Grape pomace flour alleviates Pseudomonas aeruginosa-induced hepatic oxidative stress in grass carp by improving antioxidant defense

Use of grape by-products in aquaculture: New frontiers for a circular economy application

Grape by-products have already been used in cosmetics, food industries, but also animal feed industry, especially monogastrics and in aquaculture. Grape by-products have been studied for a long time and their principal activities are antimicrobial and antioxidant. Concerning aquaculture, the great demand and necessity to replace animal sources with vegetable ones, has placed grape by-products as possible new phytonutrients with beneficial properties. The purpose of this review is to describe the use of grape by-products in aquaculture, during the last decade, concerning their effects on: 1) gut health and welfare status; 2) growth performances; 3) quality of fillets and flesh during the rearing cycle and shelf-life products. Although other studies highlighted that the high supplementation of grape by-products could negatively affect fish health and growth, due to antinutritional factors (tannins), grape by-products are proven to be valuable phytonutrients that can be incorporated into fish feed to enhance growth and health during rearing conditions. Even in fish products, their utilization has proven to elongate the properties and shelf-life of fillets and minces. Further studies to evaluate the possible integrations or replacements with grape by-products in fish feed in order to evaluate their effectiveness in aquaculture from a sustainable circular economy perspective will be desirable to enhance the use of these products.

Indole-3-acetic acid impacts biofilm formation and virulence production of Pseudomonas aeruginosa

Bacterial pathogenesis involves complex mechanisms contributing to virulence and persistence of infections. Understanding the multifactorial nature of bacterial infections is crucial for developing effective interventions. The present study investigated the efficacy of indole-3-acetic acid (IAA) against Pseudomonas aeruginosa with various end points including antibacterial activity, minimum inhibitory concentration (MIC), virulence factor production, biofilm inhibition, bacterial cell detachment, and viability assays. Results showed significant biofilm inhibition, bacterial cell detachment, and modest effects on bacterial viability. Microscopic analysis confirmed the disintegrated biofilm matrix, supporting the inhibitory effect of IAA. Additionally, molecular docking studies revealed potential mechanisms of action through active bond interactions between IAA and virulence proteins. These findings highlight IAA as an effective antibiofilm agent against P. aeruginosa.

Effect of Dietary Insect Meal and Grape Marc Inclusion on Flavor Volatile Compounds and Shell Color of Juvenile Abalone Haliotis iris

Almost 60% of the fish meal produced globally is used in aquaculture feeds. Fish meal production relies on finite wild-marine resources and is considered as an unsustainable ingredient. Insect meal (IM) is considered a sustainable source with high levels of protein suitable for growth promotion. Grape marc (GM) is a waste byproduct of the winery industry rich in pigments with antioxidant capacity. However, the inclusion of both ingredients can affect the flavor of the meat of abalone and the color of the shell due to different nutritional profiles. The aim of this study was to evaluate the effect of the dietary inclusion of IM and GM on the flavor volatile compounds and shell color of the juvenile Haliotis iris in a 165-days feeding trial. Abalone were offered four experimental diets with different levels of IM and GM inclusion and a commercial diet (no IM or GM). Soft bodies of abalone were used to characterize volatile compounds using solid-phase microextraction gas chromatography-mass spectrometry, and color changes were analyzed in ground powder of abalone shells using color spectrophotometry 400-700 nm (visible). The results showed 18 volatile compounds significantly different among the dietary treatments. The inclusion of IM did not significantly affect the flavor volatile compounds detected, whereas the inclusion of GM reduced volatile compounds associated with lipid-peroxidation in abalone meat. The inclusion of IM and GM did not significantly affect the lightness nor the yellowness, blueness, redness, and greenness of the ground shells. The supplementation of abalone feeds with GM can help to reduce off-flavour compounds which may extend shelf-life of raw abalone meat.

