Isolation and evaluation of putative probiotic strains from different teleost to prevent Pseudomonas aeruginosa infection in Cyprinus carpio

Abstract

Probiotics renowned as valuable microbes serve as a potential alternative to control diseases in aquaculture and are considered as an efficient and environment-friendly approach to reduce the use of antibiotics. The present study aims at the isolation of putative probiotic bacteria from the intestinal tract of different fish species from the Doaba region of Punjab, India. In this study, isolated bacterial strains were characterized based on their morphological, biochemical and molecular characterization by 16S rRNA gene sequencing, followed by in vitro evaluation of different selection parameters described in FAO/WHO guidelines. A total of 169 different bacterial strains were isolated from the gastrointestinal tract of 52 different fish species. After in vitro evaluation, out of 169 bacterial strains only five bacteria (S3, S7, BDK2', BDK7 and BDK9) identified as Enterococcus and Bacillus species showed antagonistic activity against the fish pathogen Pseudomonas aeruginosa (MTCC 4 673). These isolates were screened based on their response towards bile tolerance, pH tolerance, adhesion and drug susceptibility to different antibiotic discs. And, the in vivo results indicated improved growth and survival against the infection (P. aeruginosa) after oral administration of the probiotics. The observations of in vitro and in vivo evaluation indicatethat these isolated probiotic strains serve as effective probiotics and can be used as a novel and safe treatment to cure current issues in aquaculture. K E Y W O R D Saquaculture, Cyprinus carpio, Doaba region, Pseudomonas aeruginosa, putative probiotics

Evaluation of Bacillus paramycoides Strains Isolated from Channa Fish sp. on Growth Performance of Labeo rohita Fingerlings Challenged by Fish Pathogen Aeromonas hydrophila MTCC 12301

“…In the present study, both isolates exhibited good adhesion capacity, fulfilling the important criteria of probiotic selection. Adhesion capacity of Bacillus isolates was also reported by [31,38].…”

“…At optical density (OD 600), the absorbance was set to 0.3 to standardize the no. of bacteria (10 8 CFU/mL) [37,38]. Probiotic-enriched diets were prepared by spraying the bacterial broth onto the basal diet and mixing meticulously to achieve a dose of 1 × 10 8 CFU/g.…”

Probiotics in Fish Nutrition—Long-Standing Household Remedy or Native Nutraceuticals?

“…However, it is essential to confirm such effects in an in vivo challenge experiment. Improved resistance towards pathogens, expressed as higher survival rates, occurs in several aquaculture species, including tilapia [124,140], carb [141,142], rainbow trout [143], cod [144], and several other species.…”

Two Probiotic Candidates of the Genus Psychrobacter Modulate the Immune Response and Disease Resistance after Experimental Infection in Turbot (Scophthalmus maximus, Linnaeus 1758)

“…However, confirmation of such effects in an experimental challenge is essential. Here, improved resistance towards the pathogen is expressed in higher survival rates of the infected animals [46][47][48][49][50]. Probiotics compete with the pathogens for binding sites for settlement and nutrients, referred to as competitive exclusion.…”