Effect of vertebrate steroid hormones on the ovarian maturation stages of orange mud crab, Scylla olivacea (Herbst, 1796)

摘要

Orange mud crab, Scylla olivacea soughted as delicacy because their flesh is tasty and has high quality which boosted its commercial value in Malaysia. This studies focused on S. olivacea ovarian maturation after the introduction of steroid-based hormones i.e. 17 alpha-hydroxyprogesterone (17 alpha-OHP) and 17 alpha-hydroxypregnenolone (17 alpha-OHPL). The effects brought by these hormones were explored through external morphology, histology of oocyte and haemolymph hormone expressions. The crabs, S. olivacea were collected from Kuala Muda, Kedah on the West Coast of Peninsular Malaysia (5 degrees 39' N 100 degrees 19'E). After brief incubation, the crabs were introduced with treatments (through injection) of 95% alcohol (mu l/g BW), 17 alpha-OHP (0.01 mu g/g BW and 0.1 mu g/g BW) and 17 alpha-OHPL (0.01 mu g/g BW and 0.1 mu g/g BW). During the treatment period, ovary coloration, gonad somatic index (GSI), oocyte diameter, oocyte structure and, levels of 17 alpha-OHP as well as 17 alpha-OHPL in haemolymph were collected every 10 days throughout the 60 days of treatment. Crabs injected with 95% alcohol showed negligible signs of ovarian maturation compared to those injected with hormones. However, crabs injected with 17 alpha-OHPL showed increased ovarian maturity, produced the highest GSI (2.51 +/- 0.72%) and produced large oocytes (diameter = 178.63 mu m) with uniform development compared to crabs injected with 17 alpha-OHP. In addition, decreased 17 alpha-OHPL concentrations in the crab's haemolymph signifies utilization (of this hormone) to produce oestrogen. Hence, the findings obtained from this study depict fundamental biological information of the crab, S. olivacea. Nevertheless, the use of matured female S. olivacea is highly recommended for better results.