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UPV Theses and Dissertations

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    Evaluation of feeding performance of early siganid, Siganus guttatus, larvae fed with mixed zooplankton
    Andrade, Maria Shiela S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1999-04)
    Siganus guttatus is an economically important rabbitfish for commercial farming. It is very important to evaluate their feeding performance particularly the effects of different diets for this larvae and to determine their growth and survival after being fed on different diets. Newly-hatched siganid, Siganus guttatus, larvae were reared in 500-L fiberglass tanks and fed either on copepod nauplii and rotifers alone or combination of both. Copepod nauplii proliferated in tanks consisted mainly of Pseudodiaptomus sp., and Acartia sp. Siganid larvae successfully commenced feeding (feeding incidence) on early stage copepod nauplii even if their abundance was low. Selective feeding ability of larvae seemed to start from day 6 and the larvae thereafter preferred to feed nauplii than rotifers. Survival of the siganid larvae was significantly higher when fed with with combination of rotifers and copepod nauplii compared to those fed with either rotifers or copepod alone. The growth of the larvae however are the same for all treatments. Results of this study suggest that coastal calanoid copepods of the genus Pseudodiaptomus sp. and Acartia sp. could be reproduced in tanks and their nauplii can be used as food for siganid larval rearing.
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    Effects of sodium Iodine -enriched brine shrimp (Artemia salina) on the growth, survival and metamorphosis of Rabbitfish (Siganus guttatus) bloch larvae
    Legaspi, Ma. Irene C. (Institute of Aquaculture, College of Fisheries and Ocean Sciences, 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.
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    Growth and yield Rabbitfish (Siganus guttatus) reared in river floating net cages at various stocking densities and feeding schemes
    Abalos, 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.