Sex steroid profiles, gonadal histology and early development of clarias batrachus linneaus in captivity

Clarias batrachus is a local species in South East Asia and is the most popular in terms of aquaculture and aquarium trade among Asian species. Its excellent nutritional profile and ability to perform in water environments with depleted water quality condition has made it a good candidate for aquaculture. It could accommodate high density stocking and ensure high yield per unit area. The fish is threatened and is getting extinct due to overexploitation of water resource, habitat loss, and unguarded introduction of exotic species such as Clarias gariepinus and indiscriminate use of agrochemicals particularly pesticides in the paddy fields which is the popular natural breeding ground of the species. This has made it increasingly difficult to obtain the seed of the species from the wild. Aquaculture is the only platform upon which the extinction of this promising species can be arrested and the fact that hatchery-bred fish has to be induced to spawn due to lack of spontaneous spawning in captivity has made the study of the reproductive biology of this species a necessity. Consequently, reproductive hormonal profile and gonadal development of C. batrachus were investigated at the University Putra Malaysia Aquaculture Research Station in Puchong, Selangor, Malaysia from February 2012 to January 2013. The brood stocks for the study were obtained from the wild at Negeri Sembilan. Commercial Enzyme Linked Immunosorbent Assay (ELISA) was used to assay plasma sex steroid hormones, 17β-estradiol, 11-ketotestosterone and testosterone. The range values of 17β-estradiol, 11-ketotestosterone, male and female testosterones were 111.68 ± 3.62 pg/ml (December) to 695.30 ± 8.94 pg/ml (October), 6.61 ± 0.24 pg/ml (September) to 80.27 ± 5.29 pg/ml (August), 26.67 ± 0.98 pg/ml (September) to 209 21 ± 19.49 pg/ml (October) and 7.02 ± 0.06 pg/ml (February) to 49.99 ± 2.17 pg/ml (October) respectively. The monthly values of 17β-estradiol, 11-ketotestosterone and testosterone were significantly different (P