Bath Challenge (bath + challenge)

Distribution by Scientific Domains

Selected Abstracts

Strong genetic influence on IPN vaccination-and-challenge trials in Atlantic salmon, Salmo salar L.

A Ramstad
Abstract Two series of experimental challenge trials were performed for evaluation of multivalent oil-adjuvanted vaccines with and without an infectious pancreatic necrosis virus (IPNV) antigen component. In both the trial series, Atlantic salmon were hatched, reared, vaccinated and subjected to temperature and light manipulation to induce smoltification. When ready for sea the fish were transported to the VESO Vikan experimental laboratory for bath or cohabitant challenge with IPNV. In the first series, four vaccination and bath challenge trials involving 2-year classes of experimental fish were conducted. In the second series, three groups of eyed eggs of Atlantic salmon allegedly differing in their innate resistance to IPNV were used (Storset, Strand, Wetten, Kjøglum & Ramstad 2007). Hatching, rearing and smoltification were synchronized for each group, and fish from each genetic group were randomly allocated IPN vaccine, reference vaccine or saline before being placed into parallel tanks for bath or cohabitant challenge. In the first series of trials, IPN-specific mortality commenced on day 10,12 after bath challenge. Replicates showed similar results. In trials 1 and 2 belonging to the same experimental fish year class, the average cumulative control mortality reached 60.6% and 79.5%, respectively, whereas in trials 3 and 4 belonging to the following year class the control mortality was consistently below 50%. In the second series of trials, the experimental fish originating from allegedly IPN susceptible parents consistently showed the highest cumulative mortality among the unvaccinated controls (>75%) whereas smolts derived from allegedly IPNV resistant parents showed only 26,35% control mortality. The IPN-vaccinated fish experienced significantly improved survival vs. the fish immunized with reference vaccine, with RPS values above 75% in the IPN susceptible strain. In the IPN resistant strain, the protection outcomes were variable and in part non-significant. The outcome of both the trial series suggests that control mortalities above 50% are necessary to reliably demonstrate specific protection with IPN vaccines. [source]

First description of non-motile Yersinia ruckeri serovar I strains causing disease in rainbow trout, Oncorhynchus mykiss (Walbaum), cultured in Spain

B Fouz
Abstract Yersinia ruckeri, the causal agent of enteric redmouth (ERM) disease, was isolated from epizootics that occurred in different Spanish rainbow trout, Oncorhynchus mykiss (Walbaum), farms in which vaccination against ERM had been performed. In all episodes, the most pronounced clinical signs exhibited by affected fish were severe haemorrhages in the mouth, eyes and around the vent. The isolates were identified as Y. ruckeri serovar I by 16S rRNA sequencing together with serological tests. They lacked motility and lipase activity and thus belonged to biotype 2, and were highly virulent for juvenile rainbow trout, both by intraperitoneal injection (from 3.1 × 102 to 6.3 × 103 cfu per fish) and bath challenge (5.1,7.3 × 106 cfu mL,1). This is the first description of Y. ruckeri serovar I biotype 2 causing disease in cultured trout in Spain vaccinated with commercial ERM vaccines. The occurrence of this emergent pathogen in Spanish continental aquaculture from its first isolation in 2001 to date is also documented. [source]

Dose-dependent influences of dietary ,-1,3-glucan on innate immunity and disease resistance of hybrid striped bass Morone chrysops×Morone saxatilis

Peng Li
Abstract To investigate potential use of dietary ,-1,3-glucan for health management of hybrid striped bass, juvenile fish were fed diets supplemented with yeast glucan (MacroGuard®) at 0.05%, 0.1% or 0.2% of diet for 4 weeks, followed by immune response assays and a bath challenge with Streptococcus iniae. Dietary glucan significantly (P<0.05) enhanced neutrophil oxidative radical production, and fish fed 0.1% glucan had a significant (P<0.05) reduction in mortality (10%) after bacterial challenge compared with fish fed the control diet (46.7%). However, accumulative mortality of fish fed 0.2% glucan was not significantly different from that of fish fed the control diet. To further elucidate this observation, macrophages from sub-adult hybrid striped bass were isolated and cultured in L-15 medium with 10% foetal calf serum and penicillin/streptomycin supplemented with 0.2, 0.5, 1, 2, 5, 20 and 100 ,g soluble glucan (MacroGuard®) mL,1 for 24 and 48 h. Intracellular superoxide anion production was significantly (P<0.001) increased by 0.5 ,g glucan mL,1, but significantly (P<0.001) suppressed by doses >5 ,g glucan mL,1. It is concluded that dietary yeast glucan has potential for use in diet formulations of hybrid striped bass to limit the adverse effects of S. iniae, but dosage should be an important consideration in administration. [source]

Protection against atypical furunculosis in Atlantic halibut, Hippoglossus hippoglossus (L.); comparison of a commercial furunculosis vaccine and an autogenous vaccine

S Gudmundsdóttir
Abstract Atlantic halibut, Hippoglossus hippoglossus (L.), was shown to be sensitive to infection by three different isolates of Aeromonas salmonicida ssp. achromogenes in pre-challenge tests using intraperitoneal (i.p.) and intramuscular (i.m.) injections as well as bath challenges. A commercial furunculosis vaccine, Alphaject 1200, and an autogenous vaccine, AAS, based on the challenge strain, induced immune protection as shown in challenge tests 8 weeks post-immunization. The survival rate of vaccinated fish after i.p. challenge was 100%, whereas mortality of control fish was 61%. Employing i.m. challenge, relative percentage survival induced by the furunculosis vaccine and the AAS vaccine was 47 and 44, respectively. Mortality of i.m. injected controls was 68%. Vaccinated fish behaved normally following vaccination but the weight gain was significantly reduced in vaccinated fish 8 weeks post-vaccination compared with control fish receiving phosphate-buffered saline. At the same time, intra-abdominal adhesions were observed in fish injected with either of the two vaccines or adjuvant alone. Antibody response against A. salmonicida ssp. achromogenes was detected in sera from fish receiving either vaccine. [source]