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Title: Genetic approaches to improvement of tilapia culture in Thailand
Author: Pongsri, C.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1994
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Masculinization and feminization of the Jitralada strain of Oreochromis niloticus (L.) could be induced with a high level of success by oral administration of a 40-mg kg-1 of 17-α-methyltestosterone and 40-mg mg^-1 of ethynyl-estradiol, respectively, to the first-feeding fry for a period of 21 days. On the other hand, optimization of dosage and means of application of 17-β-oestradiol or Pueraria mirifica roots are still needed in inducing reliable feminization of this strain. Differences in the results obtained are discussed and it is concluded that there are significant genetic differences between strains in the readiness with which sex reversal can be brought about. The modification and application of starch gel and SDS-polyacrylamide gel electrophoresis are proved useful and powerful in the investigation of biochemical studies of tilapia. The use of fin tissue in starch gel electrophoresis was advantageous and gave adequate data for the identification of tilapiine fish. Allozymes studies of the Jitralada strain of O.niloticus (L.) in Northeastern Thailand provided clear evidence of gene leakage and introgression from O.mossambicus at the Chaiyaphum Inland Fisheries Station. The results of inheritance studies on F1 hybrids between O.niloticus and O.aureus and back-crosses, at the ADA* locus and blood serum protein, fit well to Mendelian inheritance. Expression of the ADA* locus is found to be controlled by a single autosomal gene. The pattern of blood serum protein of O.spilurus, O.aureus, O.niloticus and F1 hybrids between O.niloticus and O.aureus from 8% SDS-polyacrylamide gel electrophoresis were investigated. A band of 63 kDa in molecular weight was present only in F1 female hybrids between O.niloticus and O.aureus. A model is proposed to explain this phenomenon.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available