Pituitary adenylate cyclase activating polypertide (tPACAP38) and vitellogenin (Vtg) expressions in male tilapia hybrids (Califonia 0. niloticus x 0. Mossambicus) exposed to DE-71 under freshwater and saline water conditions

• Main Author: Calma, Rosemarie R.
• Format: text
• Language: English
• Published: Animo Repository 2014
• Subjects: Food Science
• Online Access: https://animorepository.dlsu.edu.ph/etd_doctoral/1181
• Institution: De La Salle University

The estrogenic effects of DE-71 on male euryhaline tilapia hybrids (California O. mossambicus x O. niloticus) reared in saline water condition were investigated based on the expressions of protein, gene fragments and cDNA sequences of tPACAP38 and Vtg. The histological effects on the gonads and liver were also described. A total of 910 tilapia eggs were reared in gradual salinity until yolk sac resorption stage then exposed to 100ppm E2, solvent control and different concentrations of DE-71 (0.2, 2.0, 20 and 200 ppm) dissolved in acetone through dietary route for 30 days. Results revealed that tPACAP38 protein were induced by DE-71 but was not affected by different treatment concentrations or exposure to either freshwater or saline water conditions. The gene expression of tPACAP38 showed a three to nine fold increase in DE-71 or E2 treatments under saline water. Likewise, a high concentration of DE-71(200ppm) downregulated the protein and gene expressions of tVtgAa in saline water but not in E2. The different treatments and water conditions did not significantly affect the protein and gene expressions of tVtgAb. Under freshwater condition DE-71 induced the protein expression of tVtgC but the varying concentrations have no significant effect. However, under saline water condition, the relative gene expression of tVtgC is upregulated three to six folds by the increasing concentrations of DE-71 and five folds in E2. The gene sequences that code for the tPACAP38 mature peptide and the Vtg isoforms were highly conserved in the different treatments and the quality of the nucleotide sequences are better in DE-71 and E2 treatments under freshwater for tPACAP38, for tVtgAa and tVtgAb under saline water and in either water conditions for tVtgC. The histological sections of the gonads from different concentrations of DE-71 and water conditions did not show ovotesticular formation or changes on the gonadal cells as expected, but E2- treated fish have ovaries at perinucleolar stages. The hepatocytes from DE-71 treated fish are normal in both water conditions compared to E2-treated fry in saline water which were observed to have few vacuolizations.