Lactic Acid Bacteria in Finfish—An Update

Abstract

A complex and dynamic community of microorganisms, play important roles within the fish gastrointestinal (GI) tract. Of the bacteria colonizing the GI tract, are lactic acid bacteria (LAB) generally considered as favorable microorganism due to their abilities to stimulating host GI development, digestive function, mucosal tolerance, stimulating immune response, and improved disease resistance. In early finfish studies, were culture-dependent methods used to enumerate bacterial population levels within the GI tract. However, due to limitations by using culture methods, culture-independent techniques have been used during the last decade. These investigations have revealed the presence of Lactobacillus, Lactococcus, Leuconostoc, Enterococcus, Streptococcus, Carnobacterium, Weissella, and Pediococcus as indigenous species. Numerous strains of LAB isolated from finfish are able to produce antibacterial substances toward different potential fish pathogenic bacteria as well as human pathogens. LAB are revealed be the most promising bacterial genera as probiotic in aquaculture. During the decade numerous investigations are performed on evaluation of probiotic properties of different genus and species of LAB. Except limited contradictory reports, most of administered strains displayed beneficial effects on both, growth—and reproductive performance, immune responses and disease resistance of finfish. This eventually led to industrial scale up and introduction LAB-based commercial probiotics. Pathogenic LAB belonging to the genera Streptococcus, Enterococcus, Lactobacillus, Carnobacterium, and Lactococcus have been detected from ascites, kidney, liver, heart, and spleen of several finfish species. These pathogenic bacteria will be addressed in present review which includes their impacts on finfish aquaculture, possible routes for treatment. Finfish share many common structures and functions of the immune system with warm-blooded animals, although apparent differences exist. This similarity in the immune system may result in many shared LAB effects between finfish and land animals. LAB-fed fish show an increase in innate immune activities leading to disease resistances: neutrophil activity, lysozyme secretion, phagocytosis, and production of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α). However, some LAB strains preferentially induces IL-10 instead, a potent anti-inflammatory cytokine. These results indicate that LAB may vary in their immunological effects depending on the species and hosts. So far, the immunological studies using LAB have been focused on their effects on innate immunity. However, these studies need to be further extended by investigating their involvement in the modulation of adaptive immunity. The present review paper focuses on recent findings in the field of isolation and detection of LAB, their administration as probiotic in aquaculture and their interaction with fish immune responses. Furthermore, the mode of action of probiotics on finfish are discussed.

Progress and perspectives of short‐chain fatty acids in aquaculture

“…2018a; Ringø et al . ). For instance, microbial metabolism involved in carbohydrate fermentation converts indigestible dietary carbohydrates into short‐chain fatty acids (SCFAs) (Piazzon et al .…”

“…Intriguingly, the intestine of aquatic animals is an ideal environment for colonization and proliferation of symbiotic microbes (Han et al 2010;Tran et al 2017;Wang et al 2018). Gut microbiota plays important roles in host health and nutritional metabolism through multiple mechanisms (R ıos-Covi an et al 2016;Li et al 2018a;Ringø et al 2018). For instance, microbial metabolism involved in carbohydrate fermentation converts indigestible dietary carbohydrates into short-chain fatty acids (SCFAs) (Piazzon et al 2017), thereby affecting the host's physiology.…”

Use of Lactic Acid Bacteria During Pikeperch (Sander lucioperca) Larval Rearing

“…The balance of this microbiota is influenced by a variety of factors including, but not limited to, feed type, animal physiology, and immunological factors. Such microbiota in endothermic animals are dominated by gram-positive bacteria such as LAB [22,23]. LAB are characterized by the following: (1) cell-surface properties for mediating adhesion, (2) survival within the gastrointestinal tract, (3) resilience to stress conditions, (4) ability to produce antioxidants, (5) antimicrobial effects, and (6) the positive influence on the immune system [24].…”

Exogenous enzymes as functional additives in finfish aquaculture

“…4. It is generally accepted that the changes in diet composition have an impact on fish microbiota (Einar et al, 2018;Ringo et al, 2006;Silva et al, 2011). Recently, more and more studies have been carried out to investigate the effects of exogenous enzymes on the microbiota of fish, and elucidating that the effects of dietary enzymes on intestinal status are both timely and novel.…”