Finfish Breeding and Hatchery Management (2+1)

Unit 3 - Breeding of major carps

3.4.1. Synthetic spawning agents

• The stimulation of pituitary gonadotropin secretion by synthetic LH-RH has been demonstrated in a number of teleosts.
• Since LH-RH (natural or synthetic) alone is not very effective in inducing spawning in fish, a combination of LH-RH-a (GnRH-a) and a dopamine antagonist for induced ovulation and spawning in cultured fish is a highly effective procedure called the Linpe method.
• Some workers reported successful spawning of catla, rohu and mrigal with LH-RH analogue at 10-20 mg/kg b.w. and also obtained 100% ovulation with pimozide at 10mg/kg b.w.
• Parameswaran et al. (1988) achieved successful spawning in mrigal with LH-RH-a, buserelin acetate in combination with progesterone.
  
• Investigations of Jose et al. (1989) with LH-RH-a indicated successful breeding of mrigal and Labeo fimbriatus.
  

The Linpe method and ovaprim

• Both of these rapidly gained acceptance in fish farms in China and India and has now been commercialized by Syndel Laboratories, Inc., Vancouver, British Columbia, Canada, under the tradename ovaprim.
• The ovaprim spawning kit is especially formulated for use with salmonids, cyprinids and other freshwater cultured fish.
• It has been used successfully in a number of species in several countries and is gaining wide acceptance as the preferred method for induced ovulation and spawning of cultured freshwater fish.
• For example, in India, based on field trials (during 1988-90) with ovaprim for induced spawning of Indian major carps, fringe lipped carp, silver carp, bighead carp and grass carp in various fish farms located in different agro-climatic regions, Nandeesha et al. (1990, 1991) concluded that in economic terms, the use of ovaprim is advantageous.
• The spawning success, quantity of eggs obtained, the fertilization rate and hatching percentage remained consistently higher with ovaprim as compared to carp pituitary extract (CPE) or human chorionic gonadotropin (HCG) in almost all instances.
• The results also indicate that nearly 40% more fry can be obtained by using ovaprim in place of commercial CPE.
• Most of the carps tested generally spawned within 10-14 hours after injection. Ovulation and spawning has been successfully induced in India by the Linpe method in the Asian catfish, Clarias batrachus (Manickam and Joy, !989) and Indian catfish, Heteropneustes fossilis (Manickam, 1992).
  
• Similarly, indigenous preparations, viz. Ovatide (M/s. Hemmopharma Ltd., Mumbai) and WOVA-FH (M/s. WOCKHARDT Ltd., Mumbai) are also being used commonly for the commercial spawning of carps and other fishes in India.
• A combination of busereline (LHRH-a) and domperidone has been successfully used for the spawning of IMC (Basavaraja et al., 2007).