Masters Theses
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/12
Browse
3 results
Search Results
Item Effect of different bio-augmentation agents on the biochemical composition of bacterial floc and growth of juvenile Penaeus monodon cultured in concrete tanksDianala, Rex Delsar B. (University of the Philippines Visayas, 2012-10)The effect of bio-augmentation agents on the biochemical composition of biofloc, growth ofjuvenile Penaeus monodon, and antimicrobial activity of BFT water against Vibrio harveyi was investigated. P. monodon juveniles were cultured in pond soil-lined concrete tanks for 150 d using biofloc technology with bio-augmentation. Three commercial bio-augmentation agents (Pond Protect™, Pond Dtox™, BZT Waste Digester™) were tested against a control with no bio-augmentation agent application. At the end of the culture period, floc and shrimp collected for proximate analysis, and biofloc water tested for activity against V. harveyi. Average body weight (ABW), food conversion ratio (FCR), and specific growth rate (SGR) of the shrimp were computed. Bio augmentation with Pond Protect™ resulted in significantly higher (p < 0.05) crude protein content of the biofloc although this did not translate to higher shrimp yield nor growth performance. BZT Waste Digester™ as bio-augmentation agent significantly increased (p < 0.05) shrimp ABW. No apparent relationship between floc composition and shrimp carcass composition was observed. BFT water, with and without bioaugmentation agents, completely inhibited V. harveyi within 24 h. This study demonstrates that bio-augmentation agents could enhance the biochemical composition offloc and affect shrimp growth. BFT water was also shown to have potent antimicrobial properties against V. harveyi.Item Survival of nursery-reared juvenile milkfish, Chanos-chanos at different transport density, temperature and anaesthetic combinationsFailaman, Alan N. (University of the Philippines Visayas, 2020-06)Experiments were conducted to optimize transport conditions of nursery cultured juvenile milkfish in a closed plastic bag based transport system. In the first experiment combined effects of temperature (25-27°C, 20-22°C and 15-17°C) and anesthetics (2-phenoxyethanol at 200 mgL-1 for initial sedation and 80 mgL-1 for transport sedation) on oxygen consumption and survival ofjuvenile milkfish, Chanos chanos, were evaluated. Another experiment was conducted to optimize transport conditions at fish densities of 200, 400, 600, 800 and 1000 gL-1 for 4, 8, 12,16 and 20 hour duration. The study showed no significant difference on oxygen consumption rates ofmilkfishjuveniles subjected to various water temperature range and anesthetic combinations. Temperature range of 20 to 22°C in combination with anaesthetic (2-phenoxyethanol) application was the best condition for long duration confinement of milkfish juvenile in closed plastic transport bags. The study established the optimum juvenile milkfish transport density and the effective transport duration. With anaesthetic application (2-phenoxyethanol), juvenile milkfish density of 600 gL-1 is effective for 20 hours oftransport duration, 800 gL-1 for 8 hours oftransport duration and 1000 gL-1 effective for 4 hours transport duration. These results provide a practical protocol for the transport of juvenile milkfish from the nursery culture area to the grow-out production area.Item Effects of sodium iodide-enriched brine shrimp (Artemia salina) on the growth, survival and metamorphosis of rabbitfish (Siganus guttatus) bloch larvaeCabanilla-Legaspi, Ma. Irene C. (University of the Philippines Visayas, 2018-06)Metamorphosis is considered the most crucial stage in larval fish development that dictates the overall larval fish survival and production output in a hatchery system. This physiological process is modulated by thyroid hormones produced from the thyroid gland the biosynthesis of which is dependent on the supply and availability of the mineral iodine. The present study evaluated the supplementation of iodine to rabbitfish (Siganus guttatus) larvae to determine the influence of this mineral on thyroid hormone levels, metamorphosis, growth performance, stress tolerance and survival. To efficiently deliver iodine to the larvae, the enrichment protocol was optimized by exposing the Artemia to increasing concentrations of this mineral (0.05 g L-1,0.1 g L-1, 0.2 g L-l, 0.4 g L-1 and 0.8 g L-1). The best iodine enrichment treatment was selected (0.8 g NaI L-1) and used to evaluate the influence of this mineral on larval development, growth, metamorphosis, stress tolerance and survival. Results suggest that growth of rabbitfish in terms of body weight was higher in the treated group (0.20±0.01g) as compared to the control group (0.14±0.01g). This significant growth response is associated with accelerated period of metamorphosis by 11.2 days and a lower muscle fiber count in the treated group (0.003±0.005 μm2-1). Higher levels of triiodothyronine (T3) and thyroxine (T4) were also observed in the group receiving the iodine-enriched Artemia that coincides with the larvae’s accelerated period to metamorphose. T3 in the treated group (15.31±1.22 ng g-1) is higher compared with the control (8.67±1.5 ng g-1) and T4 in the treated group (459.25±136.9 ng g-1) is also higher compared with the control group (170.86±92.55ng g-1) at 27 days after hatching which coincides with the onset of metamorphosis leading to early metamorphosis of larvae in the treated group. In addition, the present results showed that the larvae in treated group were significantly tolerant to stress, quantified as the cumulative stress index (15.33±2.40 CSI) indicating the positive response of the larvae to the dietary iodine enrichment. In summary, sodium iodide-enriched live food (Artemia) accelerated rabbitfish larvae metamorphosis, improved growth and stress tolerance in rabbitfish larvae. The results of this study can be used as a model iodine enrichment protocol to improve the hatchery output of other high-valued marine fish species in culture.