Bioactive immunostimulants as health-promoting feed additives in aquaculture. A review

Bioactive immunostimulants could be derived from different sources like plants, animals, microbes, algae, yeast, etc. Bioactive immunostimulants are the most significant role to enhance aquatic production, as well as the cost of this method, which is effective, non-toxic, and environment-friendly. These immunostimulants are supportive to increase the immune system, growth, antioxidant, anti-inflammatory, and disease resistance of aquatic animals' health and also improve aquatic animal feed. Diseases are mainly targeted to the immune system of aquatic organisms in such a way that different processes of bioactive immunostimulants progress are considered imperative techniques for the development of aquaculture production. Communicable infections are the main problem for aquaculture, while the mortality and morbidity connected with some outbreaks significantly limit the productivity of some sectors. Aquaculture is considered the mainly developing food production sector globally. Protein insists is an important issue in human nutrition. Aquaculture has been an exercise for thousands of years, and it has now surpassed capture fisheries as the most vital source of seafood in the world. Limited study reports are available to focal point on bioactive immunostimulants in aquaculture applications. This review report provides information on the nutritional administration of bioactive immunostimulants, their types, functions, and beneficial impacts on aquatic animals’ health as well as for the feed quality development in the aquaculture industry. The scope of this review combined to afford various kinds of natural derived bioactive molecules utilization and their beneficial effects in aquaculture applications

Beneficial effects of Persian shallot (Allium hirtifolium) extract on growth performance, biochemical, immunological and antioxidant responses of rainbow trout Oncorhynchus mykiss fingerlings

The aim of this study was designed to analyze the effect of Persian shallot (Allium hirtifolium) extract (PSE) on growth performance, biochemical parameters, antioxidant and immunity status of rainbow trout (Oncorhynchus mykiss) fingerlings. The rainbow trout (25.33 ± 0.15 g) were treated with four effective dosages of 0.5, 1, 2, and, 3% PSE in four separated with one control group for 60 days. At the end of experiment, the rainbow trout treated with PSE showed minimum feed conversion ratio (FCR), maximum weight gain (WG) and specific growth rate (SGR). Increased values of total protein, albumin and globulin were observed in PSE-fed fish; meanwhile, aspartate and alanine aminotransferases (AST, ALT) and alkaline phosphatase (ALP) activities as well as triglyceride, cholesterol, glucose, and cortisol levels significantly decreased in animals fed with 1–2% PSE diet. Activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), total immunoglobulin (total Ig), lysozyme activity, alternative complement hemolytic activity (ACH50), and respiratory burst (NBT) significantly (P < 0.05) increased in the PSE, with highest values in the treatments of 1–2% diet. The dietary PSE supplementation significantly (P < 0.05) decreased levels of malondialdehyde (MDA). A maximum significant amount (P < 0.05) in skin mucus was found in 1–3% PSE, while significant enhancement in total Ig and ACH50 were found in 0.5–3% PSE. All parameters analyzed in this study point at the usefulness of employing PSE in aquaculture as growth, antioxidant and immune system promoter. The optimum inclusion level was estimated to range between 1 and 2%. © 2022 Elsevier B.V

Mucosal immune parameters, immune and antioxidant defence related genes expression and growth performance of zebrafish (Danio rerio) fed on Gracilaria gracilis powder

