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Title: Effects of ovaprim stimulation on egg production, hatching rate and fry survival rate in red tilapia (Oreochromis niloticus)
Authors: Mohd Faizzi Mohd Yusof
Keywords: Oreochromis niloticus
Egg incubation
Ovaprim stimulation
Issue Date: 2008
Publisher: University of Malaya
Abstract: The main objective of this study was to measure various reproductive parameters after spawning induction using ovaprim (1.0 ml/kg) in three groups of body weight and body length of red tilapia fish (Oreochromis niloticus). In addition, the study was also conducted to observe the correlations between reproductive characteristics with fish body sizes and types of egg incubation. Blood samples were collected from each group randomly by selecting induced broodstocks which had been cultured in laboratory conditions. Serum levels of 17β-oestradiol (E2) were measured by means of radioimmunoassay technique. Number of eggs, total weight of eggs, weight of one egg and diameter of eggs were measured in all spawned fish that were ovulated on the second day after administration of ovaprim (1.0 ml/kg) with split injections. Meanwhile, hatching rate and fry survival rate were evaluated by using artificial incubation, whereby, maternal incubation as a comparative study was done to evaluate fry survival rate. Fish body size does affect (P<0.01) in terms of number of eggs per female when large female tilapia fish (>450 g) produced the highest mean number of eggs (1314.3±158.5 eggs per female), and it was also positively correlated with total weight of eggs (P<0.01). A significant negative correlation was also obtained between weight of one egg produced and fish body size, indicating that size is a factor influencing egg weight in spawning induction. Relative egg weight was lower for the bigger fish body size compared with the smaller fish body size. A significant effect (P<0.05) of body size on serum 17β-oestradiol levels was found. Medium fish body size produced the highest 17β-oestradiol concentration (113.454±29.351 pg/ml). Meanwhile, on day 2 and during afternoon on day 1 to 3 exhibited the highest 17β- oestradiol concentrations (81.424±20.047 pg/ml and 94.055±28.287 pg/ml, respectively), indicating favourable oocyte maturation stimulation and ovulation for all sizes of induced red tilapia fish. Hatching rate was inversely related to the number of eggs per female incubated in an artificial incubator and increase in hatchability would increase the fry survival rate of red tilapia fish in an artificial incubation (P<0.01). Comparison between artificial and maternal incubations, demonstrated that both incubation systems are suitable for fry survival rates of this species. Overall fry survival rate was not significantly different (P>0.05) in artificially incubated eggs (94.885±0.687%) when compared with those brooded in the maternal mouth throughout the embryonic development (94.952±1.388%). It can be seen that artificial incubation provides approximately similar results to those of maternal incubation. The present study has provided essential fundamental descriptions of reproductive parameters via ovaprim stimulation on red tilapia fish within laboratory conditions. In conclusion, the findings on the reproductive performance of the hormonally induced spawning may be applied to other fish species so that fish culturists may be able to develop proper hatching operations, adjusting and adapting available technology to local conditions.
Description: Dissertation (M.Sc.) -- Faculty of Science, University of Malaya, 2008.
URI: http://dspace.fsktm.um.edu.my/handle/1812/491
Appears in Collections:Masters Dissertations : Science

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