Humoral and skin mucosal immune parameters, intestinal immune related genes expression and antioxidant defense in rainbow trout (Oncorhynchus mykiss) fed olive (Olea europea L.) waste

Synergistic interaction of nanoparticles and probiotic delivery: A review

Nanotechnology is an expanding and new technology that prompts production with nanoparticle-based (1-100 nm) organic and inorganic materials. Such a tool has an imperative function in different sectors like bioengineering, pharmaceuticals, electronics, energy, nuclear energy, and fuel, and its applications are helpful for human, animal, plant, and environmental health. In exacting, the nanoparticles are synthesized by top-down and bottom-up approaches through different techniques such as chemical, physical, and biological progress. The characterization is vital and the confirmation of nanoparticle traits is done by various instrumentation analyses like UV-Vis spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, X-ray diffraction, atomic force microscopy, annular dark-field imaging, and intracranial pressure. In addition, probiotics are friendly microbes which while administered in sufficient quantity confer health advantages to the host. Characterization investigation is much more significant to the identification of good probiotics. Similarly, haemolytic activity, acid and bile salt tolerance, autoaggregation, antimicrobial compound production, inhibition of pathogens, enhance the immune system, and more health-beneficial effects on the host. The synergistic effects of nanoparticles and probiotics combined delivery applications are still limited to food, feed, and biomedical applications. However, the mechanisms by which they interact with the immune system and gut microbiota in humans and animals are largely unclear. This review discusses current research advancements to fulfil research gaps and promote the successful improvement of human and animal health.

Comparative Effect of Chemical and Green Zinc Nanoparticles on the Growth, Hematology, Serum Biochemical, Antioxidant Parameters, and Immunity in Serum and Mucus of Goldfish, Carassius auratus (Linnaeus, 1758)

Recently, nano feed supplement research has great attention to improving healthy aquatic production and improving the aquatic environment. With the aims of the present study, chemical and green synthesized nanoparticles are characterized by various instrumentation analyses, namely UV-Vis spectrophotometry (UV-Vis), X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscope (SEM). After characterization analysis of these nanoparticles utilized in aquatic animals, the composition ratio is as follows: controls (without ZnO-NPs (0 mg/L)), T1 (0.9 mg/L ZnO-NPs), T2 (1.9 mg/L ZnO-NPs), T3 (0.9 mg/L GZnO-NPs), T4 (1.9 mg/L GZnO-NPs). SEM investigation report demonstrates that the structure of the surface of green synthesized zinc oxide nanoparticles (GZnO-NPs) was conical shape and the size ranging was from 60 to 70 nm. Concerning hematological parameters, the quantity of hemoglobin increased in different doses of green zinc nanoparticles, but the values of MCV and MCH decreased somewhat. However, this decrease was the highest in the T2 group. Total protein and albumin decreased in T2 and triglyceride, cholesterol, glucose, cortisol, creatinine, and urea increased, while in T3 and T4 groups, changes in biochemical parameters were evaluated as positive. Mucosal and serum immunological parameters in the T2 group showed a significant decrease compared to other groups. In zinc nanoparticles, with increasing dose, oxidative damage is aggravated, so in the T2 group, a decrease in antioxidant enzymes and an increase in MDA were seen compared to other groups. In this regard, the concentration of liver enzymes AST and ALT increased in the T2 group compared with control and other groups. This can confirm liver damage in this dose compared with control and other groups. This research work suggests that green synthesized form of zinc nanoparticles in higher doses have less toxic effects in comparison to the chemical form of zinc nanoparticles and can act as suitable nutrient supplements in aquatic animals.

Synbiotic Agents and Their Active Components for Sustainable Aquaculture: Concepts, Action Mechanisms, and Applications

Aquaculture is a fast-emerging food-producing sector in which fishery production plays an imperative socio-economic role, providing ample resources and tremendous potential worldwide. However, aquatic animals are exposed to the deterioration of the ecological environment and infection outbreaks, which represent significant issues nowadays. One of the reasons for these threats is the excessive use of antibiotics and synthetic drugs that have harmful impacts on the aquatic atmosphere. It is not surprising that functional and nature-based feed ingredients such as probiotics, prebiotics, postbiotics, and synbiotics have been developed as natural alternatives to sustain a healthy microbial environment in aquaculture. These functional feed additives possess several beneficial characteristics, including gut microbiota modulation, immune response reinforcement, resistance to pathogenic organisms, improved growth performance, and enhanced feed utilization in aquatic animals. Nevertheless, their mechanisms in modulating the immune system and gut microbiota in aquatic animals are largely unclear. This review discusses basic and current research advancements to fill research gaps and promote effective and healthy aquaculture production.

Cytokine networks that suppress fish cellular immunity

Immunosuppressive cytokines are a class of cytokines produced by immune cells and certain non-immune cells that have a suppressive effect on immune function. Currently known immunosuppressive cytokines include interleukin (IL)-10, transforming growth factor beta (TGF-β), IL-35, and IL-37. Although latest sequencing technologies have facilitated the identification of immunosuppressive cytokines in fish, IL-10 and TGF-β were the most well-known ones that have been widely studied and received continuous attention. Fish IL-10 and TGF-β have been identified as anti-inflammatory and immunosuppressive factors, acting on both innate and adaptive immune systems. However, unlike mammals, teleost fish underwent a third or fourth whole-genome duplication event, which significantly expanded the gene family associated with the cytokine signaling pathway, making the function and mechanism of these molecules need further investigation. In this review, we summarize the advances of studies on fish immunosuppressive cytokines IL-10 and TGF-β since their identification, mainly focusing on production, signaling transduction, and effects on the immunological function. This review aims to expand the understanding of the immunosuppressive cytokine network in fish.

Immunonutrition: facilitating mucosal immune response in teleost intestine with amino acids through oxidant-antioxidant balance

Comparative animal models generate fundamental scientific knowledge of immune responses. However, these studies typically are conducted in mammals because of their biochemical and physiological similarity to humans. Presently, there has been an interest in using teleost fish models to study intestinal immunology, particularly intestinal mucosa immune response. Instead of targeting the pathogen itself, a preferred approach for managing fish health is through nutrient supplementation, as it is noninvasive and less labor intensive than vaccine administrations while still modulating immune properties. Amino acids (AAs) regulate metabolic processes, oxidant-antioxidant balance, and physiological requirements to improve immune response. Thus, nutritionists can develop sustainable aquafeeds through AA supplementation to promote specific immune responses, including the intestinal mucosa immune system. We propose the use of dietary supplementation with functional AAs to improve immune response by discussing teleost fish immunology within the intestine and explore how oxidative burst is used as an immune defense mechanism. We evaluate immune components and immune responses in the intestine that use oxidant-antioxidant balance through potential selection of AAs and their metabolites to improve mucosal immune capacity and gut integrity. AAs are effective modulators of teleost gut immunity through oxidant-antioxidant balance. To incorporate nutrition as an immunoregulatory means in teleost, we must obtain more tools including genomic, proteomic, nutrition, immunology, and macrobiotic and metabonomic analyses, so that future studies can provide a more holistic understanding of the mucosal immune system in fish.

Effects of stress conditions on plasma parameters and gene expression in the skin mucus of farmed rainbow trout (Oncorhynchus mykiss)

The aim of this study was to investigate the physiological response of rainbow trout (Oncorhynchus mykiss) before slaughtering in the last phase of farming analyzing skin mucus and plasma. Two groups of rainbow trout were considered: Group UN ("unstressed"), represented by fish randomly captured from raceways, in the last phase of a standard fattening cycle; Group S ("stressed"), collected at the end of the pre-slaughtering tank, soon after slaughtering. The fish skin mucus was swabbed from head to tail using a sterile plastic spatula and the blood was collected through an endocardial puncture. qRT-PCR was used to study the gene expression in skin mucus. The mRNA expression levels of the IL-6 and IgD genes were higher in the S than in the Group UN. The plasma analysis showed an only a decrease in the glucose plasma levels in the Group S when compared to the Group UN. The present results indicated that the procedures adopted after slaughtering only affected changes in plasma glucose and skin mucus activity in rainbow trout suggesting that management protocol was compatible with non-stressful farming conditions.

