Microalgae and phytase dietary supplementation improved growth and gut microbiota in juvenile European seabass (Dicentrarchus labrax).

Fishmeal and fish oil have been the main sources of protein and fatty acid for aquaculture fish. However, their increasing price and low sustainability have led the aquafeed industry to seek sustainable alternative feedstuffs to meet the nutritional requirements of fish and improve their health and performance. Plant proteins have been successfully used to replace fishery derivatives in aquafeeds, but the presence of anti-nutritional substances is a potential drawback of this approach.

Circular and L50-like leaderless enterocins share a common ABC-transporter immunity gene.

Microbes live within complex communities of interacting populations, either free-living in waters and soils or symbionts of animals and plants. Their interactions include the production of antimicrobial peptides (bacteriocins) to antagonize competitors, and these producers must carry their own immunity gene for self-protection. Whether other coexisting populations are sensitive or resistant to the bacteriocin producer will be key for the population dynamics within the microbial community.

-Derived Compound Propyl Propane Thiosulfonate (PTSO) Reduces Vibrio Populations and Increases Body Weight of European Seabass () Juveniles.

The global demand for fish products is continuously increasing as the population grows, and aquaculture plays an important role in supplying this demand. However, industrial antibiotic misuse has contributed to the spread of antimicrobial resistance among pathogenic bacteria, therefore, several antibiotic alternatives have been proposed. In this study, we have analyzed the effects of -derived propyl propane thiosulfonate (PTSO) in European seabass juveniles' growth and performance.

Beneficial Shifts in the Gut Bacterial Community of Gilthead Seabream () Juveniles Supplemented with -Derived Compound Propyl Propane Thiosulfonate (PTSO).

This study analyzes the potential use of an -derived compound, propyl propane thiosulfonate (PTSO), as a functional feed additive in aquaculture. Gilthead seabream () juveniles had their diet supplemented with this -derived compound (150 mg/kg of PTSO) and were compared with control fish. The effects of this organosulfur compound were tested by measuring the body weight and analyzing the gut microbiota after 12 weeks.

Antimicrobial Activity of the Circular Bacteriocin AS-48 against Clinical Multidrug-Resistant .

The treatment and hospital-spread-control of methicillin-resistant (MRSA) is an important challenge since these bacteria are involved in a considerable number of nosocomial infections that are difficult to treat and produce prolonged hospitalization, thus also increasing the risk of death. In fact, MRSA strains are frequently resistant to all β-lactam antibiotics, and co-resistances with other drugs such as macrolides, aminoglycosides, and lincosamides are usually reported, limiting the therapeutical options. To this must be added that the ability of these bacteria to form biofilms on hospital surfaces and devices confer high antibiotic resistance and favors horizontal gene transfer of genetic-resistant mobile elements, the spreading of infections, and relapses.

Enterocin Cross-Resistance Mediated by ABC Transport Systems.

In their struggle for life, bacteria frequently produce antagonistic substances against competitors. Antimicrobial peptides produced by bacteria (known as bacteriocins) are active against other bacteria, but harmless to their producer due to an associated immunity gene that prevents self-inhibition. However, knowledge of cross-resistance between different types of bacteriocin producer remains very limited.

Extract Implements Weaned Piglet's Productive Parameters by Modulating Distal Gut Microbiota.

Antimicrobial resistance (AMR) has risen as a global threat for human health. One of the leading factors for this emergence has been the massive use of antibiotics growth-promoter (AGPs) in livestock, enhancing the spread of AMR among human pathogenic bacteria. Thus, several alternatives such as probiotics, prebiotics, or phytobiotics have been proposed for using in animal feeding to maintain or improve productive levels while diminishing the negative effects of AGPs.

-Based Phytobiotic Enhances Egg Production in Laying Hens through Microbial Composition Changes in Ileum and Cecum.

Phytobiotics (bioactive compounds extracted from plants) are one of the explored alternatives to antibiotics in poultry and livestock due to their antimicrobial activity and its positive effects on gut microbiota and productive properties. In this study, we supplemented a product based on garlic and onion compounds in the diet to laying hens at the beginning of their productive life (from 16 to 20 weeks post-hatching). The experimental group showed a significant increase in the number of eggs laid and in their size, produced in one month compared to the control.

Synergy of the Bacteriocin AS-48 and Antibiotics against Uropathogenic Enterococci.

The genus comprises a ubiquitous group of Gram-positive bacteria that can cause diverse health care-associated infections. Their genome plasticity enables easy acquisition of virulence factors as well as antibiotic resistances. Urinary tract infections (UTIs) and catheter-associated UTIs are common diseases caused by enterococci.

Preclinical studies of toxicity and safety of the AS-48 bacteriocin.

The antimicrobial potency of the bacteriocin AS-48 is well documented, but its clinical application requires investigation, as its toxicity could be different in (haemolytic and antibacterial activity in blood and cytotoxicity towards normal human cell lines) and (e.g. mice and zebrafish embryos) models.

Subchronic toxicity study in BALBc mice of enterocin AS-48, an anti-microbial peptide produced by Enterococcus faecalis UGRA10.

