http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/5678 2026-02-22T10:39:45Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1530 Title: Evaluation of the acute toxicity of profenofos and its effects on the behavioural pattern of genetically improved farmed Tilapia Fingerlings. [Oreochromis niloticus (Linnaeaus., 1758)]. Authors: Dayananda, N.G.; Surendran, S.N. Abstract: Profenofos is an organophosphate insecticide which acts as acetylcholinesterase inhibitor. It is a potential contaminant to the aquatic ecosystems which can effect on non-targeted organisms including fish. The aim of this study was to determine the 72 h LC50 value of Profenophos® and to investigate the changes in behavioral pattern of genetically improved farmed tilapia fingerlings. ((2 ± 0.5) g of average weight and (6 ± 0.5) cm of average length). Three tank setup were prepared with three different concentrations of Profenophos® i.e. 0.2 mgL-1, 0.3 mgL-1 and 0.4 mgL-1 and one tank was maintained as a control tank without Profenophos®. There were three replicates for each concentration and the control setup. Each tank setup was introduced with four tilapia fingerlings. All the tank setups were maintained under the equal conditions of average temperature (30 ± 1 °C), pH (7), photoperiod of 12 hours dark and 12 hours light, and the average dissolved oxygen (DO) concentration of 6.4 mg L-1. Mortality and the behavioral changes were assessed at 24, 48, and 72 hours. Seventy two hours LC50 was determined by probit analysis using the MS Excel 2013 software. The calculated 72 h LC50 value of insecticide Profenophos® to Oreochromis niloticus fingerlings was 0.26 mgL-1 at 30 ± 1 °C. The behavioral responses of fish exposed to Profenophos® were included loss of balance, moving in spiral fashion with sudden jerky movements, lying on their sides and rapid flapping of the operculum with the mouth open. The present study reveals that Profenophos® is toxic to genetically improved strain of Oreochromis niloticus and have affected on behavioral changes at low concentrations. 2020-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1527 Title: Establishement and characterization of spleen cell lines by using Balb/c mice as a model. Authors: Amarasinghe, A.A.K.P.; Eswaramohan,T. Abstract: The spleen is the largest secondary lymphoid organ in the body and it has a complex cell composition because of the immunocytes' maturity and settling down. Changes in the composition of immunocytes are critical to immune response. In vitro culturing of immune cells is the best way to study the behaviour and architecture of the cells. Considerable research works on spleen cell culture have not been conducted in Sri Lanka. The objective of this research project was to establish and characterize a spleen cell line from BALB/c mice as a model. BALB/c strain of the laboratory-bred mouse was chosen as the model organism as they are small in size and they have a short gestational period that permits easy manipulation. Animals were reared in the Animal House, Department of Zoology, University of Jaffna under parasite-free conditions. A BALB/c mouse was dissected and the spleen was isolated from the mouse. The spleen was minced into small residue particles and digestion was done by mixing tissue residues with collagenase solution. Cells were filtered by using a micro-pore filter unit and the cell suspension was centrifuged to obtain a single-cell suspension. The precipitate of the centrifuged cell suspension was mixed with the growth medium and seeded in the cell culture plate consists of the growth medium. 48hours cultured cells were examined under the microscope and a low growth rate was observed. Some cells were in the stage of fission. Cells have poorly adhered with the culture plate and cells were identified from the cell suspension. Additional research is needed to develop a continuous cell line. Immuno-phenotyping using flow cytometry can also be used to identify, quantify, and isolate the immune cells. 2020-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1516 Title: Toxicological effects of Napthalene on the early development of Zerrafish ((Danio rerio). Authors: Vithushi, K.; Thulasitha, W.S. Abstract: Polycyclic aromatic hydrocarbons and their derivatives constitute a large proportion present in diesel or crude oil and are identified as one of the major aquatic pollutants of which naphthalene (Nap) is one of the important chemicals. Therefore, the present study was carried out to identify the toxicological effects of Nap on the early developmental stages of a lower vertebrate model; zebrafish (Danio rerio). Healthy same-aged embryos (6 hours post fertilization –hpf) were obtained by induced spawning and utilized in this experiment. Nap was dissolved in 1% Dimethyl sulfoxide (DMSO) and the following concentrations were applied to respective groups (60, 40, 20, 10 and 5 mg/L). Egg water alone and DMSO with egg water were used as control. Percentage of mortality and developmental deformities were recorded at 24, 48, 72 and 96 hpf. All the treatments were done in triplicates. The results showed that LC50value in embryos for Nap based on Probit analysis was 19.91 mg/L. Embryos showed developmental deformities such as pericardial edema, yolk sac edema, yolk sac fluid accumulation, yolk sac turbidity, spinal cord bent, haemorrhage and bent tail upon Nap treatment. The minimum concentration of Nap that showed developmental deformities was 20 mg/L. Percentage of mortality increased with the increasing concentration of Nap. The results revealed that, Nap showed developmental toxicity on zebrafish embryos and the toxicity is concentration-dependent. Further studies are being conducted to confirm the developmental toxicity of Nap based on histological analysis. 2020-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/1515 Title: Survey and identification of Lobsters in Pointpedro coastal water, Jaffna, Northern Province, Sri Lanka Authors: Kirillawala, K.A.L.K.J.; Sivakumar, P. Abstract: Lobsters are one of the economically important marine crustacean groups occupying variety of habitats. They have a great demand in the domestic market as a delicacy and is a foreign exchange earner for the country. In Sri Lanka, six spiny lobsters have been recorded under two major lobster families. However, taxonomic status of available lobster species is poorly understood in Jaffna peninsula. Therefore, the present study was conducted with the aim of documenting lobsters in Point Pedro coastal waters, Jaffna. A field survey was conducted by suitable field collections of lobsters in Point Pedro coastal waters from September 2019 to February 2020. Samples were initially identified with the help of morphological features at the sample collection site by using the standard keys. At present study, five species of Family Palinuridae were recorded. They are Panulirus versicolor (Lareille, 1804), P. ornatus (Fabricius 1798), P. homarus (Linnaeus, 1758), P. polyphagus (Herbst, 1793) and P. longipes (A. Milne Edwards, 1868). Although this study was the first study on the survey of lobsters in Point Pedro coastal waters, Jaffna, Northern province, Sri Lanka, further field surveys and studies are required to confirm the distribution and occurrence of these lobsters. 2020-01-01T00:00:00Z