Effects of Dietary Medlar (Mespilus germanica L.) Extract on Growth Performance, Innate Immune Characteristics, Antioxidant Status, and Responses to Crowding Stress in Rainbow Trout (Oncorhynchus mykiss)

High stocking density is a stress factor that potentially affects physiological and immune responses. In this study, the effects of medlar (Mespilus germanica) extract (ME) supplementation on growth performance, antioxidant, immune status, and stress responses in rainbow trout (Oncorhynchus mykiss) were studied. Six hundred fish (40.19 ± 1.09 g; average fish weight ± standard error) were distributed randomly into five experimental groups (assayed in triplicates). The experimental diets were formulated as follows: 0 (T1, control), 0.5% (T2), 1% (T3), 1.5% (T4), and 2% (T4). After 60 days feeding trial, the fish were confined, and the density increased (60 kg/m3) for further 14 days. Results showed significant increases in final weight (FW), weight gain (WG), specific growth rate, and feed intake in the T4 compared to the control (P < 0.05). The feed conversion ratio (FCR) in T4 significantly decreased compared to the control (P < 0.05). Also, the treated groups showed significant improvements in catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), lysozyme (LYZ), total immunoglobulin (total Ig), respiratory burst activity (RBA), total protein, and phagocytosis (PHA) (P < 0.05). Moreover, compared with the control group, supplementation could significantly decrease glucose (GLU) and cortisol (CORT), alanine transaminase (ALT), lactate dehydrogenase (LDH), aspartate transaminase (AST), and alkaline phosphatase (ALP) (P < 0.05). After the challenge, FW and WG in all treated challenge groups were significantly improved compared to the control group (P < 0.05). FCR showed a significant decrease in all treated challenged groups compared to the control group (P < 0.05). However, malondialdehyde, CAT, GPx, SOD, LYZ, complement activity (C3 and C4), total Ig, RBA, peroxidase, and PHA in challenged treated groups were significantly increased compared to the control group (P < 0.05). All treated challenged groups showed lower ALT, LDH, AST, ALP, GLU, and CORT levels than the control group (P < 0.05). The experiment herein successfully demonstrated that dietary ME stimulated fish growth, antioxidant status, and immune responses in crowding conditions and can be recommended as beneficial feed additives for rainbow trout.

Dietary Olive Leaf Extract Differentially Modulates Antioxidant Defense of Normal and Aeromonas hydrophila-Infected Common Carp (Cyprinus carpio) via Keap1/Nrf2 Pathway Signaling: A Phytochemical and Biological Link

Olive leaves are an immense source of antioxidant and antimicrobial bioactive constituents. This study investigated the effects of dietary incorporation of olive leaf extract (OLE) on the growth performance, hematobiochemical parameters, immune response, antioxidant defense, histopathological changes, and some growth- and immune-related genes in the common carp (Cyprinus carpio). A total of 180 fish were allocated into four groups with triplicate each. The control group received the basal diet without OLE, while the other three groups were fed a basal diet with the OLE at 0.1, 0.2, and 0.3%, respectively. The feeding study lasted for 8 weeks, then fish were challenged with Aeromonas hydrophila. The results revealed that the group supplied with the 0.1% OLE significantly exhibited a higher final body weight (FBW), weight gain (WG%), and specific growth rate (SGR) with a decreased feed conversion ratio (FCR) compared to the other groups (p < 0.05). An increase in immune response was also observed in the fish from this group, with higher lysosome activity, immunoglobulin (IgM), and respiratory burst than nonsupplemented fish, both before and after the A. hydrophila challenge (p < 0.05). Similarly, the supplementation of the 0.1% OLE also promoted the C. carpio's digestive capacity pre- and post-challenge, presenting the highest activity of protease and alkaline phosphatase (p < 0.05). In addition, this dose of the OLE enhanced fish antioxidant capacity through an increase in the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and decreased hepatic lipid peroxidation end products (malondialdehyde-MDA), when compared to the control group, both pre- and post-infection (p < 0.05). Concomitantly with the superior immune response and antioxidant capacity, the fish fed the 0.1% OLE revealed the highest survival rate after the challenge with A. hydrophila (p < 0.05). A significant remarkable upregulation of the hepatic sod, nrf2, and protein kinase C transcription levels was detected as a vital approach for the prevention of both oxidative stress and inflammation compared to the infected unsupplied control group (p < 0.05). Interestingly, HPLC and UPLC-ESI-MS/MS analyses recognized that oleuropein is the main constituent (20.4%) with other 45 compounds in addition to tentative identification of two new compounds, namely oleuroside-10-carboxylic acid (I) and demethyl oleuroside-10-carboxylic acid (II). These constituents may be responsible for the OLE exerted potential effects. To conclude, the OLE at a dose range of 0.66-0.83 g/kg w/w can be included in the C. carpio diet to improve the growth, antioxidant capacity, and immune response under normal health conditions along with regulating the infection-associated pro-inflammatory gene expressions, thus enhancing resistance against A. hydrophila.

SpPdp11 Administration in Diet Modified the Transcriptomic Response and Its Microbiota Associated in Mechanically Induced Wound Sparus aurata Skin

Skin lesions are a frequent fact associated with intensive conditions affecting farmed fish. Knowing that the use of probiotics can improve fish skin health, SpPdp11 dietary administration has demonstrated beneficial effects for farmed fish, so its potential on the skin needs to be studied more deeply. The wounded specimens that received the diet with SpPdp11 showed a decrease in the abundance of Enterobacteriaceae, Photobacterium and Achromobacter related to bacterial biofilm formation, as well as the overexpression of genes involved in signaling mechanisms (itpr3), cell migration and differentiation (panxa, ttbk1a, smpd3, vamp5); and repression of genes related to cell proliferation (vstm4a, areg), consistent with a more efficient skin healing processes than that observed in the wounded control group. In addition, among the groups of damaged skin with different diets, Achromobacter, f_Ruminococcaceae, p_Bacteroidetes, Fluviicola and Flavobacterium genera with significant differences showed positive correlations with genes related to cell migration and negative correlations with inflammation and cell proliferation and may be the target of future studies.

Recent Advances, Challenges, Opportunities, Product Development and Sustainability of Main Agricultural Wastes for the Aquaculture Feed Industry – A Review

Million tonnes of agricultural waste are generated annually worldwide. Agricultural wastes possess similar profiles to the main products but are lower in quality. Managing these agricultural wastes is costly and requires strict regulation to minimise environmental stress. Thus, these by-products could be repurposed for industrial use, such as alternative resources for aquafeed to reduce reliance on fish meal and soybean meal, fertilisers to enrich medium for growing live feed, antimicrobial agents, and immunostimulatory enhancers. Furthermore, utilising agricultural wastes and other products can help mitigate the existing environmental and economic dilemmas. Therefore, transforming these agricultural wastes into valuable products helps sustain the agricultural industry, minimises environmental impacts, and benefits industry players. Aquaculture is an important sector to supply affordable protein sources for billions worldwide. Thus, it is essential to explore inexpensive and sustainable resources to enhance aquaculture production and minimise environmental and public health impacts. Additionally, researchers and farmers need to understand the elements involved in new product development, particularly the production of novel innovations, to provide the highest quality products for consumers. In summary, agriculture waste is a valuable resource for the aquafeed industry that depends on several factors: formulation, costing, supply, feed treatment and nutritional value.

Effects of a Phytogenic Supplement Containing Olive By-Product and Green Tea Extracts on Growth Performance, Lipid Metabolism, and Hepatic Antioxidant Capacity in Largemouth Bass (Micropterus salmoides) Fed a High Soybean Meal Diet

A 10-week growth trial was conducted to investigate the effects of a phytogenic feed additive (PFA) containing olive by-products and green tea extracts supplemented to a reduced fishmeal/high soybean meal diet on the growth performance, hepatic antioxidant capacity, lipid metabolism, and liver health of largemouth bass (Micropterus salmoides). Three experimental diets were tested: (1) a control high fishmeal (40%) and low soybean meal (15.57%) diet (named HFM), (2) a reduced fishmeal (30%) and high soybean meal (30.97%) diet (named HSB), and (3) a HSB diet supplemented with the PFA at 500 mg/kg (named HSB+P). Each diet was assigned to four replicate tanks, each containing 30 largemouth bass (initial body weight, IBW = 48.33 ± 0.01 g). The results showed that increasing the soybean meal content in the diet did not negatively affect growth performance, whereas supplementation with PFA significantly increased weight gain and specific growth rate of largemouth bass compared to both HFM and HSB groups. Reducing fishmeal and increasing soybean meal in the diet caused oxidative stress with a higher content of ROS in the liver. However, the hepatic antioxidant capacity was enhanced, with reduced ROS and increased GSH-Px levels in the HSB+P group. Moreover, the decrease of plasma TG, LDL-C, and LDL-C/TC, and downregulation of lipogenesis and cholesterol synthesis gene expression in liver, indicated that supplementation with the PFA improved fish lipid metabolism. Protein retention efficiency was also significantly increased in largemouth bass fed the diet with PFA supplementation, which regulated (enhanced) AKT-mTOR phosphorylation. These results clearly indicated that a PFA containing olive by-product and green tea extracts can positively improve growth performance, protein retention efficiency, antioxidant capacity, and lipid metabolism of largemouth bass fed a reduced fishmeal/high soybean meal diet.

Dietary Arthrospira platensis in Rainbow Trout (Oncorhynchus mykiss): A Means to Reduce Threats Caused by CdCl2 Exposure?

The rainbow trout (Oncorhynchus mykiss) is one of the most commercially sought-after freshwater fish species and one of the most farmed in the world. On the other hand, aquaculture breeding frequently results in outbreaks of infectious diseases and pests, and compromises the production and welfare of fish. Arthrospira platensis (known as "Spirulina") has been used as a supplement in diets to enhance fish welfare in recent years because of its beneficial properties. This study aimed to assess the possible protective effects of Arthrospira platensis on rainbow trout specimens exposed to three different doses of the toxicant CdCl₂. The experiment was carried out using five experimental treatments of 40 individuals each: control group; group II (0.2 mg CdCl₂ per kg of commercial fish feed); group III (0.2 mg Kg^-1 of CdCl₂ plus 2.5 g per kg of A. platensis); group IV (0.2 mg Kg^-1 of CdCl₂ plus 5 g per kg of A. platensis); group V (0.2 mg Kg^-1 of CdCl₂ plus 10 g per kg of A. platensis). During the experiment, dietary supplementation of A. platensis normalized all serum and blood parameters altered by the presence of CdCl₂. A. platensis also had a protective effect on markers of oxidative stress.

