Effects of dietary inclusion of Moringa oleifera leaves on growth and some systemic and mucosal immune parameters of seabream

Fishmeal substitution by zooplankton or Daphnia magna biomass meals in the diet of Nile tilapia: Effects on growth, gut histological changes, bacterial abundance and stress tolerance

Fishmeal substitution with sustainable feed sources is highly essential towards sustainable production. This study aimed to investigate the effects of substituting fishmeal (FM) with Daphnia magna biomass meal (DBM) or zooplankton biomass meal (ZBM) on growth performance, liver and intestinal histology, gut bacterial abundance and stress tolerance of Nile tilapia, Oreochromis niloticus, fry. Nile tilapia fry (0.23 ± 0.04 g) were randomly assigned to five groups of three replicates. The control diet comprised 300 g/kg FM, and the FM was substituted with DBM or ZBM at levels of 25% and 50% (DBM-25, DBM-50, ZBM-25 and ZBM-50 respectively) in the other experimental diets. The experiment lasted 56 days in 1.5 m3 concrete tanks. The results revealed that weight gain and feed conversion ratio (FCR) significantly (p ≤ 0.035 and 0.025 respectively) improved with a polynomial response with a peak at 25% ZBM and a linear increase with DBM up to 50% of FM. Histometric indices of the distal intestine showed improvements (p ≤ 0.001) in villus height, villus width, crypt depth and muscle thickness of fish fed DBM or ZBM compared to the control. In the meantime, there were no histological abnormalities in the liver sections. The replacement of FM with DBM or ZBM could modulated gut bacterial abundance, including total bacterial count, Escherichia coli, Bacillus subtilis, and Lactobacillus sp. The fish-fed DBM or ZBM-containing diets had higher (p ≤ 0.05) tolerances to salinity stress than the control group. In conclusion, DBM or ZBM could replace FM up to 50% and 25%, respectively with improved fish growth performance, FCR, gut histology and tolerance to salinity stress.

Development, characterization, and immunomodulation performance of spray-dried Moringa oleifera seed extract in Longfin yellowtail Seriola rivoliana

Moringa oleifera is one of the most promising plants in aquaculture because it improves the health status, zootechnical parameters and resistance against diseases. This research evaluates the physicochemical, antioxidant values of spray-dried Moringa oleifera seed extract microencapsulates obtained at 140 and 180 °C with whey protein concentrate (WPC) and maltodextrin (MD) as wall materials in two different proportions: WPC 100% and WPC-MD (3:1). Also, immune response of peripheral blood leukocytes (PBL) of Longfin yellowtail Seriola rivoliana stimulated with spray-dried Moringa oleifera seed for 24 h was assessed. The physicochemical parameters show that the recovery yield for all the treatments was of 65% and microencapsulates demonstrated to be stable in the physicochemical tests with low solubilization times and protection against humidity. For WPC-MD (3:1)/140 °C, bioactive compound retention and antioxidant potential were higher than in other combinations. The immunological test show that any treatments was non-cytotoxic against peripheral blood leukocytes. WPC-MD (3:1)/140 °C treatment enhanced immune parameters as phagocytosis, respiratory burst, myeloperoxidase activities and nitric oxide production. Immune related genes as IL-1β and TNF-α were up-regulated in those stimulated leukocytes with WPC-MD (3:1)/140 °C. The results suggest that this combination may be a good alternative for animal health as a medicinal and immunostimulant additive.

Skin mucus metabolomics provides insights into the interplay between diet and wound in gilthead seabream (Sparus aurata)

The molecular processes underlying skin wound healing in several fish species have been elucidated in the last years, however, metabolomic insights are scarce. Here we report the skin mucus metabolome of wounded and non-wounded gilthead seabream (Sparus aurata) fed with silk fibroin microparticles, a functional additive considered to accelerate the wound healing process. The three experimental diets (commercial diet enriched with 0 mg (control), 50 mg or 100 mg of silk fibroin microparticles Kg^-1) were administered for 30 days and thereafter, a skin wound was inflicted. Skin mucus was collected on day 30 of feeding and 7 days post-wounding and subjected to metabolomic analysis by Ultra Performance Liquid Chromatography coupled with a high-resolution quadrupole-orbitrap mass spectrometry. The most enriched metabolite class was amino acids and derivatives, followed by nucleotides, nucleosides and analogues and carbohydrates and their derivatives. Metabolomic profiles revealed that the diet had a more profound effect than wounding in skin mucus. Metabolic pathway analysis of significantly affected metabolites revealed perturbations in the aminoacyl t-RNA biosynthesis in the skin. In particular, skin wound resulted in a decreased methionine level in mucus. Further, silk fibroin supplementation increased methionine level in skin mucus, which correlated with several wound morphometric parameters that characterized the epithelial healing capacity in seabream. The results provided new insight into the physiological consequences of skin wounds and how these processes could be influenced by dietary manipulation.

