Probiotics from kefir: Evaluating their immunostimulant and antioxidant potential in the carpet shell clam (Ruditapesdecussatus).

This study aimed to investigate the impact of incorporating kefir into the diet on biometric parameters, as well as the immune and antioxidant responses of the carpet shell clam (Ruditapes decussatus) after an experimental infection by Vibrio alginolyticus. Clams were divided into a control group and a treated group. The control group was fed on spirulina (Arthrospira platensis) alone. While, the treated group was fed on spirulina supplemented with 10% dried kefir. After 21 days, clams were immersed in a suspension of V. alginolyticus 5 × 105 CFU mL -1 for 30 min. Seven days after experimental infection, survival was 100% in both groups. The obtained results showed a slight increase in weight and condition index in clams fed with kefir-supplemented diet for 21 days compared to control clams. Regarding antioxidant responses, the treated group showed higher superoxide dismutase activity compared to the control group. However, the malondialdehyde level was lower in the treated clams than in the control. In terms of immune parameters, the treated group showed slightly elevated activities of phenoloxidase, lysozyme and alkaline phosphatase, whereas a decreased lectin activity was observed compared to the control group. The obtained results suggest that kefir enhanced both the antioxidant and immune response of infected clams.

Effects of selenoprotein extracts from Cardamine hupingshanensis on growth, selenium metabolism, antioxidant capacity, immunity and intestinal health in largemouth bass Micropterus salmoides.

This study aimed to assess the impact of dietary selenoprotein extracts from Cardamine hupingshanensis (SePCH) on the growth, hematological parameters, selenium metabolism, immune responses, antioxidant capacities, inflammatory reactions and intestinal barrier functions in juvenile largemouth bass (Micropterus salmoides). The base diet was supplemented with four different concentrations of SePCH: 0.00, 0.30, 0.60 and 1.20 g/Kg (actual selenium contents: 0.37, 0.59, 0.84 and 1.30 mg/kg). These concentrations were used to formulate four isonitrogenous and isoenergetic diets for juvenile largemouth bass during a 60-day culture period. Adequate dietary SePCH (0.60 and 1.20 g/Kg) significantly increased weight gain and daily growth rate compared to the control groups (0.00 g/Kg). Furthermore, 0.60 and 1.20 g/Kg SePCH significantly enhanced amounts of white blood cells, red blood cells, platelets, lymphocytes and monocytes, and levels of hemoglobin, mean corpuscular volume and mean corpuscular hemoglobin in the hemocytes. In addition, 0.60 and 1.20 g/Kg SePCH increased the mRNA expression levels of selenocysteine lyase, selenophosphate synthase 1, 15 kDa selenoprotein, selenoprotein T2, selenoprotein H, selenoprotein P and selenoprotein K in the fish liver and intestine compared to the controls. Adequate SePCH not only significantly elevated the activities of antioxidant enzymes (Total superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase), the levels of total antioxidant capacity and glutathione, while increased mRNA transcription levels of NF-E2-related factor 2, Cu/Zn-superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase. However, adequate SePCH significantly decreased levels of malondialdehyde and H2O2 and the mRNA expression levels of kelch-like ECH-associated protein 1a and kelch-like ECH-associated protein 1b in the fish liver and intestine compared to the controls. Meanwhile, adequate SePCH markedly enhanced the levels of immune factors (alkaline phosphatase, acid phosphatase, lysozyme, complement component 3, complement component 4 and immunoglobulin M) and innate immune-related genes (lysozyme, hepcidin, liver-expressed antimicrobial peptide 2, complement component 3 and complement component 4) in the fish liver and intestine compared to the controls. Adequate SePCH reduced the levels of pro-inflammatory cytokines (tumour necrosis factor-α, interleukin 8, interleukin 1ß and interferon γ), while increasing transforming growth factor ß1 levels at both transcriptional and protein levels in the liver and intestine. The mRNA expression levels of mitogen-activated protein kinase 13 (MAPK 13), MAPK14 and nuclear factor kappa B p65 were significantly reduced in the liver and intestine of fish fed with 0.60 and 1.20 g/Kg SePCH compared to the controls. Histological sections also demonstrated that 0.60 and 1.20 g/Kg SePCH significantly increased intestinal villus height and villus width compared to the controls. Furthermore, the mRNA expression levels of tight junction proteins (zonula occludens-1, zonula occludens-3, Claudin-1, Claudin-3, Claudin-5, Claudin-11, Claudin-23 and Claudin-34) and Mucin-17 were significantly upregulated in the intestinal epithelial cells of 0.60 and 1.20 g/Kg SePCH groups compared to the controls. In conclusion, these results found that 0.60 and 1.20 g/Kg dietary SePCH can not only improve growth, hematological parameters, selenium metabolism, antioxidant capacities, enhance immune responses and intestinal functions, but also alleviate inflammatory responses. This information can serve as a useful reference for formulating feeds for largemouth bass.

