UPV Theses and Dissertations
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Item Time series forecasting model of dengue incidence in the Province of Iloilo with meteorological factors as external regressorsAcebuque, Jason Clement S.; Cuachon, Anna Nicole O.; Deala, Carl Laurence L.; Esmenos, Arian Claudine F.; Galupo, Bealou Patrishe D.; Jubelag, Carmelli S.; Legayada, Precious Jemimah D.; Namuag, Maulene Mae J.; Palmon, Gladys A.; Salvador, June Luis C.; Sampani, Gian Justin P.; Tolentino, Jimel V. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)The province of Iloilo posted the highest increase of dengue cases in the Western Visayas region in 2016, despite the noted 2.2% decrease of clinically confirmed cases nationwide. The province has placed adequate attention on technical elements, specifically on the outbreak preparedness, yet it is important to give additional efforts to strengthen the surveillance and information system in the province. A seasonal autoregressive integrated moving average with external regressor (SARIMAX) model was formulated to forecast the future monthly number of dengue cases in Iloilo province using the meteorological parameters as the explanatory variables. It was found that only the rainfall variable significantly affects the number of dengue cases in Iloilo province, hence, the only variable included in the SARIMAX model as the external regressor. The final forecasting model SARIMAX(3,l,l)(l,0,0)12 is capable of representing the number of dengue cases in subsequent months with relative accuracy. The forecasts of dengue incidence from the final model are imperative for assessing future healthcare and public health programs in the province of Iloilo.Item Induction of molting in hatchery-reared mud crab Scylla serrata juvenilesDe la Cruz, Joanna Joy Y. (University of the Philippines Visayas, 2014-03)The effects of lime, temperature and autotomy of chelipeds on growth, survival and molting of mud crab Scylla serrata juveniles were investigated under laboratory conditions. Hatchery produced S. serrata (45-day old) at the intermolt stage with internal carapace width of 2.0-2.3 cm and body weight of 1.7-2.2 g were exposed to lime concentrations of 0, 100, 200 ppm at daily and weekly application, temperature of ambient, 29, 32 and 35 °C and subjected to autotomy. The juveniles were allowed to molt twice prior to termination. The survival of juveniles declined with increasing levels of lime. Mean survival rate of juveniles without lime was 47% while 100 and 200 ppm lime ranged from 29 to 32%. No significant differences were found in the specific growth rate (% SGR) and molt interval (days) in all lime treatments after the first and second molts. All juveniles held in 35 °C had 100% mortality in the first molt due to incomplete molting therefore it was excluded from data analysis. SGR of crab juveniles in the ambient (2.75 ± 0.15%) and 29 °C (3.20 ± 0.18%) were comparable but significantly different (P<0.01) with those juveniles in 32 °C (4.12 ± 0.39%). The molt interval of the crab juveniles after second molt was significantly shorter with increasing temperature (29 °C: 32 ± 0.80 days, 32 °C: 28 ± 1.11 days) compared to ambient temperature (39 ± 0.93 days). The mean survival of juveniles in various temperature levels upon termination was 62, 85 and 65% for ambient temperature, 29 and 32 °C, respectively. Juveniles with intact chelipeds (5.80 ± 0.47%) and one cheliped autotomized (5.45 ± 0.30%) had a significantly higher SGR compared to juveniles with both chelipeds autotomized (4.20 ± 0.52%) in the first molt but no significant difference was observed in the second molt. This trend was observed because the autotomized chelipeds were not fully regenerated after the first molt. The molt interval was significantly shorter in the autotomized juveniles compared to juveniles with intact chelipeds. The interval was 36, 28 and 23 days for intact, one and two chelipeds autotomized, respectively. The survival of juveniles with intact chelipeds (60.61 ± 6.06%) was comparable with autotomized chelipeds (one cheliped: 