Now showing items 1-2 of 2

    • Conference paper

      Induced spawning of the mangrove red snapper, Lutjanus argentimaculatus 

      AC Emata, B Eullaran & M de los Santos - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Wild-caught mangrove red snapper, Lutjanus argentimaculatus, reared for a year in 4.0 m diameter by 1.5 m deep circular concrete tank spontaneously matured and were used for induced spawning trials. On 19 August 1992, a sexually mature female (4.6 kg BW) and male (3.2 kg BW) fish were given a single intramuscular injection of 1500 IU human chorionic gonadotropin (hCG)/kg BW. Spawning occurred 27 h after injection with total egg collection of 1.3 M. Hatching occurred 16 h after spawning at 28 °C and 32 ppt. On 18 March 1993, the same male and female together with a newly-caught spermiating male (6.3 kg BW) were injected intramuscularly with 100 µg luteinizing hormone-releasing hormone analogue (LHRHa)/kg BW. Spawning occurred 44 hours after injection with the total egg collection of 0.7 M. Hatching occurred 16 hours after spawning at the same temperature and salinity as the first trial. The successful spawning trials encourage further research to determine the effective minimum dose of hCG and LHRHa.
    • Conference paper

      LHRHa and pimozide-induced breeding in the catfish, Clarias macrocephalus (Gunther) 

      JD Tan-Fermin, RSJ Gapasin, AM Tan, MA Garcia & AC Emata - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Clarias macrocephalus is endemic yet dwindling freshwater foodfish in the Philippines. Induced breeding protocol was developed by monitoring the size and maturation of eggs at 0-48 h after a simultaneous injection of luteinizing hormone-releasing hormone analogue (LHRHa; 0.0005 - 0.10 µg/g BW) and pimozide (PIM; 1 µg/g BW). Based on its similar osmotic pressure with catfish plasma, eggs were fixed in 1% phosphate-buffered formalin. Mean egg diameter of fish that were induced to mature increased during ovulation. Oocyte maturation, indicated by oocytes with germinal vesicle breakdown (GVBD), was observed at least 12 h post-injection in fish given 0.01 - 0.10 µg LHRHa + 1 µg PIM/g BW, followed by ovulation 4 h thereafter. Results showed that a simultaneous injection of C. macrocephalus with 0.05 µg LHRHa + 1 µg PIM/g BW at 1800-1900 h followed by stripping at 16-20 h post-injection resulted in high ovulation, fertilization and hatching rates.