ARS | Publication request: The longevity of Bolbophorus damnificus in channel catfish

Submitted to: Annual Eastern Fish Health Workshop
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2010
Publication Date: May 24, 2010
Citation: Mitchell, A.J., Farmer, B.D. 2010. The longevity of Bolbophorus damnificus in channel catfish [abstract]. Annual Eastern Fish Health Workshop. p.92.

Technical Abstract: Mortality, lower feed consumption, and slower or reduced growth occur in commercially grown channel catfish infected with the prodiplostomula of Bolbophorus damnificus. In this study, we determined the length of time that B. damnificus prodiplostomula remain in muscle tissue of the channel catfish. More than 200 channel catfish were infected with PCR-determined B. damnificus cercariae harvested from naturally infected rams-horn snails. A mean of 8.3 (+/=3.6, SD) prodiplostomula were found in muscle tissue of fish (n=11) in the 3-weeks, post-infection sample. The channel catfish then were acclimated to water temperatures of either 18 or 28 degrees C. After 11.3 – 11.4 months, an average of 6.8 (+/=3.5) and 5.9 (+/=3.0) prodiplostomula were found in fish held at 18 or 28 degrees C, respectively. There was no significant difference in parasite numbers between the fish held at the two temperatures and no significant decline in the mean number of parasites over time at either temperature. Channel catfish, examined from 13 to 30 months post infection all contained viable prodiplostomula definitively identified as B. damnificus. At 18 months, 11 intact prodiplostomula (10 with movement) were found in the one fish sampled and at 30 months, the last fish sampled contained 3 intact trematodes (one displayed slight movement). This indicates that viable B. damnificus prodiplostomula will remain in commercially raised channel catfish for the entire 18 - 30 month production cycle and could impact fish growth throughout the cycle. The channel catfish could also serve as carriers of the parasite for the duration of their production cycle.