Growth-promoting and immunostimulatory effects of phytobiotics as dietary supplements for Pangasianodon hypophthalmus fingerlings

A 56-day feeding experiment was designed to evaluate the impacts of five herbal extracts, namely Ginkgo biloba (GB), Moringa oleifera (MR), Myristica fragrans (NM), Silybum marianum (MT), and Astragalus membranaceus (AT) on growth, serum immune indices, and ammonia-N stress resistance of Pangasianodon hypophthalmus fingerlings. Fish were fed on a diet with no herbal additives (reference or CNT), and several plant extracts-based diets were supplied with two inclusion doses of each extract (1.0 and 2.0 g/kg). After the end of the feeding, fish in all groups were exposed to acute ammonia stress, mortalities were recorded every 2 h for a duration of 10 h, and then survival percent was assessed. Results showed that growth was upgraded significantly in groups fed plant extracts-based diets compared to the CNT group. Serum proteins (albumin and total protein), lysozyme, complement C3, bactericidal, and myeloperoxidase activities were increased significantly in groups fed plant extracts-based diets in relation to the CNT group. The total immunoglobulin levels were increased significantly only in fish groups fed GB, MT, and NM-based diets. Post-exposure to acute ammonia stress, the Kaplan-Meier survival curve presented significantly higher survival of fish groups that fed plant extracts-enriched diets than those fed the CNT diet. The aforementioned results suggest that using herbal extracts as feed supplements can beneficially enhance the growth, the immunity of P. hypophthalmus fingerlings and may increase their tolerance in the face of extrinsic stressors. These findings may pave the way for the potential and regular application of herbal extracts in diets of P. hypophthalmus at their early life stages to raise their immunity and maintain aquaculture sustainability.

Dietary supplementation with Moringa oleifera leaves extract reduces the impacts of sub-lethal fipronil in Nile tilapia, Oreochromis niloticus

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^-1 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^-1 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.

Improving survival, growth, feed utilization, antioxidant status, and fatty acids profile of European seabass, Dicentrarchus labrax, larvae fed silymarin, Silybum marianum, supplemented weaning diet

To sustain normal development, high survival, and rapid growth, marine fish larvae require a diet rich in polyunsaturated fatty acids, which could decrease the risk of reactive oxygen species accumulations. Consequently, a 60-day feeding experiment was conducted to determine the effect of silymarin (SM) supplementation in weaning diets on the growth performance, survival, antioxidant enzyme activities, and fatty acids profile of European seabass (Dicentrarchus labrax) larvae. Four isonitrogenous and isolipidic diets were investigated using SM at levels of 0, 200, 400, and 600 mg kg−1 (SM0.00, SM200, SM400, and SM600, respectively). The findings showed that, in a dose-dependent manner, increasing dietary levels of SM enhanced survival, growth, and feed utilization. In the SM600 group, the weight gain, survival, and feed conversion ratio (FCR) improved by 123.21, 11.66, and 38.72%, respectively, compared to the control group. The dose-response analysis demonstrated a strong positive correlation (R2=0.96) between SM levels and weight increase, and a strong negative correlation (R2=0.88) between SM levels and FCR. The antioxidant enzyme activities of larvae given SM-enriched diets were significantly greater than those of the control group. Compared to the control group, the CAT and SOD improved by 81.77 and 5.08 % in the SM600 group. In addition, the saturated fatty acid content reduced while the unsaturated fatty acid content increased, particularly in the SM600 group. The results indicate that supplementing the micro diet of European seabass larvae during weaning with SM at a dose of 600 mg kg-1 increases growth, survival, antioxidant status, and fatty acid profiles.

Effect of Tributyrin on Growth Performance and Pathway by which Tributyrin Regulates Oligopeptide Transporter 1 in Juvenile Grass Carp (Ctenopharyngodon idellus)

Simple Summary

Oligopeptide transporter 1 (PepT1) plays a role in the transportation and absorption of oligopeptides, which is an important part of protein nutrition and affects the growth of animals. Tributyrin (TB), the precursor of butyrate, exhibits similar functions to those of the butyrate in intestinal nutrients absorption. The analysis of TB on the growth of grass carp and its regulation pathway on PepT1 may help us to better understand the functions of TB and oligopeptide transportation via PepT1, which can be modulated by diet. In this study, we demonstrated that an appropriate level of tributyrin supplementation in the diet promoted the growth of juvenile grass carp and elevated the expressions of caudal type homeobox 2 (CDX2), specificity protein 1 (SP1), and PepT1 in the grass carp intestine and primary intestine cell. In addition, CDX2 and SP1 regulating the expression of PepT1 was investigated. Finally, CDX2/SP1-mediating tributyrin regulation on PepT1 was elucidated. This study verified the effect of tributyrin on the growth of juvenile grass carp and clarified the tributyrin regulation pathway on CDX2/SP1-PepT1.

