Autochthonous probiotic bacteria modulate intestinal microbiota of Pirarucu, Arapaima gigas

Abstract

This study aimed to investigate the ability of two probiotic strains (Lactococcus lactis subsp. lactis and Enterococcus faecium) to colonize Arapaima gigas intestines and their competence in modulating gut microbiota, morphology, and immunological status. A total of 135 A. gigas (58.86 ± 10.25 g) were divided into three treatments: (a) fish fed a diet containing L. lactis subsp. lactis at 1 × 108 CFU−1, (b) fish fed a diet containing E. faecium at 1 × 108 CFU−1, and (c) fish fed a diet nonsupplemented with probiotic. After 21 days, 12 fish per treatment were sampled. Blood and posterior intestine were sampled for further analysis. High‐throughput sequencing results demonstrated that the relative abundance of Cetobacterium genus was high in all treatments. The number of thrombocytes increased in both groups fed the probiotic, and eosinophils were higher in fish fed E. faecium. Serum antimicrobial activity of fish fed L. lactis subsp. lactis was higher when compared with the other two treatments. In conclusion, both strains could populate the intestinal mucosa of A. gigas and could be used as probiotics in pirarucu production as they can influence hematoimmunological parameters and decrease the abundance of pathogenic bacteria in the gut of pirarucu within 21 days of feeding.

Seleção in vitro de isolados do trato gastrointestinal de Colossoma macropomum, com potencial probiótico

“…A capacidade de inibir o crescimento de patógenos é uma característica importante para a seleção de probióticos no ramo da aquicultura [60][61][62]. Diversos estudos já demonstraram a capacidade das BAL em inibir micro-organismos patógenos Gram positivos e negativos [15,19,21,63], corroborando com os achados deste trabalho.…”

“…Normalmente, estes micro-organismos passam por uma triagem in vitro para avaliar o seu potencial probiótico, que inclui caracterização fenotípica, bioquímica, e mais recentemente molecular [14,15]. Além disso, são necessários testes de antagonismo frente à patógenos, resistência a antimicrobianos, entre outros.…”

In vitro selection of autochthonous bacterium with probiotic potential for the neotropical fish piauçu Megaleporinus microcephalus

“…Several studies have reported the benefits of the use of autochthonous lactic acid bacteria for aquaculture (Dias et al, 2018;Pereira et al, 2019;Jatobá et al, 2017;Sousa et al, 2019;Yamashita et al, 2020). Among the bacteria with probiotic potential, Enterococcus faecium stands out because of its ability to completely colonize the intestinal tract of the host when compared with heterotrophic bacteria and which is most likely related to its rapid growth rate in the intestine (Dias et al, 2019;Souza et al, 2019).…”

“…In vitro assays can aid in the selection of autochthonous bacteria with probiotic potential, determining their survival in different physiological conditions as well as their inhibitory capacity against pathogens (Dias et al, 2019;Pereira et al, 2019;Paixão et al, 2020;Qi et al, 2020;Sousa et al, 2019). Some studies have reported positive results for both in vitro and vivo assays using autochthonous probiotic bacteria in aquaculture, such as Lactobacillus spp.…”

The key role of functional aquafeeds to achieve a more sustainable aquaculture

“…The study also showed that gene expression data can help explain some of the mechanisms behind the benefits of using probiotics in fish feeds, namely on fish intestinal morphology, immunity, and disease resistance. Similarly, do Vale Pereira, Pereira, Soares, Mouriño, and Merrifield () showed that probiotic bacteria can modulate the gut microbiome, morphology, and immune status of Pirarucu ( Arapaima gigas ). In addition to specific fish species effects, probiotic strain, and culture settings where probiotics are used, the timing of their supplementation is also of importance for the successful use of probiotics.…”