Inhibition of fish pathogens by the microbiota from rainbow trout ( Oncorhynchus mykiss , Walbaum) and rearing environment

Safety assessment, genetic relatedness and bacteriocin activity of potential probiotic Lactococcus lactis strains from rainbow trout (Oncorhynchus mykiss, Walbaum) and rearing environment

“…In a previous work, we isolated and taxonomically identified a large collection of LAB (1620 isolates) from aquacultured rainbow trout and rearing environment (tank vegetation [algae] and tank water) along the whole fish life cycle (from larvae to adult trout), and 75 L. lactis strains were selected according to their antimicrobial activity against L. garvieae and other relevant gram-positive and gram-negative fish pathogens [25]. The main objectives of the present study were the evaluation of the safety of these 75 L. lactis strains using a previously reported in vitro subtractive screening beyond the QPS approach [26], the establishment of their genetic relatedness, the identification of the bacteriocinogenic isolates and the biochemical and genetic characterization of the bacteriocin produced by the most promising strain as probiotic for rainbow trout farming as an alternative or complementary strategy to antibiotics and vaccines for disease prevention, which would also improve the quality and safety of fish and fish products.…”

Characterization of Pediococcus acidilactici strains isolated from rainbow trout (Oncorhynchus mykiss) feed and larvae: safety, DNA fingerprinting, and bacteriocinogenicity

“…From these isolates, a total of 7 were selected for further characterization due to their direct antimicrobial activity against at least 3 of the tested fish pathogens, and were taxonomically identified as Pediococcus acidilactici. In addition, P. acidilactici L-14, a strain previously isolated from rainbow trout larvae (Araújo et al 2015a), showed direct antimicrobial activity against 7 of the tested fish pathogens. The extracellular antimicrobial (bacteriocin) activity, safety assessment, and genetic relatedness of these 8 P. acidi lactici strains were determined in order to select the most suitable strain to be used as a probiotic for aquaculture.…”

“…In addition, Pediococcus acidilactici L-14, isolated previously by Araújo et al (2015a) from rainbow trout larvae, was the most active strain, inhibiting a total of 7 fish pathogens. According to the sizes of the inhibition halos, the most susceptible indicators were Lacto coccus garvieae JIP29-99, L. garvieae CF00021, and L. garvieae CF01144, followed by L. garvieae CECT5807, Aeromonas salmonicida LMG3776, and Carnobacterium maltaromaticum LMG 14716.…”

“…In this study, we used the strain Pediococcus acidilactici L-14, previously isolated from aquacultured rainbow trout larvae by Araújo et al (2015a) (not labeled as L-14 in that study), and the strains isolated here from aquacultured rainbow trout feed. P. acidilactici L-14, the strains isolated from feed, the Grampositive fish pathogens (Lactococcus garvieae JIP29-99, L. garvieae CECT5807, L. garvieae CF01144, L. garvieae CF00021, and Carnobacterium maltaromaticum LMG14716), and the indicator microorganism P. damnosus CECT4797 were aerobically grown in MRS at 30°C.…”

“…Recently, LAB isolated from rainbow trout (Oncorhynchus mykiss, Walbaum) have shown the ability to inhibit the growth of fish pathogens, and these strains have been proposed as probiotics to prevent bacterial fish diseases (Pérez-Sánchez et al 2014, Ringø et al 2014. The genus Pediococcus is one of the best characterized LAB groups, and pediococci have been isolated from ripened cheese, processed meat, plant materials, and fish (Cai et al 1999, Todorov & Dicks 2009, Araújo et al 2015a and are used as starter cultures for the production of fermented foods (Lee et al 2014). Furthermore, some pediococci produce ribosomally synthesized antimicrobial peptides referred to as bacteriocins (pediocins), and PA-1/AcH (PedPA-1) is the most thoroughly characterized pediocin (Papagianni & Anastasiadou 2009).…”