Dietary Mannan Oligosaccharide Research Articles

A synergistic effect of dietary β-glucan and mannan oligosaccharide on growth performance, haematology, body composition, nutrient utilisation, and intestinal morphology in pompano, Trachinotus ovatus

Pompano (Trachinotus ovatus) is an economically important aquacultural species. Intensive pompano cultivation faces numerous obstacles including pathogens, environmental stress, and the use of chemicals and drugs. It has been demonstrated that prebiotics, particularly mannan oligosaccharide (MOS) and β-glucan (BG), support growth and improve general health in a variety of species. However, studies on the effects of combining BG and MOS on the pompano performance are lacking. Thus, this study examined the influence of BG and MOS on pompano weighing 13.12±0.14 g for 8 weeks. The results revealed that fish fed BG, MOS, or BG+MOS had significantly increased growth rates (P≤0.001). The survival rate ranged from 97.3% to 99.4% without significant differences (P≤0.022). Fish in the control group had the highest coefficient of variation (CV) (30.78%), whereas fish in the MOS+BG group had the lowest CV (23.10%). RBC and WBC counts were higher in all supplemented-diet treatments (P ≤ 0.042). Among the supplemented diets, the combination diet resulted in the highest RBC and WBC count. The feed conversion ratios (FCR) of fish fed BG, MOS, or MOS + BG decreased significantly (P≤0.017). The FCR of fish fed both BG and MOS was lower than that of fish fed either BG or MOS (P≤0.032). Fish fed both BG and MOS had a higher feed conversion eficiency (FCE) than those fed only BG or MOS (P≤0.014). Protein content was the highest in pompanos fed BG + MOS and lowest in fish fed only BG or MOS. Dietary BG, MOS, or BG + MOS decreased the lipid content in pompano (P≤0.037). The protein efficiency ratio of pompano fed BG+MOS diet was significantly increased (P≤0.021). Villus length, villus width, and villous surface area increased in fish fed the supplemented diet, with the highest values observed in fish fed the combination of BG and MOS. It is recommended to offer pompano, T. ovatus, a mixture of 1 g kg β-glucan and 4 g kg mannan oligosaccharide to improve growth performance, hematology, feed and nutrient utilization, and gut morphology.

Ameliorative effect of BIO-MOS® as a dietary supplementation on growth performance, physiological response, oxidative status, and immunity-linked gene expression in Nile tilapia (Oreochromis niloticus) fingerlings challenged with Aeromonas hydrophila.

Mannanoligosaccharides (MOS) usage in fish production has drawn more attention because of their positive benefits on disease resistance and fish performance. The ongoing research was executed to assess the potential advantages of Bio-Mos® dietary supplementation regarding the growth outcomes, physiological response, oxidative biomarkers, and immunity-linked gene expression in Nile tilapia (Oreochromis niloticus) fingerlings exposed to bacterial infection with Aeromonas hydrophila. Four experimental diets were developed using a 30% protein baseline diet, with Bio-Mos® added at variable levels; 0.0, 0.5, 1, and 2 g/kg, respectively. 240 healthy Nile tilapia fingerlings were split into 4 groups at random and assigned to 12 glass aquariums (three replicates of 20 fish/treatment). Diets were admitted at a 3% rate of fish biomass/aquarium for 8 weeks. Following the feeding trial, fish from every treatment were intraperitoneally injected with pathogenic A. hydrophila, and then observed for 15 days to record the survival rate percent (SR%) post challenge. Results revealed significant improvement in growth performance, physiological response, immunological parameters (phagocytic index, phagocytic activity, and lysozyme), and antioxidant parameters [catalase, malondialdehyde, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD)] among Bio-Mos® treated groups. Moreover, Bio-Mos® increased the expression of tumor necrosis factor alpha and Interleukin 1β, genes linked to the liver immune system. Growth-related genes (GHr), antioxidant-related genes (SOD and GSH-Px). In fish subjected to pathogens, dietary MOS supplementation could significantly lower oxidative stress, showing promise as a preventative supplement for Nile tilapia in place of antibiotics. On the other hand, Bio-Mos® considerably improved each of the three intestinal morphological measures (villus width, villus length, and crypt depth), showing the best overall intestinal structure-improving impact. The challenge with A. hydrophila caused marked degenerative alterations in the intestine, hepatopancreas, spleen, and posterior kidney of Nile tilapia, in the control group. However, lesion severity was greatly decreased and showed marked amelioration with an increased concentration of Bio-Mos®. The A. hydrophila-challenged groups revealed a 100% SR% mainly among the Bio-Mos® supplemented groups. It is recommended to enrich the Nile tilapia fingerlings diets with 2 g.kg-1 of MOS for better results on the growth rate, physiological response, immunological response, and intestinal absorptive capacity.