Abstract

The nutritional functions of tributyrin (TB) have been extensively studied, but questions remain regarding its influence on the growth of juvenile grass carp (Ctenopharyngodon idellus) and the regulation pathway to PepT1 in the intestine of grass carp. To answer the remaining questions, feeding trials, cell trials, and peritoneal injection trials were conducted in this study. The results showed that an appropriate level of TB (0.5 g/kg and 1.0 g/kg) supplementation in feed significantly promoted the growth performance of juvenile grass carp. The expressions of intestine genes (CDX2, SP1 and PepT1) related to oligopeptide transportation increased in the 0.5 g/kg TB group of feeding trials and both the 5 mM and 10 mM TB groups of the intestine cell trials, respectively. Subsequently, the injection trials of inhibitors CDX2 and SP1 demonstrated that the inhibition of CDX2 or SP1 decreased the mRNA expression of PepT1. Finally, the results of independent or combined treatments of TB and the inhibitors suggested that CDX2/SP1 mediated TB regulation on PepT1. These findings may help us to better understand the functions of TB on growth and PepT1 oligopeptide transportation, which could be modulated by dietary TB through the CDX2/SP1-PepT1 pathway in juvenile grass carp.

Physiological Performance, Antioxidant and Immune Status, Columnaris Resistance, and Growth of Nile Tilapia That Received Alchemilla vulgaris-Supplemented Diets

The current perspective is a pioneering trial to assess the efficacy of the dietary supplementation of Alchemilla vulgaris powder (AVP) in the diet of Nile tilapia (Oreochromis niloticus) on growth performance, blood picture, hepatic and renal biomarkers, immune status, and serum and tissue antioxidant capacity and to investigate the resistance against Flavobacterium columnare challenge. Fish (n = 360) were distributed into six groups (three replicates each) and received increasing AVP supplementation levels (0, 2, 4, 6, 8, and 10 g kg⁻¹) for 60 days. Furthermore, fish were exposed to the bacterial challenge of a virulent F. columnare strain and maintained under observation for 12 days. During the observation period, clinical signs and the cumulative mortality percentage were recorded. The results demonstrated that the growth performance, feed conversion ratio, and hematological profile were noticeably enhanced in the AVP-supplemented groups compared to the control. The most promising results of weight gain and feed conversion ratio were recorded in the groups with 6, 8, and 10 g AVP kg⁻¹ diets in a linear regression trend. The levels of hepatorenal function indicators were maintained in a healthy range in the different dietary AVP-supplemented groups. In a dose-dependent manner, fish fed AVP dietary supplements displayed significant augmented serum levels of innate immune indicators (lysozyme, nitric oxide, and complement 3) and antioxidant biomarkers (Catalase (CAT), superoxide dismutase (SOD), total antioxidant (TAC), and reduced glutathione (GSH) with a marked decrease in myeloperoxidase (MPO) and malondialdehyde (MDA) levels). Likewise, hepatic CAT and SOD activities were significantly improved, and the opposite trend was recorded with hepatic MDA. The highest AVP-supplemented dose (10 g/kg) recorded the highest immune-antioxidant status. Based on the study findings, we highlight the efficacy of AVP as a nutraceutical dietary supplementation for aquaculture to enhance growth, physiological performance, and immune-antioxidant status and as a natural economic antibacterial agent in O. niloticus for sustaining aquaculture. It could be concluded that the dietary supplementation of 10 g AVP/kg enhanced O. niloticus growth, physiological performance, immune-antioxidant status, and resistance against F. columnare.

Moringa oleifera Leaf Powder Dietary Inclusion Differentially Modulates the Antioxidant, Inflammatory, and Histopathological Responses of Normal and Aeromonas hydrophila-Infected Mono-Sex Nile Tilapia (Oreochromis niloticus)