Hydroxytyrosol-rich extract from olive juice as an additive in gilthead sea bream juveniles fed a high-fat diet: Regulation of somatic growth

The dietary inclusion of plant-based products in fish feeds formulation is required for the sustainable development of aquaculture. Moreover, considering functional diets, hydroxytyrosol, one of the major phenolic compounds found in olives (Olea europaea), has been identified as a potential candidate to be used in the aquafeeds industry due to its health promoting abilities. The aim of this study was to evaluate the effects of the inclusion of an olive juice extract rich in hydroxytyrosol as an additive (0.52 g HT/kg feed) in a high-fat (24% lipids) diet in gilthead sea bream (Sparus aurata) juveniles. Moreover, the experimental diets, with or without the extract, were administered daily at a standard (3% of total biomass in the tank) or restricted ration (40% reduction) for 8–9 weeks. Growth and biometric parameters, insulin-like growth factor 1 (IGF-1) plasma levels and growth hormone/IGF axis-, myogenic- and osteogenic-related genes expression in liver, white muscle and/or bone were analyzed. Moreover, in vitro cultures of vertebra bone-derived cells from fish fed the diets at a standard ration were performed at weeks 3 and 9 to explore the effects of hydroxytyrosol on osteoblasts development. Although neither body weight or any other biometric parameter were affected by diet composition after 4 or 8 weeks, the addition of the hydroxytyrosol-rich extract to the diet increased IGF-1 plasma levels, regardless of the ration regime, suggesting an anabolic condition. In muscle, the higher mRNA levels of the binding protein igfbp-5b and the myoblast fusion marker dock5 in fish fed with the hydroxytyrosol-rich diet suggested that this compound may have a role in muscle, inducing development and a better muscular condition. Furthermore in bone, increased osteogenic potential while delayed matrix mineralization after addition to the diet of the olive juice extract was supported by the upregulated expression of igf-1 and bmp4 and reduced transcript levels of osteopontin. Overall, this study provides new insights into the beneficial use of hydroxytyrosol as a dietary additive in gilthead sea bream functional diets to improve muscle-skeletal condition and, the aquaculture industry.

Protective effects of summer savory (Satureja hortensis) oil on growth, biochemical, and immune system performance of common carp exposed to pretilachlor herbicide

There are many reports on the deleterious effects of herbicides on aquatic organisms which lead to tremendous biological, environmental and economical damage. In this regard, in the present study, the protective effect of summer savory (Satureja hortensis) essential oil (SEO) against pretilachlor, one of the most used herbicides was investigated in common carp (Cyprinus carpio). The fish assigned to six treatment groups (T₁: control treatment; T₂: 25% LC₅₀ pretilachlor herbicide; T₃: 50% LC₅₀ pretilachlor herbicide; T₄: 1% SEO; T₅: 25% LC₅₀ pretilachlor herbicide + 1% SEO; and T₆: 25% LC₅₀ pretilachlor herbicide + 1% SEO) for 21 days. The results showed that the SEO-containing treatments significantly increased the survival rate (SR) (P < 0.05). The highest final weight (FW), specific growth rate (SGR), and feed conversion ratio (FCR) were observed in the T₄ treatment (P < 0.05). There was a significant increase in glucose (GLU) level in pretilachlor treatments and a significant decrease in SEO-containing treatments compared to the control (P < 0.05). The significantly highest total protein (TP) content was observed in T₄ treatment containing SEO. Cholesterol (CHOL) and triglyceride (TRIG) levels decreased in SEO-containing treatments with the lowest level in T₄ treatment (P < 0.05). Alternative complement pathway activity (ACH₅₀), activity levels of superoxide dismutase (SOD), and glutathione peroxidase (GP_X) showed an increasing trend in SEO-containing treatments with the highest level in T₄ treatment (P < 0.05). The activity of liver enzymes showed a significantly lowest level in T₄ treatment. To conclude, our findings revealed that the use of SEO in fish exposed to pretilachlor herbicide could improve growth, strengthen the immune system and exert a protective effect on common carp.

Dietary Salvia officinalis leaves enhances antioxidant-immune-capacity, resistance to Aeromonas sobria challenge, and growth of Cyprinus carpio

The current perspective is a pioneer to assess the efficacy of Salvia officinalis leave powder (SOLP) on growth, intestinal enzymes, physiological and antioxidant status, immunological response, and gene expression of Common carp (Cyprinus carpio). We also looked into fish resistance after being challenged with Aeromonas sobria, a pathogenic zoonotic bacteria. Fish (N = 120) were fed four different experimental diets in triplicate for 8 weeks. The control diet (SOLP0 - without SOLP); meanwhile, the other three diets included SOLP of 2, 4, and 8 g kg^-1 concentrations (SOLP2, SOLP4, and SOLP8), respectively. Findings demonstrated that fish fed SOLP4 and SOLP8 diets had better growth performance and improved digestion by noticeable enhancing lipase and amylase enzymes activity than other groups. Additionally, the antioxidant (superoxide dismutase and glutathione peroxidase) and immune activities (immunoglobulin M, nitric oxide, and antiprotease) clarified a significant increase (p < 0.05) in SOLP4 and SOLP8 groups. Enriched diets with SOLP4 and SOLP8 exhibited better expression of splenic genes (IL-1β, IL-6, IL-10, TLR-2, and SOD), intestinal genes (Slc26a6) and (PepT1 or Slc15a1), and muscular genes (IGF-1 and SOD), while MSTN was down-regulated. After 8 weeks of the experimental trial, C. carpio challenged by A. sobria exhibited the highest cumulative mortality (66.67%), while SOLP8-dietary intervention showed the best results in enhancing the fish resistance against A. sobria by lessening mortalities to 13.33% followed by SOLP4 diet (20%). The outcomes indicate that the expression of splenic, muscular, and intestinal genes confirm the efficacy of SOLP on enhancing growth, digestion, and immune-antioxidant status, and recommend the potential use of SOLP especially at 4 g kg^-1 level as a valuable natural economic diet additive in C. carpio culture for sustaining aquaculture.

Can Agri-Food Waste Be a Sustainable Alternative in Aquaculture? A Bibliometric and Meta-Analytic Study on Growth Performance, Innate Immune System, and Antioxidant Defenses

The agri-food industry generates a large amount of waste every year, which is both an environmental and economic problem, especially for the countries in charge of its disposal. Over the years, there has been a growing interest especially in plant waste, since they are rich in compounds with high nutritional and nutraceutical value. As a result, several scientific disciplines are investigating their alternative use in the formulation of dietary supplements for human or animal use, or as biostimulants for agricultural purposes. In this review, using a meta-analytical approach, we summarize the main and most recent findings related to the use of plant waste as potential ingredients in dietary supplementation for fish grown under controlled experimental conditions. In particular, in this review, it has been highlighted that plant waste may have not only positive effects on growth performance, but also beneficial effects on modulation of the innate immune system and antioxidant defenses. Finally, the bibliometric study and a mapping provide an overview of the recent publications, showing the research strength across the country, the number of potential collaborations among institutions, and the main research focus, demonstrating how this topic is growing in interest, especially in Europe.

Maternal oxidized soybean oil exposure in rats during lactation damages offspring kidneys via Nrf2/HO-1 and NF-κB signaling pathway

BACKGROUND

Cooking oil is an indispensable component of the human diet. However, oils usually undergo thermal oxidation. Oxidized soybean oil (OSO) has been shown to have detrimental effects on humans and has emerged as a root cause of many chronic diseases. The objective of this work was to evaluate the effects of puerpera exposure to OSO on kidney damage in the mother and offspring using lactating rats as an experimental model.

RESULTS

Pathological sections and ultrastructure showed that OSO exposure resulted in various levels of damage to lactating rats and their offspring. OSO induced oxidative stress in the kidneys of lactating rats, as evidenced by increased levels of hydrogen peroxide, interleukin (IL)-1β, and IL-8. OSO increased the activities of glutathione peroxidase and superoxide dismutase. OSO upregulated the expression of apoptosis-related genes, nuclear factor-erythroid 2-related factor 2 (Nrf2), and nuclear factor κB-related inflammatory factor genes. In the offspring of the OSO-exposed mothers, hydrogen peroxide, malondialdehyde, IL-6, and tumor necrosis factor-alpha contents were increased. Furthermore, OSO enhanced the levels of Nrf2, NAD(P)H quinone oxidoreductase 1, heme oxygenase 1, and p65 and decreased B-cell lymphoma 2.

CONCLUSION

These findings indicated that the kidneys of two generations of rats were compromised by oxidative damage when fed OSO during lactation. This study provides evidence for increasing the genes expression of the Nrf2/heme oxygenase 1 pathway to alleviate the kidney damage caused by OSO in the mother and offspring. © 2021 Society of Chemical Industry.

