Browsing by Author "De Silva, M.P.K.S.K."
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Item Comparative Study on Total Chlorophyll, Carotenoid, Fucoxanthin in Seaweeds Ulva reticulata, Sargassum ilicifolium and Gracilaria multipartita and Colour Enhancing Commercial Ornamental Fish Feeds(Uva Wellassa University of Sri Lanka, 2019-02) Samarakoon, S.M.N.U.; De Silva, M.P.K.S.K.; Senaarachchi, W.A.R.K.; Liyanage, N.P.P.Seaweeds are photosynthetic marine macro algae, contain various natural colour pigments. Considering high bioavailability and low cost of processing, this study aimed on evaluating the potential of using seaweeds as a feed additive for colour enhancement of ornamental fish compared to commercial colour enhancing ornamental fish feeds by assessing three types of pigments. Three algae species (green algae-Ulva reticulata, brown algae-Sargassum ilicifolium and red algae-Gracilaria multipartita) were collected from Dickwella area. Pigments were extracted into 10 ml of 99% acetone from sun-dried algae and from 3 types of commercial feeds having green, brown and red colours. Total chlorophyll, carotenoid and fucoxanthin content of seaweeds and commercial feeds were quantified using UV spectrophotometer. Non-normally distributed data were analyzed by Kruskal Wallis test in Minitab version 17 at 0.05 significant level. Highest total chlorophyll content was observed in U. reticulata (70.50±0.39 µg g-1) & S. ilicifolium (59.53±4.34 µg g-1) and it was significantly different from their respective colour feeds (green 4.57±1.63 µg g-1 and brown 7.69±5.56 µg g-1). Similarly, U. reticulata and S. ilicifolium had significantly different carotenoid content (1.44±0.16, 2.11±0.07 µg g-1) compared to their respective colour feeds (green 0.22±0.09 µg g-1 & brown 0.21±0.07 µg g-1). Chlorophyll & carotenoid content had no significant difference between G. multipartita and its respective red colour feed. Fucoxanthin content was also higher in seaweeds (U. reticulata 2.12±0.89 µg g-1, S. ilicifolium 4.69±3.05 µg g-1 and G. multipartita 1.52±0.82 µg g-1) than three commercial feeds (green 1.82±1.81 µg g-1, brown 0.53±0.33 µg g-1 & red 0.49±0.06 µg g-1) with no significant difference. Results indicate that sun-dried seaweeds contained comparatively high level of pigments studied; the selected sea weeds may be taken as an effective feed additive for the colour enhancement of ornamental fish.Item Effect of Methyltestosterone Treated Feed on Growth and Gonadal Histology of Red Blonde Guppy Fish (Poecilia reticulata)(Uva Wellassa University of Sri Lanka, 2018) Sampath, S.N.T.I.; De Silva, M.P.K.S.K.In ornamental guppy fish (Poecilia reticulata) industry, male fish has higher demand as they are more colourful and attractive than females. Female guppy could be sex reversed and masculinized by using androgenic hormones. Present study assessed the effect of Methyltestosterone (MT) on growth and gonad differentiation of guppy fish. Three diets used in the study (A, B and C) had similar ingredients in same proportions except in diet A. In diet A, twenty five percent of fish meal was replaced by autolyzed prawn shells. Methyltestosterone was added (100 ppm/ Kg) to diets A & B and diet C was the control of the experiment. Guppy fish (0.009g±1.66x104) was stocked in glass tanks of size 18"x8"x6" at 20 fish /tank. Each treatment was triplicated. Mean body weight of fish in each tank was measured once every two weeks. After 120 days gonads were preserved and histological sections were taken. Highest body weight gain (0.225g±0.007), relative growth (44.67±6.53), survival rate (80.0% 2,7.64) was observed in fish fed with diet C. Mean body weight gain of fish fed with diet C was significantly different (P=0.04) from fish fed with diet B indicating that MT exerts negative effect on growth. Male to female ratio in control group was approximately 1:3 and 100% males were observed in fish fed with MT treated feed. Testis of male fish in control group contained spermatozeugmata (SZ) which are regular shaped cysts with clearly distinguished and methodically arranged different stages of spermatogenesis, while masculinized female fish had a different gonadal histology with irregular shaped SZ having stages of spermatogenesis not clearly distinguished