This study aimed to detect the impact of Moringa oleifera leaf powder dietary inclusion on the antioxidant and innate immune responses of mono-sex Nile tilapia fingerlings. A total of 180 fingerlings were allocated in a random method into three groups with triplicate each. One group (1^st group) received the control diet (basal diet (BD) free of moringa) and the other groups (2^nd and 3^rd) fed BD containing M. oleifera leaf powder at 5 and 10% of the diet, respectively. After 6 weeks of feeding, fish were randomly redistributed into four replicates and rested for 24 h. Then, each fish in the first two replicates was injected with 0.2 mL of PBS, while the others were injected with 0.2 mL of A. hydrophila suspension (1.8 × 10⁶ CFU/mL). Healthy fish fed on M. oleifera leaf powder showed enhanced immune response manifested by significant increases in phagocytic and lysozyme activities with a marked H/L ratio (P < 0.05). In addition, significant alterations of the lymphocytic and heterophilic population in circulation with increasing infiltration in tissue such as the spleen were noticed. Also, M. oleifera significantly upregulated the antioxidants, CAT and GPx, proinflammatory cytokines, IL1-β, IL-8, and IFN-γ relative mRNA levels. On the other hand, following A. hydrophila challenging conditions, M. oleifera caused downregulations of IL1-β, IL-8, and IFN-γ transcription levels, and also lowered the CAT and GPx mRNA levels. In addition, a marked reduction of leukocytic infiltration plus a significant improvement of the degenerative changes in intestinal architecture has occurred. So, M. oleifera leaf powder can be included in the fish diet to enhance immune response under normal health conditions and lower the infection-associated inflammatory response.

Growth Performance, Immune-Related and Antioxidant Genes Expression, and Gut Bacterial Abundance of Pacific White Leg Shrimp, Litopenaeus vannamei, Dietary Supplemented With Natural Astaxanthin

The current study examines the effect of dietary supplementation of ethanolic extract of Arthrospira platensis NIOF17/003, which is mainly natural astaxanthins (97.50%), on the growth performance, feed utilization, bacterial abundance, and immune-related and antioxidant gene expressions of the Pacific white leg shrimp, Litopenaeus vannamei. A total of 360 healthy L. vannamei postlarvae (0.19 ± 0.003 g) were divided into four groups (0, 2, 4, and 6 g natural astaxanthins/kg diet) each in three replicates, at an initial density of 30 PLs per tank (40 L capacity). The shrimp were fed the tested diets three times a day at a rate of 10% of their total body weight for 90 days. Diets supplemented with different astaxanthin levels significantly improved shrimp growth performance and feed conversion ratio compared to the control diet. No significant differences were observed in survival rates among all experimental groups. The immune-related genes (prophenoloxidase, lysozyme, beta-glucan binding protein, transglutaminase, and crustin) mRNA levels were significantly upregulated in groups fed with different concentrations of the natural astaxanthins in a dose-dependent manner. The prophenoloxidase gene is the highest immune-upregulated gene (14.71-fold change) in response to astaxanthin supplementation. The superoxide dismutase mRNA level was significantly increased with increasing dietary astaxanthin supplementation. In addition, increasing astaxanthin supplementation levels significantly reduced the count of heterotrophic bacteria and Vibrio spp. in the culture water and shrimp intestine. Overall, the current results concluded that diet supplementation with natural astaxanthin, extracted from Arthrospira platensis, enhanced the growth performance, immune response, and antioxidant status of L. vannamei.

Modulatory Effect of Papaya Extract against Chlorpyrifos-Induced Oxidative Stress, Immune Suppression, Endocrine Disruption, and DNA Damage in Female Clarias gariepinus

Chlorpyrifos (CPF) is one of the widely used organophosphorus pesticides in agriculture activities and its presence in the aquatic environment has been broadly recorded. In the present study, we investigated the effect of CPF exposure on oxidative stress, innate immunity, sexual hormones, and DNA integrity of female African catfish, Clarias gariepinus, in addition to the potential use of dietary supplementation of papaya, Carica papaya (CP), extract against CPF toxicity. Apparent healthy female catfish (300 ± 10 g) were divided into four groups with three replicates each. The first group served as the negative control (fed on a basal diet) and the other groups exposed to CPF (8.75 µg/L) with or without CP extract (250 mg/kg body weight) for six weeks. The results revealed that CPF exposure exhibited marked elevations in stress markers (glucose and cortisol), serum aspartate aminotransferase, alanine aminotransferase activities, testosterone, and luteinizing hormone level. Moreover, CPF increased the percentage of hepatic DNA damage. In addition, catfish exposed to CPF experienced significant decline in serum total protein, albumin, follicles stimulating hormone, estradiol hormone levels, AChE, immunoglobulin, and lysozyme activity. CPF induced significantly oxidative stress in hepatic and renal tissues. The dietary supplementation with CP extract at a level of 250 mg/kg body weight succeeded to alleviate the negative effects of CPF on the physiological, immunological, and antioxidant status of female catfish. In addition, CP extract alleviated the endocrine disruption and hepatic DNA damage and counteracted the subchronic CPF toxicity in female African catfish. Finally, the CP extract may be used as a feed additive in the aquatic diet.

