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

Abstract

This study evaluated the effects of autochthonous single‐strain and multi‐strain (mix) probiotics on the zootechnical performance and sanitary conditions of juvenile neotropical fish. Fingerlings of tambaqui (Colossoma macropomum) were fed three diets of single‐strain probiotics (two Enterococcus faecium strains and one Bacillus cereus autochthonous strain) and a multi‐strain probiotic diet (a mix of three probiotic strains) for 120 days. After dietary supplementation, 90 tambaquis were intraperitoneally injected with Aeromonas hydrophila at a concentration of 1.8 × 108 CFU·g−1. Clinical signs of disease, infectious intensity and accumulated mortality rates were evaluated. The use of diets containing probiotics, regardless of strain, enhanced productive performance from 90 experimental days (p < 0.05). The multi‐strain probiotics reduced the presence of potentially pathogenic bacteria in the intestine. Fish fed probiotics showed improved resistance to A. hydrophila infection, while the diets containing B. cereus (an autochthonous probiotic) and multi‐strain probiotic promoted the lowest mortality rates and higher leucocyte and thrombocyte counts (p < 0.05). The results revealed that the use of probiotics as a single autochthonous or multi‐strain probiotic enhanced fish growth, prevented dysbiosis and increased disease resistance.

Enrichment of Artemia sp. with autochthonous probiotics at different levels in larviculture of piauçu Megaleporinus macrocephalus

“…This influence of probiotic strains on adhesion by exclusion and expressive reduction of potentially pathogenic bacteria has been widely proposed as a characteristic of the probiotic effect on the host. This mechanism of exclusion of these microorganisms is linked to the production of antimicrobial in the quorum sensing (Mouriño et al, 2017;Chauhan and Singh, 2019;Dias et al, 2022).…”

“…An aliquot (100 μL) of each dilution (10 -1 , 10 -2 , 10 -3 , 10 -4 and 10 -5 CFU•mL) was seeded in petri dishes containing culture medium (MRS Agar) and incubated at 30°C for 48 h to obtain the counts of probiotic bacteria in CFU•g -1 . (adapted from Jatobá et al, 2008;Vázquez-Silva et al, 2016;Dias et al, 2022). The analyses were carried out in quadruplicate.…”

“…After the supplementation period, the fish were submitted to an acute bacterial challenge by the immersion method against the pathogen A. hydrophila to assess their ability to resist infections (adapted from Nikapitiya et al, 2018). The pathogenic bacteria were cultured in BHI broth and incubated at 30°C for 24 h according to Mouriño et al (2017) and Dias et al (2022). The bacteria were cultured to an optical density (OD) of 600 nm, sedimented by centrifugation (3,500 rpm at 4°C for 10 min) and resuspended in sterile buffered saline (0.65%).…”

“…Therefore, 45 post-larvae were submitted to an acute challenge by A. hydrophila (lethal dose 1 × 10 8 CFU•mL -1 ) in a completely randomized design, consisting of larvae that received Artemia enriched with E. faecium (T1: 1 × 10 4 ; T2: 1 × 10 6 ; and T3: 1 × 10 8 CFU•mL -1 ), challenged with the pathogen, the group that received Artemia without probiotics (C+, positive control), infected with the pathogenic bacterium, and the group (C-, negative control) with sterile saline solution (0.65%) without A. hydrophila. Group C was used as a parameter for the experiment safety, as described by Dias et al (2022).…”