Cytological status of hepatocytes in respect to seasons influencing ovarian activities has been studied in Mastacembelus armatus (Hamilton). Histologically, the hepatocyte of female liver was provided with distinct nucleus and basophilic cytoplasmic granules. In M. armatus different germ line cells were recognized on the basis of size and histoarchitecture of the cells. By examining seasonal changes in relation to hepatocytes and ovary, it was found that during growth and maturation phases the density of cytoplasmic granules of hepatocytes was increased in number as well as the nucleus become hypertrophied. These features were well correlated with the occurrence of cortical alveolus and yolk granule stage in the ovary. During spawning phase the cytoplasmic granules were sparse in the hypertrophied hepatic cells. This was due to the dynamic cytological activities like vitellogenesis and occurrence of mature oocytes in the ovary. However, no significant alterations were noticed in the hepatocytes during post spawning phase due to the appearance of new germ line cells in the ovary. Cytological changes in the hepatocytes were correlated with the reproductive phases in female M. armatus.

Introduction: Mastacembelusarmatus, an indigenous fish species of southern Asia, also resides in Indian subcontinent. This fish species is facing an alarming declining in their number in the last decade. Due to its moderate cost, it is mainly taken by the lower income group of people of the society. Reproductive care, by artificial breeding, has been taken for those fish species having a high cost in the market or becoming less in number in nature for business purposes or preserving the biodiversity, respectively. Aim of the study: The present study was undertaken to understand the structure of hypothalamic nulceiof M. armatus, because these are ultimately responsible for the maintenance of pituitary-gonadal endocrine cascade. Material and methods:This work had been done purely on histological techniques.Hypothalamic region with the brain was first dissected out then followed by fixation, embedding in paraffin wax, sectioning, staining and microphotography. Results: In the present investigation the nucleus preopticus (NPO) are paired, eachnuclear area being situated on either side of the third ventricle. The NPO iselongated in structure and the differentiated zones, the pars magnocellularis andpars parvocellularis. The neurosecretory nuclei ofnucleus lateralis tuberis (NLT) are very prominent and occupy a position nearer to the pituitary gland. The cells of the NLT aredivided into two subgroups. The comparatively larger α – cells are located anterior end of lateral wall of the hypothalamus and the β – cells are located above the pituitary gland. Conclusion: Understanding the hypothalamic architecture and cell types for this fish species is of immense importance to save this indigenous variety by artificial breeding.

Gonadosomatic index is a less expensive and alternative method than histological observation for the determination of spawning season in fish species. Mastacembelus armatus, an indigenous fish species of southern Asia, also resides in Indian subcontinent. This fish species is facing an alarming declining in their number in the last decade. Due to its moderate cost, It is mainly taken by the lower income group of people of the society. Reproductive care, by artificial breeding, has been taken for those fish species having a high cost in the market or becoming less in number in nature for business purposes or preserving the biodiversity, respectively. The present study was undertaken to understand the spawning season of the fish Mastacembelus armatus by calculating the gonadosomatic index, so in recent future artificial breeding can be done in this fish species. The mean GSI value for testes is 0.95 ± 0.06, 1.42 ± 0.22, 2.10 ± 0.38 and 0.72 ± 0.08 in growth, maturation, spawning and resting phase respectively. The mean GSI value for ovary is 1.38 ± 0.4, 2.86 ± 0.84, 12.50 ± 1.70 and 1.80 ± 0.15 in growth, maturation, spawning and resting phase respectively. In this study it was found that spawning season include one peak in a year and mainly it falls in the months of June to August in both the sexes.