| Author | Nacario, Evelyn N. |
| Call Number | AIT Thesis no.AE-87-35 |
| Subject(s) | Tilapia
|
| Note | A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The present study dealt with the optimization of treatment regimes
for the masculinization of gonadally undifferentiated Nile tilapia fry, in
net enclosures in ponds, by administration of 17 a-Methyltestosterone
(MT)- treated feed at concentrations of 40 and 60 mgMT /kg diet for 40
days. Following a Latin-square design of treatment factors MT (0-40-60
ppm) and stocking density (4-8-12 fish / I), nine treatment combinations
were established . The results indicated that fish growth in terms of
specific growth rate, daily weight gain, percentage weight gain and mean
individual fish weight, and the rate of food conversion were highly correlated with differences in stocking rate. Androgen concentrations directly affected the rate of success for sex reversal. At the highest MT
concentration (60 ppm) the male percentage was 82. 98% . This was succeeded by a percentage reversal of 72.83% which corresponded to the 40
ppm MT dose, and for the control diet, 59 . 74% . Success rates of sex
reversal for this study were relatively low possibly due to the
temperature-dependent hormone efficacy phenomenon and the interference
of natural food over the intake of treated diets . Overall fish survival
did not significantly vary amongst treatments (p::;; 0 .01), although differences in percentage survival during hormone treatment (evaluated at
the end of Phase I) was noticeable to a certain degree (p ~ 0.10), on
an MT-based comparison. This was ascribed to non-uniformity in initial
stocking size and the tendency of cannibalism of young tilapia fry. |
| Year | 1987 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Wee, Kok Leong |
| Examination Committee(s) | Edwards, Peter ;Lin, Chang Kwei |
| Scholarship Donor(s) | The Government of Australia |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1987 |