In the present study zebrafish (Danio rerio) has been used as model organism to establish the effects of dietary supplementation of Gracilaria gracilis powder (GP) on mucosal and innate immune parameters, antioxidant enzymes, and growth. In order to establish these features, zebrafish were fed for eight weeks with experimental diets containing different levels of Red algae, 0.25, 0.5 and 1 of GP; also, a group was fed with control diet. At the end of the experimental period the antioxidant superoxide dismutase and catalase (SOD, CAT) genes expression, interleukin 1 beta (il-1β), lysozyme (LYZ), tumor necrosis factor alpha (TNF-α) for immune-related genes expression, total immunoglobulin (Ig), total protein, alkaline phosphatase (ALP) activity for innate immune parameters, and growth performance have been established. The GP dietary supplementation showed differences in SOD and CAT expression in zebrafish whole body respect to the control group. Non-signifcant differences were noticed among the different groups in case of TNF-α LYZ and il-1expression (P > 0.05). The skin mucus total Ig and total protein in the group fed on 1 of GP were significantly higher respect to control group (P 0.05). The results obtained in the present study revealed that G. gracilis could be takes in account as fishes diet supplementation for its immune system stimulants effects. © 2018 Elsevier Lt

Enhanced growth performance, oxidative capacity and immune responses of common carp, Cyprinus carpio fed with Artemisia absinthium extract-supplemented diet

In the present study, the effects of Afsanteen (Artemisia absinthium) aqueous extract (AE) were investigated on growth performance, innate immunity, and oxidative status of common carp, Cyprinus carpio. Common carp juveniles were fed experimental diets that contained 0, 0.5, 1 or 1.5% of AE for 60 days (75 fish/treatment). Thereafter, the fish growth performance, feed efficiency, serum immune-related, biochemical, and antioxidant parameters were determined. The results showed that diets containing 0.5 and 1% of AE enhanced the growth performance and feed efficiency of the fish. Fish fed with AE supplemented diets (at all concentrations) also displayed higher levels of serum lysozyme, alternative complement, total immunoglobulin, superoxide dismutase, and total protein levels compared to the control diet; the highest levels were observed at 1% AE level. Serum albumin levels of all AE-supplemented treatments were significantly higher than the control treatment. Dietary AE supplementation significantly increased plasma glutathione peroxidase activities; the highest value was related to the fish fed 0.5% AE. All AE treatments showed significantly lower serum catalase activities compared to the control; the lowest value was related to 1.5% AE. 0.5 and 1% AE significantly decreased serum malondialdehyde levels. All AE- treated fish exhibited significantly lower serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities; the lowest values were observed in 0.5% or 1% AE. In conclusion, dietary inclusions of AE in juvenile common carp increased growth performance and feed efficiency, improved the innate immunity and antioxidant response, and improved hepatic health. AE at 0.5–1% levels is recommended for common carp diet formulation. © 2021 Elsevier B.V

Effects of host-associated probiotic Bacillus altitudinis B61-34b on growth performance, immune response and disease resistance of Nile tilapia (Oreochromis niloticus) raised under biofloc system

This investigation was performed to assess the influences of the host-associated probiotic Bacillus altitudinis B61-34b (BAA) on growth, immune response and disease resistance to Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus). Fish (25.50 ± 0.52 g fish−1) were distributed into 15 aquaria (150 litres tank−1) at density of 20 fish tank−1. The fish were fed basal diets with BAA inclusions in different concentrations: 0 (BAA1—Control), 106 (BAA2), 107 (BAA3), 108 (BAA4) and 109 (BAA5) CFU ml−1 for 8 weeks. A completely randomized design with three replications was used. The results indicated that BAA administration generated greater (p < 0.05) skin mucus and peroxidase activities compared to the control, with maximum levels recorded in BAA4 and BAA5. Higher serum immunities, such as serum lysozyme, serum peroxidase, complement, phagocytosis and respiratory burst activities were observed in the BAA4 and BAA5 dietary groups compared to the control, BAA1, BAA2 and BAA3 diets. The relative percentage of survival, growth performance and FCR were also significantly higher (p < 0.05) in the BAA4 and BAA5 groups. In conclusion, dietary supplementation of B. altitudinis at 108 CFU ml−1 can improve Nile tilapia's growth performance, skin mucus and serum immunities, and disease resistance

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. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Cornelian cherry (Cornus mas L.) fruit extract improves growth performance, disease resistance, and serum immune-and antioxidant-related gene expression of common carp (Cyprinus carpio)

