Co‐infections commonly arise when two or multiple different pathogens infect the same host, either as simultaneous or as secondary concurrent infection. This potentiates their pathogenic effects and ...leads to serious negative consequences on the exposed host. Numerous studies on the occurrence of the bacterial, parasitic, fungal and viral co‐infections were conducted in various tilapia species. Co‐infections have been associated with serious negative impacts on susceptible fish because they increase the fish susceptibility to diseases and the likelihood of outbreaks in the affected fish. Co‐infections can alter the disease course and increase the severity of disease through synergistic and, more rarely, antagonistic interactions. In this review, reports on the synergistic co‐infections and their impacts on the affected tilapia species are highlighted. Additionally, their pathogenic mechanisms are briefly discussed. Tilapia producers should be aware of the possible occurrence of co‐infections and their effects on the affected tilapia species and in particular of the clinical signs and course of the disease. To date, there is still limited information regarding the pathogenicity mechanisms and pathogen interactions during these co‐infections. This is generally due to low awareness regarding co‐infections, and in many cases, a dominant pathogen is perceived to be of vital importance and hence becomes the target of treatment while the treatment of the co‐infectious agents is neglected. This review article aimed at raising awareness regarding co‐infections and helping researchers and fish health specialists pay greater attention to these natural cases, leading to increased research and more consistent diagnosis of co‐infectious outbreaks in order to improve control strategies to protect tilapia when infected with multiple pathogens.
Probiotics are live beneficial bacteria introduced into the gastrointestinal tract through food or water, promoting good health by enhancing the internal microbial balance. Probiotic microbes produce ...bacteriocins, siderophores, lysozymes, proteases, and hydrogen peroxides, inhibiting the growth of harmful pathogens. Such beneficial bacteria also produce many enzymes such as amylase enzyme by Aeromonas spp., Bacillus subtilis, Bacteridaceae, Clostridium spp., Lactobacillus plantarum, and Staphylococcus sp., and protease and cellulase enzymes by B. subtilis, L. plantarum, and Staphylococcus sp. In aquaculture, probiotics confer several benefits and play important roles in improving growth performances, disease resistance, immunity, health status, intestinal epithelial barrier integrity, gut microbiome, and water quality. In addition, the practical application of probiotics in aquaculture diets could minimize antibiotic side effects. Promoting these feed additives for fish would help to improve their productive performance and feed utilization and, therefore, boost fish production and safeguard human health. This review provides updated information regarding definitions, sources of bacterial probiotics, probiotic use in fish diets against pathogenic bacteria, mechanisms of action, beneficial aspects, and potential applications of probiotics in fish. It is anticipated that these will be of significant value for nutritionists, agricultural engineers, researchers, pharmacists, scientists, pharmaceutical industries, and veterinarians.
•Zinc oxide nanoparticles induced liver, kidney, and gills oxidative damage.•Lycopene protected against zinc oxide nanoparticles toxicity.•Resveratrol protected against zinc oxide nanoparticles ...toxicity.•Lycopene and resveratrol exerted antioxidant effects.
Industrial products contained nano-zinc oxide (ZnONP) can gain access to the aquaculture environment causing hazardous effects on the living biota. Therefore, this work was planned to examine the ameliorative effects of dietary supplementation of lycopene (LYC) and/or resveratrol (RES) against ZnONP toxicity in Nile tilapia. Five groups with 20 fish each were used; Control, received tap water only; ZnONP group, was intoxicated with ZnONP (50 mg/L); ZnONP-LYC group, was exposed to ZnONP and LYC (500 mg/ kg of the diet); ZnONP-RES group, was exposed to ZnONP and RES (50 mg/kg of the diet); ZnONP-LYC-RES group, was exposed to ZnONP and a combination of LYC and RES. The experiment was continued for 30 days. Fish blood and tissues were then assembled for determination of liver and kidney function and oxidative stress status in liver, kidney, and gills tissue. Results revealed a considerable elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), cholesterol, urea, and creatinine with a noticeable lowering of total proteins and albumin serum levels in response to ZnONP intoxication. In addition, there were significant increase in malondialdehyde (MDA) and reduction in the reduced-glutathione (GSH) levels and superoxide dismutase (SOD) and catalase (CAT) activities. However, treatment with LYC and/or RES ameliorated the ZnONP-inflicted oxidative stress which possibly attributed to their beneficial antioxidant activities.