Effect of Spirulina platensis on growth, hematological, biochemical, and immunological parameters of Nile tilapia (Oreochromis niloticus).

This study was conducted to evaluate the effects of Spirulina platensis in Nile tilapia diets on growth performance, blood hematological and biochemical parameters, immunological status, and intestinal histomorphometry. A total of 228 fish were randomly allocated into four groups with triplicates (19 fish per replicate). The first group was fed the control diet, which contained no Spirulina supplementation. The other three groups were fed diets containing graded levels of powdered Spirulina: 2.5%, 5.0%, and 10.0% in the second, third, and fourth group, respectively. S. platensis was added to the diets partially substituting the fish meal content. The experiment lasted for 8 weeks. The results showed that dietary Spirulina supplementation improved (P < 0.05) the body weight and length, weight gain, specific growth rate, condition factor, and feed conversion efficiency. Moreover, Spirulina increased significantly (P < 0.05) the hemoglobin, PCV, RBCs, and WBCs count. Also, it increased the lymphocytes, eosinophils, IgM level, lysozyme activity, and phagocytic activity in the blood. Additionally, the Spirulina raised (P < 0.05) the serum albumin level but reduced (P < 0.05) the creatinine and urea levels. The addition of Spirulina increased (P < 0.05) the height and width of intestinal villi and the lymphocytes and goblet cells count in the intestine. The obtained results were increased by increasing the inclusion level of Spirulina, especially for body weight and length, weight gain, FCR, phagocytic activity, and intestinal parameters. In conclusion, supplementing S. platensis can improve the growth performance of fish. Moreover, it can stimulate the immunity of fish through increasing the level of immunological blood indicators (IgM, lysozyme, phagocytic activity, lymphocytes, and eosinophils) as well as the local intestinal immunity (lymphocytes and goblet cells). So, it can be recommended to use S. platensis in fish diets not only to improve the growth performance but also to enhance the immune status.

Psidium guajava L.- dichloromethane and ethyl acetate fractions ameliorate striped catfish (Pangasianodon hypophthalmus) status via immune response, inflammatory, and apoptosis pathways.

Psidium guajava L. is known to possess immune-modulatory properties in humans and other mammals. Although the positive effects of P. guajava-based diets on the immunological status have been shown for some fish species, the underlying molecular mechanisms of its protective effects remain to be investigated. The aims of this study were to evaluate the immune-modulatory effects of two guava fractions from dichloromethane (CC) and ethyl acetate (EA) on striped catfish with in vitro and in vivo experiments. Striped catfish head kidney leukocytes were stimulated with 40, 20, 10 and 0 µg/ml of each extract fraction, and the immune parameters (ROS, NOS, and lysozyme) were examined at 6 and 24 h post stimulation. A final concentration of each fraction at 40, 10 and 0 µg/fish was then intraperitoneally injected into the fish. After 6, 24, and 72 h of administration, immune parameters as well as the expression of some cytokines related to innate and adaptive immune responses, inflammation, and apoptosis were measured in the head kidney. Results indicated that the humoral (lysozyme) and cellular (ROS and NOS) immune endpoints were regulated differently by CC and EA fractions depending on dose and time in both, in vitro and in vivo experiments. With regards to the in vivo experiment, the CC fraction of the guava extract could significantly enhance the TLRs-MyD88-NF-κB signaling pathway by upregulating its cytokine genes (tlr1, tlr4, myd88, and traf6), following the upregulation of inflammatory (nfκb, tnf, il1ß, and il6) and apoptosis (tp53 and casp8) genes 6 h after injection. Moreover, fish treated with both CC and EA fractions significantly enhanced cytokine gene expression including lys and inos at the later time points - 24 h or 72 h. Our observations suggest that P. guajava fractions modulate the immune, inflammatory, and apoptotic pathways.