59.60 ± 4.04%; two chelipeds: 47.22 ± 2.78%). Based on the results, the suggested optimum temperature level for rearing S. serrata juveniles was at 29 °C. Likewise, autotomy of one cheliped can promote molting without adversely affecting the growth and survival of the juveniles. On the other hand, the application of lime did not improve the molting of juveniles due to occurrence of high pH and alkalinity. This also resulted in the low survival and growth of Juveniles.Item The response of Sandfish Holothuria scabra (Jaeger) juveniles to salinity and temperature changesCaber, Dieyna B. (University of the Philippines Visayas, 2016-02)Sandfish Holothuria scabra is one of the most economically valuable species of sea cucumbers. Despite being the subject of many research projects and is currently cultured commercially, many of its basic physiological aspects are not yet known or established. This study was conducted to determine the effect of salinity and temperature on the oxygen consumption rate (OCR) of sandfish juveniles. Initially, acclimation to lower salinity was compared to direct transfer. ANOVA showed that the OCR of sandfish juveniles acclimated for 30 and 120 min to 30 and 25 ppt from ambient salinity (35 ppt) were not significantly different (P>0.05) to that of sandfish directly transferred. At 8 h, the OCR values at 30 min acclimation were 0.012 ± 0.002 mgO2/L/h/g at 35 ppt, 0.019 ± 0.004 mgO2/L/h/g at 30 ppt (direct transfer), 0.015 ± 0.001 mgO2/L/h/g at 30 ppt (acclimated), 0.019 ± 0.002 mgO2/L/h/g at 25 ppt (direct transfer) and 0.013 ± 0.002 mgO2/L/h/g at 25 ppt (acclimated). At 120 min acclimation, the OCR were 0.012 ± 0.002,0.019 ± 0.004, 0.015 ± 0.000,0.019 ± 0.002, and 0.013 ± 0.001 mgO2/L/h/g, respectively. In the second part of the study, when sandfish juveniles were exposed to salinities of 35 (ambient salinity) 30 and 25 ppt and temperatures of 34,29 (ambient temperature) and 24 °C over 8 h, their OCR values fluctuated at the highest temperature and even more so at the lowest temperature. Because the experiments at different temperatures were conducted separately, the results could not be compared statistically. However, due to the degree of OCR fluctuation it appears that the sandfish juveniles were stressed at 34 °C and more stressed at 24 °C. This is supported by stress indicators observed visually during the experiment. The absence of OCR fluctuation at ambient temperature (29 °C) indicates that this is the more appropriate temperature for sandfish culture. Based on the results of the study, salinity has no effect on sandfish OCR up to 10 ppt below ambient. These results may be useful for selecting optimal conditions for growth and survival, as well as selecting optimal locations for stock enhancement purposes.Item Quality changes in Tilapia (Oreochromis niloticus) after delayed icing and subsequent storage in iceSaluan-Abduhasan, Fathma (College of Fisheries, University of the Philippines in the Visayas, 1985-04)Quality changes in tilapia (Oreochromis niloticus) iced directly on harvesting were compared to those occurring when icing was delayed. Chemical and sensory examinations showed that the shelf life of tilapia was 26 days when iced immediately. 20 days and 16 days with 4 and 8 hours delay, respectively. Fish kept at ambient temperature for 12 hours were rejected after one day in ice. These results suggest that for every hour delay in icing the effective shelf life is reduced by approximately one day up to the 8th hour delay. Total volatile nitrogen values increased with storage time. Likewise, K-value and hypoxanthine values increased as storage time increased. The initial bacterial load ranged from 103- 104 cfu/g of fish with H2S-producers count of less than 100 cfu/g of fish. At rejection, the microbial load was 108~109 cfu/g of fish with HgS-producers count of 106-107 cfu/g. The typical off odours of naturally spoiling fish have been reproduced in blocks of sterile muscle by organisms such as Alteromonas putrefaciens, Pseudomonas sp, pseudomonas maltophilia, Pseudomonas flourescens and pseudomonas stutzeri.