Enterococcus faecium as potential probiotic for ornamental neotropical cichlid fish, Pterophyllum scalare (Schultze, 1823)

Abstract

The production of ornamental fishes has been intensified to attend the global market. With this expansion, an increase in infections and infirmities has been observed, most of which are attributed to pathogenic bacteria. Dietary supplements to improve growth and immunity of these animals have been introduced as a safe way to control and prevent disease outbreaks. This study therefore aims to isolate, identify, select and evaluate strains of lactic acid bacteria that show potential as probiotics for Pterophyllum scalare. Of 16 initial isolates, five strains were molecularly identified as Enterococcus faecium. Profiles of probiotic candidate strains were based on: catalase test and hemolytic activity; in vitro tolerance responses to NaCl (0.5; 1.0; 1.5; 2.0; 2.5 and 3.0%), pH (4, 5, 6, 8, and 9), and bile salts (5%); pathogen inhibition halo size maximum growth rate; and final counts of viable cells. In vivo effectiveness of the best performing strain in vitro was determined by growth and survival parameters for post-larvae over a period of 40 days. All strains fulfilled the criteria as probiotics in animals, with Strain 4 showing the best results in vitro, and improving growth and viability of fish in vivo.

Effect of Enterococcus faecium as a Water and/or Feed Additive on the Gut Microbiota, Hematologic and Immunological Parameters, and Resistance Against Francisellosis and Streptococcosis in Nile Tilapia (Oreochromis niloticus)

“…Similar results were found by Reda et al (2018), where antibacterial activity in Nile tilapia intestinal bacteria was observed against the pathogens Aeromonas sobria, Aeromonas hydrophila, Pseudomonas aeruginosa, Pseudomonas putida, and Staphylococcus aureus. Dias et al (2019) isolated E. faecium from the digestive tract of juvenile neotropical ornamental cichlid fish (Pterophyllum scalare) and reported that we found an antagonism to S. aureus, P. aeruginosa, E. coli, and A. hydrophila, which demonstrate the probiotic potential of this bacterium in different fish species. Of note, due to the bacterial genome used as a probiotic and with the use of bioinformatics, possible mutations, resistance genes, and antibacterial metabolites can be discovered, which can be used to define bacteria as a potential probiotic.…”

Comparative effects of autochthonous single‐strain and multi‐strain probiotics on the productive performance and disease resistance in Colossoma macropomum (Cuvier, 1818)

“…A completely randomized design with four treatments in quadruplicate was used, corresponding to two diets with probiotic strains isolated from the continental fish species Enterococcus faecium (1) at 2 × 10 6 CFU·g −1 (Dias et al, 2019) and Enterococcus faecium (2) at 1 × 10 8 CFU·g −1 of feed (Sousa et al, 2019); one diet with a species‐specific probiotic Bacillus cereus at 2.8 × 10 6 CFU.g −1 (Dias et al, 2018); one diet with a multi‐strain probiotic composed of E. faecium (1 and 2) and B. cereus strains at 1 × 10 8 CFU·g −1 , which were stipulated in the previous in vitro experiment; and a control group (without the inclusion of the probiotic).…”

“…The probiotic strains used in this study included two strains of Enterococcus faecium ( E. faecium 1, Dias et al, 2019; E. faecium 2, Sousa et al, 2019) and one autochthonous Bacillus cereus strain from tambaqui (Dias et al, 2018), which were acquired from the Laboratory of Health of Aquatic Organisms at the Brazilian Agriculture Research Corporation (EMBRAPA) in Aracaju, Sergipe/Brazil.…”

Probiotic potential of autochthonous bacteria from tambaqui Colossoma macropomum

“…Several bacteria from the genera Bacillus , Lactobacillus and Lactococcus have been successfully isolated from the intestine of healthy fish and are known as the main groups of probiotic bacteria in aquaculture (Balcázar et al, 2006; Irianto & Austin, 2002; Ringø & Gatesoupe, 1998). Recent studies, however, have revealed new potential isolates, such as bacteria from the genera Staphylococcus (Kanjan & Sakpetch, 2020; Rajeswari et al, 2016), Enterococcus (Dias et al, 2019) and Pediococcus (Jaafar et al, 2019; Xing et al, 2013). As knowledge about emerging species of fish of economic interest continues to advance, different strains with promising probiotic activity are being described.…”