Effects of Shrimp Shell-Derived Chitosan on Growth, Immunity, Intestinal Morphology, and Gene Expression of Nile Tilapia (Oreochromis niloticus) Reared in a Biofloc System.

Chitosan (CH) shows great potential as an immunostimulatory feed additive in aquaculture. This study evaluates the effects of varying dietary CH levels on the growth, immunity, intestinal morphology, and antioxidant status of Nile tilapia (Oreochromis niloticus) reared in a biofloc system. Tilapia fingerlings (mean weight 13.54 ± 0.05 g) were fed diets supplemented with 0 (CH0), 5 (CH5), 10 (CH10), 20 (CH20), and 40 (CH40) mL·kg-1 of CH for 8 weeks. Parameters were assessed after 4 and 8 weeks. Their final weight was not affected by CH supplementation, but CH at 10 mL·kg-1 significantly improved weight gain (WG) and specific growth rate (SGR) compared to the control (p < 0.05) at 8 weeks. Skin mucus lysozyme and peroxidase activities were lower in the chitosan-treated groups at weeks 4 and 8. Intestinal villi length and width were enhanced by 10 and 20 mL·kg-1 CH compared to the control. However, 40 mL·kg-1 CH caused detrimental impacts on the villi and muscular layer. CH supplementation, especially 5-10 mL·kg-1, increased liver and intestinal expressions of interleukin 1 (IL-1), interleukin 8 (IL-8), LPS-binding protein (LBP), glutathione reductase (GSR), glutathione peroxidase (GPX), and glutathione S-transferase (GST-α) compared to the control group. Overall, dietary CH at 10 mL·kg-1 can effectively promote growth, intestinal morphology, innate immunity, and antioxidant capacity in Nile tilapia fingerlings reared in biofloc systems.

Immunostimulatory effect of mannan-oligosaccharides supplementation diet in milkfish (Chanos chanos).

The current study was designed to examine the impacts of dietary mannan-oligosaccharides (MOS) on growth, hemato-biochemical changes, digestive-antioxidant enzyme activity, immune response, and disease resistance of milkfish (Chanos chanos) fed diets contained MOS i.e. 1g, 2g, and 3g MOS. The growth parameters were significantly influence in milkfish fed all MOS diets, whereas the feed conversion ratio (FCR) and protein efficiency ratio (PER) were significantly influence with 2g or 3g MOS diets. The total protein (TP), globulin (GB), and glucose (GLU) levels, amylase, protease, liver enzymes were found significantly high in fish fed 2g or 3g MOS diets; but, lipase, trypsin, and alkaline phosphatase (ALP) enzymes were increased significantly at 3g MOS diet. All MOS inclusion levels were significantly increased total and Lactobacillus intestinal microflora population. The oxidative enzymes activity as superoxide desmutase (SOD) and catalyze (CAT) were progressively increased with all MOS supplementation diet, but the glutathione peroxidase (GPx) and lactate dehydrogenase (LDH) content were found significantly high in fish fed 2g or 3g MOS diets. Similarly, the reduced glutathione (GSH) and glutathione reductase (GR) contents were observed significantly high level in fish fed 3g MOS diet. The phagocytic (PC) and lysozyme (LYZ) activities were found gradually increase in fish fed increasing level of MOS diets, while the respiratory burst (RB) and malondialdehyde (MDA) activities were seen significant in fish fed 2g and 3g MOS diets. The current research work confirmed that C. chanos fed diets contained 3g kg-1 MOS recorded better growth performance, digestive-antioxidant, immune response, and disease resistance.

Modulatory effects of longan seed powder on growth performance, immune response, and immune-antioxidant related gene expression in Nile tilapia (Oreochromis niloticus) raised under biofloc system.

