THE EFFECT OF FERTILIZATION MEDIA pH ON SPERMATOZOA FERTILIZATION PROCESS AS THE RESULTS OF SEXING ON PANGASIUS (PANGASIONODON HYPOPHTHALMUS)

Pangasius (P. hypophthalmus) is one of the freshwater commodities of an important economic value. The pH on fertilization media can influence fertilization and affect sex determination (Sandra and Norma, 2009). Sexing with Percoll Density Gradient Centrifugation (PDGC) method can separate X and Y spermatozoa based on their size (Rustidja, 1999). The study analyzed the results of X and Y spermatozoa sexing on Pangasius using the PDGC method and specified the ability of pH in influencing X and Y spermatozoa in the fertilization process. The results showed that, at stage 1, the spermatozoa head on the top layer (La) was larger than that on the bottom layer. The spermatozoa head length (HL) on the top layer was 2.59 ± 0.19 μm with a wide length (WL) of 1.62 ± 0.11 μm. Meanwhile, on the bottom layer, the HL was 2.27 ± 0.12 μm with a WL of 1.44 ± 0.07 μm. Therefore, the top layer was identified as X (female) and the bottom layer as Y (male). The average value of spermatozoa concentration after PDGC at the top layer was 7.11 ± 1.743 x 107 cells/mL and at the bottom layer was 3.57 ± 1.075 x 107 cells/mL. The average value of motility at the top layer was 61.67 ± 7.637% and at the bottom layer was 46.67 ± 5.773%, and the average value of viability at the top layer was 61.04 ± 7.27% and at the bottom layer was 55.17 ± 2.53%. This study revealed that the effect of pH on the fertilization rate (FR) with Y control spermatozoa was -177.8 + 68.377 x -4.234 x2, R² = 0.603. The finding confirmed that the best treatment for this control was pH 8.07 and FR 98.27%. The assessment on Y top layer spermatozoa resulted in of -100.27 + 40.836 x – 2.568 x2, R² 0.637. The finding showed that the best treatment for the top layer spermatozoa was pH 7.95 and FR 62.07%. The examination on Y bottom layer spermatozoa generated an equation of -32.195 + 22.746 x -1.4619 x2, R² = 0.523. It can be said that the best treatment in the bottom layer was pH 7.78 and FR 56.28%. However, the hatching rate (HR) to pH treatment on each treatment did not show significant differences (P >0.05). To sum up, the PDGC method on Pangasius spermatozoa could separate the spermatozoa based on the top and bottom layer size. The PDGC method could produce female seeds on the top layer by 85% and male seeds on the bottom layer by 68%.