Background :
Most species of teleost fishes are seasonal breeders and only a few breeds continuously. For gonadal maturation, an acute surge of gonadotropic hormone (GTH) is required which normally does not occur in fish reared under captive condition. High concentration of GTH is required to interact with large number of receptors in ovarian and testicular somatic cells resulting in final maturation followed by ovulation and spermiation. Since gonadal maturation ultimately depends on the endocrine system, hormonal manipulation appears as the most direct approach to broodstock development. Nowadays, gonadotropin releasing hormone (GnRH), is successfully used to induce breeding in different fish. As per the feedback from officials and farmers associated with fish breeding, the supply of these inducing hormones is not enough to meet the demand of ever-increasing hatcheries throughout the country. Currently, various GnRH based synthetic hormones in injectable form are available for induced breeding in fish but varying degree of success has been reported. Another issue of the existing inducing hormones is high viscosity making it difficult to inject. Therefore, there is a need to develop a potent and easy to inject GnRH formulation for efficient induced breeding in fish :
Technology :
Through a series of laboratory experiments and field evaluation studies, ICAR-DCFR has developed and validated a potent GnRH injectible formulation which consistently performed well in terms of spawning, fertilization and hatching. On a comparative scale, the developed hormonal formulation gave better result than some of the tested existing inducing agent in different fish species at different geographical location. The developed hormonal formulation is less viscous, hence easy to inject. Overall, this injectible GnRH formulation is highly efficient in inducing spawning in different fish species.