Dietary muramidase increases ileal amino acid digestibility of wheat and corn-based broiler diets without affecting endogenous amino acid losses.

The objective of these studies was to evaluate the impact of dietary muramidase (MUR) on endogenous amino acids (AA) losses and digestibility of nutrients in wheat and corn-based broiler diets. In experiment 1, the effect of dietary MUR on the flow of endogenous AA (EAA) at the jejunum and terminal ileum of broilers were assessed using either the nitrogen (N) free diet method (NFD) or the highly digestible protein diet method (HDP; 100 g casein/kg diet). Sialic acid and muramic acid concentrations were measured in the jejunal content. In experiment 2, a 2x2x2 factorial arrangement of treatments with 2 base grains (wheat or corn), with low or high metabolizable energy (ME) levels, and without or with MUR supplementation was implemented. All diets contained phytase, xylanase, and cellulase. Apparent ileal digestibility (AID) of dry matter (DM), protein (CP), amino acids (AA), crude fat, and energy, as well as the apparent total tract metabolizability (ATTM) of DM, CP, and gross energy (GE) were determined. The standardized ileal digestibility (SID) of AA was obtained by correcting AID values for basal ileal EAA obtained from chicks fed with NFD or HDP in experiment 1, jejunal EAA flow of all AA was higher (P < 0.001) compared to the ileum, but this effect was method dependent. Jejunal, but not ileal, EAA flow measured with HDP was higher compared to NFD, as well as sialic acid (P < 0.001) and muramic acid (P < 0.004) concentrations. Muramidase inclusion had no effect on basal EAA flow, independently of the segment and the method used. In experiment 2, dietary MUR supplementation increased the AID of CP (P < 0.05), all AA, and tended (P = 0.07) to increase the AID of GE, independently of the cereal type used. However, ATTM of DM and GE, but not CP, increased with MUR inclusion compared with the control treatments, especially in wheat and low ME diets (P < 0.05). In conclusion, MUR supplementation improved AID of CP and AA without affecting EAA losses and increases energy utilization.

Effects of recombinant anti-lipopolysaccharide factor expressed by Pichia pastoris on the growth performance, immune response and disease resistance of Litopenaeusvannamei.

The codon-optimized anti-lipopolysaccharide factor (ALF) sequence was introduced into pPICZαA vector and transformed into Pichia pastoris GS115. The recombinant ALF yeast supernatant (rALF-mix) was freeze-dried and evaluated as a feed additive for Litopenaeus vannamei. It was found by antibacterial activity test in vitro that the rALF-mix had antibacterial activity under different pH and temperature conditions. The 0, 0.00375%, 0.0075%, 0.015%, 0.03% and 0.06% of rALF-mix were added respectively to make the six experimental diets. After a 10-week feeding trial with shrimps (2.36 ± 0.02 g), it was found that the weight gain rate (WGR) and protein efficiency ratio (PER) of shrimp in the groups with 0.0075%, 0.015% and 0.03% of dietary rALF-mix supplementation were significantly higher than those in the control group (P < 0.05). Dietary rALF-mix supplementation significantly increased the total haemocyte count, respiratory burst, phagocytic activity, total anti-oxidative capacity (T-AOC), phenol oxidase activity, nitric oxide synthase activity, lysozyme (LYZ) activity, serum antibacterial capacity in the hemolymph and the T-AOC, LYZ in the hepatopancreas of shrimps (P < 0.05). The malondialdehyde contents in hemolymph and hepatopancreas were significantly decreased (P < 0.05). Meanwhile, the expression levels of toll, immune deficiency, heat shock protein 70, crustin and lipopolysaccharide-ß-glucan binding protein in the gill of shrimps were significantly increased (P < 0.05). After the challenge test, it was showed that dietary rALF-mix supplementation significantly improved the resistance of L. vannamei to Vibrio parahaemolyticus (P < 0.05). In conclusion, the rALF-mix can be used as a functional feed additive to improve the growth, immunity and disease resistance of shrimp. Based on the quadratic regression analysis for WGR, the optimal supplemental level of rALF-mix in diet for shrimp was estimated to be 0.02813%.

Chitosan-Ocimum basilicum nanocomposite as a dietary additive in Oreochromis niloticus: Effects on immune-antioxidant response, head kidney gene expression, intestinal architecture, and growth.

