Propolis: Properties and composition, health benefits and applications in fish nutrition

Environmental epigenetics: Exploring phenotypic plasticity and transgenerational adaptation in fish

Epigenetics plays a vital role in the interaction between living organisms and their environment by regulating biological functions and phenotypic plasticity. Considering that most aquaculture activities take place in open or natural habitats that are vulnerable to environmental changes. Promising findings from recent research conducted on various aquaculture species have provided preliminary evidence suggesting a link between epigenetic mechanisms and economically valuable characteristics. Environmental stressors, including climate changes (thermal stress, hypoxia, and water salinity), anthropogenic impacts such as (pesticides, crude oil pollution, nutritional impacts, and heavy metal) and abiotic factors (infectious diseases), can directly trigger epigenetic modifications in fish. While experiments have confirmed that many epigenetic alterations caused by environmental factors have plastic responses, some can be permanently integrated into the genome through genetic integration and promoting rapid transgenerational adaptation in fish. These environmental factors might cause irregular DNA methylation patterns in genes related to many biological events leading to organs dysfunction by inducing alterations in genes related to oxidative stress or apoptosis. Moreover, these environmental issues alter DNA/histone methylation leading to decreased reproductive competence. This review emphasizes the importance of understanding the effects of environmentally relevant issues on the epigenetic regulation of phenotypic variations in fish. The goal is to expand our knowledge of how epigenetics can either facilitate or hinder species' adaptation to these adverse conditions. Furthermore, this review outlines the areas that warrant further investigation in understanding epigenetic reactions to various environmental issues.

Therapeutic uses and applications of bovine lactoferrin in aquatic animal medicine: an overview

Aquaculture is an important food sector throughout the globe because of its importance in ensuring the availability of nutritious and safe food for human beings. In recent years, this sector has been challenged with several obstacles especially the emergence of infectious disease outbreaks. Various treatment and control aspects, including antibiotics, antiseptics, and other anti-microbial agents, have been used to treat farmed fish and shrimp against diseases. Nonetheless, these medications have been prohibited and banned in many countries because of the development of antimicrobial-resistant bacterial strains, the accumulation of residues in the flesh of farmed fish and shrimp, and their environmental threats to aquatic ecosystems. Therefore, scientists and researchers have concentrated their research on finding natural and safe products to control disease outbreaks. From these natural products, bovine lactoferrin can be utilized as a functional feed supplement. Bovine lactoferrin is a multi-functional glycoprotein applied in various industries, like food preservation, and numerous medications, due to its non-toxic and ecological features. Recent research has proposed multiple advantages and benefits of using bovine lactoferrin in aquaculture. Reports showed its potential ability to enhance growth, reduce mortalities, regulate iron metabolism, decrease disease outbreaks, stimulate the antioxidant defense system, and recuperate the overall health conditions of the treated fish and shrimp. Besides, bovine lactoferrin can be considered as a safe antibiotic alternative and a unique therapeutic agent to decrease the negative impacts of infectious diseases. These features can be attributed to its well-known antibacterial, anti-parasitic, anti-inflammatory, immunostimulatory, and antioxidant capabilities. This literature review will highlight the implications of bovine lactoferrin in aquaculture, particularly highlighting its therapeutic features and ability to promote immunological defensive pathways in fish. The information included in this article would be valuable for further research studies to improve aquaculture's sustainability and the functionality of aquafeeds.

Castanea crenata honey reduces influenza infection by activating the innate immune response

Influenza is an acute respiratory disorder caused by the influenza virus and is associated with prolonged hospitalization and high mortality rates in older individuals and chronically ill patients. Vaccination is the most effective preventive strategy for ameliorating seasonal influenza. However, the vaccine is not fully effective in cases of antigenic mismatch with the viral strains circulating in the community. The emergence of resistance to antiviral drugs aggravates the situation. Therefore, developing new vaccines and antiviral drugs is essential. Castanea crenata honey (CH) is an extensively cultivated food worldwide and has been used as a nutritional supplement or herbal medicine. However, the potential anti-influenza properties of CH remain unexplored. In this study, the in vitro and in vivo antiviral effects of CH were assessed. CH significantly prevented influenza virus infection in mouse Raw264.7 macrophages. CH pretreatment inhibited the expression of the viral proteins M2, PA, and PB1 and enhanced the secretion of proinflammatory cytokines and type-I interferon (IFN)-related proteins in vitro. CH increased the expression of RIG-1, mitochondrial antiviral signaling (MAVS) protein, and IFN-inducible transmembrane protein, which interferes with virus replication. CH reduced body weight loss by 20.9%, increased survival by 60%, and decreased viral replication and inflammatory response in the lungs of influenza A virus-infected mice. Therefore, CH stimulates an antiviral response in murine macrophages and mice by preventing viral infection through the RIG-1-mediated MAVS pathway. Further investigation is warranted to understand the molecular mechanisms involved in the protective effects of CH on influenza virus infection.

