UPV Theses and Dissertations
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Item Effects of high and low protein diets on the gut evacuation rate of Tilapia niloticaAndrada, Bryan Andrew S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1999-03)Gut evacuation rate of young Nile tilapia, Tilapia nilotica fed commercial pelleted diets containing high or low protein diet were determined in the laboratory. The decline in gut fullness of the fish with time was examined at low and high protein diets. Two mathematical models were used to express the decline in gut fullness of the fish with time. Fish fed the low protein diet followed more closely the linear model while those fed the high protein diet followed the logarithmic model. The level of protein resulted in different gut evacuation rates (GER), expressed as coefficients b of the gut fullnesstime curve. GER values were higher in either linear or logarithmic models for fish fed low protein diet than for those fed high protein diet.Item Diel feeding patterns of angelwing clam Pholas (Monothyra) orientales (Gmelin, 1970)Alojepan, Marbe Joy L. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1999-04)Filtration rate of Pholas orientalis measured using the indirect suspension deletion method and monitored by direct algal cell counts. Phytoplankton Isochrysis galbana was used as food at an algal cell concentration of 2.5 x 103 cells ml ”'. Biological rhythms have been demonstrated in all animals and plants except bacteria. They control rhythmic patterns in behavior and physiology of a living organism. Biological rhythms, or oscillations, have a “period” that is measured from one arbitrary point or phase of the rhythm to the next occurrence of that phase. They are best demonstrated in a 24 h cycle or circadian cycle. There is a widely varying feeding activity in the 24h cycle of P. orientalis observed at a constant temperature of 27$C and hydrogen ion concentration of 35%o Like any other bivalves, P. orientalis has defined feeding periods equivalent to food uptake at 2400h-0300h. Such observation could be supported by a previous study by Corda stating that optimal feeding was obtained at total darkness. Periods of digestion occur shortly after the periods of feeding. P. orientalis when actively feeding were observed to have extended siphons, larger valve openings, and an inclination of 45. One primary external stimulus that affected filtration rate was the amount of light present. Biorhythms provide temporal information, such as the time of day or season of the year, which facilitates adaptation of the organism to internal or external environments.Item A comparative study of the effects of supplementary feeding and artificial substrate on the production of milkfish fingerlings in brackishwater pondsAdeyemi, Frederick F. (University of the Philippines Visayas, 1983-03)ABSTRACT The growth and survival of milkfish fry in response to supplementary feeding and artificial substrate were evaluated at stocking densities of 75 and 100 fry/m2 for a period of 56 days from August 21 to October 15, 1982. The study was conducted in eighteen 40m2 experimental nursery ponds of the University of the Philippines Brackishwater Aquaculture Centre, Leganes, Iloilo. A 3 x 2 factorial experiment in completely randomized design was used and six treatment combinations between level of inputs (no inputs, supplementary feeding or artificial substrate) and stocking density (75 or 100 fry/m2) were investigated with three replicates per treatment. The best fish growth was obtained in Treatment VI (100 fry/m2 with substrate) with mean final weight and length of 1.59 gm. and 5.36 cm. respectively while Treatment IV (100 fry/m2 without feeding or substrate) gave the poorest fish growth with mean final weight and length of 0.83 gm. and 4.60 cm. respectively. Differences in mean weight and length among treatments were however, not statistically significant. Mean percentage survival was significantly higher at a stocking density of 75 fry/m2 (82.8%) than at 100 fry/m2 (64.1%) but supplementary feeding or artificial substrate ix did not show any statistically significant effect on survival. At either 75 or 100 fry/m2 stocking density, supplementary feeding gave a numerically higher percentage survival than artificial substrate. Economic analysis revealed that a stocking density of 75 fry/m2 without supplementary feeding or artificial substrate was the most profitable treatment with a return on investment of 39.2%. At a stocking density of 100 fry/ m2, supplementary feeding with rice bran was more profitable than the use of artificial substrate with returns on investment of 22.6% and 9.1% respectivelyItem Growth and yield Rabbitfish (Siganus guttatus) reared in river floating net cages at various stocking densities and feeding schemesAbalos, Rosie S. (University of the Philippines Visayas, 1995-03)Six treatment combinations consisted of three stocking densities of 50, 100, 200, rabbitfish (Siganus guttatus) per cubic meter (m3) at two feeding schemes of sliding 10, 8, 6, 5% commercial feed of fish biomass (F1) and 5% commercial feed of fish biomass daily with Chaetomorpha linum. "lumut" fed to satiation (F2) were tested to determine the growth and yield of rabbitfish in river floating net cages for 120 days. The F1 at stocking density of 50 fish/m3 and fed commercial feeds daily at sliding (10-8-6-5% BW) feeding scheme registered the highest mean growth of 105.6 g/fish. However, statistical analysis showed no significant difference (P>0.05) in growth among treatments. In terms of production, the F2 at 200 fish/m3 and fed commercial feeds at 5% BW plus "lumut" registered the highest mean production of 18.23 kg/m3 . Production was highly significant (P<0.01) in between stocking densities but not between feeding schemes. Survival (90 - 96%) and mean feed conversion ratios (3.6 - 4.4) were not significantly different (P>0.05) among treatments. Rearing S. guttatus in floating net cage at 200 fish/m fed commercial feeds daily at 5% BW plus "lumut" fed to satiation appeared to give the highest net income of P705.96/m and a benefit-cost-ratio of 1.42.