Several studies have looked into the use of basil, Ocimum basilicum (L.) in aquaculture as a dietary additive; however, more research is needed to see the possibility of it's including in nanocarriers in aquafeeds. An experiment was undertaken to highlight the efficacy chitosan-Ocimum basilicum nanocomposite (COBN), for the first time, on Nile tilapia (Oreochromis niloticus) growth, stress and antioxidant status, immune-related parameters, and gene expression. For 60 days, fish (average weight: 23.55 ± 0.08 g) were fed diets provided with different concentrations of COBN (g/kg): 0 g [COBN0], 1 g [COBN1], 2 g [COBN2], and 3 g [COBN3], where COBN0 was kept as control diet. Following the trial, the fish were challenged with pathogenic bacteria (Aeromonas sobria) and yeast (Candida albicans) infection. In comparison to the control (COBN0), a notable increase in growth parameters (weight gain, feed intake, and specific growth rate) and intestinal morphometric indices (average intestinal goblet cells count, villous width, and length) in all COBN groups was observed, where COBN2 and COBN3 groups had the highest values. The COBN diets significantly (p < 0.05) declined levels of serum triglycerides, glucose, cholesterol, and hepatic malondialdehyde. Moreover, the higher levels of serum biochemical biomarkers (growth hormone, total protein, globulin, and albumin), immunological parameters (phagocytic activity%, nitric oxide, and lysozyme), and hepatic antioxidant parameters (superoxide dismutase, total antioxidant capacity, and glutathione peroxidase) were obvious in the COBN2 and COBN3 groups followed by COBN1. The immune-antioxidant genes (TNF-α, IL-10, IL-1ß, TGF-ß, GPx, and SOD) were found to be considerably up-regulated in all COBN groups (COBN2 and COBN3 followed by COBN1). Fifteen days post-challenge with A. sobria and C. albicans, the highest survival rate was recorded in the COBN2 group (83.33 and 91.67%) followed by the COBN3 group (75 and 83.33%), respectively. The findings showed that a dietary intervention with COBN can promote growth, intestinal architecture, immunity, and antioxidant markers as well as protect O. niloticus against A. sobria and C. albicans infection. As a result, the COBN at a dose of 2 g/kg could be used as a food additive for the sustainable aquaculture industry.

The growth performance, antioxidant and immune responses, and disease resistance of Litopenaeus vannamei fed on diets supplemented with Indian ginseng (Withania somnifera).

In the current study, white-leg shrimp (Litopenaeus vannamei) were fed on diets containing varying doses of Withania somnifera aqueous extract (WSAE) at a rate of 0 (control), 0.5, 1.0, and 2.0 g/kg feed for 56 days. After the feeding trial, shrimps in all groups were challenged with the exposure to Vibrio harveyi for ten days during which animals' mortality was observed. It is noted that the dietary WSAE linearly and quadratically stimulated shrimp's growth indices particularly at the treatment of 2.0 g/kg feed. Compared to the control group, the WSAE-fed L. vannamei had significantly higher villi length, villi width, and absorption area particularly in the treatment of 2.0 g/kg feed. Furthermore, L. vannamei fed on WSAE-enriched diets consumed more feed and exhibited higher total proteolytic activity, lipase, and α-amylase activities as compared with the control group. The dietary WSAE at escalating levels linearly and quadratically enhanced the antioxidant activity (serum superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), total antioxidant capacity, and reduced glutathione) and the immune response (total hemocyte counts, total protein, lysozyme, and phagocytic activity). Similarly, the mRNA expression levels of cMn-SOD, CAT, and GPx genes were linearly and quadratically upregulated in the hepatopancreas of L. vannamei fed on WSAE-enriched diets (especially in the 2.0 g/kg feed treatment), while their lowest levels were significantly observed in the control group. On the other hand, malondialdehyde levels were significantly decreased in WSAE-supplemented shrimp groups, and its highest levels were observed in animals fed on the control diet. After the bacterial exposure, the survival rates of L. vannamei fed on 1.0 and 2.0 g WSAE/kg feed (61.3% and 66.7%, respectively) were higher than those in the control animals. Taken together, the results obtained herein indicate that inclusion of WSAE in diets of L. vannamei effectively enhanced the growth, antioxidant biomarkers, immune response, and resistance to the V. harveyi infection, particularly at the treatment of 2.0 g/kg feed.

