|Renukdas, Nilima - University Of Arkansas At Pine Bluff|
|Kelly, Anita - University Of Arkansas At Pine Bluff|
|Kaimal, Sindhu - University Of Arkansas At Pine Bluff|
Submitted to: Western Fish Disease Workshop
Publication Type: Proceedings
Publication Acceptance Date: 2/28/2017
Publication Date: 4/4/2017
Citation: Renukdas, N.N., Kelly, A.M., Farmer, B.D., Kaimal, S. 2017. Characterization of tlr-4 in fathead minnow challenged with columnaris (flavobacterium columnare) in an ultra-low flow system. Western Fish Disease Workshop, April 3-7, 2017, East Lansing, Mi. p. 1.
Technical Abstract: Columnaris disease, caused by the bacteria Flavobacterium columnare, is one of the most serious bacterial infections affecting the aquaculture industry today. Columnaris is transmitted horizontally from fish to fish. The disease is highly contagious and may be spread through contaminated nets, specimen containers, and even food. Outbreaks are commonly caused due to stress such as overcrowding, low dissolved oxygen, high ammonia and nitrite concentrations. Arkansas baitfish farms routinely suffer substantial losses due to columnaris disease. Columnaris outbreaks occur in fathead minnow (Pimephales promelas) especially following harvest while they are being held in vats and during the transport prior to being sold. Toll-like receptors (TLRs) play key roles in the innate immune system in response to a wide range of pathogen infections. Among various TLRs, TLR4 recognizes the lipopolysaccharides of gram negative bacteria. The goal of this study was to determine if the TLR4 receptors are expressed in fathead minnow challenged with F. columnare in an ultra-low flow system. A columnaris challenge tank study in an ultra-low flow system was conducted at three different fathead minnow densities; 400/m3, 800/m3 and 1600/m3 and at two different temperatures; 22 deg C and 28 deg C and triplicated. LSU- 04-066 strain of Flavobacterium columnare was used to challenge fathead minnows. Dissolved oxygen, flow, total ammonia nitrogen, and fish mortality were recorded post-challenge for 48 hrs. Total mortality occurred within 24 h at all fish densities held at 28 deg C and within 30 hrs at 22 deg C. Tank water and fish tissue (gills, kidney, and spleen) samples were processed for the presence of columnaris using real time PCR. TLR4 were identified from gill tissue samples tissues. TLRs are currently being sequenced. This study demonstrated that TLR4 is expressed in response to Columnaris infection in fathead minnows.