This study evaluated the use of cornelian cherry (Cornus mas L.) fruit extract on the growth performance, immune responses, and disease resistance in common carp (Cyprinus carpio). A total of 192 fish (initial body weight of 18.34 ± 1.8 g) were randomly distributed in 12 tanks with 16 fish per tank (4 treatments with 3 replications) and fed with diets containing cornelian cherry extract (CCE) at the rate of 0, 0.25, 0.5 and 1%. The final weight of common carp fed CCE at 0.5% was significantly higher than fish fed 0 and 0.25% doses (p < 0.05). In addition, weight gain and specific growth rate were increased, and feed conversion ratio decreased in fish-fed diets containing 0.5 and 1% CCE compared to other groups. The challenge test with A. hydrophila revealed that common carp-fed CCE had a lower mortality rate than the control. The lysozyme activity was markedly higher in common carp fed 0.5% of cornelian cherry extract than in control. The total immunoglobulin and total protein showed higher values in fish fed 0.5 and 1% than the control. The catalase gene showed higher mRNA levels in fish fed 0.5 and 1% than the control. Glutathione reductase gene expression was markedly upregulated in common carp fed 1% of CCE than the control and 0.25% groups. The glutathione S-transferase gene showed higher mRNA levels in fish fed 0.5 and 1% than the control and 0.25% groups. The superoxide dismutase gene expression was markedly higher in common carp fed 0.5% of CCE than in control. The CC-chemokine and interleukin-10 showed higher mRNA levels in fish fed 0.5% than the remaining groups. Hypoxia-inducible factor 1-alpha gene expression was markedly upregulated in common carp fed 1% of CCE than the control and 0.25% groups. The heat shock 70 kDa protein and interleukin-1 beta genes showed higher mRNA levels in fish fed 0.25, 0.5, and 1% than the control. In conclusion, the supplementation of CCE at 0.5–1% is recommended to enhance the growth performance and relieve the impacts of A. hydrophila infection in common carp. © 202

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

A six-week feeding trial was carried out to evaluate the effects of inclusion of dietary olive waste cake (OWC, 0, 0.5, 2.5 and 5 g kg−1 diet) on performance, antioxidant condition and immune responses of rainbow trout (Oncorhynchus mykiss) (2.5 ± 0.1 g). Supplementing diet with 2.5 and 5 g OWC kg−1 diet significantly enhanced serum and mucosal lysozyme activity in fish. Regarding mucosal immunity, fish fed 2.5 and 5 g OWC kg−1 diets had higher skin mucus total Ig concentrations than other groups. In relation to antioxidant status, those in 2.5 g OWC kg−1 and the control groups exhibited the highest and the least liver superoxide dismutase and glutathione peroxidase activities, respectively. Furthermore, the activity of liver glutathione S transferase in fish fed 2.5 and 5 g OWC kg−1 diets was higher than the other treatments. In respect to gut cytokines gene expression, our findings demonstrated dietary OWC did not influence interlukines-1β and 10 genes expression, but relative expression of IL8 gene gradually up-regulated with increasing dietary OWC level. Moreover, fish fed 0.5 g OWC kg−1 and the control diets had the highest and the lowest gut tumor necrosis factor-α gene expression values, respectively. The relative expression of transforming growth factor-β significantly down-regulated in gut of fish fed 2.5 and 5 g OWC kg−1 diets compared to other groups. Supplementing diet with OWC pronouncedly improved growth and feed conversion ratio in fish compared to the control. Overall, the findings of this study suggested that inclusion of 2.5 g OWC kg−1 diet can improve growth rate, oxidative stress status, humoral and skin mucosal immune responses in O. mykiss fingerlings and it can be considered as a functional feed additive for this species. © 2020 Elsevier Lt

A zebrafish HCT116 xenograft model to predict anandamide outcomes on colorectal cancer

