Parental Effects and Commercial-Scale Sperm Cryopreservation Techniques for Blue Catfish

Abstract

Catfish are an important U.S. aquaculture species, with the channel catfish (Ictalurus punctatus) female by blue catfish (I. furcatus) male hybrid constituting most of the harvest. Hatchery issues persist with male blue catfish due to late sexual maturity, lethal sperm collection procedures, and variable sperm quality. There is also a lack of biomarkers that can be used to predict fresh and cryopreserved sperm quality. Thus, the objectives were to (i) relate male morphometrics, hormones, and sperm parameters to offspring traits; (ii) examine parental contributions to offspring traits using cryopreserved sperm; (iii) pinpoint physiological biomarkers of fresh and frozen-thawed sperm quality and cryotolerance; and (iv) develop new sperm freezing technology using large volume straws (2.5 mL). In this thesis, it was demonstrated that male broodstock size was positively related to offspring performance, cryopreserved sperm kinematic traits were positively related to hatching success, and maternal and paternal effects were significant throughout early ontogeny. Moreover, males with “good and “bad” sperm quality had varying concentrations of sperm fatty acids, where levels of monounsaturated (MUFA) and n-6 polyunsaturated fatty acids (PUFA) predicted sperm quality. Finally, sperm frozen at -20ºC/min with methanol (10%) and 100 mmol trehalose had similar results to fresh sperm. Overall, this research will identify biomarkers related to sperm quality and offspring performance. Results also establish the groundwork for future commercial-scale gene banking for an economically important farm animal, the blue catfish.