Immunomodulatory effects of bacteriocinogenic and non-bacteriocinogenic Lactococcus cremoris of aquatic origin on rainbow trout (Oncorhynchus mykiss, Walbaum)

Abstract

Lactic Acid Bacteria (LAB) are a group of bacteria frequently proposed as probiotics in aquaculture, as their administration has shown to confer positive effects on the growth, survival rate to pathogens and immunological status of the fish. In this respect, the production of antimicrobial peptides (referred to as bacteriocins) by LAB is a common trait thoroughly documented, being regarded as a key probiotic antimicrobial strategy. Although some studies have pointed to the direct immunomodulatory effects of these bacteriocins in mammals, this has been largely unexplored in fish. To this aim, in the current study, we have investigated the immunomodulatory effects of bacteriocins, by comparing the effects of a wild type nisin Z-expressing Lactococcus cremoris strain of aquatic origin to those exerted by a non-bacteriocinogenic isogenic mutant and a recombinant nisin Z, garvicin A and Q-producer multi-bacteriocinogenic strain. The transcriptional response elicited by the different strains in the rainbow trout intestinal epithelial cell line (RTgutGC) and in splenic leukocytes showed significant differences. Yet the adherence capacity to RTgutGC was similar for all strains. In splenocyte cultures, we also determined the effects of the different strains on the proliferation and survival of IgM+ B cells. Finally, while the different LAB elicited respiratory burst activity similarly, the bacteriocinogenic strains showed an increased ability to induce the production of nitric oxide (NO). The results obtained reveal a superior capacity of the bacteriocinogenic strains to modulate different immune functions, pointing to a direct immunomodulatory role of the bacteriocins, mainly nisin Z.

Terminalia arjuna Bark Powder as a Potential Immunomodulator in Labeo rohita: Enhanced Hematological, Adaptive, and Humoral Responses against Bacterial Pathogens and Concordant Liver Histomorphology

“…Overall, the results of the study provide further evidence that biomarkers can have a negative impact on the adaptive immunity of fish. However, the severity of the impact appears to vary depending on the fish’s individual immune [ 53 ] response. Further studies are needed to better understand the mechanisms by which IBR affects the adaptive immunity of fish, and to develop effective strategies for preventing and treating the disease.…”

Bacteriostasis of nisin against planktonic and biofilm bacteria: Its mechanism and application

“…Sadraei et al (2022) found that the cell proliferation and differentiation increased in bone marrow mesenchymal stem cells pretreated with nisin on a poly-L-lactic-acid scaffold. Moreover, a great number of studies have shown that nisin has immune regulation function (Contente et al, 2023;Jia et al, 2019;Malaczewska & Kaczorek-Lukowska, 2021;Malaczewska et al, 2019;Singh et al, 2014).…”

Antimicrobial Activity, Genetic Relatedness, and Safety Assessment of Potential Probiotic Lactic Acid Bacteria Isolated from a Rearing Tank of Rotifers (Brachionus plicatilis) Used as Live Feed in Fish Larviculture

“…This interest has been mostly directed towards vaccination and the use of probiotics. However, due to the immature state of the larvae immune system, which renders vaccination less effective and costlier, the interest for probiotic bacteria has been growing [2,[12][13][14].…”

“…In aquaculture, probiotics can be defined as live micro-organisms, usually bacteria or yeasts, that, when administered through feed or the rearing environment, confer beneficial effects to the host such as protection against ichthyopathogens, the stimulation of the immune system, competition for adhesion sites in the mucosa, improved tolerance to stress, host nutrition enhancement, and water quality improvement [14][15][16][17][18]. Usually, both the host and the rearing environment have been regarded as the most suitable sources for the isolation of probiotic candidates for larviculture.…”