Fish Skin Mucus Extracts: An Underexplored Source of Antimicrobial Agents

Abstract

The slow discovery of new antibiotics combined with the alarming emergence of antibiotic-resistant bacteria underscores the need for alternative treatments. In this regard, fish skin mucus has been demonstrated to contain a diverse array of bioactive molecules with antimicrobial properties, including peptides, proteins, and other metabolites. This review aims to provide an overview of the antimicrobial molecules found in fish skin mucus and its reported in vitro antimicrobial capacity against bacteria, fungi, and viruses. Additionally, the different methods of mucus extraction, which can be grouped as aqueous, organic, and acidic extractions, are presented. Finally, omic techniques (genomics, transcriptomics, proteomics, metabolomics, and multiomics) are described as key tools for the identification and isolation of new antimicrobial compounds. Overall, this study provides valuable insight into the potential of fish skin mucus as a promising source for the discovery of new antimicrobial agents.

Dietary Debaryomyces hansenii promotes skin and skin mucus defensive capacities in a marine fish model

“…Pseudomonas is considered an opportunistic pathogen whose infections in S. aurata occur under environmental stress ( 87 ). The results observed herein suggest that feeding the fish with D. hansenii not only could increase mucus production but also could increase its enzymatic and antibacterial defense components, thus protecting the host from potential pathogenic bacteria ( 88 ).…”

Revealing Metabolic Dysregulation Induced by Polypropylene Nano- and Microplastics in Nile Tilapia via Noninvasive Probing Epidermal Mucus

“…Histamine is an important immune mediator that plays a critical role in allergic reactions and inflammatory processes. , Upregulation of histamine may indicate the presence of inflammation or immune activation within the tilapia epidermal mucus. , 4-Hydroxynonenal (4-HNE) is a lipid peroxidation product formed during the oxidation of fatty acids, serving as a metabolic byproduct. , The upregulation of 4-HNE is often a consequence of oxidative stress and cell damage . Antimicrobial and antifungal functions are possessed by piscine epidermal mucus, which offers a protective layer for the fish against pathogenic microorganisms and bacteria from the external environment. , The reduced secretion of caprylic acid may decrease the ability of the body to resist microbes, aligning with the function of epidermal mucus . This underscores the importance of caprylic acid in maintaining immune function and defending against microbial invasion. , As an antioxidant, niacinamide serves to alleviate the generation of free radicals and maintain normal cellular function. , The decrease in niacinamide levels may negatively impact cellular capacity to cope with oxidative stress, thereby increasing the risk of cell damage and inflammation .…”

“…33 Antimicrobial and antifungal functions are possessed by piscine epidermal mucus, which offers a protective layer for the fish against pathogenic microorganisms and bacteria from the external environment. 9,34 The reduced secretion of caprylic acid may decrease the ability of the body to resist microbes, aligning with the function of epidermal mucus. 35 This underscores the importance of caprylic acid in maintaining immune function and defending against microbial invasion.…”

“…6,8 Approximately 26% of these constituents are free amino acids and amino acid derivatives. 9 This ex vivo excreta also contains choline substances that regulate phospholipid synthesis and lipid metabolism. 6,10 Under the pressure of environmental pollution, the production and composition of mucus in fish may change, leading to health issues or an increased susceptibility to bacterial pathogens.…”

“…These invasive sampling methods undoubtedly compromise the welfare of the organisms involved. , Hence, the acquisition of information about the biological stress through noninvasive or minimally invasive means is extremely imperative. Piscine epidermal mucus, as an endogenous metabolite, is enriched with active components, including glycoproteins, polysaccharides, immunoglobulins, and hydrolases. , Approximately 26% of these constituents are free amino acids and amino acid derivatives . This ex vivo excreta also contains choline substances that regulate phospholipid synthesis and lipid metabolism. , Under the pressure of environmental pollution, the production and composition of mucus in fish may change, leading to health issues or an increased susceptibility to bacterial pathogens. , Therefore, the piscine epidermal mucus may serve as a sample reflecting the immune status and stress-induced changes, thereby aiding researchers in comprehending the physiological conditions and potential health concerns of fish. , …”