Effects of dietary rambutan (Nephelium lappaceum L.) peel powder on growth performance, immune response and immune-related gene expressions of striped catfish (Pangasianodon hypophthalmus) raised in biofloc system

This study aimed to evaluate the effects of rambutan peel powder (RP) on growth, skin mucosal and serum immunities, and immune-related gene expression of striped catfish (Pangasianodon hypophthalmus) reared in a biofloc system. Three hundred fingerlings (17.14 ± 0.12 g fish^-1) were randomly selected and assigned to five treatments corresponding to five diets: 0 g kg^-1 (control - RP0); 10 g kg^-1 (RP10); 20 g kg^-1 (RP20); 40 g kg^-1 (RP40), and 80 g kg^-1 (RP80) for 8 weeks. At weeks 4 and 8 post-feeding, growth, skin mucus, and serum immunity parameters were determined, whereas immune-related gene expressions were performed at the end of the feeding trial. Based on the results, skin mucus lysozyme (SML) and skin mucus peroxidase (SMP) were significantly higher in fish fed the RP diets compared to the control diet (P < 0.05). The highest SML and SMP levels were observed in fish fed RP40 diet, followed by RP20, RP80, RP10, and RP0. Fish-fed RP diets had higher serum lysozyme and serum peroxidase activities, with the highest value found in the RP40 diet (P < 0.05), followed by RP20, RP80, and RP10. Similarly, immune-related gene expressions (IFN2a, IFN2b, and MHCII) in the liver were significantly up-regulated in fish fed RP40. Up-regulation (P < 0.05) of IL-1, IFN2a, IFN2b, and MHCII genes was also observed in fish intestines, with the highest values observed in fish fed RP40 diet, followed by RP10, RP20, RP80, and RP0. Fish-fed diet RP diets also showed enhanced growth and FCR compared to the control, with the highest values observed in fish fed diet RP40. However, no significant differences in survival rates were found among diets. In conclusion, dietary inclusion of RP at 40 g kg^-1 resulted in better growth performance, immune response, and immune related gene expressions of striped catfish (Pangasianodon hypophthalmus).

Immune-antioxidant trait, Aeromonas veronii resistance, growth, intestinal architecture, and splenic cytokines expression of Cyprinus carpio fed Prunus armeniaca kernel-enriched diets

Currently, the intervention of plant by-products in the fish diet has gained tremendous attention owing to the economic and high nutritious value. The current study is a pioneer attempt to incorporate the apricot, Prunus armeniaca kernel powder (PAKP) into the Common carp, Cyprinus carpio diets, and assess its efficacy on growth, digestion, intestinal morphology, immunity, antioxidant capacity, and splenic cytokines expression, besides the antibacterial role against Aeromonas veronii infection. Apparently healthy fish (N = 120) with an initial body weight of 24.76 ± 0.03g were allotted in 12 glass aquaria (60 L) and randomly distributed into four groups (triplicates, 10 fish/aquarium). The control group (PAKP0) was fed a basal diet without additives. The second, third, and fourth groups were provided PAKP diets with various concentrations (2.5 (PAKP2.5), 5 (PAKP5), and 10 g kg^-1 (PAKP10)) respectively. After 60 days (feeding trial), sub-samples of the fish (12 fish/group) were intraperitoneally injected with 1 × 10⁷ CFU mL^-1 of A. veronii. Results revealed that body weight gain, feed conversion ratio, and specific growth rates were significantly augmented in the PAKP10 group in comparison to the other groups. The dietary inclusion of PAKP at all concentrations boosted the digestive capacity and maintained the intestinal morphology (average villus length, villus width, and goblet cells count) with a marked improvement in PAKP10. Moreover, fish fed on PAKP10 followed by PAKP5 then PAKP2.5 diets had noticeably elevated values of immunological biomarkers (IgM, antiprotease, and lysozyme activity) and antioxidant capabilities (the total antioxidant capacity, superoxide dismutase, and reduced glutathione) as well as significant up-regulation of immune and antioxidant-related genes (TGF-β2, TLR-2, TNF-α, IL-10, SOD, GPx, and GSS). Fourteen days post-infection with A. veronii, the highest relative percentage survival of fish was observed in PAKP10 (83.33%), followed by PAKP5 (66.67%), and PAKP2.5 (50%). Our results indicated that a dietary intervention with PAKP could promise growth, digestion, immunity, and protect C. carpio against A. veronii infection in a dose-dependent manner. This offers a framework for future application of such seeds as a growth promotor, immune-stimulant, and antioxidant, besides an alternative cheap therapeutic antibacterial agent for sustaining the aquaculture industry.

Dietary inclusion of rambutan (Nephelium lappaceum L.) seed to Nile tilapia (Oreochromis niloticus) reared in biofloc system: Impacts on growth, immunity, and immune-antioxidant gene expression

An eight-week feeding trial was carried out to determine the effects of rambutan seed (RS) as a feed additive on the growth, skin mucus, serum immune parameters, and gene expression of Nile tilapia (Oreochromis niloticus) raised under a biofloc system. Nile tilapia fingerlings (14.77 ± 0.80 g fish^-1) were fed five experimental diets containing 0, 5, 10, 20, and 40 g kg^-1 of RS, corresponding to five treatments (RS0, RS5, RS10, RS20, and RS40) with three replications per treatment. The results showed that fish consuming the RS10 and RS20 diets presented a substantial (P < 0.05) improvement in specific growth rate (SGR), weight gain (WG), and feed conversion ratio (FCR) after eight weeks. The highest values were recorded in the RS10 diet; however, there were no significant (P > 0.05) differences exhibited in the fish survival rates between treatments. The RS supplementation diets demonstrated greater immunological parameters, particularly skin mucus and serum immune responses (P < 0.05), than that of the control after eight the eight-week feeding trial. The highest level was seen in fish fed the RS10; followed by the RS20, RS40 (P > 0.05), and RS5 diets. Regarding gene expressions, IL1, IL8, LBP, GSTa, and GSR genes were significantly up-regulated in fish provided the RS10 diet in comparison to the control and other supplemented diets (P < 0.05). However, no significant up-regulation was found in these genes among the RS0, RS5, RS20, and RS40 diets, with the exception of the GPX gene. Similarly, up-regulation of IL-8, LBP, GSTa, GPX, and GSR were noted in fish fed the RS10 diet (P < 0.05). Notably, no significant differences were evident in these genes among the RS5, RS20, and RS40 diets. In conclusion, fish fed RS10 (10 g kg^-1) significantly enhanced growth, skin mucus, serum immunities, and immune-antioxidants related gene expressions of Nile tilapia raised under biofloc system.

Health benefits and potential applications of fucoidan (FCD) extracted from brown seaweeds in aquaculture: An updated review

Nowadays, the application of immunomodulators in aquaculture has become of an urgent need because of high incidence of fish and shrimp diseases. For a long time, researchers have paid great interest to find suitable, relatively economical, and environmentally safe immunostimulant products to be used either as feed or water additives to boost immunity and increase the resistance of fish and shrimp against the challenging pathogens. Probiotics, prebiotics, synbiotics, phytobiotics, herbal extracts, microalgae, macroalgae, and essential oils have been extensively evaluated. Brown seaweeds (Phaeophyceae) are a large group of multi-cellular macroalgae that are widely distributed in marine aquatic environments. They are abundant in several bioactive sulfated polysaccharides known as fucoidan (FCD). Research studies demonstrated the beneficial functions of FCD in human medicine because of its immunomodulating, antioxidant, anti-allergic, antitumor, antiviral, anti-inflammatory, and hepatoprotective effects. In aquaculture, several researchers have tested the benefits and potential applications of FCD in aquafeed. This literature review provides an updated information and key references of research studies that focused principally on using FCD in aquaculture. Its effects on growth, intestinal health, antioxidant capacity, and immune responses of several finfish and shellfish species will be discussed. This review paper will also highlight the potential efficacy and mechanisms of FCD in the modulation of toxicity signs and increasing the resistance of fish and shrimp against bacterial and viral infections. Hence, this contribution will be valuable to maintain aquaculture sustainability and to improve the health and welfare of farmed fish and shrimp.

Effects of dietary Astragalus caudiculosus (Boiss & Huet, 1856) supplementation on growth, hematology, antioxidant enzyme activities, and immune responses in rainbow trout (Oncorhynchus mykiss Walbaum, 1792)

The potential dietary utilization of Astragalus caudiculosus (AC) in rainbow trout (Oncorhynchus mykiss) was investigated. Four different fish groups (control, AC1, AC2.5, and AC5) were assigned and received the AC-containing diet for 90 days at the rates of 0, 1, 2.5, and 5%, respectively. Results indicated that the growth performance of the AC supplemented fish improved significantly (P < 0.05). Among non-specific immune parameters examined, while lysozyme activity of the AC supplemented fish increased (P < 0.05), oxidative radical production decreased in AC1 and AC2.5 fish groups (P < 0.05) but did not differ in the AC5 group (P > 0.05) compared to the control. Moreover, myeloperoxidase activity was not affected by the AC supplementation (P > 0.05). All pro-inflammatory and anti-inflammatory cytokine gene expressions, except IL-1β, were up-regulated, especially in the fish groups fed with 2.5 and 5% AC supplemented feed (P < 0.05). AC administration caused an elevation in GPx and G6PDH activities, and a decrease in SOD, CAT, and lipid peroxidation (P < 0.05). Overall, AC extract was found to improve the growth, antioxidant status, and immune response of the fish.