Polyphenols are plant-derived compounds with known biological activities and potential health benefits. Over the past decade, there are an increasing number of studies have investigated the ...application of polyphenols and polyphenol-rich additives in aquaculture as functional feed additives. There are several types of polyphenolic compounds such as flavonoids, phenolic acids, lignans, and stilbenes of widely known beneficial influences on the overall performances and immunity of fish, and thereby improving the health status and production of fish farms. This review discusses the beneficial applications, optimum recommended dose, and potential side effects of these natural compounds on the growth performance, proximate body composition, immune responses, disease resistance, reproductive performance, and fillet quality of different fish species. Also, it points out that the biological functions and mechanisms associated with the polyphenolic compounds involved in the pathways of antioxidant and pro-oxidant activities, as well as the modulation of gene expression and different immune parameters. The output of this review article provided overwhelming evidence to support the claim that natural polyphenols can be considered as relatively safe and viable alternatives to synthetic chemical compounds that not only to improve the fish health status but also to enhance the fish quality, productivity, and food safety while reducing the use of chemicals and antibiotics in the aquatic eco-systems.
This study assessed the restorative dietary effects of Moringa oleifera (MO) leaves extract against the negative impacts of sub-lethal fipronil (FIP) toxicity in Nile tilapia. To achieve this ...purpose, the growth, body composition, haemato-biochemical measurements, serum immunity, and antioxidant condition of Nile tilapia have been examined. Fish were arranged into 6 experimental groups in quadruplicates. Three groups were fed on diets supplemented with 0.0 (reference group), 1.0 (MO1), and 2.0 (MO2) g kg
of MO leaf extract. The other three groups were fed on the same MO levels and concomitantly subjected to a sub-lethal FIP concentration (4.2 µg L
for 3 h only per day) and defined as FIP, FIP + MO1, and FIP + MO2. The experiment lasted for 8 weeks. Results unveiled that growth parameters were significantly decreased alongside an increased feed conversion ratio in the FIP-intoxicated group. The moisture and crude protein (%) were decreased significantly together with a significant increase of the crude lipids (%) in the fish body of the FIP group. Sub-lethal FIP toxicity induced hypochromic anemia, leukopenia, hypoproteinemia, hypoalbuminemia, hypoglobulinemia, and hepato-renal failure (increased urea and creatinine concentrations, as well as ALT and AST enzymes). Exposure to sub-lethal FIP also induced (a) immunosuppression manifested by a decline in total IgM, complement C3, and lysozyme activities, (b) enzymatic antioxidant misbalance manifested by decreases in SOD and CAT activities, and (c) oxidative stress (declined T-AOC and elevated of MDA concentrations). On the other side, dietary supplementation with MO leaf extract in FIP + MO1 and FIP + MO2 groups noticeably modulated the aforementioned parameters. Therefore, we can conclude that dietary MO could reduce sub-lethal FIP toxicity in Nile tilapia with a possible recommendation for regular prophylaxis supplementation in Nile tilapia diets.
The use of herbal essential oils in aquafeeds is an important approach to maintain the fish health status. The origanum essential oil (OEO), extracted from Origanum vulgare, was included at levels of ...0, 5, 10, 15, and 20 g per kg diet to evaluate its beneficial effects on antioxidant, immunity status, and expression of immune-related genes of common carp, Cyprinus carpio L. After 8 weeks, dietary inclusion of OEO significantly increased the activities of hepatic superoxide dismutase and catalase (P < 0.05); meanwhile, levels of hepatic malonaldehyde significantly decreased (P < 0.05). The levels of serum lysozyme activity, phagocytic activity, and phagocytic index have been linearly and quadratically increased by dietary OEO in a dose-dependent regime showing their highest levels in 15–20 g OEO/kg diet. Moreover, dietary OEO significantly upregulated the relative expression of hepatic interleukin-1beta (IL-1β) and interleukin-10 (IL-10) genes (P < 0.05). Dietary OEO maintained the normal histomorphological criteria and density of melanomacrophage centers of spleens, and hematopoietic tissues of the anterior kidneys in all fish groups with respect to the control. After challenge with pathogenic bacterium Aeromonas hydrophila, the 10-day cumulative mortality significantly decreased (P < 0.05); meanwhile, the relative percent of survival of common carp significantly increased by OEO administration (P < 0.05) in a dose-dependent manner. The obtained results reflect the beneficial roles of dietary OEO to boost the antioxidative status and the immune responses in common carp with an optimum level of 15 g/kg diet.
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•Fish fed origanum essential oil (OEO) had better antioxidative and immune status with an optimum level of 15 g/kg diet.•The dietary OEO maintained the normal histological structure of spleen and anterior kidney tissues of treated fish.•The OEO supplementation increased the transcription of hepatic IL-1β and IL-10 genes.•Fish fed diets supplemented OEO had high resistance against Aeromonas hydrophila infection.
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.