This study evaluates the effects of longan seed powder (LS) on the growth performance, immunological response, and immune-antioxidant related gene expression of Nile tilapia (Oreochromis niloticus). Three hundred fish (13.82 ± 0.06 g) were divided into five experiments and fed 5 diets, including the basal diet (control without LS) and basal diet containing 10 (LS10), 20 (LS20), 40 (LS40), and 80 (LS80) g kg-1 LS for eight weeks. A completely randomized design (CRD) with three replications was utilised. The growth performance and immune response were measured at weeks 4 and 8 post feeding, while the gene expressions were determined at the end of the feeding trial. The results revealed that administration of LS could significantly (P < 0.05) improve specific growth rate (SGR), weight gain (WG), and feed conversion ratio (FCR) in Nile tilapia as compared to the control group. However, no significant differences (P > 0.05) were observed in survival rates among treatments. LS-supplemented diets showed enhanced serum peroxidase activity (SPA), serum lysozyme activity (SLA), skin mucus lysozyme activity (MLA), and skin mucus peroxidase activity (MPA) at weeks 4 and 8 post-feeding, with the highest values observed in the LS20 diet (P < 0.05). Additionally, LS-supplemented diets significantly up-regulated (P < 0.05) immune and antioxidant related gene expressions (IL1, IL8, LBP, GSTa, GPX, and GSR) in the liver and intestine, with highest values observed in the LS20 treatment. The present results confirmed the beneficial effects of LS as a functional feed additive and immunostimulant for Nile Tilapia culture in a biofloc system.

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.

Changes in immune genes expression, immune response, digestive enzymes -antioxidant status, and growth of catla (Catla catla) fed with Astragalus polysaccharides against edwardsiellosis disease.

The effect of four level of Astragalus polysaccharides (APs) supplementation diets, (CD: control diet and three experiment diet (E), EA: 100 mg kg-1 APs; EB: 200 mg kg-1 APs; EC: 300 mg kg-1 APs) on growth, changes in haemato-biochemical parameters and metabolic-digestive enzymes, enhancement of antioxidant activity, innate-adaptive immune response, and cytokine gene expression were studied in catla (Catla catla) against Edwardsiella tarda. The healthy and challenged groups fed the CD displayed no mortality, while fish fed EA or EC revealed 10% mortality, but the mortality was only 5% in diet EB. Fish fed diet EB and EC revealed significantly better growth rates and high RBC count during the experimental period. Albumin and globulin levels were significant improved when fish were fed the diet EB and EC from weeks 6-8. The superoxide dismutase (SOD) was significant ameliorated by EB feeding from weeks 4-8. In contrast, serum myeloperoxidase (MPO), catalase (CAT), malondialdehyde (MDA)/lipid peroxidation (LPO), glutathione peroxidase (GPx), respiratory burst activity (RBA), bactericidal action (BCA), serum lysozyme activity (SLA), nitric oxide synthase (NOS), head kidney leukocytes response proliferation (HKLP), hemolytic action (HLA), hydrogen peroxides (H2O2), and immunoglobulin (Ig) were significantly improved from week 6-8. Groups fed the APs enriched diets had significant ameliorated interleukin (IL)-1ß and interferon (IFN)-γ mRNA expression after 6 and 8 weeks of feeding. However, IL-10 and major histocompatibility complex (MHC)-1 mRNA expressions were significant enhanced in catla fed all APs diets on week 8. APs enriched diets revealed significant improved tumor necrosis factor (TNF)-α and TNF receptor-associated factor-6 (TRAF6) mRNA expression on week 4, but toll-like receptor-2 (TLR2) and TLR4 mRNA expression were significant enhanced by diet EB and EC after weeks 6 and 8. Similarly, the lysozyme (Lyz)-C and Lyz-G mRNA levels in the head kidney (HK) increased by APs feeding on weeks 6 and 8, whereas the EB diet, the expression of nucleotide binding oligomerization domain-1 (NOD1) was significantly improved on weeks 6 and 8, but NOD2 mRNA expression was only significant enhanced after 8 weeks of diet EB. By feeding healthy catla and E. tarda challenged fish fed diet EB, resulted in significantly increased growth, haemato-biochemical indices, metabolic-digestive enzymes, antioxidant activities, innate-adaptive immune responses, and cytokine gene expression mainly between 6 and 8 weeks.

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.

Dietary supplementation of lemon verbena (Aloysia citrodora) improved immunity, immune-related genes expression and antioxidant enzymes in rainbow trout (Oncorrhyncus mykiss).