Dietary mannan-oligosaccharides enhance hematological and biochemical parameters, reproductive physiology, and gene expression of hybrid red tilapia (Oreochromis niloticus x O. mossambicus)

This study was carried out to evaluate the effects of dietary supplementation of mannan-oligosaccharides (MOS) on physiological performance, reproduction capacity and gene expression of hybrid red tilapia (Oreochromis. niloticus x O. mossambicus) broodstock reared in concrete tanks (3.5 × 3.2 × 0.9 m). Four isonitrogenous (30% cp), isocaloric (18.72 MJ kg−1) diets containing 0.0, 0.5, 1.0 and 1.5 g kg‐1 MOS were prepared. The diets were fed to triplicate groups of red tilapias broodfish (155 ± 5.65 g) stocked at a male: female ratio of 1:3, to satiation twice a day for two months. At the termination of the feeding trial, fish in each tank were netted and weighed. Blood samples were collected from five fish per tank to determine the hematological and biochemical parameters. The fish were then dissected for assessing the reproductive performance and its related genes. The results indicate that the values of hematological parameters (RBCs, Hb, and Htc) total protein, albumin, globulin, and reproductive hormones (testosterone, follicle-stimulating hormone and luteinizing hormone) were significantly increased by MOS dietary inclusion (1.0–1.5 g kg-1), while liver function enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were significantly decreased in fish fed with 1.5 g /kg of MOS (p < 0.05). Reproductive performances, including GSI, total number of fries per female and mean fry weight were significantly improved with increasing dietary MOS to 1.5 g kg−1. Gonads maturation was also enhanced with supplemental MOS to 1.5 g kg−1. In males, the highest testosterone concentration was recorded at 1.5 g MOS kg−1 diet. In females, FSH and LH were significantly increased with increasing MOS levels up to 1.0 g kg−1, and then leveled off. Conversely, the highest E2 and Prog concentration was obtained at 1.5 g kg−1. The expression of CYP19a, FSHR, FOXL2, CYP1A, ESR1, and ESR2A were significantly upregulated in the gonads of fish fed diets treated with MOS, up to a concentration of 1.5 g kg-1. These results suggest that a dietary supplementation of MOS (1.5 g kg−1) could enhance the reproductive performance of red tilapia.

Effects of Dietary Mannan Oligosaccharides on Growth, Nonspecific Immunity and Tolerance to Salinity Stress and Streptococcus iniae Challenge in Golden Pompano, Trachinotus ovatus