Mooseer (Allium hirtifolium) boosts growth, general health status, and resistance of rainbow trout (Oncorhynchus mykiss) against Streptococcus iniae infection

In large-scale aquaculture, the fast growth rate of fish is positively influenced by feed additives such as medicinal plants. This is however; infectious disease may reduce fish growth and cause devastating economic loss. The present study investigated in vitro antibacterial efficacy of Mooseer (Allium hirtifolium) extract against Streptococcus iniae and its in vivo effects on growth, biochemical parameters, innate immunity of rainbow trout (Oncorhynchus mykiss). Therefore, six experimental diets were designed to include different levels of Mooseer from zero (as control), 5, 10, 15, 20, and 25 g per kg diet respectively referred to as M1 to M5. Results from the antibacterial evaluation showed that Mooseer extract inhibits S. iniae growth with MIC and MBC values of 128 and 256 μg ml^-1. Appreciable results were obtained in the groups supplemented with Mooseer. Mooseer enhanced growth performance, and modulated serum biochemical and immunological parameters (total protein, albumin, triglyceride, glucose, cortisol, cholesterol, lysozyme, Ig, ACH50, ALP, and protease activity), and liver enzymes (ALT, AST and ALP). The greatest effects were found for higher doses of Mooseer supplementation (M4 and M5). Meanwhile, results from the survival rate of fish challenged with S. iniae showed higher survival in M2 and M4 treatments. The present findings suggest the beneficial use of Mooseer in rainbow trout diet, with 20 g kg^-1 inclusion as the recommended dose.

Can Betadine (10% povidone-iodine solution) act on the survival rate and gill tissue structure of Oranda goldfish (Carassius auratus)?

Industrial chemical solutions are widely used as a method to disinfection of aquaculture water and environments. The aim of the present study was to evaluate the toxicity effect of Betadine (10% solution of povidone-iodine) as a disinfectant solution on the survival and gill tissue of Oranda goldfish (Carassius auratus). For these purposes, 225 fingerling Oranda goldfish with an average weight 5 ± 0.67 g were divided into 15 groups with 3 replications. Fish were exposed to series of concentrations (0, 10, 20, 40, 60, 80, 90, 100, 120, 140, 160, 180, 200, 220 and 240 mg/L) of Betadine for 96 h. The mortality of fish and the samples of gill were observed at 6, 12, 18, 24, 48, 72 and 96 h after exposure. The results of the present study showed that the half-life of Betadine was less than 24 h and mortality were not record after 24 h. The highest mortality rate was at 240 mg/L, and LC₅₀ 24 h of Betadine was 158.800 mg/L. Histopathological results showed that lethal concentrations of Betadine lead to hyperemia, hypertrophy, hyperplasia and adhesion of secondary lamellar of the gill. Moreover, fish that were exposed to these concentrations displayed clinical signs such as anxiety, darkening of the skin. Overall results showed that Betadine have short half-life in the aquatic environment and are toxic to fish at very high concentrations, therefore it can be considered as practically non-toxic and useful for disinfection of the aquatic environment.

Growth performance, hematological responses and economic indexes of Colossoma macropomum (Cuvier, 1818) fed graded levels of glycerol

The aim of this study was to evaluate the performance, hematological responses and economic indicators of juvenile tambaqui Colossoma macropomum fed different levels of partial replacement of corn by glycerol (0%, 25%, 50%, 75%, and 100%). The experiment was conducted for 90 days in the production of aquatic organisms lab at the Nilton Lins University, Manaus, Brazil, in a completely randomized design, and consisted of four treatments, four repetitions and two sampling times. In total, 240 juveniles were used with initial average weight and standard length of 15.32 ± 1,61 g and 8.03 ± 0.22 cm, respectively. The fish were maintained in twenty 310 L water tanks that had a closed system with no reuse, continuous aeration, siphoning and replacement of water every 48 h. Feeding was twice a day with the experimental diets, which contained 28% crude protein. The following parameters were considered: zootechnical checks (weight gain + survival %), welfare (health) (hepatosomatic index + condition factor + viscerosomatic index), economic (Economic efficiency rate + economic profitability index) and hematology (hematology + metabolites + ions). The results of the study show that diets for juvenile tambaqui can contain up to 50% replacement of corn by glycerol without compromising the fishes' development under the conditions studied.

Impact of Hygrophila auriculata supplementary diets on the growth, survival, biochemical and haematological parameters in fingerlings of freshwater fish Cirrhinus mrigala (Hamilton, 1822)

The present study investigates the effects of Supplementary diet Hygrophila auriculata on the growth, survival, biochemical and haematological parameters of Cirrhinus mrigala. The seaweed was administered to the fish possessing an initial average weight of 14.063 ± 1.828 g. Fish were fed with supplementary diet H. auriculata exhibited significant difference (P < 0.05) in the growth performance, haematological indices such as RBC count, haematocrit volume, haemoglobin, WBC, MCV, MCH and MCHC concentration in contrast to the control after a period of 8 weeks. Also, there were significant differences in biochemical parameters (P < 0.05), between the fish supplemented with dietary H. auriculata extract and the control group. These findings suggest that the administration of H. auriculata extract has a positive effect on the immunological indices and the immune system activity in Mrigal fish.

Gut immune-related gene expression, histomorphometry and hematoimmunological assays in Nile tilapia (Oreochromis niloticus) fed Aspergillus oryzae fermented olive cake

Fermentation strategy is well documented to improve the nutritional value of agricultural waste by-products such olive cake (OC), which, in turn, provides healthy, safe, and affordable feedstuff. This study assessed the combined impact of Aspergillus oryzae-fermented OC (AFOC) on the growth performance, intestinal morphometry, blood biochemistry, lysozyme activity, gut immune-related genes, and flesh quality of Nile tilapia. We divided 225 fish into five groups and further subdivided into three replicates (n = 15 each) and fed them five diets (Control, AFOC5, AFOC10, AFOC15, AFOC20) to determine AFOC nutritional value and its optimized incorporation level in the diet. The trial continued for 3 months. The crude protein content of OC improved by 7.77% after A. oryzae fermentation, while lipid content decreased by 14.19%. In addition, growth and feed utilization significantly improved at (10.8-11.2) % AFOC dietary level. High-density lipoprotein (HDL) significantly improved, and the serum lysozyme level was significantly higher in the AFOC10 group compared to other groups. Interestingly, gut-related inflammatory cytokines tumor necrosis factor alpha (TNF- α) and interleukin 1 beta (IL-1β) revealed higher relative mRNA expression in the AFOC10 group compared to other groups. The histomorphometric parameters was greatly influenced by the AFOC incorporation level (10%-20%). These findings suggested that A. orzae fermentation modifies the nutritional quality of OC, as seen through its positive impact on the growth performance, local and systemic immunity, and intestinal absorptive capacity of Nile tilapia. The recommended dose for dietary AFOC was around 11.

The influence of coconut oil on the growth, immune, and antioxidative responses and the intestinal digestive enzymes and histomorphometry features of Nile tilapia (Oreochromis niloticus)

The trials of finding non-conventional and alternative aquafeed ingredients are increasing. In this sense, this study evaluated the influence of coconut oil on the growth, feed utilization, immune, and antioxidative responses of Nile tilapia. Five test diets were formulated by mixing coconut oil with the other ingredients at 0, 1, 2, 3, and 4% of the total ration and presented for tilapia for 60 successive days. The final weight, SGR, weight gain (WG), and feed intake were superior in fish delivered 2% of coconut oil (P < 0.05). Concurrently, fish that received 2% coconut oil had lower FCR and higher PER than fish of the control and 4% groups (P < 0.05). Higher lipase activity was observed in fish of 2% and 3% levels than the remaining groups (P < 0.05). Besides, the amylase and protease activities of fish in 1%, 2%, and 3% groups were higher than the 0% level (P < 0.05). The total blood cholesterol, RBCs, and PCV showed higher values in Nile tilapia fed 2% and 3% coconut oil (P < 0.05). The lysozyme and phagocytic activities were higher in fish fed 2% and 3% levels than the control (P < 0.05), while the phagocytic index in 2% and 3% levels was higher than 0% and 4% levels. Furthermore, SOD and CAT were higher in fish fed 1%, 2%, and 3% than fish fed 0% and 4% levels while GSH was higher in fish of 1%, 2%, and 3% than fish fed 0% level (P < 0.05). However, the MDA level was markedly lower in fish fed 25, 3%, and 4% coconut oil than the 0% level (P < 0.05). The intestine's histological structure in all groups appeared normal, forming of intestinal villi projecting from the intestinal wall. Also, the structure of the hepatopancreas had a normal architecture in all groups. To sum up, the inclusion of coconut oil at 2 to 3% is recommended as a replacer for fish oil in Nile tilapia diets.