The use of veterinary drugs for the treatments of fish diseases has often health and environmental side effects and thus alternative more sustainable strategies are needed. In this study we have explored the effect of dietary administration of lemon verbena (Aloysia citrodora) leaves powder on growth, immune parameters and antioxidant enzyme activity of rainbow trout (Oncorrhyncus myskiss). The results show that adding lemon verbena (LV) leaves powder (0.5, 1 and 2%), as feed supplement does not affect significantly rainbow trout growth, but increases the levels of some immune parameters. All enriched-diets induced an increase in the levels of lysozyme activity and total immunoglobulin in rainbow trout serum (P < 0.05), whilst 1 and 2% enriched-diets increased lysozyme and immunoglobulin in skin mucus. Expression of interleukin-1ß (IL-1ß) was enhanced in all fish supplemented with LV leaves powder (0.5, 1 and 2%) whilst only the diet with the highest dose (2%) induced a significantly higher expression of IL-8 and tumour necrosis factor (TNF-α). Fish fed with LV leaves powder at 1 and 2% had significantly lower expression of transforming growth factor (TGF-ß, P < 0.05). Furthermore, all enriched-diets significantly increased the activity of super oxide dismutase (SOD, P < 0.05) and diets containing 1 and 2% of LV leaves powder also increased activity of glutathione-S-transferase (GST) and glutathione peroxidase (GPx). In conclusion, LV leaves powder administered as feed supplement at 2% enhances the expression of some immune-related genes (IL-1ß, IL-8 and TNF- α), rises the levels of lysozyme and total immunoglobulin in serum and skin mucus and increases the activity of antioxidant enzymes (SOD, GST and GPx) in rainbow trout.

Ginger (Zingiber officinale) extract affects growth performance, body composition, haematology, serum and mucosal immune parameters in common carp (Cyprinus carpio).

The present study was designed to investigate the dietary effects of ginger extract (Zingiber officinale) on common carp (Cyprinus carpio). Three hundred and sixty fish weighing 10.9 ± 0.17 g were randomly divided into four experimental treatments in triplicates. Four experimental diets were designed containing different inclusion levels of ginger extract as 0% (control), 0.1%, 0.2%, and 0.4% named T1, T2, T3, and T4, respectively, and fish were fed 3% of body weight daily for 60 days. Feed conversion ratio, weight gain, and specific growth rate parameters were measured higher in the groups fed with ginger extract compared to the control, especially in T3 (P < 0.05). Also, fish treated with ginger extract showed lower carcass moisture and lipid, but higher protein contents compared to the control. The results showed significant increase in the number of erythrocytes and leucocytes, as well as the level of hematocrit and hemoglobin in fish fed with supplemented diets. In addition, significant enhancement was observed in cases of serum parameters, including total protein, albumin, globulin, lysozyme, superoxide dismutase, catalase, and total immunoglobulins in T3 and T4 compared to the control. The lowest serum cortisol level was noticed in T3. Furthermore, the T3 group showed the highest activities of skin mucus lysozyme, alkaline phosphatase, and protease (P < 0.05). In conclusion, the present results demonstrated that Zingiber officinale extract at a 0.2% level can effectively improve the growth and health status of Common Carp (Cyprinus carpio).

Effects of dietary monoterpene, myrcene, administration on immune- and health-related genes expression in common carp gill following exposure to copper sulfate.

The present study assessed the potential benefits of myrcene administration to suppress negative effects of copper exposure on immune-, antioxidant-, tight junction-, stress- and osmoregulatory-related gene expressions in common carp (Cyprinus carpio) gill. Fish were fed with diets containing 0% (control), 0.5% (M0.5) and 1% (M1) myrcene for 6 weeks, and then, exposed to 0.25 mg/L copper for further two weeks. The fish gill samples were taken for gene expression assays after six and eight weeks. The results showed that there were interaction effects of myrcene levels and copper exposure on superoxide dismutase (sod), catalase (cat), glutathione peroxidase (gpx), glutathione-s-transferase (gst), glutathione reductase (gr), heat shock protein-70 (hsp70), interleukin 1-beta (il1b), interleukin 10 (il10), tumor necrosis factor-alpha (tnfa), occludin (occl), caludin 3 (cld3), caludin 7 (cld7), and Na+-K+-ATPase (nka) genes expressions. Overall, the M0.5 treatment had significantly lower antioxidant genes expression, and higher hsp70, cytokines, tight-junction proteins, and nka genes expression, compared to the control treatment, before copper exposure. Copper exposure significantly down-regulated most of the tested genes (except il10), however, the M0.5 treatment had significantly higher antioxidant (except gpx), hsp70, cld7, and nka gene expression compared to the control treatment. The M1 treatment showed fluctuated antioxidant gene expressions, down-regulated gene expression of the pro-inflammatory cytokines, and occl, and up-regulation of cld3 gene expressions, before copper exposure. After copper exposure, this treatment had significantly higher gr and cat expression compared to the control; moreover, there was a marked up-regulation in il10 gene expression in this treatment, which was the highest value among all treatment combinations. In conclusion, copper exposure significantly down-regulates antioxidant-, inflammatory-, and tight junction-related along with hsp70 and nka genes expression in common carp gills. Pre-treatment with 0.5% myrcene is beneficial to suppress such negative effects, probably due to its antioxidant properties. However, myrcene administration must be done with caution, as higher levels may interfere with antioxidant and immune defenses.