Assessing differences in the bioaccessibility of phenolics present in two wine by-products using an in-vitro model of fish digestion

Increasing attention is currently being paid to the protective role of polyphenols in health and oxidative status in fish. For this reason, the potential use of different natural sources of such compounds, like wine by products, is under study. One key step required to gain a better understanding on the biological roles of polyphenols for a given species is to assess the different factors affecting their digestive bioaccessibility, and a great number of such studies is based in the use of in vitro digestion models. In the present study the potential digestive bioavailability of the phenolic compounds present in wine bagasse and lees was evaluated for two fish species showing great differences in their digestive phisyiology: the omnivorous gilthead sea bream (Sparus aurata) and the herbivorous flathead grey mullet (Mugil cephalus). The study was developed using in vitro models adapted to simulate their digestion and a factorial experimental design that simultaneously evaluated the effects of the ingredient used as source of polyphenols, presence or absence of feed matrix, fish species and digestion time. The release of the phenolic compounds was evaluated using ultra-high performance liquid chromatography (UHPLC) coupled to high resolution mass spectrometry (HRMS) detection. Both the presence of feed matrix and the type of wine by-product showed a significant effect on the digestive release of both total and specific types of polyphenols while fish species showed to be significant only for some specific compounds, like eriodyctiol or syringic acid. The time of digestion was not identified as a statistically significant factor in the release of phenolic compounds due to the great variability in the patterns observed that were classified as early, sustained and late. The observed great variations in the patterns of release of different types of phenolic compounds with time suggest an important effect of gut transit rates on the net bioavailability of a given phenolic compound in the live fish. The present study is, to our knowledge, the first one on which an in vitro approach was applied to assess to what extent the possible complexation of wine polyphenols present in wine by-products with either digestive enzymes or components of the feed matrix could limit their bioaccessibility if included in diets of two different fish species.

Antioxidative and immunostimulant potential of fruit derived biomolecules in aquaculture

Huge amounts of non-edible by-products could be generated from fruit industrial processes. They consist mainly of peels together with low amounts of pulp and seeds. These by-products pose an environmental hazard due to soil, air, and water pollution. Moreover, treating these by-products is very expensive and under strict governmental regulations. Nevertheless, they are an excellent source of bioactive constituents, such as phenols, flavonoids, terpenes, and glucans. Based on their constituents, these by-products can significantly enhance the antioxidant defense, immune response, and modulation of gut microbiota and host resistance against various diseases. Therefore, sustainable valorization of fruits by-products can efficiently obtain value-added products that improve the well-being of organisms and reduce environmental stress, in addition to earning an additional industrial income. Since aquaculture is a vital economic sector, there is urgent to look for inexpensive natural food additives that improve health and maintain high nutritional quality for farming organisms without harming the environment and human health. Therefore, using fruit wastes as feed additives represents a striking alternative for fruitful aquaculture. In order to make use of these value-added products, it is a dire need to determine their biological effects on aquaculture organisms by understanding their mechanism of action. In this context, this review will holistically address a comprehensive focus on utilizing fruits by-products and their immunostimulant and antioxidative action.

First Ever Whole Genome Sequencing and De Novo Assembly of the Freshwater Angelfish, Pterophyllum scalare

This research work is the first to ever sequence and perform a de novo assembly of the genome of the freshwater angelfish, Pterophyllum scalare . The final genome assembly consisted of 15,486 contigs and was 734.79 Mb in size with an 86.5% BUSCO score. Functional annotation of the genome revealed 24,247 protein-coding sequences related to other fish species. 14,329 (59%) of the identified genes were orthologous to Archocentrus centrarchus , a closely related South American cichlid.

Antioxidant and Anti-Inflammatory Actions of Polyphenols from Red and White Grape Pomace in Ischemic Heart Diseases

Grape pomace (GP) represents a very reliable source of polyphenols because it could be found globally as a remnant of the wine industry. During the winemaking process, two types of GP are generated: red GP and white GP, according to the produced wine, red or white. Grape pomace represents a viable source of polyphenols, mainly flavanols, procyanidins anthocyanins, and resveratrol which possess antioxidant and anti-inflammatory activities. Multiple differences were observed between red and white GP in terms of their antioxidant and anti-inflammatory activity in both in vitro and in vivo studies. Although most studies are focused on the antioxidant and anti-inflammatory effect of red grape pomace, there are still many variables that need to be taken into consideration, as well as extensive study of the white GP. It was observed that in both in vitro and in vivo studies, the GP polyphenols have a direct antioxidant activity by acting as a free radical scavenger or donating a hydrogen atom. It also possesses an indirect antioxidant and anti-inflammatory activity by reducing mitochondrial reactive oxygen species (ROS) generation, malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), interleukin-1-beta (IL-1β), interleukin-6 (IL-6), nuclear factor kappa-light-chain-enhancer of activated B cells (NF- κβ), and inhibitor of nuclear factor kappa-B kinase subunit beta (Iκκβ) levels or nitrate oxide-4 (NOX4) expression and by increasing the levels of antioxidants enzymes like superoxide dismutase (SOD), catalase (CAT) glutathione reductase (GRx) and glutathione peroxidase(GPx). Besides these activities, many beneficial effects in ischemic heart diseases were also observed, such as the maintenance of the ventricular function as close as possible to normal, and the prevention of infarcted area extension. In this context, this review intends to present the actual knowledge of grape pomace’s potential antioxidant and anti-inflammatory activity in ischemic heart disease, knowledge gathered from existing in vitro and in vivo studies focused on this.