The Gene Regulatory Roles of Herbal Extracts on the Growth, Immune System, and Reproduction of Fish

The crucial need for safe and healthy aquatic animals obligates researchers in aquaculture to investigate alternative and beneficial additives. Medicinal herbals and their extracts are compromised with diverse effects on the performances of aquatic animals. These compounds can affect growth performance and stimulate the immune system when used in fish diet. In addition, the use of medicinal herbs and their extracts can reduce oxidative stress induced by several stressors during fish culture. Correspondingly, aquatic animals could gain increased resistance against infectious pathogens and environmental stressors. Nevertheless, the exact mode of action where these additives can affect aquatic animals' performances is still not well documented. Understanding the mechanistic role of herbal supplements and their derivatives is a vital tool to develop further the strategies and application of these additives for feasible and sustainable aquaculture. Gene-related studies have clarified the detailed information on the herbal supplements' mode of action when administered orally in aquafeed. Several review articles have presented the potential roles of medicinal herbs on the performances of aquatic animals. However, this review article discusses the outputs of studies conducted on aquatic animals fed dietary, medicinal herbs, focusing on the gene expression related to growth and immune performances. Furthermore, a particular focus is directed to the expected influence of herbal supplements on the reproduction of aquatic animals.

Impacts of pineapple peel powder on growth performance, innate immunity, disease resistance, and relative immune gene expression of Nile tilapia, Oreochromis niloticus

An 8-week growth trial was conducted to examine the efficacy of pineapple peel powder (PAPP) on growth rate and immunity of Nile tilapia, O. niloticus. Three hundred Nile tilapia (20.91 ± 0.11 g) were fed five diets containing different levels of PAPP at 0, 10, 20, 30 and 40 g kg^-1 PAPP, respectively. After four and eight weeks of the feeding trial, growth rates, and immune responses were tested. A challenge test using Streptococcus agalactiae and relative immune gene expression were performed after eight weeks of PAPP feeding. It was found that skin mucus and serum lysozyme, skin mucus and serum peroxidase, alternative complement, phagocytosis, and respiratory burst activities were significantly increased with the addition of PAPP. The maximum (P ≤ 0.05) innate immune values were noted in fish fed 10 g kg^-1 PAPP. Similarly, the up-regulation of IL1, IL8, and LBP gene expressions were also detected in fish fed PAPP diets, with the maximum value was found in 10 g kg^-1 PAPP fed fish. The relative percentage of survival (RPS) of Oreochromis niloticus after the challenge test were (56.00%, 72.00%, 60.00%, and 44.00%) for the 5, 10, 20 and 40 g kg^-1 PAPP diets, respectively. Fish fed the 10 g kg^-1 PAPP supplemented diet achieved the highest (P < 0.05) survival rate against S. agalactiae. Growth and feed efficiency were outstandingly (P < 0.05) enhanced in the PAPP groups. In conclusion, PAPP can be potentially used as a feed additive in Nile tilapia culture under Biofloc system.

Effect of diet enriched with Agaricus bisporus polysaccharides (ABPs) on antioxidant property, innate-adaptive immune response and pro-anti inflammatory genes expression in Ctenopharyngodon idella against Aeromonas hydrophila

The effect of Agaricus bisporus polysaccharides (ABPs) supplemented diet on growth rate, antioxidant capacity, innate-adaptive immune response, proinflammatory and antiinflammatory genes expression in Ctenopharyngodon idella against Aeromonas hydrophila is reported. In both normal and challenged groups fed with 1.0 and 1.5 mg kg^-1 ABPs diets resulted in a significant weight gain and feed intake. The survival was 100% in normal fish fed without or with any ABPs diet; the challenged fish fed with 1.0 mg kg^-1 ABPs diet had 98.6% survival. The RBC and WBC counts, Hb, and Hct levels were significant in both normal and challenged groups fed with 1.0 and 1.5 mg kg^-1 ABPs diets. A significant increase in total protein and albumin level was observed in both groups fed with 1.0 and 1.5 mg kg^-1 ABPs diets. Significant increase in GPx, ROS, GR, GSH, PC, and MnSOD activity was observed in HK of both groups fed with 1.0 and 1.5 mg kg^-1 ABPs diets; similarly both groups when fed with the same ABPs diets showed significant Lz, C3, and C4 activity. However, both groups fed with 1.0 mg kg^-1 ABPs diet showed significant β-defensin, LEAP-2A, IL-6, and NF-κB P65 mRNA expression. Similarly, IFN-γ2, IL-10, and TNFα mRNA expressions were significant in both groups fed with 1.0 mg kg^-1 ABPs diet. The results indicate that both normal and challenged C. idella fed with a 1.0 mg kg^-1 ABPs diet had better growth, antioxidant status, immune response, and pro-anti-inflammatory gene modulation against A. hydrophila.

Shift in skin microbiota and immune functions of zebrafish after combined exposure to perfluorobutanesulfonate and probiotic Lactobacillus rhamnosus

Dysbiosis of fish skin microbiome and immunity by environmental pollutants are rarely studied in toxicological research in spite of their importance for fish health. In the present study, adult zebrafish were exposed to 0 and 10 μg/L of perfluorobutanesulfonate (PFBS) for 40 days, with or without the supplementation of probiotic Lactobacillus rhamnosus, with objectives to explore the interaction between PFBS pollutant and probiotic bacteria on skin mucosal microbiota and immune response. Amplicon sequencing analysis found that PFBS alone significantly disturbed the microbial community composition and abundance on the skin, favoring the growth of stress-tolerant bacteria (e.g., Deinococcus and Enhydrobacter genera). However, the administration of probiotic inhibited the dysbiosis of PFBS and shaped the skin microbiome in the combined exposure group. PFBS single exposure also promoted the production of mucus on the skin of male zebrafish, which may be related to the growth of Limnobacter bacteria. In contrast, probiotic supplements remarkably improved the immune functions in male skin mucus from the combined group, as evidenced by the consistent increases in lysozyme activity, immunoglobulin concentrations and peroxidase activity. Overall, the present study provides the first clue about the singular and combined effects of PFBS and probiotic on skin microbiota and immunity, highlighting the beneficial action of probiotic L. rhamnosus against PFBS stress.

Chemically and Green Synthesized ZnO Nanoparticles Alter Key Immunological Molecules in Common Carp (Cyprinus carpio) Skin Mucus

This study was conducted to compare the effects of commercially available (C) and green synthesized (GS) Zinc oxide nanoparticles (ZnO-NPs) on immunological responses of common carp (Cyprinus carpio) skin mucus. GS ZnO-NPs were generated using Thymus pubescent and characterized by UV–vis diffuse reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). Fish (n = 150) were randomly allocated into five groups in triplicate and received a waterborne concentration of 0% (control), 25%, and 50% of LC50 96 h of commercially available (C1 and C2) and green synthesized ZnO-NPs (GS1 and GS2) for 21 days. Results from XRD displayed ZnO-NPs with 58 nm in size and UV-vis DRS, EDX, and FT-IR analysis showed that some functional groups from plant extract bonded to the surface of NPs. The SEM images showed that ZnO-NPs have conical morphology. Acute toxicity study showed a higher dose of LC50_96h for green synthesized ZnO-NPs (78.9 mg.L⁻¹) compared to the commercial source (59.95 mg.L⁻¹). The highest activity of lysozyme and alternative complement activity (ACH50) were found in control and GS1 groups. A significant decrease in alkaline phosphatase activity (ALP) was found in C1 and C2 groups compared to other treatments. Protease activity (P) was significantly decreased in the C2 group compared to the control and GS groups. Total immunoglobulin (total Ig) content was the highest in the control. In addition, total Ig in the GS1 group was higher than GS2. The exposure to ZnO-NPs lowered total protein content in all experimental groups when compared to control. Present findings revealed lower induced immunosuppressive effects by green synthesized ZnO-NPs on key parameters of fish skin mucus.

Carvacrol, Thymol, and Garlic Essential Oil Promote Skin Innate Immunity in Gilthead Seabream (Sparus aurata) Through the Multifactorial Modulation of the Secretory Pathway and Enhancement of Mucus Protective Capacity

One of the main targets for the use of phytogenics in aquafeeds is the mucosal tissues as they constitute a physical and biochemical shield against environmental and pathogenic threats, comprising elements from both the innate and acquired immunity. In the present study, the modulation of the skin transcriptional immune response, the bacterial growth capacity in skin mucus, and the overall health condition of gilthead seabream (Sparus aurata) juveniles fed a dietary supplementation of garlic essential oil, carvacrol, and thymol were assessed. The enrichment analysis of the skin transcriptional profile of fish fed the phytogenic-supplemented diet revealed the regulation of genes associated to cellular components involved in the secretory pathway, suggesting the stimulation, and recruitment of phagocytic cells. Genes recognized by their involvement in non-specific immune response were also identified in the analysis. The promotion of the secretion of non-specific immune molecules into the skin mucus was proposed to be involved in the in vitro decreased growth capacity of pathogenic bacteria in the mucus of fish fed the phytogenic-supplemented diet. Although the mucus antioxidant capacity was not affected by the phytogenics supplementation, the regulation of genes coding for oxidative stress enzymes suggested the reduction of the skin oxidative stress. Additionally, the decreased levels of cortisol in mucus indicated a reduction in the fish allostatic load due to the properties of the tested additive. Altogether, the dietary garlic, carvacrol, and thymol appear to promote the gilthead seabream skin innate immunity and the mucus protective capacity, decreasing its susceptibility to be colonized by pathogenic bacteria.

