UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

Masters Theses

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/12

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Start date: 2000End date: 2004

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    The effect of sex reversal treatment on the growth and survival of two strains of Nile tilapia (Oreochromis niloticus) and Mossambique tilapia (Oreochromis mossambicus) raised in brackishwater
    Badillo, Susan Delos Santos (University of the Philippines Visayas, 2000-08)
    A study to determine the effects of sex reversal (SRT) on the growth and survival of two strains of Nile tilapia (Oreochromis niloticus) and Mossambique tilapia (Oreochromis mossambicus) was conducted in four 2m x lm x 1.5m suspended hapa nets in UPV-IA Hatchery and Biology brackishwater fishpond for 75 days. The experimental treatments and codes used in this study were the following, Treatment GGn (GIFT/normal), Treatment GGsrt (GIFT/sex reversal), Treatment MMn (Moss/normal), Treatment MMsrt (Moss/sex reversal), Treatment GEn (GIFT-Egypt/normal) and Treatment GEsrt (GIFT-Egypt/sex reversal). Juvenile fry (average weight 0.0 1g) were subjected to sex reversal treatment by feeding fish diet with methyltestosterone at 60 mg per kg of feed for three weeks in freshwater. After SRT, the fingerlings were nursed in fine mesh net (0.5 mm mesh, 2m x 1m x 1m) for 30 days until the fish attained the weight from 3.0 g to 5.3 g. They were individually tagged by fin clipping method. They were acclimated from 0 ppt to 20 ppt prior to experimental proper. Juvenile fish of 3.40-5.44 g were communally stocked at 25 fish each treatment. Juvenile fish were fed with a commercial feed at 15% of their mean body weight per day from 1-30 days and 10% per day of their mean body weight from day 31-75 days culture period. Within the normal treatments, there was no significant (P>0.05) difference in mean body weights between Treatments GGn and GEn but both are significantly higher (P<0.01) than Treatment MMn. Within the sex reversed treatments, mean body weight in Treatment GGsrt was not significantly (P>0.05) different from Treatment GEsrt, but showed high significant (P<0.01) difference with Treatment MMsrt, similar to the normal treatments. The highest average final biomass of 808.88 g was obtained in Treatment GGsrt followed by Treatment GEsrt (795.58 g) and lowest in treatment MMn (367.63 g). The biomass gain of tilapia within the normal treatments ranged from 282.6 g to 672.95 g. Treatment GGn showed no significant (P>0.05) different from Treatment GEn, but both were significantly higher from Treatment MMn. The same trend was observed within sex reversal treatments. Treatment GGn obtained the highest (589.70%) percentage biomass gain and Treatment MMn (335.01%) was the lowest within the normal treatments. In sex reversal treatment, Treatment GGsrt has no significant difference with Treatment GEsrt, but both showed a high significant difference in Treatment MMsrt. Highest specific growth rate was observed in Treatment GGn (2.62 g day-1) and lowest in Treatment MMn (1.97 g day-1). Mean condition factor (MCF) of tilapia was highest in Treatment GGn (1.60), followed by Treatment GEn (1.56) and lowest in Treatment MMsrt (1.17). Within the normal treatments, Treatment GGn and GEn showed no significant difference (P>0.05), but both were significantly higher (P<0.01) than Treatment MMn. Within the SRT treatment, all treatments showed highly significant (P<0.01) difference from each other with highest at Treatment GGsrt and lowest at Treatment MMsrt. Mean survival ranged from 95% to 100%. Highest percent male population was obtained in hormone-treated fish (95-100%) compared to normal treatments (64-71%). Sex reversal treatment did not improve growth and survival of the two strains of Nile tilapia (O. niloticus), but improved the growth of Mossambique tilapia (O. mossambicus) significantly after 75 days under the conditions this experiment was conducted.
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    Environmental impacts of marine cage farm (Lobster culture) in Van Phong Bay, Khanh Hoa, Vietnam
    Du, Hoang Trung O. (University of the Philippines Visayas, 2003-07)
    The study carried out two surveys at five sites in lobster cage farming activities, during rainy season (November 2002) and dry season (February 2003). It includes 236measured data on physical and chemical parameters of water quality, 115 data on sediment characteristics, and 30 macrobenthic samples. The results of the study indicate that the lobster cage farming activities are related to the accumulation of organic materials on seabed of the cage farm. The impacts of lobster cage farms on water quality might come directly from the cage farm and indirectly from the release of organic and inorganic matter from sediment bottom which significantly changed depending on the season. This could be seen in the total inorganic nitrogen (TIN) concentration at the bottom, which is higher by 6-10 times during the dry season than that during the rainy season. Moreover, cage farming enriches the water column through the release of nutrient and particulate organic matter and affects the sea bottom with deposition of sediment particles. The study clearly marked variation in organic matter and chlorophyll-a concentrations in sediment. In addition, the particulate organic carbon in water samples also showed the negative impact under the cage. The results of sediment trap exhibited high organic content at stations near the cage (stations 2 and 3) as compared to the station farther the cage and the control site. On the other hand, organic matter in surface sediment was significantly higher under the cage than in the control site. This suggests that accumulation of organic material under and near the cage is highly deposited by particles that come from the cage farm. There were observed changes in benthic community in terms of species, abundance, and biomass. Changes in benthic composition were