Few studies have examined the use of animal models to evaluate the in-vivo toxicity of antimicrobial peptides, but such research is essential to their safe use in foods. This study was performed to evaluate any adverse effects of enterocin AS-48, a circular bacteriocin produced by Enterococcus strains, when administered to BALB/c mice at concentrations of 50, 100, and 200 mg/kg in the diet for 90 days. Animals dosed with nisin at a dietary concentration of 200 mg/kg served as a reference treated group.

Egg Production in Poultry Farming Is Improved by Probiotic Bacteria.

Antimicrobial resistance (AMR) is one of the most serious threats for human health in the near future. Livestock has played an important role in the appearance of antibiotic-resistant bacteria, intestinal dysbiosis in farming animals, or the spread of AMR among pathogenic bacteria of human concern. The development of alternatives like probiotics is focused on maintaining or improving production levels while diminishing these negative effects of antibiotics.

Effects of Enterococcus faecalis UGRA10 and the enterocin AS-48 against the fish pathogen Lactococcus garvieae. Studies in vitro and in vivo.

The aim of this study was to evaluate the effects of Enterococcus faecalis UGRA10 and its enterocin AS-48 against the fish pathogen Lactococcus garvieae. The minimum bactericidal concentrations of AS-48 against L. garvieae CECT 5807, 5806, and 5274 were 15.

Seasonal and Sexual Differences in the Microbiota of the Hoopoe Uropygial Secretion.

The uropygial gland of hoopoe nestlings and nesting females hosts bacterial symbionts that cause changes in the characteristics of its secretion, including an increase of its antimicrobial activity. These changes occur only in nesting individuals during the breeding season, possibly associated with the high infection risk experienced during the stay in the hole-nests. However, the knowledge on hoopoes uropygial gland microbial community dynamics is quite limited and based so far on culture-dependent and molecular fingerprinting studies.

Control of Propionibacterium acnes by natural antimicrobial substances: Role of the bacteriocin AS-48 and lysozyme.

We report the high susceptibility of several clinical isolates of Propionibacterium acnes from different sources (skin, bone, wound exudates, abscess or blood contamination) to the head-to-tail cyclized bacteriocin AS-48. This peptide is a feasible candidate for further pharmacological development against this bacterium, due to its physicochemical and biological characteristics, even when it is growing in a biofilm. Thus, the treatment of pre-formed biofilms with AS-48 resulted in a dose- and time-dependent disruption of the biofilm architecture beside the decrease of bacterial viability.

LAB Bacteriocins Controlling the Food Isolated (Drug-Resistant) Staphylococci.

Staphylococci are a group of microorganisms that can be often found in processed food and they might pose a risk for human health. In this study we have determined the content of staphylococci in 7 different fresh goat-milk cheeses. These bacteria were present in all of them, ranging from 10 to 10 CFU/g based on growth on selective media.

Autophagic-related cell death of Trypanosoma brucei induced by bacteriocin AS-48.

The parasitic protozoan Trypanosoma brucei is the causative agent of human African trypanosomiasis (sleeping sickness) and nagana. Current drug therapies have limited efficacy, high toxicity and/or are continually hampered by the appearance of resistance. Antimicrobial peptides have recently attracted attention as potential parasiticidal compounds.

Enterocin AS-48 as Evidence for the Use of Bacteriocins as New Leishmanicidal Agents.

We report the feasibility of enterocin AS-48, a circular cationic peptide produced by , as a new leishmanicidal agent. AS-48 is lethal to promastigotes as well as to axenic and intracellular amastigotes at low micromolar concentrations, with scarce cytotoxicity to macrophages. AS-48 induced a fast bioenergetic collapse of promastigotes but only a partial permeation of their plasma membrane with limited entrance of vital dyes, even at concentrations beyond its full lethality.

Nest Bacterial Environment Affects Microbiome of Hoopoe Eggshells, but Not That of the Uropygial Secretion.

The study of associations between symbiotic bacterial communities of hosts and those of surrounding environments would help to understand how bacterial assemblages are acquired, and how they are transmitted from one to another location (i.e. symbiotic bacteria acquisition by hosts).

The Hoopoe's Uropygial Gland Hosts a Bacterial Community Influenced by the Living Conditions of the Bird.

Molecular methods have revealed that symbiotic systems involving bacteria are mostly based on whole bacterial communities. Bacterial diversity in hoopoe uropygial gland secretion is known to be mainly composed of certain strains of enterococci, but this conclusion is based solely on culture-dependent techniques. This study, by using culture-independent techniques (based on the 16S rDNA and the ribosomal intergenic spacer region) shows that the bacterial community in the uropygial gland secretion is more complex than previously thought and its composition is affected by the living conditions of the bird.

The bacteriocin AS-48 requires dimer dissociation followed by hydrophobic interactions with the membrane for antibacterial activity.

The molecular mechanism underlining the antibacterial activity of the bacteriocin AS-48 is not known, and two different and opposite alternatives have been proposed. Available data suggested that the interaction of positively charged amino acids of AS-48 with the membrane would produce membrane destabilization and disruption. Alternatively, it has been proposed that AS-48 activity could rely on the effective insertion of the bacteriocin into the membrane.