Vitellogenin Dynamics and Reproductive Morphology at Sexual Maturity of Philippine Mallard (Anas platyrhynchos domesticus L) Fed with Zinc Die
1Arnolfo M. Monleon, 2Angel L. Lambio, 2Renato SA Vega, 2Severino S.Capitan and 3Carmelita M. Rebancos
1School of Agriculture, Marinduque State College, Torrijos, Marinduque, Philippines;2Animal and Dairy Sciences Cluster, College of Agriculture, University of the Philippines, LosBaños, College, Laguna, Philippines; 3School of Environmental Science, University of the Philippines, Los Baños, College, Laguna, Philippines.
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The vitellogenin (Vtg) is a precursor for the synthesis of egg yolk protein. Feeding with zinc-supplemented diet is hypothesized to increase the circulating Vtg thereby enhancing reproductive development in Philippine mallard (Anas platyrhynchos domesticus L). A total of 80 ducks, aged 16 weeks old, were randomly assigned to treatment groups; namely: group A with 40 ducks fed with 30 ppm zinc-diet (zinc positive) and group B with 40 ducks fed with no added zinc (zinc negative). All ducks were kept individually in cage. Twenty ducks each group were processed at sexual maturity for the determination of selected reproductive parameters, namely: ovary weight, oviduct weight, stroma weight, follicular development, and reproductive indices. The circulating Vtg at sexual maturity (155.11±10.83 days old) were determined from the blood sera. The sera were assayed in duplicate using 96–well microplate and read the optical density at 415nm in a microplate reader (Model 680, S/N 123669). The zinc concentration of the samples was calculated using the nonlinear regression formula ΔOD = a x [Zn2+] / (b + [Zn2+]. Results show that the circulating Vtg in the blood serum of ducks at sexual maturity were 0.69±0.07 µg Zn dL-1. The zinc-supplemented diet has insignificantly influenced the concentration of circulating Vtg. There was also insignificant difference in the reproductive morphology of ducks fed with or without added zinc. The Vtg concentration was found not correlated with the selected reproductive parameters at sexual maturity.
Keywords: Philippine mallard, Reproductive morphology,Vitellogenin, Zinc.