different between stations near the cage and the control site. This indicates that benthic community patterns were affected under the cage and those near the cage farming activities. Macrobenthic communities were dominated by polychaete species during the two surveys. Polychaetes represented more than 55% of benthic abundance as well as greater than 60% ofthe number of species. This study shows that it may be possible that some polychaete species such as Magelona sp, Myriochelle sp, can be important bio-indicators of heavy organic load in the cage farms. On the other hand, polychaete species Prionospio aficana, Orbinia vietnamensis might be considered as candidate indicator species for detection of organic enrichment in the cage farms. In addition, these can serve as baseline information for future studies to evaluate the environmental impact of cage farm. The relationship and interaction between factors that cause eutrophication is therefore particularly important for future studies.
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    Nutritional value of fish silage, with Gracilaria Sp. and Abalone Viscera as poultry feed
    Patadjai, Andi Besse (University of the Philippines Visayas, 2004-11)
    Study on fish silage prepared with , with and without abalone viscera was conducted to evaluate the rate of hydrolysis during the ensiling process. The fish-Gracillaria sp.-abalone viscera silage was further subjected to nutritional value test as poultry feed. Three silage were prepared using 5% propionic acid and formic acid (ratio 1:1) to contain: a) 100% fish by catch (Silage F), b) 70% fish by catch and 30% Gracilaria sp. (Silage FG) and c) 70% fish by catch, 25% Gracilaria sp. and 5% abalone viscera (Silage FGA). These silage were stored for 15 days and stirred daily. Chemical components such as pH, amino nitrogen, polypeptide, and monosaccharide content were determined at regular intervals within the 15-day ensiling period. Isonitrogenous feeds were then formulated to contain fish-Gracillaria sp.- abalone viscera silage Feed (II) and fish silage (Feed III). Nutritional value of these diet (i.e. Feed II and Feed III) were compared with that of commercial feed (Feed I) which was used as the control, based on the growth response of chickens. Results showed that rate of decrease in pH value was sufficiently rapid to stabilize the three silage. Silage F showed significantly higher pH value throughout the ensiling period, compared with Silage FG and Silage FGA. No significant difference (P<0.05) was, however, found between Silage FG and Silage FGA. Results can be attributed to incorporation of Gracilaria sp. in silage production, which provided favorable condition to decrease the pH value. Amino nitrogen content of all silage increased with ensiling time. Silage F exhibited the highest amino nitrogen content during 15 days of ensiling, followed by that of Silage FGA. Although the amino nitrogen content of Silage FGA was higher than that of Silage FG, significant differences (P<0.05) were noted only after 12 days of ensiling. Polypeptide content of all silage decreased after 3 days of ensiling. Silage FGA exhibited the highest polypeptide content after 9 days of ensiling. Monosaccharide content of all silage fluctuated during the ensiling period. However, the highest value was noted with Silage FGA, followed by Silage FG on the 3rd day of ensiling. This could be attributed to the highest polysaccharide hydrolysis rate exhibited by Silage FGA throughout the ensiling period. The best feed conversion ratio (FCR) and protein efficiency ratio (PER) were obtained with chickens given feed containing fish-Gracilaria sp. -abalone viscera silage (Feed II) during the 3-week feeding time. Body weights of chickens given Feed II were significantly higher than those given Feed III until the 3rd week of feeding. Reduction of fish content by as much as 30% and its substitution with 25% of Gracilaria and 5% of abalone viscera in silage (Feed II) gave the same effect on growth rate of chickens as that of silage made up of 100% fish (Feed III), and commercial feed (Feed I) without any mineral deficiency symptoms (e.g. slipped tendon or leg weakness and abnormal feather growth). Fish-Gracilaria .sp.-abalone viscera silage could be used as an ingredient for the production of an acceptable/palatable and nutritious feed for poultry.
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    Tolerance and behavioral response of Juvenile Siganus guttatus to Abaca Pulp Mill effluent
    Bradecina, Raul G. (College of Fisheries and Ocean Sciences, University of the Philippines in the Visayas, 2003-04)
    Acute bioassay and avoidance-preference tests were done on juvenile S. guttatus using lethal and sublethal concentrations of Abaca pulp mill effluent to assess the fish tolerance and behavioral response to the toxic stress and determine its effect to the chemoreception of biologically important odors. Acute bioassay response data were analyzed by log-probit method. Behavioral response data were calculated from the mean reaction values of the fish samples in the Y-maze apparatus. Results show the fish has a very narrow resistance to the toxic stress of the effluent with LT50 values of 1.6 h for the highest (100% vv-1) and 37 h for the lowest (10%vv-1) concentrations. The 48 h LC50 was located at 9%vv-1 which indicated the fugacity of the effluent and the sensitivity of the fish to its toxicity. The lowest concentration of the effluent with observed significant effect (LOEC) was located at 10%. The fish showed pronounced and significant discriminating ability at lethal concentration of the effluent. Avoidance reactions of the fish were only observed at 9% vv-1 (lethal) and 0.9 % vv-1 (sublethal) concentrations. The avoidance threshold was found at 0.74 % vv-1. Juvenile S. guttatus has a very narrow acuity to the effluent, which was located at a tenth ofthe mean lethal concentration value. Abaca pulp mill did not mask chemoreception of biologically important odors in juvenile S. guttatus.