The synergetic effect of Bacillus species and Yucca shidigera extract on water quality, histopathology, antioxidant, and innate immunity in response to acute ammonia exposure in Nile tilapia.

Acute ammonia toxicity suppresses the immune function and enhances the inflammatory pathways in Nile tilapia. The aim of this study was to compare the effect of Bacillus strains probiotic mixture (BS) or Yucca shidigera liquid extract (YSE) alone or their combination in water treatment and in reliving toxicity of an acute ammonia exposure in Nile tilapia through the assessment of fish immune response, inflammatory pathway, oxidative stress response with respect to the histopathological changes, gene expression, enzymes levels and phagocytosis. Five groups were used; the 1st and 2nd groups fed the basal diet; the 3rd group fed basal diet with BS in water, 4th group fed basal diet and supplemented with YSE in water and 5th group received a combination of BS and YSE. After two weeks of treatments, the 2nd, 3rd, 4th, and the 5th groups were exposed to acute ammonia challenge for 72 h. Fish exposed to ammonia displayed significant decreases in RBCs, Hb, PCV, WBCs, phagocytic activity (PA) and index (PI), lysozyme activities and serum antioxidant enzymes (glutathione peroxidase (GPX) and catalase (CAT)). Also, a significant increase in Malondialdehyde (MDA), degenerative changes in the gills, hepatopancrease and spleen associated with an elevated un-ionized ammonia level. A significant restoration of the hematological parameters was observed with the use of BS, YSE or their combination. Additionally, they improved the innate immunity, antioxidant responses, and histopathological changes. At transcriptomic level, ammonia toxicity significantly lowered the mRNA transcription levels of Nuclear erythroid 2-related factor 2 (Nrf2), quinone oxidoreductase 1 (NQO-1), Heme oxygenase 1 (HO-1) and Heat shock proteins (HSP70). While nuclear factor kappa ß (NFкß), Tumor necrosis factor α (TNF-α), Interleukin 1ß (IL-1ß), and Interleukin 8 (IL8), transcription levels were increased. Interestingly, BS and YSE and their combination significantly increased the expression of these genes with the highest levels reported with BS and YSE combination. We observed that, the most pronounced restoration of some important inflammatory and immune related genes close to the control level was observed when BS-YSE mix was used. Furthermore, a restored water pH, and a maintained ammonia level to the control level were observed in this group. Otherwise, equal effects for the three treatments were observed on the assessed parameters. We recommend the used of BS-YSE mix for water ammonia treatment and relieving ammonia toxicity in fish.

Growth, hemato-biochemical, immune-antioxidant response, and gene expression in Nile tilapia (Oreochromis niloticus) received nano iron oxide-incorporated diets.

Nanotechnology has recently played a key role in tackling many aquacultures issues. Hence, the present study targets the evaluation of dietary inclusion of nano iron oxide (nFe2O3) on growth performance, hematology, immune-antioxidant responses, ionic regulation and expression of related genes in Nile tilapia (Oreochromis niloticus). Fish were fed supplementary nFe2O3 at rates of zero (control), 0.5, and 1 g/kg diet for 30 days. Obtained data demonstrated that nFe2O3 significantly (P < 0.05) augmented growth performance (final weight and length, body mass gain, specific growth rate, feed conversion ratio, and length gain rate). Hematological picture {RBCs, Hb, MCV, MCH and MCHC, and leukocytes interpretations (WBCs and monocytes)}; and biochemical indexes including (AST and ALT; total protein; and glucose, and cortisol) were significantly (P < 0.05) improved in nFe2O3 supplemented groups. Plasma ionic concentration was also altered with nFe2O3 supplementation, and 1g nFe2O3 revealed the most marked increase in plasma (Na+) potassium (K+) levels. Similarly, IgM, nitrous oxide (NO), and lysozyme activity, plus superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities showed a remarkable improvement in 1g nFe2O3 group compared to the control. Expression of Insulin-Like Growth Factor-1 (IGF-1) and interleukin 1-ß (IL-1ß) genes were significantly up-regulated in nFe2O3 supplemented groups. Briefly, dietary nFe2O3 inclusion had enhanced properties on growth; hemato-biochemical; immune, antioxidative profiles; and related genes expression of O. niloticus, with a recommended concentration of 1g nFe2O3.

