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Inverness, MS, United States

Green C.C.,Louisiana State University | Yant D.R.,Hybrid Catfish Company
Journal of the World Aquaculture Society | Year: 2011

Channel catfish, Ictalurus punctatus, pituitary powder (CP) was prepared and administered to determine the effect of pituitary preparation, head selection criteria, and season of collection on the biological potency of this gonadotropic preparation. Pituitaries were harvested from three catfish processing plants throughout the months of December, February, March, and April to investigate the effect of season on CP potency. Gravid female channel catfish were injected intraperitoneally (IP) with priming (2 mg/kg) and resolving doses (8 mg/kg) of CP treatments, luteinizing hormone-releasing hormone analog (LHRHa), or saline. Pharmaceutical grade Carbopol 971P resin (CAR) was tested as a 1% aqueous dispersion in physiological saline and administered with CP (10 mg/kg) as a IP single injection at a final volume of 2 mL per kg as a slow-release vehicle. Individual females were hand-stripped, and eggs were fertilized with freshly harvested blue catfish, Ictalurus furcatus, spermatozoa. Pituitaries processed with either acetone or ethanol/acetone resulted in significantly different ovulation rates of 35 and 73%, respectively (P≤ 0.01). Ovulation success was not significantly different among CP and LHRHa treatment groups. Ovulation rates were not significantly different among treatment groups of CP collected in April (74%) or December (67%), or collected from male (69%), or small individuals (55%). The shortest latency period among CP treatment was from CP collected in December and from males at 39.1 ± 0.7 and 38.5 ± 0.4 h, respectively. The CAR vehicle treatment performed poorly resulting in an average ovulation rate of 19.0%, with 3.3% viable embryos at 36 h post-fertilization. Pituitaries collected from channel catfish potentially represent a viable spawning aid for the production of hybrid channel × blue catfish. © by the World Aquaculture Society 2011.

Broach J.S.,University of Florida | Ohs C.L.,University of Florida | DiMaggio M.A.,University of Florida | Green C.C.,Louisiana State University | Yant D.R.,Hybrid Catfish Company
North American Journal of Aquaculture | Year: 2015

Abstract: Pinfish Lagodon rhomboides and Pigfish Orthopristis chrysoptera are commonly used as marine baitfish in the southeastern United States. Hormone efficacy studies for spawning induction have been conducted with both species, but spawning aids derived from piscine pituitary extracts have yet to be evaluated. Pituitary extract from Channel Catfish Ictalurus punctatus (CCPE) was chosen to determine its efficacy on spawning induction. The CCPE was dissolved in a saline solution and then injected into female broodfish at 5, 10, 20, or 40 mg/kg. The treated females were then paired with conspecific males receiving half the corresponding female dose. Ovaprim served as a positive control at a dose of 0.5 mL/kg for female broodfish and 0.25 mL/kg for males. A single pair of broodfish was randomly stocked according to treatment into separate 1,600-L tanks within recirculating systems. Broodfish were monitored daily over 72 h after injection for spawning occurrences, and qualitative characteristics including egg and larval morphometrics and viability were quantified. Channel Catfish pituitary extract failed to induce spawning in Pinfish among all dosages administered. All CCPE dosages induced at least one spawn in Pigfish. No significant differences were detected in spawning frequency among treatments although the 10- and 20-mg/kg CCPE dosages and the Ovaprim control each induced ≥50% of Pigfish females to spawn compared with only 16.7% of females treated with the 5- and 40-mg/kg dosages. Floating eggs from Pigfish females in the 10-mg/kg CCPE treatment were significantly larger than eggs produced using either the 20-mg/kg CCPE or Ovaprim treatment. Hatching success, larval survival to first feeding, larval length at hatch and first feeding, and oil droplet diameter of recently hatched Pigfish larvae were significantly greater for those larvae from the Ovaprim treatment than for those from the 10- and 20-mg/kg CCPE treatments. Data from these experiments demonstrate the potential use of CCPE to induce spawning in Pigfish, a popular marine baitfish species. Received June 23, 2014; accepted December 26, 2014 © 2015, © American Fisheries Society.

Chatakondi N.G.,Harvest Select Farms | Chatakondi N.G.,U.S. Department of Agriculture | Yant D.R.,Hybrid Catfish Company | Kristanto A.,Auburn University | And 3 more authors.
Journal of the World Aquaculture Society | Year: 2011

This study addresses rapid methods to identify mature channel catfish, Ictalurus punctatus, females for induced spawning with luteinizing hormone releasing hormone analog (LHRHa) and common carp pituitary extract (CPE) and the effects of stage of maturity, hormone dose, season, and cannulation before hormone injection. Hormonal intervention is the most effective method for inducing maturation and spawning in channel catfish × blue catfish, Ictalurus furcatus, hybrids. A total of 80 mature channel catfish were staged for maturity based on secondary sexual characteristics and 20-30 oocytes cannulated to ascertain their maturation stage based on the position of gonadal vesicle. Twenty females were randomly assigned to one of the four hormone regimes (priming + resolving dose): CPE 2 + 8 mg/kg (CPEC); LHRHa 20 + 40 μg/kg (LHRHaL); LHRHa 20 + 60 μg/kg (LHRHaM); and LHRHa 20 + 80 μg/kg (LHRHaH) and a fifth treatment consisted of 20 females selected based on apparent maturity as evidenced by external appearance were injected with CPE, 2 + 8 mg/kg without cannulation (CPEO). Two trials were conducted in early part of the spawning season and two trials in peak season. External methods to identify maturity correlated (r = 0.63) with that of "germinal vesicle position" method to identify the stage of maturity in females. Mean percent of females that ovulated, hatched, and fry produced per kg body weight did not differ (P > 0.05) among the five hormone treatments. The mean percent females that ovulated was higher (P < 0.05) for CPE-induced females that were identified as "excellent" females based on external examination. The performance of cannulated females did not differ (P > 0.05) with that of non-cannulated catfish. The mean egg quality of hormone-induced females and percent of females ovulated in response to hormone treatment established a weak but significant linear relationship (Y = 3.85 + 0.008 × ovulation, r 2 = 0.39, P < 0.05). © by the World Aquaculture Society 2011.

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