A HISTOLIGICAL EVALUATION OF THE DEVELOPMENT OF RESPIRATORY STRUCTURES IN CATFISHES

Nathan J.C. Backenstose*, Karim Ane, Anthony Moss, Rex A. Dunham
 
School of Fisheries, Aquaculture and Aquatic Sciences
Auburn University
203 Swingle Hall
Auburn, Alabama 36849
njb0012@auburn.edu
 

In the realm of finfish production, Siluriformes is one of the most dominant orders on an international scale. Within the United States the family Ictiluridae is most common, while Pangasiids and Clariids are cultured in Africa, Asia, and parts of Europe. In more tropical climates the capacity for production is exponentially greater than in the U.S. due to the ability for higher stocking densities per unit of area. Representative species from these families have distinct morphologies resulting in the presence or absence of an accessory respiratory organ. Ictalurids such as Channel Catfish (Ictalurus punctatus) do not have an accessory respiratory organ however Tra (Pangasius sutchi), and Walking Catfish (Clarias batrachus) possess the advantage to use atmospheric oxygen to supplement in periods of low dissolved oxygen. Using histological and microdissection techniques we identified critical stages of development in Channel Catfish and Tra at which gill and accessory respiratory structures develop and become active. Using these highlighted critical stages of development, we will utilize RNA sequencing to determine the levels of expression for genes that are active in gill structures and air breathing organs.