Effects of elephant's foot (Elephantopus scaber) extract on growth performance, immune response, and disease resistance of nile tilapia (Oreochromis niloticus) fingerlings.

Medicinal plant has been applied as an alternative strategy for antibiotics and chemotherapeutics for controlling the outbreak of diseases in tilapia farming. In this study, five doses of Elephantopus scaber extract (ESE) were added to the basal diet at 0, 2.5, 5, 10, and 20 g kg-1 feed of Nile tilapia fingerlings (13.92 ±â€¯0.06 g initial weight) in triplicate. After 4- and 8- weeks post-feeding, fish were sampled to determine the effects of the ESE supplemented on fish's growth performance, humoral, and skin mucus immune response. After 8 weeks post-feeding, a challenge test against Streptococcus agalactiae was carried out using 10 fish from each tank. Fish fed ESE showed significantly increased serum lysozyme (SL), serum peroxidase (SP), alternative complement (ACH50), phagocytosis (PI), and respiratory burst (RB) compared to the control group (P < 0.05). The skin mucus lysozyme (SMLA) and skin peroxidase (SMPA) were stimulated in fish fed ESE diets. Dietary inclusion of ESE significantly (P < 0.05) promoted final body weight (FW), weight gain (WG), and specific growth rate (SGR); while a reduction in feed conversion ratio (FCR) was observed in fish fed 5 g kg-1 ESE, after 8 weeks post-feeding. The challenge study indicated that the relative percent survival (RSP) was 38.10%, 76.19%, 66.67%, and 47.62% in Diet 2, Diet 3, Diet 4, and Diet 5, respectively. Among the supplemented groups, dietary of 5 g kg-1 ESE showed significantly higher RPS and the highest resistance to S. agalactiae in comparison with other groups. In conclusion, supplementation of ESE (5 g kg-1) enhanced the humoral and mucosal immunity, promoted growth performance, and improved disease resistance of Nile tilapia against Streptococcus agalactiae.

Protective efficacy of Shilajit enriched diet on growth performance and immune resistance against Aeromonas hydrophila in Oreochromis mossambicus.

We investigated the effects of dietary enriched with Shilajit in three dose levels: 2.0, 4.0, and 6.0 g kg-1 in the basal diet on growth rate, non-specific immune response, and disease resistance for 60 days in Oreochromis mossambicus against an opportunist pathogen, Aeromonas hydrophila. The results showed that the Shilajit enriched diets at 4.0 and 6.0 g kg-1 diets significantly (p < 0.05) enhance survival rate, weight gain (WG), protein efficiency ratio (PER), specific growth rate (SGR), and feed efficiency (FE), whereas it significantly decrease the feed conversion ratio (FCR) from weeks 1-4 when compared with control. The innate immune parameters, such as the phagocytic, complement, respiratory burst, and lysosome activities in infected fish fed with all Shilajit enriched diet were significantly (p < 0.05) enhances on weeks 2-4. A very low cumulative mortality, 8.0% and 12.0% were observed in the infected fish fed with 4.0 and 6.0 g kg-1 Shilajit enriched diets, whereas 18% mortality was found with 2 g kg-1 diet. In conclusion, 4.0 and 6.0 g kg-1 Shilajit enriched diets significantly increased the growth performance, innate immune response, and disease resistance in O. mossambicus against A. hydrophila infection.