and not arranged methodically.Item Extraction of Protein from Discarded Shellfish Waste; Value Added Shrimp By-products for fish Feeds(Uva Wellassa University of Sri Lanka, 2019-02) Senaarachchi, W.W.A.R.K.; De Silva, M.P.K.S.K.Shrimp head and shell waste is a rich protein source having the possibility to use in fish feed formulation. Extraction of these valuable proteins from shrimp waste is restricted due to strong covalent bonds ß (1-4) found in chitin-protein. Present study aimed to extract the proteins in high percentages by breaking the chitino-protein bonds in shrimp shells, combining the activity of proteolytic endoenzymes in crab shell waste and temperature activated autolysis. Two tests were conducted. Test I-pressure cooked ground shrimp waste was mixed with ground crab waste at crab: shrimp ratios of 0:1, 1:1, 1:2, 1:3, 1:4 and, 1:9. Tests II: using the same crab: shrimp ratios in Test I without pressure cooking. All the samples in triplicates were heated with continuous stirring at 55 0C for 15 minutes. Each hydrolysate was dried at 60 0C and weighed. Crude protein percentage was determined by Kjeldhal Analysis. Data were analysed by one-way ANOVA using SPSS 17 version. No significant difference in crude protein percentage (p > 0.05) between pressure cooked and uncooked samples with the same ingredient ratios. Highest crude protein content was recorded in crab: shrimp 1:2 (69.00 ± 12.66%) in cooked samples and in 1:9 (68.66 ± 9.45%) of uncooked samples. In contrast crab: shrimp ratio of 1:9 of cooked samples had comparatively low protein percentage (55.00 ±7.54%). Lowest crude protein percentage recorded in crab: shrimp 0:1 in both uncooked (41.56 ± 5.56%) and cooked samples (42.00 ± 23.38%) as there is no crab wastes are added. Present study reveals that incorporation of crab shell wastes to uncooked shrimp waste and temperature induced autolysis is an efficient method to extract higher amount of protein from shellfish wastes.Item Suitability of Plant Based Ingredients: Rice Bran, Coconut Poonac and Maize as Binders for Quality Improvement of Fish Feed Additive Made from Autolyzed Shrimp Waste(Uva Wellassa University of Sri Lanka, 2019-02) Jayasundara, J.M.S.K.; De Silva, M.P.K.S.K.; Senaarachchi, W.A.R.K.; Liyanage, N.P.P.Discarded shrimp shells, a good source of natural astaxanthin, proteins and lipids can be used as a feed additive to enhance colouration and growth of ornamental fish. Temperature-induced autolysis of shrimp waste breaks the chitin-protein bonds and releases these nutrients. Hydrolysate extracted by autolysis is sticky and perishable at room temperature (30 °C). The main Objective of this study was to improve quality and shelf life of shellfish waste extract using plant-based ingredients as binders. Shellfish waste (100 g) was subjected to thermal autolysis at 55 0C for 15 minutes with continuous stirring. Resultant Hydrolysate was mixed with powdered rice bran, coconut poonac and maize separately in different ratios of hydrolysate: plant ingredient (1:1, 1:2 and 1:3) each in triplicates. Protein and moisture content were determined in oven-dried samples. Samples at room temperature were checked for changes in physical properties (colour, stickiness, odour) and fungal formation (clotting) once a week for one-month period. Highest crude protein percentage was observed in samples of 1:1 hydrolysate: plant ingredient ratio (rice bran: 38.13±8.20%, coconut poonac: 47.83±3.75% and maize: 36.76±5.74%) with significant differences (P=0.002) of treatments among three binders. Protein content and stickiness reduced with increasing binder content. Rancid odour, colour change and clotting were minimal during this time period with highest binder content (1:3). Moisture percentage was significantly different (P<0.05) among samples of 1:1, 1:2 and 1:3 ratios and lowest (9.54±1.79) in samples with 1:2 ratio prepared using coconut poonac. Coconut poonac with highest protein and lowest moisture content is advantageous than other two binders. As there is no difference observed in physical properties in three ingredients, maize and rice bran are also suitable as binders. Selection of plant ingredient and suitable ratio depend on protein level and storing period of additive as required by farmer.