The effects of dietary supplementation with mannan oligosaccharide (MOS) on growth performance, haematological parameters, abundance of intestinal Vibrio spp., immune response, and tolerance to low salinity stress and Streptococcus iniae challenge were evaluated in pompano (Trachinotus ovatus). Pompano (3.24 ± 0.45 g) were fed six diets including a basal diet as control, and the basal diets supplemented with 0.1%, 0.2%, 0.4%, 0.6%, or 0.8% MOSs for 8 weeks. The results showed that pompano fed 0.1%–0.4% MOS had significantly improved specific growth rates ( P ≤ 0.039 ). Dietary MOS did not affect the survival rate of pompano ( P = 0.192 ). WBC count was significantly higher in fish fed diets containing 0.1%–0.6% MOS. Dietary MOS increased lymphocytes count ( P ≤ 0.042 ) and reduced monocytes and basophils counts ( P ≤ 0.019 ); however, no effects were found on neutrophils and eosinophil numbers ( P ≥ 0.064 ). Intestinal Vibrio spp. counts reduced in fish fed diets containing 0.1%–0.4% MOS ( P ≤ 0.035 ). The phagocytic ratio significantly increased in pompano fed diets containing 0.1%–0.6% MOS ( P ≤ 0.015 ), while the phagocytic index and serum lysozyme activity in fish fed 0.1%–0.4% MOS were significantly higher than the control ( P ≤ 0.035 ). There were significant positive correlations between MOS levels and fish growth on days 14, 28, 42, and 56 ( P ≤ 0.049 ). In addition, dietary MOS levels were highly correlated with blood parameters, abundance of intestinal Vibrio spp., and immune responses. Optimal dietary MOS requirements for maximal growth were estimated to be 0.440% on day 21 (R2 = 0.861), 0.385% on day 28 (R2 = 0.877), 0.371% on day 42 (R2 = 0.891), and 0.365% on day 56 (R2 = 0.750), showing decreasing tendency in MOS requirement as fish size increased. Furthermore, the optimal MOS concentration for maximal immunity based on lysozyme activity was estimated to be 0.431% (R2 = 0.817) on day 56. In addition, fish fed 0.1%–0.4% MOS showed better resistance to low salinity stress and Streptococcus iniae challenges ( P ≤ 0.014 ). In conclusion, MOS supplementation effectively reduced the prevalence of intestinal Vibrio spp. and enhanced the growth, immune responses, and tolerance to low salinity stress and Streptococcus iniae in juvenile pompano.

Effects of dietary mannan oligosaccharides and coated calcium butyrate on performance, carcass parameters, blood biochemistry and meat quality of growing Japanese quails

Aim of study: Despite previous research into mannan oligosaccharides (MOS) and calcium butyrate coated with palm oil (CCB) in poultry, there is a notable gap in the literature regarding the effects of these feed additives, either individually or in combination, on the growth performance, carcass values, blood biochemistry, immune response, and meat quality of growing Japanese quails.&#x0D; Area of study: Türkiye&#x0D; Material and methods: A total of 168 mixed-sex one-day-old quails were randomly allocated to one of four treatment groups, with each group containing 7 birds per cage. The control group was fed a basal diet, while the treatment groups received the following additives: 1 g/kg of CCB, 2 g/kg of MOS, and a combination of MOS+CCB added to the basal diet, respectively.&#x0D; Main results: None of the treatments had a significant impact on performance, relative organ weights, total protein, albumin, globulin, total cholesterol, high-density lipoprotein cholesterol, and lipoprotein lipase concentrations in blood serum, or humoral immunity on day 28. However, the inclusion of MOS and CCB in the diet, either individually or in combination, increased carcass yield and reduced low-density lipoprotein cholesterol and triglyceride levels in the blood serum. Additionally, these additives helped maintain optimal pH levels and lower malondialdehyde concentrations in the breast meat. Moreover, the combination of MOS + CCB significantly improved water holding capacity and antibody titers against the Newcastle Disease vaccine on day 42 in Japanese quails.&#x0D; Research highlights: The natural feed additives CCB and MOS contribute to enhanced carcass yield, improved meat quality, and strengthened humoral immunity, while simultaneously lowering lipid values in the bloodstream.

Dietary mannan oligosaccharides elevated growth performance, gut morphology, microbiota, body composition, feed and nutrient utilisation of pompano, Trachinotus ovatus

