Interative effects of high temperature and hormone feeding duration on sex reversal of Nile Tilapia (Oreochromis niloticus) | |
| Author | Rahma, Aulia |
| Call Number | AIT Thesis no.AQ-13-02 |
| Subject(s) | Nile tilapia--Feeding and feeds Fishes--Feeding and feeds |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Aquaculture and Aquatic Resource Management |
| Publisher | Asian Institute of Technology |
| Abstract | Tilapia sex is not differentiated at early stage of life. This is the critical period for gonad differentiation in which hormonal or other treatments can direct tilapia develop male sex. The interaction effect of high temperature and reduction of 17-αMethyltestosterone hormone (MT) feeding period and its effect on the sex ratio of tilapia were studied in Aquaculture and Aquatic Resource Management (AARM) hatchery and ponds in Asian Institute of Technology (AIT), Bangkok, Thailand. High temperature treatment (360C) was given to10 days post fertilization (dpf) fry of Chitralada strain tilapia for 48 hours.MT feeding was startedat12 dpf in earthen pond for periods of 21,14 and 7 days. The percentage of male tilapia was significantly different among the groups (p˂0.05);while the highest percentage(99%)of males was observed with the groups given MT feed for 21 days with or without high temperature treatment and the lowest male percentage (55±5%) was in the group without high temperature treatment and without MT hormone. The group treated with high temperature treatment and without MT hormone resulted in 65±3% male tilapia. Reduction of MT feeding duration to the fry treated with high temperature resulted in reduction of male tilapia percentage. High temperature treatment followed by 14 days and 7 days MT feeding duration resulted 95±1% and 88±1% male tilapia respectively. However, male percentage (95±1%) in the group given MT feed for14 days after high temperature treatment was not significantly different (p˃0.05) with male percentage in the groups given MT for21 days. Growth performance of tilapia was affected by pond condition. The interaction between high temperature and MT hormone treatment did not affect growth performance. High temperature treatment affected survival rate(94±1%) of fry compared with survival rate(99±1%) obtained in normal in cubation in hatchery. The reduction of MT feeding period combined with high temperature(360C) treatment could decrease the male percentage production. High temperature treatment seemed to be the minor factor affecting sex ratio and the major factor was MT hormone feeding treatment. Exogenous steroid(MT hormone feeding)is better than high temperature treatment in directing the mechanism in testicular development. Two days exposure of 10 dpf tilapia fry tohigh temperature was not enough to change the pathway towards testicular differentiation. Therefore the combination of these treatments seemed not effective to increase the male production intilapia. Longer period of high temperature treatment (more than 2 days) for Tilapia Chitralada strain is estimated to produce higher male percentage. In addition, recirculating incubation system with high temperature treatment set up is recommended in order to maintain water quality during longer treatment period rather thana non-recirculating water bath. |
| Year | 2013 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Gallardo, Wenresti; |
| Examination Committee(s) | Yakupitiyage, Amararatne;Bhujel, Ram C.;Dabbadie, Lionel; |
| Scholarship Donor(s) | The Government of The Province of Aceh, Indonesia; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2013 |