Effects of Dietary Supplementation with Honeybee Pollen and Its Supercritical Fluid Extract on Immune Response and Fillet's Quality of Farmed Gilthead Seabream (Sparus aurata)

The awareness of the correlation between administered diet, fish health and products’ quality has led to the increase in the research for innovative and functional feed ingredients. Herein, a plant-derived product rich in bioactive compounds, such as honeybee pollen (HBP), was included as raw (HBP) and as Supercritical Fluid Extracted (SFE) pollen (HBP_SFE) in the diet for gilthead seabream (Sparus aurata). The experiment was carried out on 90 fish with an average body weight of 294.7 ± 12.8 g, divided into five groups, according to the administration of five diets for 30 days: control diet (CTR); two diets containing HBP at 5% (P5) and at 10% (P10) level of inclusion; two diets containing HBP_SFE, at 0.5% (E0.5) and at 1% (E1) level of inclusion. Their effects were evaluated on 60 specimens (336.2 ± 11.4 g average final body weight) considering the fish growth, the expression of some hepatic genes involved in the inflammatory response (il-1β, il-6 and il-8) through quantitative real-time PCR, and physico-chemical characterization (namely color, texture, water holding capacity, fatty acid profile and lipid peroxidation) of the fish fillets monitored at the beginning (day 0) and after 110 days of storage at −20 °C. The results obtained showed that the treatment with diet E1 determined the up-regulation of il-1β, il-6, and il-8 (p < 0.05); however, this supplementation did not significantly contribute to limiting the oxidative stress. Nevertheless, no detrimental effect on color and the other physical characteristics was observed. These results suggest that a low level of HBP_SFE could be potentially utilized in aquaculture as an immunostimulant more than an antioxidant, but further investigation is necessary.

Remarkable positive effects of figwort (Scrophularia striata) on improving growth performance, and immunohematological parameters of fish

This study was conducted to investigate the effect of figwort on the growth and immunohematological parameters of common carp (14.20 ± 0.53 g). Four experimental diets were developed to feed fish for eight weeks: control, Figw10 (10 g/kg figwort), Figw20 (20 g/kg figwort), and Figw30 (30 g/kg figwort). The results showed that fish fed dietary Figw10 gained more weight (38.25 g) than control (P < 0.05). Regarding immunohematological parameters, fish fed dietary Figw30 had a higher level of white blood cells (31.2 10³/mm³), hematocrit (35.82%), blood performance (14.63), total protein (1.96 g/dL), albumin (0.79 g/dL), globulin (1.17 g/dL), lymphocyte (70.53%), monocyte (3.03%), alternative hemolytic complement activity (ACH50) (147.76 u/mL), lysozyme (62.19 u/mL), and bactericidal activities (135.24) than the control group (P < 0.05). After 14 days of the challenge with Aeromonas hydrophila, the Figw30 treatment had the highest survival ratio (61.76%) compared to the control with 26.46%. Further, after the challenge, fish fed dietary Figw30 had a higher value of immunoglobulin M (42.00 μg/mL), antibody titer (19.23), complement component 3 (296.39 μg/mL), and complement component 4 (97.91 μg/mL) when compared with those fed control diet (P < 0.05). In conclusion, the optimum dosage for providing the best immune response was 30 g/kg in diet.

Prospects for Protective Potential of Moringa oleifera against Kidney Diseases

Kidney diseases are regarded as one of the major public health issues in the world. The objectives of this study were: (i) to investigate the causative factors involved in kidney disease and the therapeutic aspects of Moringa oleifera, as well as (ii) the effectiveness of M. oleifera in the anti-inflammation and antioxidant processes of the kidney while minimizing all potential side effects. In addition, we proposed a hypothesis to improve M. oleifera based drug development. This study was updated by searching the key words M. oleifera on kidney diseases and M. oleifera on oxidative stress, inflammation, and fibrosis in online research databases such as PubMed and Google Scholar. The following validation checking and scrutiny analysis of the recently published articles were used to explore this study. The recent existing research has found that M. oleifera has a plethora of health benefits. Individual medicinal properties of M. oleifera leaf extract, seed powder, stem extract, and the whole extract (ethanol/methanol) can up-increase the activity of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), while decreasing the activity of inflammatory cytokines such as TNF-α, IL-1β, IL-6, and COX-2. In our study, we have investigated the properties of this plant against kidney diseases based on existing knowledge with an updated review of literature. Considering the effectiveness of M. oleifera, this study would be useful for further research into the pharmacological potential and therapeutic insights of M. oleifera, as well as prospects of Moringa-based effective medicine development for human benefits.