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Excessive application of antibiotics to control fish and shrimp diseases in aquaculture has been associated with several drawbacks, such as immune suppression, development of antibiotic-resistant ...bacterial strains, and elevated levels of antibiotic residues in animal products. To overcome this problem and to promote fish health and their productivity, several immunostimulants have been used as additives in aquafeeds. In this regard, interest in the research on the use of short-chain fatty acids (SCFA) in aquafeeds is increasing tremendously, as they exert several beneficial effects on farmed fish and shrimp. Among SCFA, butyric acid (BA); its salts, such as sodium butyrate (SB); and their protected forms have attracted particular attention of researchers as growth promoters and immunostimulants as well as for their antioxidant properties. Until date, extensive studies have been conducted on the beneficial effects of BA, SB, and their protected forms on growth performance, feed utilization, proximate body composition, intestinal health status (gut microbial communities, the histo-morphological structure of the intestinal villi, and digestive enzymes), antioxidant properties, haemato-immunological functions, expression of immune genes and pro-inflammatory cytokines, and resistance of fish and shrimp to diseases. These studies have demonstrated SCFA as promising feed additives in aquaculture. The present review article summarizes the beneficial effects of dietary supplementation of BA, SB, and their protected forms on aquatic organisms. Furthermore, the review discusses the information available pertaining to their modes of action.
In aquaculture, nutrigenomics or “nutritional genomics” is concerned with studying the impacts of nutrients and food ingredients on gene expressions and understanding the interactions that may occur ...between nutrients and dietary bioactive ingredients with the genome and cellular molecules of the treated aquatic animals at the molecular levels that will, in turn, mediate gene expression. This concept will throw light on or provide important information to recognize better how specific nutrients may influence the overall health status of aquatic organisms. In crustaceans, it is well known that the nutritional requirements vary among different species. Thus, studying the nutrigenomics in different crustacean species is of significant importance. Of interest, recognition of the actual mechanisms that may be associated with the effects of the nutrients on the immune responses of crustaceans will provide clear outstanding protection, build a solid immune system, and also decrease the possibilities of the emergence of infectious diseases in the culture systems. Similarly, the growth, molting, lipid metabolism, antioxidant capacity, and reproduction could be effectively enhanced by using specific nutrients. In the area of crustacean research, nutrigenomics has been rapidly grown for addressing several aspects related to the influences of nutrients on crustacean development. Several researchers have studied the relationships between several functional genes and their expression profile with several physiological functions of crustaceans. They found a close association between the effects of optimal feeding with efficient production, growth, reproduction development, and health status of several crustacean species. Moreover, they illustrated that regulation of the gene expression in individual cells by different nutrients and formulated feeds could improve the growth development and immunity-boosting of several crustacean species. The present review will spotlight on such relationships between the dietary nutrients and expression of genes linked with growth, metabolism, molting, antioxidant, reproduction, and immunity of several crustacean species. The literature included in this review article will provide references and future outlooks for the upcoming research plans. This will contribute positively for maintaining the sustainability of the sector of the crustacean industry.
•This review evaluates the impacts of feed ingredients on gene expressions in tissues of different crustacean species.•The interactions between nutrients and bioactive components with the genome of treated crustaceans at the molecular levels were also studied.•There is a close association between the optimal feeding effects with efficient production, reproduction development, and health status in crustaceans.•This review throws light on the effects of nutrients on the expression of genes related to growth, metabolism, molting, antioxidant status, reproduction, and immunity of crustaceans.
We investigated the dietary effects of the single application of Saccharomyces cerevisiae, Lactobacillus bulgaricus, and their combination on growth, proximate composition of whole fish body, ...antioxidant defense, and histoarchitecture of hapa-reared Mugil capito. Healthy fish (Fish weighed = 10.30 ± 0.10 g at first) were randomly allocated into 4 equal groups, each with three replicates. These groups were designed as follows: (1) a group fed a basal diet without probiotics (control), (2) a group fed a diet containing S. cerevisiae (4 g/kg diet), (3) a group fed a diet containing L. bulgaricus (2 g/kg diet), and (4) the last group fed a diet containing a combination of both, all for a duration of 60 days. Probiotic-treated groups showed significantly better growth and nutrition utilization than the control group. Significant differences were observed in the crude fat and crude protein contents among the groups, with the combination group exhibiting the highest levels. However, there were no significant variations in ash content across all groups. The highest hepatic antioxidant capacity (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) enzyme activities) was observed in the combination group. Thiobarbituric acid reactive substance (TBARS) concentrations were decreased significantly in all probiotic groups, suggesting improved oxidative stress resilience in these groups. The histomorphological analysis of the hepatopancreatic tissues revealed well-arranged parenchyma, increased glycogen storage, and melanomacrophage centers in probiotic-treated groups, particularly the combined probiotics group. Furthermore, the probiotic supplementation improved the histoarchitecture of the intestinal villi compared to the control group. To put it briefly, combined dietary administration of these probiotics improved growth, body composition, antioxidant defenses, and hepatic and intestinal health in hapa-reared M. capito, highlighting their promising role in promoting welfare and productivity.