Epigallocatechin-3-gallate ameliorates liver injury secondary to Pseudomonas aeruginosa pneumonia

Pseudomonas aeruginosa is a dangerous pathogen causing nosocomial pneumonia. P. aeruginosa infection-induced liver damage is another fatal threat, and antibiotic treatment is not effective in relieving P. aeruginosa virulence-triggered damage. We here evaluated the protective effect of epigallocatechin gallate (EGCG), a substance that inhibits virulence of P. aeruginosa through quorum quenching, on liver damage secondary to P. aeruginosa infection. Mice were pretreated with EGCG (20, 40, and 80 mg/kg) for 3 days, and then infected with P. aeruginosa through intratracheal instillation to model acute pneumonia. The mice were sacrificed after 24 h of infection, and samples were harvested for subsequent analysis. EGCG significantly decreased the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Histopathological changes of liver were significantly ameliorated by EGCG. It also significantly reduced oxidative stress that induced liver damage in P. aeruginosa infection, which relied not on the activation of the Nrf₂-HO-1 pathway but on the upregulation of the activity of antioxidative enzymes. Then, the inflammatory response in the liver was tested. EGCG inhibited the release of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) by blocking the inflammation regulating signaling of the TLR4-myD88-NF-κB pathway. EGCG upregulated the activation of nuclear receptors to stronger the liver protective activity against P. aeruginosa infection. Conclusively, EGCG exhibited a significant hepatoprotective effective against P. aeruginosa infection.

Food-derived cyanidin-3-O-glucoside alleviates oxidative stress: evidence from the islet cell line and diabetic db/db mice

Type 2 diabetes mellitus is a disease associated with an oxidative milieu that often leads to adverse health outcomes. Multiple anthocyanins have been reported to possess outstanding antioxidant activity, however, their effects on hyperglycemia-related oxidative stress remain elusive. In the present study, cyanidin-3-O-glucoside (C3G), a typical anthocyanin with various widely accepted health benefits, was applied to alleviate oxidative stress in pancreas islets under the conditions of hyperglycemia. Firstly, significantly decreased mitochondrial membrane potential (MMP) and antioxidant enzymes, as well as increased reactive oxygen species (ROS) and O₂^- levels, were detected after exposure to a series of concentrations of high glucose (HG) and palmitic acid (PA), which manifested oxidative stress triggered by mitochondrial damage. To evaluate the antioxidant effect of C3G in vitro, the islet cell line NIT-1 was used, and results proved that C3G could effectively relieve cellular oxidative stress induced by HG and PA. Furthermore, we found that the antioxidant effect of C3G was achieved by activating mitophagy via the PINK1-PARKIN signaling pathway. More importantly, an autophagy inhibitor chloroquine (CQ) was added to verify our findings at the protein level, and we observed the co-localization of mitochondria and lysosomes, which may form autophagolysosomes to clean damaged mitochondria. Immediately afterwards, more studies were conducted on pancreatic islets of diabetic db/db mice to verify the antioxidant effect of C3G discovered in islet cells. Along with the decline in fasting blood glucose, the oxidative stress in pancreas islets was successfully alleviated in diabetic db/db mice after supplementation with C3G. This was demonstrated by increased levels of ROS, and the impaired activities of anti-oxidative enzymes superoxide dismutase (SOD) and catalase (CAT) were partly reversed by C3G intervention. Our study has provided evidence for the alleviation effect of C3G against oxidative stress in pancreas islets, which may provide enlightenment for improving the health situation of diabetic patients in the future.