Effects of orange peels derived pectin on innate immune response, disease resistance and growth performance of Nile tilapia (Oreochromis niloticus) cultured under indoor biofloc system.

The present study investigates the effects of orange peels derived pectin (OPDP) on skin mucus and serum immune parameters, disease resistance and growth performance of O. niloticus cultured under indoor biofloc system. Six hundred Nile tilapia (average weight 9.09 ±â€¯0.05 g) were distributed into 15 fiber tanks (300 L per tank) assigned to five treatments repeated in triplicate. Fish were fed experimental diets contain different levels OPDP as follows: 0 (control in clear water), 0 (control in biofloc system), 5, 10, and 20 g kg-1 OPDP for 8 weeks. At weeks 4 and 8 post feeding, skin mucus lysozyme (SMLA), peroxidase activities (SMPA), serum lysozyme (SL), serum peroxidase (SP), alternative complement (ACH50), phagocytosis (PI), and respiratory burst activities (RB) as well specific growth rate (SGR), weight gain (WG), final weight (FW), and feed conversion ratio (FCR) were measured. Also, resistance against Streptococcus agalactiae was assessed after 8 weeks post-feeding. Nile tilapia fed OPDP supplemented diets had significantly higher SMLA and SMPA compared to the controls (P < 0.05). The maximum values were observed in tilapia fed 10 g kg-1 OPDP followed by 5 and 20 g kg-1 OPDP. Nevertheless, no significant differences were observed between these two supplemented diets and between the control groups (P > 0.05). Regarding the serum immunological parameters, dietary inclusion of 10 g kg-1 OPDP showed significant higher SL and PI than other supplemented groups and control groups (P < 0.05). However, no significant differences were observed in SL and PI of fish fed 5 and 20 g kg-1 OPDP (P > 0.05). Dietary administration of OPDP significantly increased SP and ACH50 compared to the controls (P < 0.05), regardless of inclusion level. Additionally, non-significant change was found in RB of OPDP fed fish when compared with the controls (P > 0.05). The challenge test revealed that relative percent of survival (RPS) in OPDP treatments were 45.45%, 81.82%, 50%, respectively. The highest RPS was noticed in fish fed 10 g kg-1 OPDP. Furthermore, dietary administration of OPDP significantly improved SGR, WG, FW, and FCR (P < 0.05). Overall, the present findings suggested that OPDP can be taken into account as functional feed additives for O. niloticus.

Effects of Cordyceps militaris spent mushroom substrate on mucosal and serum immune parameters, disease resistance and growth performance of Nile tilapia, (Oreochromis niloticus).

The aim of present study was determination effects of dietary administration of C. militaris spent mushroom substrate (SMS) on mucosal and serum immune parameters, disease resistance, and growth performance of Nile tilapia (Oreochromis niloticus). Two hundred twenty five fish of similar weight (37.28 ± 0.10 g) were assigned to the following diets [0 (T1- Control), 5 (T2), 10 (T3), 20 (T4) and 40 g kg-1 (T5) SMS]. After 60 days of feeding trial, growth performance, skin mucus lysozyme and peroxidase activities as well as serum innate immune were measured. In addition, survival rate and innate immune responses were calculated after challenge test (15 days) against Streptococcus agalactiae. The results revealed that regardless of inclusion levels, feeding Nile tilapia with SMS supplemented diets significantly increased skin mucus lysozyme and peroxidase activities as well as serum immune parameters (SL, ACH50, PI, RB, and RB) compared control group (P < 0.05). The highest increment of immune parameters was observed in fish fed 10 g kg-1 SMS which was significantly higher than other treatments (P < 0.05). Also, the relative percent survival (RSP) in T2, T3, T4, and T5 was 61.11%, 88.89%, 66.67, and 55.56%, respectively. Among the supplemented groups, fish fed 10 g kg-1 SMS showed significant higher RPS and resistance to S. agalactiae than other groups (P < 0.05). Regarding the growth performance, SGR, WG, FW, and FCR were remarkably improved (P < 0.05) in SMS groups; the highest improvement observed in 10 g kg-1 SMS treatment. According to these finding, administration of 10 g kg-1 SMS is suggested in tilapia to improve growth performance and health status.