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Identification of Bacillus strains for biological control of catfish pathogens.
- Source :
-
PloS one [PLoS One] 2012; Vol. 7 (9), pp. e45793. Date of Electronic Publication: 2012 Sep 21. - Publication Year :
- 2012
-
Abstract
- Bacillus strains isolated from soil or channel catfish intestine were screened for their antagonism against Edwardsiella ictaluri and Aeromonas hydrophila, the causative agents of enteric septicemia of catfish (ESC) and motile aeromonad septicaemia (MAS), respectively. Twenty one strains were selected and their antagonistic activity against other aquatic pathogens was also tested. Each of the top 21 strains expressed antagonistic activity against multiple aquatic bacterial pathogens including Edwardsiella tarda, Streptococcus iniae, Yersinia ruckeri, Flavobacterium columnare, and/or the oomycete Saprolegnia ferax. Survival of the 21 Bacillus strains in the intestine of catfish was determined as Bacillus CFU/g of intestinal tissue of catfish after feeding Bacillus spore-supplemented feed for seven days followed by normal feed for three days. Five Bacillus strains that showed good antimicrobial activity and intestinal survival were incorporated into feed in spore form at a dose of 8×10(7) CFU/g and fed to channel catfish for 14 days before they were challenged by E. ictaluri in replicate. Two Bacillus subtilis strains conferred significant benefit in reducing catfish mortality (P<0.05). A similar challenge experiment conducted in Vietnam with four of the five Bacillus strains also showed protective effects against E. ictaluri in striped catfish. Safety of the four strains exhibiting the strongest biological control in vivo was also investigated in terms of whether the strains contain plasmids or express resistance to clinically important antibiotics. The Bacillus strains identified from this study have good potential to mediate disease control as probiotic feed additives for catfish aquaculture.
- Subjects :
- Animal Feed
Animals
Antibiosis
Bacillus classification
Bacillus drug effects
Bacillus physiology
Bacterial Typing Techniques
Biological Control Agents
Drug Resistance, Bacterial
Enterobacteriaceae Infections microbiology
Enterobacteriaceae Infections mortality
Enterobacteriaceae Infections prevention & control
Fish Diseases mortality
Fish Diseases prevention & control
Fisheries
Gram-Negative Bacterial Infections microbiology
Gram-Negative Bacterial Infections mortality
Gram-Negative Bacterial Infections prevention & control
Intestines microbiology
Microbial Viability
Sepsis microbiology
Sepsis mortality
Sepsis prevention & control
Spores, Bacterial classification
Spores, Bacterial isolation & purification
Spores, Bacterial physiology
Aeromonas hydrophila physiology
Bacillus isolation & purification
Edwardsiella ictaluri physiology
Enterobacteriaceae Infections veterinary
Fish Diseases microbiology
Gram-Negative Bacterial Infections veterinary
Ictaluridae microbiology
Sepsis veterinary
Subjects
Details
- Language :
- English
- ISSN :
- 1932-6203
- Volume :
- 7
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- PloS one
- Publication Type :
- Academic Journal
- Accession number :
- 23029244
- Full Text :
- https://doi.org/10.1371/journal.pone.0045793