The combined impact of xylo-oligosaccharides and gamma-irradiated astragalus polysaccharides on the immune response, antioxidant capacity, and intestinal microbiota composition of broilers.

The present study investigated the individual and combined effects of xylo-oligosaccharides (XOS) and gamma-irradiated astragalus polysaccharides (IAPS) on the immune response, antioxidant capacity and intestinal microbiota composition of broiler chickens. A total of 240 newly hatched Ross 308 chicks were randomly allocated into 5 dietary treatments including the basal diet (control), or the basal diet supplemented with 50 mg/kg chlortetracycline (CTC), 100 mg/kg XOS (XOS), 600 mg/kg IAPS (IAPS), and 100 mg/kg XOS + 600 mg/kg IAPS (XOS + IAPS) respectively. The results showed that birds in the control group had lower the thymus index and serum lysozyme activity than those in the other 4 groups (P < 0.05). Moreover, there was an interaction between XOS and IAPS treatments on increasing the serum lysozyme activity (P < 0.05). Birds in the CTC and XOS + IAPS groups had lower serum malondialdehyde concentration and higher serum total antioxidant capacity activity and mucosal interleukin 2 mRNA expression of jejunum than those in the control group (P < 0.05). In addition, birds in the control groups had lower duodenal and jejunal IgA-producing cells number than these in other 4 groups (P < 0.05). As compared with the CTC group, dietary individual XOS or IAPS administration increased duodenal IgA-producing cells number (P < 0.05). Meanwhile, there was an interaction between XOS and IAPS treatments on increasing duodenal and jejunal IgA-Producing cells numbers (P < 0.05). Dietary CTC administration increased the proportion of Bacteroides, and decreased the proportion of Negativibacillus (P < 0.05). However, dietary XOS + IAPS administration increased Firmicutes to Bacteroidetes ratio, the proportion of Ruminococcaceae, as well as decreased the proportion of Barnesiella and Negativibacillus (P < 0.05). In conclusion, the XOS and IAPS combination could improve intestinal mucosal immunity and barrier function of broilers by enhancing cytokine gene expression, IgA-producing cell production and modulates cecal microbiota, and the combination effect of XOS and IAPS is better than that of individual effect of CTC, XOS, or IAPS in the current study.

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 < 0.05). The expression of Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) was markedly upregulated (P < 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 < 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 < 0.05) by a dietary 5 g sodium propionate/kg diet. The total protein level and lysozyme activity were meaningfully increased (P < 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.

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.

Effect of dietary protein levels on the growth, enzyme activity, and immunological status of Culter mongolicus fingerlings.

A 65-day growth trial was conducted to investigate the dietary protein requirements for Culter mongolicus fingerlings. Isolipidic and isoenergetic diets were formulated with five dietary protein levels (32%, 37%, 42%, 47%, and 52%). Each diet was assigned to triplicate groups of 70 C. mongolicus fingerlings (0.99±0.08 g). The results indicated that weight gain and specific growth rate (SGR) increased with increasing dietary protein levels up to 47%. The activities of intestinal trypsin and lipase were the lowest in the 32% protein and 52% protein groups, while amylase activity reduced markedly in the 47% protein group. These results suggest that different dietary protein levels may cause different transformations of nutrients. The activities of superoxide dismutase (SOD) and lysozyme were not affected by varying dietary protein levels, except for those in the 32% protein group. In contrast, the content of malondialdehyde (MDA) increased with increasing dietary protein levels and reaching a maximum in the 52% protein group, suggesting that MDA accumulation depends on the protein concentration and the potential oxidative stress. Taken together, based on the broken-line analysis of SGR, we recommended the optimum dietary protein for C. mongolicus fingerlings to be 48.97%~49.31%.

Structural characterization and immunomodulatory activities of two polysaccharides from Rehmanniae Radix Praeparata.