Characteristics of Chitosan Films with the Bioactive Substances-Caffeine and Propolis

Chitosan is a natural and biodegradable polymer with promising potential for biomedical applications. This study concerns the production of chitosan-based materials for future use in the medical industry. Bioactive substances-caffeine and ethanolic propolis extract (EEP)-were incorporated into a chitosan matrix to increase the bioactivity of the obtained films and improve their mechanical properties. Acetic and citric acids were used as solvents in the production of the chitosan-based films. The obtained materials were characterized in terms of their antibacterial and antifungal activities, as well as their mechanical properties, including tensile strength and elongation at break. Moreover, the chemical structures and surface morphologies of the films were assessed. The results showed that the solution consisting of chitosan, citric acid, caffeine, and EEP exhibited an excellent antiradical effect. The activity of this solution (99.13%) was comparable to that of the standard antioxidant Trolox (92.82%). In addition, the film obtained from this solution showed good antibacterial activity, mainly against Escherichia coli and Enterococcus faecalis. The results also revealed that the films produced with citric acid exhibited higher activity levels against pathogenic bacteria than the films obtained with acetic acid. The antimicrobial effect of the chitosan-based films could be further enhanced by adding bioactive additives such as caffeine and propolis extract. The mechanical tests showed that the solvents and additives used affected the mechanical properties of the films obtained. The film produced from chitosan and acetic acid was characterized by the highest tensile strength value (46.95 MPa) while the chitosan-based film with citric acid showed the lowest value (2.28 MPa). The addition of caffeine and propolis to the film based on chitosan with acetic acid decreased its tensile strength while in the case of the chitosan-based film with citric acid, an increase in strength was observed. The obtained results suggested that chitosan films with natural bioactive substances can be a promising alternative to the traditional materials used in the medical industry, for example, as including biodegradable wound dressings or probiotic encapsulation materials.

Effects of Bee Pollen on Growth Performance, Intestinal Microbiota and Histomorphometry in African Catfish

This study aimed to determine the dietary effects of honeybee pollen (BP) on growth parameters, intestinal microbiota, hepatic histoarchitecture, and intestinal histomorphometry of African catfish Clarias gariepinus juveniles. The feeding experiment was carried out in a recirculating aquaculture system under controlled conditions for 21 days to achieve more than a 10-fold increase in weight in fish from the control group. Fish were fed well-balanced commercial feed without any supplements and served as a reference group (group C) and other diets enriched with varying BP levels as 1% (BP1), 2% (BP2), and 3% (BP3). Results showed a significant (p < 0.05) effect of the dietary BP not only on the growth parameters (such as final body weight: 5.0 g to 6.6−7.5 g, weight gain: 0.23 g/d to 0.31−0.35 g/d, body length: 84.7 mm to 93.8−95.9 mm, and specific growth rate: 11.7%/d to 13.1−13.7%/d, group C vs. experimental groups, respectively) but also on the development of beneficially important gut microbiota, such as lactic acid-producing bacteria. In BP-enriched groups, an average of 45% higher body weight gain was observed compared to those reared in the control group. The histological analysis showed that dietary BP may have a positive effect on the development of the intestinal tract and may enhance the absorption of nutrients with the potential ability to maintain a normal hepatic histoarchitecture of the treated African catfish. The results obtained suggest the optimum level of BP additive to feed for African catfish should be 1%.

Propolis nanoparticles relieved the impacts of glyphosate-induced oxidative stress and immunosuppression in Nile tilapia

The risk of the waterborne toxicity caused by herbicides threatens the aquatic environment. In this study, propolis nanoparticles were shown to relieve the impacts of glyphosate-induced oxidative stress and immunosuppression in Nile tilapia. The control group was fed a basal diet and maintained in a glyphosate-free water (control). Simultaneously, the other three groups were exposed to sublethal concentrations of glyphosate (0.6 mg/L) and fed diets containing 0 and 10 g propolis and 10 g propolis nanoparticles for 4 weeks. Nile tilapia exposed to glyphosate for 2 and 4 weeks exhibited a significant increase in serum alanine aminotransferase, aspartate aminotransferase, urea, and creatinine values compared to the control. After 2 and 4 weeks, fish exposed to glyphosate who were not fed propolis and propolis nanoparticles showed a significant reduction in total protein, albumin, and globulin levels, lysozyme activity, and total immunoglobulin levels. Nile tilapia exposed to glyphosate displayed a significant increase in blood glucose and cortisol concentrations after 2 and 4 weeks. Furthermore, liver and gill tissues from fish exposed to glyphosate exhibited a significant increase in malondialdehyde (MDA) concentrations. Conversely, a statistically significant decrease was observed in the liver and gill MDA levels and AChE activity of the groups treated with propolis and propolis nanoparticles compared to the groups exposed to glyphosate and fed the basal diet. Fish exposed to glyphosate for 2 and 4 weeks showed a significant decrease (p < 0.05) in hepatic and gill glutathione (GSH) concentration and white blood cell and red blood cell counts compared to the control group. Meanwhile, these parameters in groups fed propolis and propolis nanoparticles were markedly ameliorated compared to exposed fish fed the basal diet. Dietary supplementation of propolis nanoparticles is superior to supplementation of propolis in the normal form for protecting Nile tilapia from glyphosate toxicity.