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UPV Theses and Dissertations

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Committee Member: search.filters.committeemember.Sanares, Roman C.Discipline: search.filters.discipline.Aquaculture

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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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    Evaluation of commercial shrimp larval diet as replacement of live foods in mudcrab larval rearing
    Burlas, Michael Rey J. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2014-04)
    The use of live food such as rotifer and Artemia entails high cost of production in the hatchery. Hence, the general objective of the study was to reduce the use of natural food in the larval rearing of mud crab. The first study was conducted to screen four types of commercial shrimp formulated larval diet (Lansy, P. japonicus, P. monodon and BP Nippai) in mudcrab Scylla serrata larval rearing. Formulated diets were fed to each stage from zoea 1 to megalopa at an equivalent of 100% dry weight of the live food. Growth index and survival were determined at the end of the experiment. Results showed that of zoea 1 fed any of the formulated diet did not molt to zoea 2. When formulated diets were fed to zoea 2, 3 and 4, there was a decreasing trend in the growth index and survival as the larvae developed. Zoea 5 fed any of the formulated diet failed to molt to megalopa stage. Among the four formulated diets, BP fed larvae had better growth and survival. BP was then used in the second study to determine the amount of formulated diet (FD) that could replace natural food (NF) such as rotifer and Artemia. Results showed that larvae fed 25% FD + 75% NF and 50% FD + 50% NF had better survival and growth than those larvae fed 100% FD + 0% NF, 75% FD + 25% NF and 0% FD + 100% NF. This study indicates that shrimp larval diet in combination with formulated diet can be used to improve the growth and survival of S. serrata larvae.
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    Evaluation of different carbon sources used in the biofloc technology (BFT) culture of Litopenaeus vannamei
    Alaban, Leovigildo Rey S. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2011-04)
    An evaluation of different carbon sources used in Biofloc technology (BFT) culture of L. vannamei was done. The experiment included five treatments: Control, RB (Rice Bran), Tap (Tapioca), Mol (Molasses) and COMBI (Molasses + Rice Bran). Evaluation of biofloc parameters - Total Suspended Solids (TSS) and Settleable Solids (SS)- showed an increasing trend in treatments with molasses (Mol and COMBI) as the culture progressed. This became significantly different (P < 0.05) in the later phase of the culture. The evaluation of environmental parameters included TAN (Total Ammonia Nitrogen), NO2-N (Nitrite Nitrogen) and Chlorophyll a. In treatments with rice bran (RB and COMBI), TAN showed an increasing trend, becoming significantly different with the rest in the later phase of the culture (P < 0.05), while NO2-N were maintained below toxic levels. Chlorophyll a didn’t show any discernable pattern. The effect on L. vannamei was evaluated based on growth (ABW-Average Body Weight, SGR-Specific Growth Rate and FCR- Feed Conversion Ratio) and yield (Survival and Biomass) parameters. Treatments with rice bran showed faster growth rates compared to the rest (P < 0.05) for most part of the culture period. However, analyses of growth parameters based on harvest data don’t show any significant difference in SGR and final ABW for all treatments. Further, poor water quality in these treatments lead to heavy mortalities which caused FCR and Biomass to be significantly different (P < 0.05) from the rest of the treatments.