Abraham, Joice (2005) Studies on some aspects of the Reproductive physiology of Metapenaeus monoceros (Fabricius). PhD thesis, Central Institute of Fisheries Education, Mumbai.
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Metapenaeus monoceros (Fabricius), also known as 'Speckled shrimp', is one of the commercially important species contributing substantially to the shrimp fisheries of India and is a potential candidate species for diversification of shrimp culture. The processes of oogenesis and spermatogenesis of the species were studied using light and electron microscopy. Biochemical changes taking place in ovary, hepatopancreas, haemolymph and muscle tissue were analysed and the yolk protein vitellin was characterized. The five stages of ovarian development based on gross morphology were related to those based on cytological changes. The mean ova diameter increased from 35.68 ~m in immature stage to 230.56 ~m in fully mature stage. Cortical bodies, characteristic of fully mature ova of most penaeids were absent in M.monoceros. Ultrastructure of oocytes at various developmental stages showed that the mode of synthesis of yolk is mostly autosynthetic with the cytoplasm abundant in mitochondria, free ribosomes, rough endoplasmic retiulum and golgi bodies. The process of spermatophore formation which took place with the help of the secretory activity of columnar epithelial cells lining the vas deferens was demonstrated. Secretions of the proximal vas deferens aided in packing the sperm mass and those of the Spermatophoric duct of median vas deferens formed the primary spermatophoric layer. The accessory duct secreted accessory structures associated with the spermatophore while secretions of the epithelial cells lining the distal vas deferens formed the secondary spermatophoric layer. Adhesive globules were formed in the terminal ampoule, where the final moulding of spermatophore took place. Spermatozoa in this species were unistellate. Variations in the biochemical constituents in different tissues showed cyclic changes in their concentration during the various maturity stages except in the muscle tissue. Mobilization of proteins from the hepatopancreas to ovary was minimal. Haemolymph proteins showed a declining trend with vitellogenesis, which is due to the transfer to ovary. A partial mobilization of lipids from the hepatopancreas to the ovary was noticed. Native polyacrylamide gel electrophoresis of ovarian tissue revealed that vitellin showed a steady increase in the level of expression with progression in maturity. Native vitellin in this species has a molecular weight of 326 kD and is a lipo-glycoprotein bound to calcium.
|Item Type:||Thesis (PhD)|
|Supervisor(s):||Manisseri, Mary K|
|Uncontrolled Keywords:||Reproductive physiology; Prawn; shrimp; Metapenaeus monoceros; Fabricius|
|Subjects:||Fish and Fisheries > Fish physiology|
Crustacean Fisheries > Prawn and Prawn fisheries
|Divisions:||CMFRI-Cochin > Marine Capture > Crustacean Fisheries|
|Deposited By:||Dr. V Mohan|
|Deposited On:||17 Feb 2011 16:01|
|Last Modified:||17 Feb 2011 16:01|
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