Time filter

Source Type

Buhl, ID, United States

Plant K.P.,University of Idaho | LaPatra S.E.,Clear Springs Foods Inc.
Developmental and Comparative Immunology | Year: 2011

Disease prevention is essential to the continued development of aquaculture around the world. Vaccination is the most effective method of combating disease and currently there are a number of vaccines commercially available for use in fish. The majority of aquatic vaccines are delivered by injection, which is by far the most effective method when compared to oral or immersion deliveries. However it is labor intensive, costly and not feasible for large numbers of fish under 20. g. Attempts to develop novel oral and immersion delivery methods have resulted in varying degrees of success but may have great potential for the future. © 2011 Elsevier Ltd.

Evenhuis J.P.,U.S. Department of Agriculture | LaPatra S.E.,Clear Springs Foods Inc. | Marancik D.,U.S. Department of Agriculture
Aquaculture | Year: 2014

Flavobacterium columnare is the etiologic agent of columnaris disease, a pervasive disease of fresh water finfish. During the past 4. years, losses that ranged from 5 to 50% in rainbow trout (Oncorhynchus mykiss) fry being reared at a constant 14.5. °C (mean weight, 0.2. g; ~. 400°days post-fertilization), have been occurring in Hagerman Valley, Idaho, USA. A total of 70 different F. columnare isolates were obtained from diseased fish and the water they were reared in. All of the isolates were confirmed to be genomovar I by 16S rRNA restriction fragment length polymorphism. Sequencing of the 16S rRNA, 16S-23S rDNA spacer region and the gyrase B subunit genes from these 70 strains revealed no sequence differences among these isolates. Whole-cell protein profiling by SDS-PAGE also indicated low variation between isolates. Virulence was assessed for a representative isolate and demonstrated a high degree of pathogenicity against rainbow trout fry at 15. °C. These results suggest the emergence of a highly successful F. columnare strain that can affect very early life stages of fish being reared at a constant 14.5. °C at a commercial rainbow trout farm in Idaho. © 2013.

Welch T.J.,U.S. Department of Agriculture | LaPatra S.,Clear Springs Foods Inc.
Fish and Shellfish Immunology | Year: 2016

Enteric redmouth disease (ERM), caused by Yersinia ruckeri, has been controlled successfully using immersion-applied bacterin vaccines for several decades. While the host response to vaccination and the mechanism of protection of this vaccine have been elucidated, the bacterial components eliciting protection have remained unclear. Here we show that highly purified serotype O1 Y. ruckeri lipopolysaccharide (LPS) is sufficient to induce a protective response to experimental challenge in rainbow trout (Oncorhynchus mykiss). Dose response experiments demonstrated that Y. ruckeri LPS at doses of 1 ng/fish and above resulted in essentially complete protection and doses as low as 0.01 ng/fish (1.38 ng/kg) resulted in significant protection, thus demonstrating the extremely high potency of this immunogen. Analysis of the Y. ruckeri genome identified a cluster of putative O-antigen biosynthetic genes specific to serotype O1 strains. This cluster primarily consisted of genes encoding proteins predicted to function in the biosynthesis of legionamic acid, a nonulosonic acid known to be part of the O-polysaccharide repeat of O1 Y. ruckeri. Mutation of the nab2 gene, a nonulosonic acid biosynthesis gene (nab gene), resulted in production of severely truncated forms of LPS. Vaccination with bacterin vaccines derived from the nab2 mutant and its wild type parent strain demonstrated that LPS is a required component of the whole-cell bacterin vaccine and suggests that LPS is the only cellular component contributing to the protective response elicited by this vaccine. We speculate that the exceptionally high potency of Y. ruckeri LPS accounts for the unusual success of this vaccine when delivered by immersion. © 2016.

Burbank D.R.,University of Idaho | Lapatra S.E.,Clear Springs Foods Inc. | Fornshell G.,University of Idaho | Cain K.D.,University of Idaho
Journal of Fish Diseases | Year: 2012

In this study, 318 bacterial strains were isolated from the gastrointestinal (GI) tracts of 29 rainbow trout, Oncorhynchus mykiss (Walbaum). These bacteria were screened in vitro for their ability to inhibit growth of Flavobacterium psychrophilum, the causative agent of coldwater disease. Bacteria observed to inhibit F. psychrophilum growth were further screened against rainbow trout bile, as an indicator of their ability to survive in the GI tract. This screening resulted in narrowing the pool to 24 bacterial isolates. Those 24 isolates were then tested for pathogenicity in rainbow trout by intraperitoneal injection. Following a 28-day challenge, eight isolates were shown to cause direct mortality and were eliminated from further study. As a result, 16 bacterial isolates were identified as probiotic candidates with the potential to control or reduce disease caused by F. psychrophilum. © 2012 Blackwell Publishing Ltd.

Wiens G.D.,National Center for Cool and Cold Water Aquaculture | LaPatra S.E.,Clear Springs Foods Inc. | Welch T.J.,National Center for Cool and Cold Water Aquaculture | Evenhuis J.P.,National Center for Cool and Cold Water Aquaculture | And 2 more authors.
Aquaculture | Year: 2013

Selective fish breeding programs for disease resistance comprise an increasingly important role in aquaculture production and offer an additional management tool for reducing bacterial-caused disease losses. Bacterial cold water disease (BCWD) is one of the most frequent causes of elevated mortality in juvenile salmonids, and we have selectively bred three genetic lines of rainbow trout for varying resistance to BCWD. These lines, designated ARS-Fp-R (resistant), ARS-Fp-C (control) and ARS-Fp-S (susceptible), differ in survival following standardized laboratory challenges with the causative agent of BCWD, Flavobacterium psychrophilum. This study evaluated survival of the genetic lines in laboratory challenges and in a production environment. Evaluations of disease resistance demonstrated a reproducible, 30% or greater, survival difference between ARS-Fp-R and ARS-Fp-S lines at body weights ranging from 0.7 to 13 g. Farm trials were performed to evaluate survival over an 80-day growth period starting after the trout began feeding. After a BCWD epizootic, the ARS-Fp-R line displayed significantly greater risk-adjusted survival (95.7%) than the ARS-Fp-S line (91.2%, Pb0.0001) and the ARS-Fp-C line (92.4%, Pb0.0001). Phenotype stability in farm-trial fish was also evaluated using laboratory challenges. The ARS-Fp-R line consistently displayed a higher, but not always statistically significant, survival percentage compared to the other lines and the data suggest that the magnitude of the survival phenotype difference is sensitive to environmental influence. In summary, the overall greater survival of the ARS-Fp-R line provides evidence of genetic improvement under production conditions. © Published by Elsevier B.V.

Discover hidden collaborations