http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/70 2026-08-02T10:39:50Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12772 Title: Vertical distribution of the Scleractinian Corals Alveopora japonica (Eguchi, 1965) and Montipora millepora (Crossland, 1995) on Southern Jeju Island, Korea Authors: Thatchaneshkanth, S.; Keshavmurthy, S.; Kyeong-Tae Lee; Jong-Seop Shin; Kwang-Sik Choi Abstract: Introduction: Jeju Island, on the southern coast of Korea, has recently experienced increases in high-latitude scleractinian corals, accompanied by shifts in hard-bottom benthic communities. However, the local distribution and condition of the high-latitude corals Montipora millepora and Alveopora japonica at Seopseom remain poorly resolved despite ongoing benthic change. We tested the working hypothesis that their occurrence and condition are structured primarily by depth-related habitat filtering, expressed through variation in light environment, hydrodynamic exposure, and available hard-bottom benthic cover, rather than by demonstrated competitive interaction alone. Methods: Depth-related patterns in epibenthic cover and the occurrence of M. millepora and A. japonica were quantified using underwater photographic transects of 20 m length at 5, 10, and 15 m depth at Seopseom, southern Jeju Island, in 2016 and 2017. Benthic cover categories and coral occurrence, condition, and colony size-frequency patterns were assessed across depths to evaluate habitat-associated distribution patterns. Results: Sargassum sp. dominated the shallow 5 m assemblage and declined with depth, whereas filamentous turf algae and Ecklonia cava increased with depth. Coralline algae, including geniculate and crustose coralline algae, showed non monotonic variation across depths. Montipora millepora occurred at all surveyed depths, whereas A. japonica was recorded only at 10–15 m. Colony size frequency distributions of both species were dominated by small colonies, suggesting recent recruitment at the study site. Discussion: The observed depth-related patterns support the interpretation that habitat filtering, and substrate context are central to structuring the distribution of M. millepora and A. japonica at Seopseom. Competition for hard substrate remains a plausible mechanism, but it was not directly tested in this study and requires explicit contact-frequency, spatial co- occurrence, or interaction-based analyses. These results provide a hypothesis-driven baseline for future monitoring aimed at resolving the ecological and environmental drivers of ongoing benthic community change on Jeju Island. 2026-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12771 Title: Understanding key volatiles in semi-moist pet foods treated with electron beam and X-ray irradiation Authors: Anand Kumar, S.; Dongbin Park; Cheorun Jo; Hyun Jung Lee Abstract: In this study, semi-moist pet food samples were irradiated with electron beam and X-rays at 0, 2.5, 5, and 10 kGy. Samples were stored under refrigeration, and volatile compounds were analyzed on days 0 and 60. X-ray irradiation produced more volatile compounds than electron beam, likely due to differences in free radical formation and radiation-matter interaction characteristics. A dose of 10 kGy promoted oxidative reactions, increasing aldehydes, ketones, and carboxylic compounds, while 5 kGy resulted in more alkanes, indicating hydrocarbon breakdown and distinct flavor development. Notably, 1,3-di-tert-butylbenzene increased consistently at 10 kGy compared to controls, suggesting formation through packaging antioxidant degradation and migration into the fat matrix, supporting its potential role as an irradiation- and packaging-related marker in semi-moist pet foods.Storage conditions significantly influenced volatile compound changes, emphasizing the need for further investigation. These results highlight the importance of optimizing irradiation dose and storage conditions to ensure the safety and quality of semi-moist pet foods, with volatile compound profiles used as chemical indicators of potential sensory changes relevant to product quality. 2026-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12770 Title: Effects of irradiation on microbiological safety and physicochemical properties of dry pet food Authors: Dongbin Park; Anand Kumar, S.; Minwoo Choi; Jae-Kyung Kim, ,; Hyun Jung Lee; Cheorun Jo Abstract: The objective of this study was to investigate the effects of electron beam (EB) and X-ray (XR) irradiation on dry pet food during long-term storage. The samples were irradiated with EB and XR at doses of 0, 2.5, 5, 10, and 20 kGy, and their microbial safety and quality/oxidation properties were analyzed over 56 days under storage conditions of 25℃ and 70% relative humidity. As a result, total aerobic bacteria and yeasts and molds significantly decreased as the doses of EB and XR increased. When treated with 10 kGy for both irradiations, no bacteria were detected in the dry pet food, and this effect remained during the 56-day storage period. While EB and XR were effective in reducing aflatoxin B1 in solution, they showed limited effect on dry pet food. On the other hand, changes in quality traits such as proximate compositions, pH, water activity, color, and volatile basic nitrogen due to EB and XR were negligible. However, both types of irradiation induced lipid and protein oxidation in dry pet food. Also, a significant increase was observed in oxidation-related volatile compounds such as hydrocarbons, aldehydes, and ketones with EB and XR treatment, which suggested these changes could potentially impact the flavor of the dry pet food. The current findings confirm the efficient microbial reduction of dry pet food by EB and XR and the consequent changes in quality and oxidative properties. Future research should focus on sensory evaluations to understand the implications of these oxidized substances on pet preferences and explore potential methods to mitigate negative effects. 2026-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12769 Title: Reproductive performance of Jersey and Jersey x Holstein Friesian crosses in the dry zone of Sri Lanka under sophisticated intensive cattle management system Authors: Thissera, W.T.L.; Sinniah, J. Abstract: The study was undertaken to evaluate the reproductive performance of imported Jersey and Jersey x Holstein Friesian cattle over a period of 9 years (2015–2023) at the National Livestock Development Board (NLDB) farm Ridiyagama, located in the dry zone of Sri Lanka. The records on reproductive traits viz. age at first calving (AFC), gestation length (GL), calving to service period (CSP), number of services per conception (SPC) and dry period (DP) of 4806 records of 1356 cows were used. Data were analyzed using general linear model with SAS online version. In addition to the above listed variables, year of calving, season of calving, year of dry off and season of dry off were included in the model. The overall least square means (±SEM) of studied reproductive traits were AFC: 28.83±0.003 months, GL: 275.56±0.003 days, CSP: 70.15±0.01 days, SPC: 4.28±0.002 and DP:144.84±0.04 days, respectively. The least square means (±SEM) of reproductive traits for Jersey and Jersey x Holstein Friesian crosses were AFC: 29.04±0.15 months and 28.7±0.13 month; GL: 276.77±1.33 days and 275.91±1.31; CSP: 67.47±1.11 days and 70.81±0.93 days; SPC: 4.06±0.29 and 4.42±0.28; DP: 139.94±4.11 days and 144.49±3.39 days, respectively. Current study revealed that AFC for both breeds lie within the optimum range of 24 to 30 months for cattle. The traits CSP, SPC, and DP exceeded standard values of 45-50 days for CSP, ≤ 2 for SPC and 60 days for DP. However, for these traits, Jersey showed lower values than Jersey x Holstein Friesian crosses indicating the adaptive nature of Jersey to the tropical climatic condition. 2025-01-01T00:00:00Z