were negligible. The results showed a significant difference between oil yields and solvents used for extraction (P<0.05). Highest oil yield was obtained (25 g of matured roe) as 1.60±0.26 g with acetone extraction for T. albacares followed by 2-propanol: hexane mixture, 2-propanol and hexane solvents were recorded oil yields of 1.43±0.89 g & 1.18±0.14 g for K. pelamis and 0.64±0.17 g for T. albacares respectively. It was revealed that roe of T. albacares is the most suitable for extraction of roe oil.

Browsing by Author "Coswatte, A.C.W.W.M.C.L.K."

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