Association of annual hormonal profile with gonad maturity of mahseer (Tor tambroides) in captivity

Abstract

Annual gonad hormonal profile of wild, matured mahseer (29 males and 23 female) averaging in weight between 0.95±0.26 and 1.19±0.23 kg for males and females, respectively, were investigated from November 2007 to November 2008 using enzyme-linked immunosorbent assay (ELISA) technique. Blood was collected from caudal vein, monthly and plasma separation by centrifugation was done to measure reproductive hormones: 17β-estradiol (E(2)), testosterone (T), and 11-keto-testosterone (11KT). Gonads were sampled for histology processing to observe their maturity. Highest T level in females and males was recorded at 0.22±0.016 and 0.88±0.014 ng/ml, respectively. The 11KT showed several peaks and the highest value was noted at 0.7±0.018 ng/ml in November 2008. The female E(2) initially was at 1.48±0.16 ng/ml and significantly increased (P<0.05) to 1.53±0.39 ng/ml in November 2008. Ovaries were laden with oocytes in several stages in all the samples while testes gonad showed a high level of spermatids throughout the year. Changes in plasma level of the gonadal hormones were correlated with the ovarian and testes maturities. In conclusion, the study suggests that mahseer can be categorized as asynchronized and multiple spawner. The information gathered is important for appropriate breeding and conservation programs of the Malaysian mahseer.

Spermatogenesis and related plasma androgen and progestin level in wild male golden mahseer, Tor putitora (Hamilton, 1822), during the spawning season

“…It has been recognised that in cystic spermatogenesis, synchronous germ cell development produces a large number of simultaneously mature SPZ, compared with semi-cystic spermatogenesis (García-López et al 2006). Except for T. tambroides (Ismail et al 2011), so far, there are no reports describing previously the testicular development of this species or any other Tor species. However, the study conducted by Ismail et al (2011) in T. tambroides did not mention the type of spermatogenesis; rather, they described the annual sex hormone profile and germ cell development.…”

“…The major bottleneck for its intensive culture is the inability of this Tor sp. to attain complete gonadal maturity in captivity (Ismail et al 2011). Artificial propagation through inducing maturation and spawning by using sex hormones has been attempted (Pandey et al 1998), with limited success.…”

“…Like other vertebrates, the gonad maturation of fish is regulated by several sex hormones (Lee and Yang 2002;Estay et al 2003;Ismail et al 2011). In males, androgen and progestin such as testosterone (T), 11-ketotestosterone (11-KT) and 17,20b-dihydoxy-4-pregnen-3-one (17,20b-P), respectively, are known to regulate testicular development by their direct influence on germ cell and also by exerting feedback effects in brain-pituitary-gonad (BPG) axis (Weltzien et al 2002).…”

“…Although 11-KT is considered as main androgen in teleost fish (Borg 1994;Koya et al 2002;García-López et al 2006;Ismail et al 2011), sporadically T is found to be the main sex steroid in certain fish (Matsuyama et al 1991). The temporal variation in plasma sex steroid levels in relation to testis development has been studied in Senegalese sole, Solea senegalensis Kaup (García-López et al 2006), Atlantic halibut, Hippoglossus hippoglossus L. (Weltzien et al 2002), Pacific herring, Clupea pallasii (Koya et al 2002), spotted halibut, Verasper variegates (Koya et al 2003), African catfish, Clarias gariepinus (Cavaco et al 1997a, b), Japanese eel, Anguilla japonica (Miura et al 1991), winter flounder, Pleuronectes americanus (Harmin et al 1995), English sole, Pleuronectes vetulus (Sol et al 1998), rainbow trout, Salmo gairdnerii Richardson (Scott et al 1980) and mahseer Tor tambroides (Ismail et al 2011). However, to our knowledge, there are no detailed studies, which focus on spermatogenic cycle of T. putitora in terms of testicular development in relation to plasma 11-KT, T and 17,20b-P.…”

Gonad Ultrasonography Image Preprocessing for Mahseer (Tor Tombroides)

“…In Malaysia, Tor Tombroides locally known as 'Kelah', is one of the highly preferred freshwater fish and this species can only be found in pristine freshwater rivers Ismail et al (2011). Mahseer can be captured in places such as The Royal Belum in Perak, Taman Negara in Pahang and also Andang River in Sarawak.…”