Title |
Gamete-associated flavobacteria of the oviparous Chinook salmon (Oncorhynchus tshawytscha) in lakes Michigan and Huron, North America |
Author |
Thomas P. Loch1* and Mohamed Faisal1,2 |
Address |
1Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, 48824, USA, 2Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, 48824, USA |
Bibliography |
Journal of Microbiology, 54(7),477-486, 2016,
|
DOI |
10.1007/s12275-016-5629-3
|
Key Words |
Flavobacterium, Chryseobacterium, fish disease, coldwater disease, eggs, Great Lakes |
Abstract |
Flavobacterial diseases, caused by multiple members of the
Family Flavobacteriaceae, elicit serious losses in wild and
farmed fish around the world. Flavobacteria are known to
be transmitted horizontally; however, vertical transmission
has been suspected but proven only for one fish-pathogenic
flavobacterial species (e.g., Flavobacterium psychrophilum).
Herein, we report on the isolation and molecular identification
of multiple Flavobacterium and Chryseobacterium taxa
from the ovarian fluid and eggs of feral Great Lakes Chinook
salmon (Oncorhynchus tshawytscha). Identified egg- and ovarian
fluid-associated flavobacteria were either well-known
flavobacterial fish pathogens (e.g., F. psychrophilum and F.
columnare), most similar to emerging fish-associated flavobacteria
(e.g., F. spartansii, F. tructae, F. piscis, C. piscium,
C. scophthalmum), or were distinct from all other described
Chryseobacterium and Flavobacterium spp., as determined by
phylogenetic analyses using neighbor-joining, Bayesian, and
Maximum Likelihood methodologies. The gamete-associated
flavobacteria fell into three groups (e.g., those that were recovered
from the ovarian fluid but not eggs; those that were
recovered from the ovarian fluid and eggs; and those that
were recovered from eggs but not ovarian fluid), a portion of
which were recovered from eggs that were surface disinfected
with iodophor at the commonly used dose and duration for
egg disinfection. Some gamete-associated flavobacteria were
also found in renal, splenic, and neurological tissues. Systemic
polymicrobial infections comprised of F. psychrophilum and
F. columnare were also detected at nearly an 11% prevalence.
This study highlights the potential role that sexual products
of female Great Lakes Chinook salmon may play in the transmission
of fish-associated flavobacteria. |