Yucca schidigera Extract Dietary Supplementation Affects Growth Performance, Hematological and Physiological Status of European Seabass

The study herein evaluated the effects of dietary supplementation with different yucca (Yucca schidigera) extract levels on rearing water quality, growth performance, protein utilization, hematological and immunological status, and economic benefits of cultured European seabass (Dicentrarchus labrax) juveniles. Yucca extract (YE) was incorporated in an experimental diet at levels of 0, 0.25, 0.50, and 1 g YE kg−1, and offered to fish reared in 70-L glass aquaria (15 fish per aquarium; three replicates each). Dietary YE supplementation significantly (P<0.05) decreased ammonia-nitrogen levels in water. Compared with the control, groups fed 0.50 and 1 g YE kg−1 diets showed improved growth performance (by 26.02% and 36.98%, respectively) and protein efficiency ratio (by 31.39% and 37.29%, respectively). In addition, hematological parameters (red blood cells, hemoglobin, hematocrit, white blood cells and neutrophil) and innate immune parameters (globulin fractions and lysozyme activity) improved with increasing dietary YE levels. Growth, hematological, and immunological parameters increased with a polynomial second-order regression models, with curves peak close to 1 g YE kg−1 diet. The cortisol level decreased significantly (P<0.05) with increasing dietary YE levels. The groups fed the 0.50 and 1 g YE kg−1 diets generated significantly (P<0.05) higher revenue than groups fed the 0.25 g YE kg−1 and the control diets. The using of YE is recommended as a dietary feed additive at a level of 1 g kg−1 for reducing the environmental footprint of fish protein production, accelerating growth, and improving health status of cultured seabass in a short-term feeding period.

The Evaluation of Arthrospira platensis Bioactivity and their Dietary Supplementation to Nile Tilapia Vegetarian Diet on Growth Performance, Feed Utilization, Body Composition and Hemato-Biochemical Parameters

The present study aimed to identify the carotenoid content and evaluate the antioxidant activities of spirulina, Arthrospira platensis (in vitro), and the effect of its supplementation to a vegetarian diet on growth performance, feed utilization, body proximate composition and physiological status of Nile tilapia, Oreochromis niloticus (in vivo). The carotenoid content of spirulina was identified by UPLC-MS/MS and showed that trans and cis β-carotene were the major carotenoids (88.3%) followed by β-cryptoxanthin and zeaxanthin. The antioxidant activity of spirulina was determined in water and crude carotenoid extracts by 2,2-diphenyl-1-picryhydrazyl (DPPH) scavenging assay, both extracts showed a significant free radical scavenging capacity. In addition, Nile tilapia fry (0.83 ± 0.01 g) was fed a vegetarian diet supplemented with different levels of spirulina for 12 weeks. The results revealed that the highest growth performance and nutrient utilization were recorded with 0.5% spirulina and the peak response determined at 0.63%-0.65% using polynomial second order regression. Also, the hemoglobin content improved in a quadratic regression model with the peak at 0.67% spirulina. Plasma total protein and lipid contents increased significantly with spirulina levels over 0.50%. Moreover, the aminopeptidase activities and glucose level decreased significantly with increasing spirulina levels. The current study recommended the supplementation of the Nile tilapia vegetarian diet with spirulina at levels of 0.63-0.65% for better growth performance and physiological status.

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.

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.

Synergism of Dietary Co-Supplementation with Lutein and Bile Salts Improved the Growth Performance, Carotenoid Content, Antioxidant Capacity, Lipid Metabolism, and Lipase Activity of the Marbled Spinefoot Rabbitfish, Siganus rivulatus

A 60-day feeding trial was conducted to assess the effects of dietary supplementation with bile salts (BS), lutein (LTN), and their combination on growth, survival, carotenoid content, and antioxidant status of rabbitfish (Siganus rivulatus) larvae. Fish were fed four isonitrogenous (34.39% protein) and isoenergetic (20.57 kJ/g) diets supplemented with BS (0.15 g kg^-1), LTN (0.1 g kg^-1), BS+LTN (0.15 and 0.1 g kg^-1, respectively), and a non-supplemented control diet. The results revealed that fish fed BS+LTN had the highest significant specific growth rate (4.37% day^-1), feed efficiency (46.55%), and survival (97.78%). Lutein supplementation improved whole-body protein content, meanwhile, fish fed a BS-supplemented diet had a higher lipid content. The carotenoid deposition was significantly increased with LTN and BS+LTN in skin, muscle, and whole body compared to the control and BS treatment. All dietary supplementation of BS and LTN showed significant improvement in total antioxidant capacity, catalase, and glutathione peroxidase activities. Additionally, LTN alone or BS+LTN significantly reduced malondialdehyde levels by 5.30 and 29.91%, respectively compared to the control. BS supplementation modulated aminopeptidases activities, triglycerides, cholesterol, and increased the activity of pancreatic lipase. Therefore, it could be inferred that dietary supplementation with LTN in combination with BS could improve the growth performance, carotenoid deposition, antioxidant status, lipid digestion, and metabolism of S. rivulatus.