Pompano (Trachinotus ovatus) is a highly economical aquaculture species; however, intensive aquaculture of pompano is associated with pathogen infection, environmental stress, drug and chemical use, causing reductions in growth, survival and economic losses. Mannan oligosaccharide (MOS) is a prebiotic that has been reported to boost the growth and health of many species; however, no study has examined the effects of MOS on pompano. In the present study, the effects of dietary MOS levels on growth, body composition, intestinal microbiota, feed, and nutrient utilisation in juvenile pompano were investigated over an 8-week experiment. Five diets containing five levels of MOS (0.1%, 0.2%, 0.4%, 0.6%, and 0.8%) were fed to pompano (mean weight, 5.16 g±0.05). The results indicated that pompano fed 0.1–0.40% MOS in the diet had the highest growth performance (p ≤ 0.009), but fish fed 0.6–0.8% MOS had no impact on growth (p ≥ 0.056). MOS had no effect on the survival rate of pompano (p ≥ 0.327). The gut surface area increased in fish fed 0.1–0.4% MOS (p ≥ 0.011), but not in fish fed 0.6–0.8% MOS (p ≥ 0.102). Total aerobic bacteria (TAB) increased in fish fed 0.1–0.4% MOS (p ≤ 0.017), but TAB was not affected at 0.6–0.8% MOS (p = 0.315), whereas Vibrio count and ratio of Vibrio to TAB significantly reduced in fish fed any levels of MOS (p ≤ 0.024). Feed conversion ratio (FCR) significantly reduced (p ≤ 0.019), while feed conversion efficiency (FCE) significantly increased (p ≤ 0.014), when pompano were fed a diet containing 0.1–0.4% MOS. Protein in fish increased in fish fed a diet providing 0.1–0.4% MOS (p ≤ 0.011), but when adding higher levels of MOS (0.6% and 0.8%) to the diets, the protein content in fish did not change (p ≥ 0.072). Lipid content was significantly reduced in fish fed 0.1–0.4% MOS (p ≤ 0.035), but not at higher levels of MOS (p ≥ 0.085). The protein efficiency ratio (PER), lipid efficiency ratio (LER), and lipid productive value (LPV) boosted in fish fed diet containing 0.1–0.6% MOS (p ≤ 0.029). Protein productive value (PPV) increased in fish served diet containing 0.1–0.4% (p ≤ 0.008). Those values did not change with 0.8% MOS (p ≥ 0.137). MOS levels had positive correlations with growth performance, FCE, PER, PPV, LER, LPV and TAB (r ≥ +0.481, p ≤ 0.001), while MOS levels showed negative correlations with intestinal Vibrio and FCR of pompano (r ≥ −0.562, p ≤ 0.003). The optimal levels of MOS were 0.424% for pompano's lowest FCR, while the best MOS concentration was 0.375% for pompano’s maximal growth.

Influence of dietary mannan-oligosaccharides supplementation on hematological characteristics, blood biochemical parameters, immune response and histological state of laying hens

This study aimed to determine the influence of dietary mannan-oligosaccharides (MOS) on the immune system, hematological traits, blood biochemical parameters, and histological state of laying hens. At 34 wk of age, The Mandarah chicken strain's 120 laying hens and 12 cocks were divided into 4 groups, each with 30 hens and 3 cocks. The first group performed as a control group, which nourished on a basal diet. The second, third, and fourth experimental groups received 0.1, 0.2, and 0.5 g/kg of MOS and a base diet, respectively. Birds obtained MOS at numerous doses significantly (P ˂ 0.05) raised serum levels of immunoglobulin Y (IgY), immunoglobulin M (IgM), and avian influenza (AI) antibodies compared to control birds. Furthermore, adding MOS at a level of 0.1 g/kg diet significantly improved the immune response of the control group. Additionally, compared to the control group, treated birds with MOS at various dosages did not significantly enhance hematological parameters such as red blood cells (RBCs), white blood cells (WBCs), hemoglobin, and hematocrit. Compared to control birds, birds fed MOS at all levels exhibited considerably lower serum cholesterol, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) values. Also, compared to other treated birds, MOS-treated birds displayed improved histological examination of the small intestine, isthmus, and testis compared to the control group, particularly in birds fed MOS at 0.1 and 0.2 g/kg diet. It could be concluded that using MOS at 0.1 or 2 g/kg diet can successfully improve the physiological performance and overall health of laying hens.