The structures and immunomodulatory activities of two polysaccharides (SDH-WA and SDH-0.2A) from Rehmanniae Radix Praeparata (RRP) were investigated. RRP crude polysaccharide was obtained by water extraction and purified. Ion chromatography, high-performance gel permeation chromatography, Fourier-transform infrared spectroscopy, methylation analysis, gas chromatography-mass spectrometry, and nuclear magnetic resonance were used to characterize the polysaccharides. The main chain of SDH-WA was →6)-α-D-Galp-(1→6)-α-D-Galp-(1→5)-α-L-Araf-(1→3,5)-α-L-Araf-(1→, terminal sugar residue α-L-Araf-(1→ linked to residue →3,5)-α-L-Araf-(1→ on the main chain by an O-3 bond. The other two terminal sugar residues α-D-Galp-(1→ and →6)-ß-D-Galp were linked to the end of the main chain. The main chain of SDH-0.2A was →2,4)-α-L-Rhap-(1→4)-α-D-GalpA-(1→. Three branched chains α-D-Galp-(1→6)-α-D-Galp-(1→5)-α-L-Araf-(1→3,5)-α-L-Araf-(1→, →3,6)-ß-D-Galp-(1→5)-α-L-Araf-(1→, and →4)-ß-D-Galp-(1→5)-α-L-Araf-(1→ were linked to the main chain residue →2,4)-α-L-Rhap-(1→ by an O-2 bond. Three terminal sugar residues α-D-Galp-(1→, α-L-Araf-(1→, and →6)-ß-D-Galp were linked to the end of the chain. Both polysaccharides showed no cytotoxic effects on and significantly promoted the phagocytic activity of RAW264.7 cells. They dose-dependently improved lysozyme activity and stimulated the production of TNF-α and IL-6 by RAW264.7 cells, but attenuated the secretion of lysozymes, TNF-α, IL-6, IL-1ß, and nitric oxide by lipopolysaccharide-induced RAW264.7 cells. The present studies suggest that PRR polysaccharide is a valuable source with immunomodulating.

Synergistic Lysozyme-Photodynamic Therapy Against Resistant Bacteria based on an Intelligent Upconversion Nanoplatform.

The rapid emergence of drug-resistant bacteria has raised a great social concern together with the impetus for exploring advanced antibacterial ways. NIR-triggered antimicrobial photodynamic therapy (PDT) by lanthanide-doped upconversion nanoparticles (UCNP) as energy donor exhibits the advantages of high tissue penetration, broad antibacterial spectrum and less acquired resistance, but is still limited by its low efficacy. Now we designed a bio-inorganic nanohybrid and combined lysozyme (LYZ) with UCNP-PDT system to enhance the efficiency against resistant bacteria. Benefiting from the rapid adhesion to bacteria, intelligently bacteria-responsive LYZ release and synergistic LYZ-PDT effect, the nanoplatform achieves an exceptionally strong bactericidal capacity and conspicuous bacteriostasis on methicillin-resistant S. aureus. These findings pave the way for designing efficiently antibacterial nanomaterials and provide a new strategy for combating deep-tissue bacterial infection.

Influence of dietary Chlorella vulgaris and carbohydrate-active enzymes on growth performance, meat quality and lipid composition of broiler chickens.

Herein, we investigated the effect of Chlorella vulgaris as ingredient (10% of incorporation) in broiler diets, supplemented or not with 2 formulations of Carbohydrate-Active enZymes (CAZymes; Rovabio Excel AP and a mixture of recombinant CAZymes, composed by an exo-ß-glucosaminidase, an alginate lyase, a peptidoglycan N-acetylmuramic acid deacetylase and a lysozyme), on growth performance, meat quality, fatty acid composition, oxidative stability, and sensory traits. One hundred twenty 1-day-old Ross 308 male birds were randomly assigned to one of the 4 experimental diets (n = 30): corn-soybean meal-basal diet (control), basal diet with 10% C. vulgaris (CV), CV supplemented with 0.005% of a commercial CAZyme cocktail (Rovabio Excel AP), (CV + R), and CV supplemented with 0.01% of a 4-CAZyme mixture previously selected (CV + M) during the experimental period lasted from day 21 to day 35. Body weight gain and feed conversion rate of broilers were not affected by C. vulgaris but digesta viscosity increased more than 2-fold (P < 0.001) relative to the control. In addition, neither cooking loss, shear force, juiciness, flavor nor off-flavor was impaired by dietary treatments (P > 0.05). By contrast, the dietary C. vulgaris increased tenderness, yellowness (b∗) and total carotenoids in breast and thigh meats. However, no additional protective effect against lipid oxidation was observed in meat with the inclusion of microalga. Chlorella vulgaris, independently of CAZymes, had a minor impact on meat fatty acid composition but improved the proportion of some beneficial fatty acids. In summary, our data indicate a slight improvement of broiler meat quality and lipid nutritional value, without impairment of broilers' growth performance, thus supporting the usefulness of this microalga in poultry diets, up to this high level of incorporation. By contrast, the selected CAZyme mixtures used do not significantly improve the release of microalga nutrients in poultry diets, through the disruption of microalga cell wall, which warrants further research.