An overview on ethnobotanico-pharmacological studies carried out in Morocco, from 1991 to 2015: Systematic review (part 1)

ETHNOPHARMACOLOGICAL RELEVANCE

The full bibliometric records of data retrieved from ethnobotanical field studies carried out in Morocco (1991-2015) was quali-quantitatively analysed. Despite the importance of traditional medicinal uses in Morocco, any comments about the methodologies and approaches adopted by reviewed studies have been undertaken. Include more data about the importance of traditional medicinal uses in Morocco.

AIM OF THE STUDY

Three key points were targeted in this review: (i) to contribute to original compilation of medicinal plants traditionally used by people at whole Morocco, by gathering and documenting the current status of these ancestral medical practices, (ii) to provide a novel insight into the relationship between local and biomedical disease concepts in Moroccan society, taking into account health-related beliefs, and their influences on medicinal plant uses, (iii) to figurout the weaknesses and the strengths of the conceptual approches and methods adopted by researchers in ethnobotanical field works.

MATERIALS AND METHODS

With the help of a computerized database querying, we conducted an extensive literature search respecting our integration criteria. We performed this bibliographic research by using the following search engines available over the Web: Google Scholar, PUBMED, Sciencedirect, Current Content Connect, SCOPUS, SPRINGER LINK, GLOBAL PLANTS, Cochrane Library and SCIRUS. The scientific names listed in the present paper have been validated according to the "The Plant List" and the African Plants Database in order to standardize ethnobotanical data on an international level. For the analysis of data gathered, quali-quantitative analyses have been performed.

RESULTS

A total of 905 medicinal plant species belonging to 116 families and 726 genera have been selected from 63 published articles. The dominant families were ASTERACEAE (111 species) followed by the FABACEAE (77 species), LAMIACEAE (75 species) and APIACEAE (46 species). The plant species listed are used to cure several public ailments. The digestive ailments represented the most important category (494 species) followed by dermatological diseases (407 species), diabetes (315 species) and urinary diseases (277 species). We assigned the importance of the plant species by several measures (including Frequency Cited (FC), Number of Uses (NU), Number of Respondents (NR) and Index of Performance (IP). The ICF (Informant Consensus Factor) calculated was important in all categories of diseases averaging 47%.

CONCLUSION

The results obtained, which cover the whole country, delineate the profile of rich wealth of indigenous knowledge on traditional uses of medicinal plants heald by Moroccan society. The total number of 905 plant species listed in this paper, are currently being utilized as medicines and the number is expected to grow as infrastructure allows greater access to unexplored parts of the country. Furthermore, the know how, regarding the plants used, is consistent because the ICF has recorded important values for most diseases treated. Furthermore, in the present paper, we suggested, for authors, some useful recommendations for ethnobotanical field works such as the respect of ethnobotanical standards including checklist of plants with international data base, the deposited voucher specimens, sampling and collection methods.

The blood and mRNA levels of antioxidant-related factors in common carp (Cyprinus carpio) fed p-Coumaric acid

The natural antioxidants are well known for their antioxidative activity without side effects when compared to antibiotics. Hence, the present study aimed at evaluating p-Coumaric acid as an antioxidant additive on the blood and mRNA levels of antioxidant-related factors in common carp (Cyprinus carpio). Fish fed the basal diet supplemented with p-Coumaric at 0, 0.5, 1, and 1.5 g/kg for 56 days, then the serum, intestine, and liver samples were collected. The growth performance of fish fed with CA showed significantly (P < 0.05) improved FW, WG, and SGR compared to those of the control one. However, the feed conversion ratio was significantly (P < 0.05) reduced in fish fed 1 and 1.5 g/kg diet levels. SOD was not significantly differed among the groups fed with varied p-Coumaric acid (P > 0.05). Serum GPX and TAC were enhanced considerably by p-Coumaric acid regarding the control with the highest being in fish fed 1.5 g/kg diet (P < 0.05). Serum CAT was more elevated in fish provided p-Coumaric acid at 1 or 1.5 g/kg than the control while fish fed 0.5 g/kg did not display significant changes. MDA level significantly decreased by all p-Coumaric acid groups compared to the control one, and the lowest level was observed in 1.5 g/kg (P < 0.05). The mRNA level of CAT was significantly upregulated in the liver by p-Coumaric acid at 1 or 1.5 g/kg (P < 0.05), while the intestine CAT did not influence by p-Coumaric acid (P > 0.05). The measured SOD in the liver and intestine samples revealed no changes in common carp fed p-Coumaric acid (P > 0.05). GPX was significantly upregulated in the intestine by p-Coumaric acid at 1 or 1.5 g/kg (P < 0.05), whereas the liver GPX was upregulated by p-Coumaric acid at 1.5 g/kg. The mRNA level of the GST gene in the intestine of common carp was upregulated by p-Coumaric acid at 1.5 g/kg, whereas the liver displayed upregulated GST in fish fed 1 g/kg diet. The present study approved the application of p-Coumaric acid as a natural antioxidant for friendly, sustainable aquaculture.

Effect of allicin on antioxidant defense system, and immune response after carbofuran exposure in Nile tilapia, Oreochromis niloticus

In this work, allicin was evaluated as an immunostimulant and antioxidant agent preventing Nile tilapia; Oreochromis niloticus against carbofuran toxicity. Fish (60 ± 8 g) were allocated to five groups; the first group (control), the second group was fed 1 g/kg allicin-supplemented diets without carbofuran intoxication, the third group exposed to 1/10 LC₅₀ carbofuran (0.246 mg/L). While the fourth, and fifth groups were fed allicin supplemented diet at concentration of 0.5 and 1 g/kg diet, respectively, and exposed to carbofuran at the same concentration similar to the one of the third group. After 30 days, fish exposed to carbofuran showed high ALT, AST, ALP, cholesterol, glucose, cortisol, uric acid, and creatinine levels. However, serum AChE, total proteins, immunoglobulins, and lysozyme activity were markedly (P ≤ 0.05) reduced in carbofuran exposed tilapia fish. Moreover, malondialdehyde (MDA) level was significantly increased in liver, and kidneys tissues of carbofuran exposed fish. Whereas, catalase (CAT) activity, superoxide dismutase (SOD), and total antioxidant capacity (TAC) were decreased (P ≤ 0.05) significantly in both liver, and kidneys tissues after exposure to carbofuran. Interestingly, tilapia fish treated with carbofuran (0.246 mg/L) and fed (0.5 and 1 g/kg diet) allicin in both the 4th & 5th groups, respectively, decreased serum biochemical parameters; and hepatorenal (MDA) levels, as well as increased AChE, immunological profile, and oxidative stress biomarkers. The results suggested that co- administration of allicin at the high dose is more capable of improving the biochemical, and immunological parameters, and tissue antioxidant responses of carbofuran treated fish.

(2-Carboxyethyl) dimethylsulfonium bromide supplementation in non-fish meal diets for on-growing grass carp (Ctenopharyngodon idella): Beneficial effects on immune function of the immune organs via modulation of NF-κB and TOR signalling pathway

The immune function of immune organs is extremely crucial for maintaining organism health status, which ultimately affects fish growth. Our previous study has found that dietary supplementation of (2-carboxyethyl)dimethylsulfonium Bromide (Br-DMPT) in non-fish meal (NFM) diet could promote the growth of grass carp (Ctenopharyngodon idella), whereas the underlying reason or mechanism for this results is largely unclear. Herein, we further explored whether dietary supplementation of Br-DMPT promoted fish growth is connected with the enhanced immune function in the immune organs (the head kidney, spleen and skin). In this study, 540 fish (216.49 ± 0.29 g) were irregularly distributed to six groups with three replicates (30 fish replicate^-1) and fed corresponding diets group containing a fish meal (FM) diet group and five different NFM diets supplemented with gradational Br-DMPT (0-520.0 mg/kg level) group for 60 days. After the 60-days feeding trial, 8 fish from each replicate were selected and then conducted a challenge test with A. hydrophila for 14 days. Our results indicated that in the NFM diets, appropriate Br-DMPT: (1) significantly decreased the morbidity of skin haemorrhage and lesion after A. hydrophila infection (P < 0.05). (2) significantly improved the innate and adaptive immune components (lysozyme, complement 3, immunoglobulin M and antibacterial peptides et al.) (P < 0.05). (3) increased the gene expressions of main anti-inflammatory cytokines partially by referring to TOR signalling pathway, and decreased the gene expressions of main pro-inflammatory cytokines partially by referring to NF-kB signalling pathway (P < 0.05). Strikingly, no statistical difference could be found in the most of above immune parameters between 260.0 mg/kg Br-DMPT diet group and FM diet group (P > 0.05). Taken together, in non-fish meal diet, appropriate supplementation of Br-DMPT could improve the disease resistance capacity, non-specific immunity and ameliorate inflammation, and simultaneously could mitigate these adverse effects induced by the non-fish meal diet in fish immune organs. Moreover, this study may be helpful to decipher the underlying mechanisms of how Br-DMPT promote fish growth by immune organs and also provide scientific theoretical evidence for the future application of Br-DMPT as a new immunopotentiator in aquaculture industry.