Dietary supplementation of drumstick tree, Moringa oleifera, improves mucosal immune response in skin and gills of seabream, Sparus aurata, and attenuates the effect of hydrogen peroxide exposure

In aquatic animals, the mucosal barrier is the first line of innate immune defence against external chemicals and pathogens. In this study, the effects of dietary Moringa oleifera leaf (MOL) supplementation on skin and gill mucosal immunity, antioxidants and stress responses were evaluated in seabream (Sparus aurata) fingerlings exposed to hydrogen peroxide (H₂O₂). A total of 144 specimens (10.11 ± 0.41 g) were divided into four treatments (three replicates per treatment contained 12 specimens each) and fed a non-supplemented control diet or a 1, 2.5 or 5% MOL-supplemented diet. After three weeks of feeding, six specimens from each aquarium were sampled for blood, mucus and tissues. The other six fish in each aquarium were subjected to H₂O₂ exposure. The results revealed that MOL did not negatively affect either cortisol or glucose levels. MOL supplementation significantly (P < 0.05) improved skin mucosal immunity-related characteristics, including phosphatase, peroxidase and lysozyme activity and IgM levels. Additionally, MOL upregulated the expression of antioxidant genes (sod and cat), an anti-inflammatory gene (tgf-β), tight junction protein genes (occludin and zo-1), c3, and igm in both the skin and gills. However, H₂O₂ exposure significantly (P < 0.05) increased both cortisol and glucose levels and disrupted skin mucosal immune function by significantly (P < 0.05) decreasing phosphatase, peroxidase, protease, antiprotease and lysozyme activity and IgM levels. H₂O₂ exposure severely decreased the mRNA levels of the studied genes. MOL dietary supplementation at the 5% level successfully attenuated the negative effects of H₂O₂ on the mucosal immune response in both the skin and gills. In conclusion, dietary MOL supplementation at the 5% level is recommended to improve S. aurata mucosal immune function under both normal and stress conditions. Additionally, exposure to H₂O₂ disrupts the mucosal immunity of fish. This contributes knowledge on the routes involved in mucosal innate immunity and could help to understand the fish resistance against chemicals exposure. Graphical abstract.

Endocrine disrupter chemicals affect the humoral antimicrobial activities of gilthead seabream males even upon the cease of the exposure

17α-ethynilestradiol (EE₂) and tamoxifen (Tmx) are pollutants world-wide distributed in aquatic environments. Gilthead seabream, Sparus aurata L., is highlighted as a species model of intensively culture in anthropogenic disturbed environments. The effects of these pollutants on gilthead seabream reproduction and some immune responses have been described but, the humoral innate antimicrobial activities have never received attention. In this work we analysed the latest in the plasma of gilthead seabream males of different ages and reproductive stages treated with 0, 2.5, 5 or 50 μg EE₂ or 100 μg Tmx g^-1 food during different times of exposure and of reverting to commercial diet (recovery). The peroxidase and protease activities decreased as the spermatogenesis of the first reproductive cycle (RC) proceeded in control fish. However, only protease and antiprotease activities showed different level at different stages of the second RC in control fish, but showed scarce disruption in fish treated with EE₂ or Tmx. Peroxidase and bactericide activities are more sensitive to EE₂, than to Tmx. The effects induced by EE₂ varied depending on the activity analyzed, the dose and the time of exposure and the reproductive stage and the age of the specimens.

Effect of Jasonia glutinosa on immune and oxidative status of gilthead seabream (Sparus aurata L.)

Jasonia glutinosa (rock-tea, RT) has numerous biological activities. In the present work, the beneficial effects of dietary RT on gilthead seabream (Sparus aurata L.) were studied. Fish fed experimental diets containing 0 (control), 10 or 30% of RT for 15 and 30 days. Samples from skin mucus, blood, head kidney, liver and gut were obtained at 15 and 30 days. The antioxidant properties from RT were analysed such as the antioxidant capacity and phenolic content. The heat shock protein 70 level (HSP70) and the total oxidized proteins were evaluated on skin mucus as stress markers. Immune parameters, both humoral (peroxidase activity, immunoglobulin M levels and complement activity) and cellular (phagocytic, respiratory burst and peroxidase activities) were determined in skin mucus, serum or head-kidney leucocytes, respectively. Concomitantly, the expression of different genes related to inflammation and oxidative stress was studied both in liver and gut. Skin mucus peroxidase was significantly increased on fish fed 10% RT for 15 days with respect to the control group. In addition, Serum IgM levels were significantly increased while HSP70 levels and oxidized proteins were significantly decreased on skin mucus from fish fed 30% RT for 30 days, respectively. Besides, cellular immune parameters (phagocytosis, respiratory burst and peroxidase activity) were significantly higher in leucocytes from fish fed the RT diets for 15 days, but not for 30 days. Finally, the gene expression of antioxidant enzymes was up-regulated in liver at 15 and in liver and gut at 30 days. However, the expression of il1b and hsp70 was down-regulated in the liver of fish fed 30% RT for 30 days with respect to the values of control fish. The possible inclusion of RT in fish diets as an additive with antioxidant and/or immunostimulant activities is discussed.