117. Impact of a non-enterotoxigenic Escherichia coli (non-ETEC) vaccine and supplementation with dietary mannan oligosaccharides (MOS) against post weaning diarrhoea (PWD) in weaned pigs

117. Impact of a non-enterotoxigenic Escherichia coli (non-ETEC) vaccine and supplementation with dietary mannan oligosaccharides (MOS) against post weaning diarrhoea (PWD) in weaned pigs

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.

Comparative Expression Profiling Reveals the Regulatory Effects of Dietary Mannan Oligosaccharides on the Intestinal Immune Response of Juvenile Megalobrama amblycephala against Aeromonas hydrophila Infection.

Mannan oligosaccharides (MOS) are functional oligosaccharides with beneficial effects on the non-specific immunity of Megalobrama amblycephala, but systematic studies on the immunomodulatory mechanisms of MOS are still lacking. To investigate the protective mechanisms of three different levels of dietary MOS supplementation on the intestinal immunity of juvenile M. amblycephala, comparative digital gene expression (DGE) profiling was performed. In this study, 622 differentially expressed genes (DEGs) were identified, while the similar expression tendency of 34 genes by qRT-PCR validated the accuracy of the DGE analyses. Gene Ontology (GO) enrichment revealed that the DEGs were mainly enriched in two functional categories of biological process and molecular function. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the DEGs were mainly related to complement and coagulation cascades, coagulation cascades, platelet activation, natural killer cell mediated cytotoxicity, Fc gamma R-mediated phagocytosis and antigen processing and presentation. In addition, the pro-inflammatory, apoptosis and tight junction-related genes were more significantly up-regulated upon infection in the dietary MOS groups to enhance host immune functions and maintain the stability of the intestinal barrier. These results will be helpful to clarify the regulatory mechanism of MOS on the intestinal immunity of M. amblycephala and lay the theoretical foundation for the prevention and protection of fish bacterial diseases.

Effects of dietary mannan oligosaccharides on growth, non-specific immunity, and intestinal health in juveniles of the Japanese sea cucumber (Apostichopus japonicus)

Effects of dietary mannan oligosaccharides on growth, non-specific immunity, and intestinal health in juveniles of the Japanese sea cucumber (Apostichopus japonicus)

Cellular antioxidant mechanism of mannan-oligosaccharides involving in enhancing flesh quality in grass carp (Ctenopharyngodon idella).

Deterioration of flesh quality has bad effects on consumer satisfaction. Therefore, effects of safe mannan-oligosaccharides (MOS) on flesh quality of grass carp (Ctenopharyngodon idella) muscle were studied. A total of 540 healthy fish (215.85 ± 0.30 g) were randomly divided into six groups and fed six separate diets with graded levels of MOS (0, 200, 400, 600, 800 and 1000 mg kg-1 ) for 60 days. This study aimed at investigating the benefits of dietary MOS on flesh quality (fatty acids, amino acids and physicochemical properties) and the protection mechanism regarding antioxidant status. Optimal MOS could improve tenderness (27.4%), pH (5.5%) while decreasing cooking loss (16.6%) to enhance flesh quality. Meanwhile, optimal MOS improved flavor inosine 5'-monophosphate (IMP) of 11.8%, sweetness and umami-associated amino acid, healthy unsaturated fatty acid (UFA) of 14.9% and n-3 polyunsaturated fatty acids (n-3 PUFAs) especially C20:5n-3 (15.8%) and C22:6n-3 (38.3%). Furthermore, the mechanism that MOS affected pH, tenderness and cooking loss could be partly explained by the reduced lactate, cathepsin and oxidation, respectively. The enhanced flesh quality was also associated with enhanced antioxidant ability concerning improving antioxidant enzymes activities and the corresponding transcriptional levels, which were regulated through NF-E2-related factor 2 (Nrf2) and target of rapamycin (TOR) signaling. Based on pH24h , cooking loss, shear force and DHA (docosahexaenoic acid, C22:6n-3), optimal MOS levels for grass carp were estimated to be 442.75, 539.53, 594.73 and 539.53 mg kg-1 , respectively. Dietary MOS is a promising alternative strategy to improve flesh quality of fish muscle. © 2022 Society of Chemical Industry.

