Location: Warmwater Aquaculture Research Unit2012 Annual Report
1a. Objectives (from AD-416):
Development of spawning aids or hormone delivery methods to improve the efficiency of channel x blue hybrid catfish embryo production.
1b. Approach (from AD-416):
Conduct spawning trials to assess the effective peptide analog or hormone delivery methods to induce maturation and ovulation in channel catfish and also to measure the associated physiological responses to the treatments.
3. Progress Report:
Hatching success of hybrid catfish eggs has been historically low and producing hybrid catfish fry in commercial quantities was considered unattainable. However, the availability of ovulating hormones (under INAD) and improved hatchery protocols have significantly improved hybrid catfish fry production in hatcheries. Hormonal intervention is the most effective method for inducing maturation and spawning in channel catfish to produce hybrid catfish. In the last 5 years, consistent commercial production of hybrid catfish coupled with superior performance in production ponds has advanced the adoption of hybrid catfish in the industry. For hybrid catfish production, hormonal manipulations need to be used as a management tool to enhance the efficiency of gamete production and hatchery operations. Pertinent aspects for its effectiveness relating to type of hormone, dosage, mode and frequency of administration need to be evaluated. Hormone-induced spawning of channel catfish is technically feasible and economically viable method to produce hybrid catfish fry in commercial hatcheries. Synthetic hormones are more efficacious than natural gonadotropin hormones to induce spawn fish. Salmon Gonadotripn releasing hormone analog sGnRHa – a potent hormone was evaluated for its efficacy (0, 5, 10 and 25 µg/Kg BW) to induce spawn channel catfish. Based on a spawning trial, minimum effective hormone dose was identified as 10 µg/Kg body weight (BW) and the collaborator has applied for sponsoring this peptide under Investigational New Animal Drug program. Individual fish were held in soft mesh bags during the hormone treatment and the responses measured include the percent of maturation of oocytes, ovulation, egg quality, relative fecundity and hatch. Plasma profiles of cortisol, estradiol and progesterone at 0 and 20 hours will provide the progress of gonadal development. Data collected from producers will further refine the efficacious dose of hormone as suspension delivery to channel catfish.