: Colon cancer is one of the leading causes of death worldwide. In recent years, cannabinoids have been extensively studied for their potential anticancer effects and symptom management. Several in vitro studies reported anandamide's (AEA) ability to block cancer cell proliferation and migration, but evidence from in vivo studies is still lacking. Thus, in this study, the effects of AEA exposure in zebrafish embryos transplanted with HCT116 cells were evaluated. Totally, 48 hpf xenografts were exposed to 10 nM AEA, 10 nM AM251, one of the cannabinoid 1 receptor (CB1) antagonist/inverse agonists, and to AEA + AM251, to verify the specific effect of AEA treatment. AEA efficacy was evaluated by confocal microscopy, which demonstrated that these xenografts presented a smaller tumor size, reduced tumor angiogenesis, and lacked micrometastasis formation. To gain deeper evidence into AEA action, microscopic observations were completed by molecular analyses. RNA seq performed on zebrafish transcriptome reported the downregulation of genes involved in cell proliferation, angiogenesis, and the immune system. Conversely, HCT116 cell transcripts resulted not affected by AEA treatment. In vitro HCT116 culture, in fact, confirmed that AEA exposure did not affect cell proliferation and viability, thus suggesting that the reduced tumor size mainly depends on direct effects on the fish rather than on the transplanted cancer cells. AEA reduced cell proliferation and tumor angiogenesis, as suggested by socs3 and pcnp mRNAs and Vegfc protein levels, and exerted anti-inflammatory activity, as indicated by the reduction of il-11a, mhc1uba, and csf3b mRNA. Of note, are the results obtained in groups exposed to AM251, which presence nullifies AEA's beneficial effects. In conclusion, this study promotes the efficacy of AEA in personalized cancer therapy, as suggested by its ability to drive tumor growth and metastasis, and strongly supports the use of zebrafish xenograft as an emerging model platform for cancer studies

Effect of a diet enriched with sodium propionate on growth performance, antioxidant property, innate-adaptive immune response, and growth-related genes expression in critically endangered beluga sturgeon (Huso huso)

Organic acids are active substances required for improving the productivity and wellbeing of aquatic animals. Herein, the study investigated the effects of sodium propionate on growth performance, antioxidative and immune responses, and growth-related genes expression in beluga sturgeon (Huso huso). For eight weeks, fish fed sodium propionate at 0, 1.2, 2.5, and 5 g kg−1. The final weight, weight gain, and SGR were substantially increased while FCR decreased by dietary sodium propionate at 2.5 and 5 g kg−1 (P &lt; 0.05). The expression of Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) was markedly upregulated (P &lt; 0.05) by dietary sodium propionate in the gills and livers of beluga. The highest mRNA level of GH and IGF-1 has been observed in fish fed a 2.5 g sodium propionate/kg diet. The red blood cells count, and hemoglobin level were meaningfully increased (P &lt; 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg−1 levels. Further, the hematocrit level was increased (P &lt; 0.05) by a dietary 5 g sodium propionate/kg diet. The total protein level and lysozyme activity were meaningfully increased (P &lt; 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg−1 levels. The highest superoxide dismutase was observed in fish fed 2.5 g sodium propionate/kg diet. Catalase activity was significantly higher in fish fed 5 g kg−1 than 1.2 g kg−1. The glutathione peroxidase activity was markedly higher in fish fed 2.5, and 5 g kg−1 than fish fed control diet. The lowest malondialdehyde levels were observed in fish fed 1.2, and 2.5 g sodium propionate/kg diets. Moreover, the highest mucosal total protein, total immunoglobulin and lysozyme were recorded in fish fed 2.5, and 5 g sodium propionate/kg diets. The obtained results indicate that dietary sodium propionate is recommended at 2.5–5 g kg−1 to improve beluga sturgeon's growth performance, feed utilization, and wellbeing. © 2022 Elsevier Lt