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Immersion Challenge (immersion + challenge)
Selected AbstractsExperimental vertical transmission of Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) from brooders to progeny in Macrobrachium rosenbergii and ArtemiaJOURNAL OF FISH DISEASES, Issue 1 2007R Sudhakaran Abstract White tail disease (WTD) is a serious problem in hatcheries and nursery ponds of Macrobrachium rosenbergii in India. Experiments were carried out to determine the possibility of vertical transmission of M. rosenbergii nodavirus (MrNV) and extra small virus (XSV) in M. rosenbergii and Artemia. Prawn broodstock inoculated with MrNV and XSV by oral or immersion challenge survived without any clinical signs of WTD. The brooders spawned 5,7 days after inoculation and the eggs hatched. The survival rate of larvae gradually decreased, and 100% mortality was observed at the post-larvae (PL) stage. Whitish muscle, the typical sign of WTD, was seen in advanced larval developmental stages. The ovarian tissue and fertilized eggs were found to be positive for MrNV/XSV by reverse transcriptase-polymerase chain reaction (RT-PCR) whereas the larval stages showed positive by RT nested PCR (nRT-PCR). In Artemia, reproductive cysts and nauplii derived from challenged brooders were normal and survival rates were within the expected range for normal rearing conditions. The reproductive cysts were found to be positive for MrNV/XSV by RT-PCR whereas the nauplii showed MrNV/XSV-positive by nRT-PCR. The PL of M. rosenbergii fed nauplii derived from challenged Artemia brooders died at 9 days post-inoculum with clinical signs of WTD. [source] Comparative challenge model of Flavobacterium columnare using abraded and unabraded channel catfish, Ictalurus punctatus (Rafinesque)JOURNAL OF FISH DISEASES, Issue 8 2003J A Bader Abstract The early entry of the fish pathogen Flavobacterium columnare and enhancement by abrasion was studied in channel catfish, Ictalurus punctatus (Rafinesque), using the polymerase chain reaction and a species-specific primer set for a bacterial 16S rRNA gene product. Evaluations were conducted following an abrasion bath immersion challenge with F. columnare. Abrasion, a practice which has historically been used prior to bacterial challenge, had significant effects on the early entry of the pathogen and on cumulative percent survival (CPS). The FvpF1,FvpR1 primer set was useful in detecting the early entry of F. columnare in mucus, skin, gill, blood, liver and trunk kidney tissues in both abraded and unabraded fish following immersion challenge at 29 ± 2 °C. Bacteria were detected earlier in all tissues in abraded fish, except in the trunk kidney. These differences were not significant, except in the case of blood. Mucus, skin and gill tissues were positive for F. columnare earliest regardless of treatment (after 5 min in abraded fish and after 15 min in unabraded fish). CPS following challenge with F. columnare was significantly affected by abrasion, which supports the use of abrasion for the F. columnare challenge model for channel catfish. [source] Effects of Oral Administration of Specific Antibodies to Rainbow Trout Oncorhynchus mykissJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2003Michael Engelbrecht Nielsen A new product called oralized fish serum concentrate (OFSC) was evaluated for a possible effect against various bacterial pathogens in rainbow trout. The OFSC produced from immune trout sera was found to contain fully functional antibodies and complement component C3. The antibodies detected in the serum concentrate were specific to Vibrio anguillarum (O1 and O2) and Aeromonas salmonicida, which had been used for vaccination of the fish prior to serum collection. The functionality of the specific antibodies in OFSC was not reduced after 6 wk storage at -20 C, 5 C, and 20 C. The serum was mixed with commercial trout feed and used for feeding rainbow trout fry (first feed period). After oral delivery of OFSC to rainbow trout for 1 mo, samples of gut content and gut tissue contained functional antibodies. In gutted fish no functional antibodies were found. This suggests that antibodies from OFSC are unable to be transferred across the gut wall in a functional state. Oral administration of OFSC did not increase survival of rainbow trout in an immersion challenge with Vibrio anguillarum. [source] | ||||||||||