Use of probiotics to control furunculosis in rainbow trout, Oncorhynchus mykiss (Walbaum)

Abstract

Aerobic heterotrophic bacteria were isolated from the intestinal contents of Atlantic salmon, Salmo salar, rainbow trout, Oncorhynchus mykiss, and turbot, Scophthalmus maximus, on tryptone soya agar and De Man Rogosa and Sharpe agar, of which 11 of 177 (6% of the total) of the isolates were antagonistic to Aeromonas salmonicida. Four of these cultures, which were identified tentatively as A. hydrophila, Vibrio fluvialis, Carnobacterium sp. and an unidentified Gram‐positive coccus, were beneficial to fish when fed singly or as an equi‐mixture. Feed supplemented with the putative probiotics indicated survival of the organisms in the gastrointestinal tract for 7 days. Feeding with the probiotics for 7 and 14 days led to better survival following challenge with A. salmonicida. There was no indication of serum or mucus antibodies to A. salmonicida, but there was an increased number of erythrocytes, macrophages, lymphocytes and leucocytes, and enhanced lysozyme activity in the fish.

Dietary probiotic supplementation improves growth and the intestinal morphology of Nile tilapia

“…In a previous study in rainbow trout, the authors observed a decrease in VFI in fish-fed probiotics when compared with the control group (Ramos et al, 2015). Some reports indicated the possibility of the enhancement of appetite by probiotics (Robertson et al, 2000), especially at the beginning of the feeding trial as reported by Irianto and Austin (2002) and in the current study. Those studies used coating as the incorporation method, which may explain the findings.…”

“…Those studies used coating as the incorporation method, which may explain the findings. Nevertheless, current trial applied water as suspension carrier, whereas Irianto and Austin (2002) used saline solution and Robertson et al (2000) used fish oil. The possible influence of the incorporation method of probiotic on feed intake may deserve further attention.…”

Preventive and Prophylactic Measures in Intensive Salmonid Fish Breeding - a Review

“…But lyophilised cells, dead cells, disrupted cells, cell-free supernatants and spores have all showed some degree of success (Merrifi eld et al, 2010). Most commonly used probiotics have been administered via the feed; however, some information regarding administration of probiotics to salmonids via rearing water is available (Irianto and Austin, 2002b;Austin et al, 1995). These methods may be more applicable in re-circulation facilities or for bathing treatments applied regularly or during times of disease.…”

“…Supplementation has proved to provide shortterm benefi ts but generally probionts have not been detected within the GI tract for periods beyond one to three weeks a er reverting to nonsupplemented diets (Robertson et al, 2000;Balcázar et al, 2007b;Panigrahi et al, 2005;Kim and Austin, 2006a) and presumably probiotic benefi ts are lost a er the probiont is removed from the host. Therefore, there appear to be 3 distinct options for administrative strategy: 1) short-term administration limited to times of need, which is eff ective for gastric colonization, stimulating the immune system, and providing protection against disease when fed prior to pathogenic infection (Irianto and Austin, 2002b); 2) constant feed supplementation incorporated into the diet, however, we must consider the possibility that it may not be appropriate to use constant probiotic supplementation for extended periods, similarly as with long-term use of immunostimulants (Sakai, 1999;Bricknell and Dalmo, 2005); or 3) cyclic feeding of supplemented diets for short periods which may provide direct benefi ts of short-term administration during the supplemental feeding phase, and during the unsupplemented stage where gastric probiotic populations persist for a number of weeks (Balcázar et al, 2007a;Kim and Austin, 2006a) it may provide certain protection against transient pathogens and continue to induce some degree of immunostimulation (Nikoskelainen et al, 2003;Balcázar et al, 2007a). Currently, there are no data supporting this hypothesis.…”

Probiotics in Aquaculture - Benefits to the Health, Technological Applications and Safety

“…Intake of probiotics has been demonstrated to modify the composition of the microbiota, and therefore assist in returning a disturbed microbiota (by antibiotics or other risk factors) to its normal beneficial composition (Gómez and Balcázar, 2008). As for the mechanisms during this physiological process, the production of antimicrobial substances, competition for nutrients or adhesion receptors, inhibition of virulence gene expression and enhancement of the immune response are all included (Irianto and Austin, 2002;Nikoskelainen, et al, 2003;Vine et al, 2004;Kim and Austin, 2006;Balcázar, et al, 2007). However, the exact mechanism by which these probiotics do this is not known.…”