Effects of Acanthopanax senticosus supplementation on innate immunity and changes of related immune factors in healthy mice.

Modern scientific research has shown that Acanthopanax senticosus (AS) can regulate the innate immunity of healthy animals, thus affecting the health of animals. However, there are few systematic reports on the changes of innate immune indices of healthy animals after consuming AS. The purpose of this project was to study the effect on healthy mice's innate immunity and changes of related immune factors induced by feeding AS root powder supplementation. The results showed that the killing rate of natural cells increased in a dose-dependent manner in a certain time period. Compared to the control group, the treatment groups (T1, T2 and T3) improved significantly in the innate immune index (lysozyme, ß-defensin-2 and duodenal secretory IgA (SIgA) to varying degrees) and induced corresponding changes of immune factors at certain time periods. The correlation between SIgA and IFN-γ in mouse serum was enhanced, and the higher the concentration of AS in the diet, the stronger the correlation was. However, there was no significant difference in growth performance among groups. It is proved that AS supplementation can enhance innate immunity and change several relevant immune factors and cells of healthy mice without affecting growth performance.

Effects of exercise in hot and humid conditions and bovine colostrum on salivary immune markers.

The purpose of this study was to examine the effects of exercise in a hot and humid environment on salivary lactoferrin and lysozyme. A secondary aim was to quantify the effects of 14-day bovine colostrum (BC) supplementation on salivary lactoferrin and lysozyme at rest and following exercise in hot and humid conditions. Using a randomized, double-blind, and counterbalanced design, ten males (20 ± 2 years, VO2max 55.8 ± 3.7 mL kg-1 min-1, 11.8 ± 2.7% body fat) ran for 46 ± 7.7 min at 95% of ventilatory threshold in a 40 °C and 50% RH environment after 14-days of supplementation with either BC or placebo. Saliva was collected pre, post, 1-h, and 4-h post exercise, and was analyzed for lactoferrin and lysozyme using ELISA. There was an immediate increase in the concentration and secretion rate of lactoferrin and lysozyme (p < 0.05) with exercise, but BC had no effect (p > 0.05). Saliva flow rate was not different between conditions [(PLA: pre: 0.54 ± 0.3, post: 0.44 ± 0.3, 1-h: 0.67 ± 0.3, 4-h: 1.0 ± 0.4 mL min-1); (BC: pre: 0.58 ± 0.2, post: 0.37 ± 0.1, 1-h: 0.63 ± 0.2, 4-h: 0.83 ± 0.4 mL min-1)]. There were no differences in thermoregulatory markers (core temperature or physiological strain index) between BC and placebo trials. Interestingly, exercise-induced heat stress did not impair mucosal immune parameters, instead participants showed a transient increase in salivary lactoferrin and lysozyme. Further, 14-day BC supplementation had no effect on mucosal immunity at any time point.

Fucoidan Supplementation Restores Fecal Lysozyme Concentrations in High-Performance Athletes: A Pilot Study.

Nutritional strategies to help promote immune competence are of particular interest for a range of population groups. This study aimed to assess the potential impacts of fucoidan, a seaweed-derived bioactive polysaccharide, on gut markers of immunity and inflammation. A group of professional team-sport athletes were selected for inclusion in the study given the recognized potential for intense physical activity to induce alterations in immune function. A retrospective analysis was performed on stored fecal samples which had been collected from professional team-sport athletes (n = 22) and healthy adults (n = 11) before and after seven days of supplementation with fucoidan (Fucus vesiculosus/Undaria pinnatifida extract, 1 g/d). Fecal concentrations of calprotectin, secretory immunoglobulin A (sIgA) and lysozyme were determined using enzyme-linked immunosorbent assays. The supplement was well tolerated by participants with no adverse events reported. At baseline, fecal lysozyme concentrations were ~73% higher in the healthy adults compared to the professional athletes (p = 0.001). For the professional athletes, a significant (~45%) increase in fecal lysozyme was observed following the supplementation period (p = 0.001). These data suggest that fucoidan supplementation may have the potential to promote the secretion of antimicrobial peptides in specific population groups and contribute to the regulation of mucosal immune health.