Current Status and Potential of Moringa oleifera Leaf as an Alternative Protein Source for Animal Feeds

The increased consumption of livestock, poultry, and fish products in people's diet threatens to drive production toward the use of more and more conventional crops in animal feeds. In this context, alleviating the tightening grain crop supply and ensuring the healthy development of animal husbandry through innovations in protein feedstuff production remain considerable challenges. Moringa oleifera is a miracle tree species with abundant nutrients, high protein biological value, and good feeding effect. As a new protein feedstuff, M. oleifera has great potential in alleviating the feeding crisis. Here, we review available literature regarding the characterization of M. oleifera in the field of animal husbandry in terms of nutrient content, digestion, and absorption characteristics, and feeding effects and present current challenges in using M. oleifera as animal feed.

The Inclusion of a Supercritical Fluid Extract, Obtained From Honey Bee Pollen, in the Diet of Gilthead Sea Bream (Sparus aurata), Improves Fish Immune Response by Enhancing Anti-oxidant, and Anti-bacterial Activities

In the present study, the immune-stimulatory effect of two levels of honey bee pollen (5 and 10%, P5 and P10 treatment, respectively) and its supercritical fluid extract (0. 5 and 1%, E0.5 and E1, respectively) included in the diet, was tested in gilthead seabream (Sparus aurata). The in vivo trial was preceded by the evaluation of antioxidant properties of three different bee pollen extracts obtained by water, ethanol 80%, and Supercritic Fluids Extraction (SFE). The preliminary evaluation attested that the SFE showed the lowest extraction yield (10.47%) compared to ethanol 80% (48.61%) and water (45.99%). SFE extract showed good antioxidant properties with high polyphenol content (13.06 mg GAE/g), radical scavenging activity (3.12 mg/ml), reducing power (38.68 mg/mL EC50). On the contrary, the water extract showed the significantly lowest polyphenol content (2 mg GAE/g; P < 0.05). The results of in vivo trial demonstrate that the diets supplemented with SFE bee pollen extract had a stimulatory effect on fish serum immunity, respect to the inclusion of raw pollen, this latter revealing some inhibitory effects in the immune response, such a decrease of serum peroxidase and lysozyme activities, particularly in P10 group significantly different (P < 0.05) from the control group. On the contrary, serum peroxidase, protease, antiprotease, were significantly increased in fish fed the diets supplemented with supercritical fluid extract, respect to the fish fed on control and on diets supplemented with 5 and 10% of raw pollen. For what concerns the bactericidal activity against Vibrio harveyii, all the treatments containing bee pollen regardless of the type showed their serum bactericidal activity significantly increased with respect to the control groups (p < 0.05). Given its high antioxidant properties, the absence of toxic solvents and the positive action carried out on improving the humoral response in gilthead seam bream, honey bee pollen SFE extract can be taken into account in the formulation of fish feeds.

Effects of BDE-47 exposure on immune-related parameters of Mytilus galloprovincialis

The persistent pollutants polybrominated diphenyl ethers (PBDEs) have been demonstrated to produce several negative effects on marine organisms. Although Mytilus galloprovincialis was extensively studied as model system, the effects of PBDEs on the innate immune system of mussels remains unclear. In this study, except for the control treatment, specimens of M. galloprovincialis were fed with microalgae treated with increasing concentrations of PBDEs (maximum level 100 ng L^-1 of BDE-47 per day). BDE-47 treatment was maintained for 15 days and then the animals were fed with the same control diet, without contaminants, for 15 days. Samples of haemolymph (HL) were obtained at T0, T15 and T30 days of the experiment to evaluate different parameters related to immunity, such as neutral red retention time, and peroxidase, protease, antiprotease, lysozyme and bactericidal activities. BDE-47 exposure for 15 days affected both the stability of haemocytes and humoral parameters. In addition, the obtained results indicated that, at 30 days, after 15 days of culture without contaminant, the immune parameters were still affected, as some of them did not return to the basal levels, and others remained stimulated. Overall the results indicate that BDE-47 exposures at environmentally realistic levels may affect various aspects of immune function in M. galloprovincialis, acting as stressor that can compromise the general welfare.