Protective effects and potential mechanisms of (2-Carboxyethyl) dimethylsulfonium Bromide (Br-DMPT) on gill health status of on-growing grass carp (Ctenopharyngodon idella) after infection with Flavobacterium columnare

In this study, the protective effects and potential mechanisms of (2-Carboxyethyl) dimethylsulfonium Bromide (Br-DMPT) were evaluated in relation to the gill health status of on-growing young grass carp (Ctenopharyngodon idella). A total of 450 grass carp (216.49 ± 0.29 g) were randomly distributed into five treatments of three replicates each (30 fish per replicate) and were fed diets supplemented with gradational Br-DMPT (0-520.0 mg/kg levels) for 60 days. Subsequently, the fish were challenged with Flavobacterium columnare for 3 days, and the gills were sampled to evaluate antioxidant status and immune responses evaluation. Our results showed that, when compared to the control group, dietary supplementation with appropriate Br-DMPT levels resulted in the following: (1) decreased gill rot morbidity and improved gill histological symptoms after exposure to F. columnare (P < 0.05); (2) improved activities and gene expression levels (except GSTP2 gene) of antioxidant enzymes and decreased oxidative damage parameter values (reactive oxygen species, malondialdehyde and protein carbonyl) (P < 0.05), which may be partially associated with the nuclear factor-erythroid 2-related factor 2 (Nrf2) signalling pathway (P < 0.05); (3) increased lysozyme (LZ) and acid phosphatase (ACP) activities and complement 3 (C3), C4 and immunoglobulin M (IgM) contents, and upregulated genes expressions of antibacterial peptides (liver-expressed antimicrobial peptide-2A, -2B, hepcidin, β-defensin and mucin2) (P < 0.05); (4) upregulated gene expressions of anti-inflammatory cytokines (except IL--4/13B) that may be partially to the TOR/(S6K1, 4E-BP1) signalling pathway, and downregulated gene expressions of pro-inflammatory cytokines (except IL-12P35) may be partially to the IKK β, γ/IκBα/NF-kB) signalling pathway (P < 0.05). Taken together, our results indicate that dietary supplementation with appropriate amounts of Br-DMPT may effectively protect on-growing grass carp from F. columnare by strengthening gill antioxidant capacity and immunity. Furthermore, based on measures of combatting gill rot, antioxidant indices (MDA) and immune indices (LZ), the dietary Br-DMPT supplementation levels for on-growing grass carp are recommended to be 291.14, 303.38 and 312.01 mg/kg diet, respectively.

Effects of dietary thyme (Zataria multiflora) extract on antioxidant and immunological responses and immune-related gene expression of rainbow trout (Oncorhynchus mykiss) juveniles

Effects of dietary hydroalcoholic extract of Zataria multiflora (ZE) on growth performance, plasma and hepatic antioxidant capacities, and humoral and skin mucus immune parameters were evaluated in rainbow trout (Oncorhynchus mykiss) juveniles. in vitro tests showed that ZE had antioxidant property comparable to butylated hydroxytoluene (BHT) at 100-200 μg/mL concentrations, although its antioxidant property was lower than BHT at concentration below 100 μg/mL. Moreover, ZE had anti-bacterial activity against Aeromonas hydrophila, which was 30-50% lower than that of tetracycline. After feeding the fish with diets supplemented with 0 (CT, 1 (ZE1), 2 (ZE2), and 3 (ZE3) g/kg ZE for eight weeks, there were no significant differences in growth performance and feed efficiency among the treatments; however, the fish in ZE2 and ZE3 treatments showed significantly higher survival than the fish in CT treatment. Blood leukocyte counts, plasma globulin, total immunoglobulin, lysozyme and bactericidal activity against A. hydrophila in ZE2 and ZE3 groups were significantly higher than that of CT group. All the ZE-treated groups had higher plasma complement activity compared to the CT group. Mucosal lysozyme and bactericidal activities of the ZE2 fish were significantly higher than the other treatments. Expression of tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, and lysozyme genes increased in head kidney of the fish treated with ZE; the highest increases were related to the ZE2 treatment. Plasma total antioxidant (TA) activities of ZE2 and ZE3 treatments were significantly higher than that of the CT treatment. Plasma and hepatic superoxide dismutase (SOD) and catalase (CAT) activities of ZE2 group were significantly higher than the other treatments. Plasma malondialdehyde (MDA) levels were significantly lower in ZE2 treatment, compared to the other treatments. However, hepatic MDA level of ZE2 treatment was significantly lower than those of the ZE1 and CT treatments. In conclusion, dietary ZE supplementation level of 2 g/kg is suggested for rainbow trout feed supplementation to augment fish survival, antioxidant and immune strength.

Effects of aqueous and ethanolic leaf extracts from drumstick tree (Moringa oleifera) on gilthead seabream (Sparus aurata L.) leucocytes, and their cytotoxic, antitumor, bactericidal and antioxidant activities

Aqueous and ethanolic extracts of drumstick, Moringa oleifera, leaves were evaluated in vitro to ascertain their principal active components and determine their immunostimulant, cytotoxic, antitumoral, bactericidal and antioxidant activities. Phytochemical screening of M. oleifera leaf extracts showed a greater abundance of phenolic and cyanogenic glycosides in aqueous than in ethanolic extracts, characterized by several flavonoids, condensed tannins and saponins. No significant effects on gilthead seabream (Sparus aurata) head-kidney leucocyte activities (phagocytic ability and capacity, respiratory burst and peroxidase) were detected after incubation for 24 h with different concentrations (0.001/1 mg mL^-1) of either extract. In addition, the aqueous extract showed a marked cytotoxic effect on both SAF-1 (at doses above 0.01 mg mL^-1) and PLHC-1 (at doses above 0.25 mg mL^-1) cell lines. The ethanolic extract improved the viability of SAF-1 cells and decreased the viability of PLHC-1 cells when used at higher concentrations. Both the ethanolic and, particularly, the aqueous extracts showed significant bactericidal activity on pathogenic Vibrio anguillarum and Photobacterium damselae strains. The antiradical activity of M. oleifera, as determined by the ABTS assay, increased in a linear dose-response with increasing extract concentrations. The results as a whole for the cytotoxic, bactericidal and antioxidant activities of M. oleifera leaf extracts point to their possible use as additives in functional diets for farmed fish.

Immunomodulation, antioxidant enhancement and immune genes up-regulation in rainbow trout (Oncorhynchus mykiss) fed on seaweeds included diets

This study investigated the stimulatory effects of dietary inclusion of Gracilariopsis persica (GP), Hypnea flagelliformis (HF) and Sargassum boveanum (SB) on immune indices, antioxidant capability and immune related genes expression of rainbow trout (Oncorhynchus mykiss). Seven iso-nitrogenous and iso-caloric diets with 0, 5 and 10% of each macroalgae were prepared and fed to rainbow trout juveniles for 83 days. Serum lysozyme (Lyz) and respiratory burst activity (NBT) along with activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and expression of LyzII, TNFα and IL-1β genes in head kidney samples were determined by days 47 and 83. Our results revealed that dietary inclusion of seaweeds improved fish immune status. Long term feeding of fish on seaweed contained diets (except for GP10) improved serum Lyz activity in comparison to control group. Similarly, extended feeding on GP5 and HF10 and HF10 included diets improved SOD and POD levels, respectively. Genes expression studies revealed that seaweeds contained diets noticeably enhanced expression of LyzII, TNFα and IL-1β in comparison to control fish. However, results revealed that such stimulatory effects were more evident at lower dietary inclusion level and shorter feeding time. In conclusion, the results depicted that dietary inclusion of the seaweeds effectively improved serum immune indices and head kidney antioxidant status and immune related genes expression in a time and dose dependent manner.

Exploitation of Agro-Industrial Waste as Potential Source of Bioactive Compounds for Aquaculture

The agroindustry generates a large amount of waste. In postharvest, food losses can reach up to 50%. This waste represents a source of contamination of soil, air, and bodies of water. This represents a problem for the environment as well as for public health. However, this waste is an important source of bioactive compounds, such as phenolic compounds, terpenes, and β-glucans, among others. Several biological activities have been attributed to these compounds; for example, antioxidant, antimicrobial, gut microbiota, and immune system modulators. These properties have been associated with improvements in health. Recently, the approach of using these bioactive compounds as food additives for aquaculture have been addressed, where it is sought that organisms, in addition to growing, preserve their health and become disease resistant. The exploitation of agro-industrial waste as a source of bioactive compounds for aquaculture has a triple objective-to provide added value to production chains, reduce pollution, and improve the well-being of organisms through nutrition. However, to make use of the waste, it is necessary to revalue them, mainly by determining their biological effects in aquaculture organisms. The composition of bioactive compounds of agro-industrial wastes, their biological properties, and their application in aquaculture will be addressed here.