Location: Warmwater Aquaculture Research Unit
Project Number: 6066-31000-012-15-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2018
End Date: Aug 31, 2020
The objective of this project is to evaluate patterns of disease resistance and susceptibility in blue catfish (Ictalurus furcatus) strains selected and reared at the Warmwater Aquaculture Research Unit (WARU). Little research effort has been devoted to understanding the nature and diversity of immune responses in blue catfish. As commercial production of hybrid catfish (I. punctatus x I. furcatus) continues to increase, optimizing trait performance of blue catfish parental lines is a critical component in long-term genetic improvement. Blue catfish have often been reported to have higher resistance or tolerance to many of the common pathogens of farm-raised catfish when compared with channel catfish. However, in many cases, these studies have used either a small number of individuals, unknown genetic backgrounds, or a single strain, calling into question broader assertions of comparative resistance. If validated, however, identification of reliable phenotypes of disease resistance in blue catfish can be critically important, allowing not only for selection within that species, but also enhancing our understanding of protective immunity through comparative approaches with channel catfish.
Full-sibling families of blue catfish from several strains will be produced at WARU, then transported to the USDA, ARS, Aquatic Animal Health Research Unit (AAHRU) in Auburn, AL for evaluation. The Cooperator will conduct disease challenges in conjunction with AAHRU scientists. The Cooperator will first examine responses to the Gram negative pathogens Flavobacterium columnare (columnaris disease) and Aeromonas hydrophila (vAh) in these fish, as challenge models are well-developed for both pathogens. The fish will be challenged in communal tanks, therefore genomic DNA will be isolated from mortalities and survivors for family assignment through DNA fingerprinting. The Cooperator will investigate differential phenotypes via approaches such as gene expression/transcriptome analysis, cellular immune assays, and serum biochemistry. Molecular/cellular correlates of resistance that are identified will be tested for their predictive ability in subsequent year classes.