Multiple Induced Spawnings of the Indian Catfish Heteropneustes fossilis (Bloch) within a Prolonged Spawning Season |
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| Authors: | Deoraj Alok T Krishnan G P Talwar Lalit C Garg |
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| Institution: | Center of Marine Biotechnology, University of Maryland, 701 E Pratt Street, Baltimore, Maryland 21202 USA; Department of Molecular Microbiology and Pathology, Washington University School of Medicine, Barnes Jewish Hospital, North Campus, Box 8050, St. Louis, Missouri 63110 USA; International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110 067 India; National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067 India |
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| Abstract: | Abstract Singhi, the Indian catfish Heteropneustes fossilis , attained gonadal maturity repeatedly in a single spawning cycle by photothermal treatment. After the first spawning, maintenance at 30 C and 14 h light/10 h dark for 3 wk induced recruitment of the next batch of mature oocytes for subsequent spawnings. The number of eggs released declined with each spawning. However, fertilizability of the eggs was maintained until the fifth spawning. Mature fish were induced to spawn by D-Lys6 salmon gonadotropin-releasing hormone agonist administration. The dose of salmon gonadotropin-releasing hormone agonist for the second and subsequent spawnings was determined to be 25-fold less compared to the dose administered for the first spawning. Fish released the maximum number of eggs upon induction when they were maintained continuously at 30 C and 14 h light/10 h dark for 6 wk. The result obtained in the present study points to a possibility of obtaining multiple spawnings from those species of farmed fish which spawn once a year. |
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