Effects of dietary mannan oligosaccharides (MOS) supplementation on metabolism, inflammatory response and gut microbiota of juvenile Nile tilapia (Oreochromis niloticus) fed with high carbohydrate diet

High-carbohydrate diet could achieve cost-sparing effect in aquafeed, but it may cause adverse effects on the growth condition or health status of fish. In order to reduce the adverse effects caused by high carbohydrate diet, mannan oligosaccharides (MOS), a commonly used prebiotics, was used as the feed additive to feed juvenile Nile tilapia (Oreochromis niloticus) (1.19 ± 0.01g) for ten weeks. Three treatments including CON (35% carbohydrate diet), HC (45% carbohydrate diet) and HM (45% carbohydrate supplemented diet with 5 g/kg MOS) were involved. The results showed that MOS supplementation increased the weight gain and body length of juvenile Nile tilapia compared with the HC group. Addition of MOS decreased serum glucose and liver glycogen by increasing enzymes activity related to glycolysis. Furthermore, supplementation of MOS decreased the high carbohydrate diet induced triglycerides accumulation in liver by reducing the expression level of genes related to TG synthesis. Dietary MOS also down-regulated the gene expression level of inflammation factors in liver. Intestinal bacterial composition analyses showed that supplementation of MOS in high carbohydrate diet altered the gut microbial composition and enriched pathways related to the glucose metabolism based on KEGG analyses. In general, our results demonstrated that MOS supplementation in high carbohydrate diet could regulate glucose and lipid homeostasis which may be related to the alteration of gut microbiota. These findings shed light on the application of prebiotics to increase the growth performance, alleviate the metabolic disorders and regulate inflammatory response in aquaculture.

Effects of mannan oligosaccharides (MOS) on glucose and lipid metabolism of largemouth bass (Micropterus salmoides) fed with high carbohydrate diet

The application of high-level of carbohydrates is regarded as an efficient way to promote “protein-sparing effects” in aquafeed, but the utilization efficiency of carbohydrates is poor in carnivorous fish. Alleviating the negative effects induced by high carbohydrate diet, including hyperglycemia and hepatosteatosis, is important for the rapid development of aquaculture. In this study, we aimed to explore the effects of mannan oligosaccharides (MOS) on metabolic disorders induced by high-carbohydrate diet in largemouth bass (Micropterus salmoides). Largemouth bass (13.64 ± 0.12 g) were supplied with 8 % carbohydrate (CON), 18 % carbohydrate (HC) and 18 % carbohydrate + 5 g/kg MOS (HM) diets for ten weeks. High carbohydrate diet significantly decreased the weight gain of largemouth bass (P < 0.05), while supplementation of MOS in high carbohydrate diet had no effect on weight gain compared with HC group. Dietary MOS significantly decreased the content of total lipid in the body compared to the HC group (P < 0.05). Addition of MOS significantly increased serum glucose (P < 0.05) but had no effect on the enzyme activity related to glycolysis and gluconeogenesis. Dietary MOS decreased the content of TG in liver by inhibiting the expression of genes correlated with lipolysis. In addition, dietary MOS alleviated liver fibrosis induced by high-carbohydrate diet in largemouth bass. Collectively, our study indicated that dietary MOS supplemented in high carbohydrate diet could improve the liver health in largemouth bass, but it did not alleviate the glucose metabolism disorders. In general, the different effects of prebiotics on metabolism should be considered when prebiotics were applied in aquaculture.

Dietary mannan oligosaccharides strengthens intestinal immune barrier function via multipath cooperation during Aeromonas Hydrophila infection in grass carp (Ctenopharyngodon Idella).

In recent years, mannose oligosaccharide (MOS) as a functional additive is widely used in aquaculture, to enhance fish immunity. An evaluation of the effect of dietary MOS supplementation on the immune barrier function and related signaling molecules mechanism of grass carp (Ctenopharyngodon idella) was undertaken in the present study. Six diets with graded amounts of MOS supplementation (0, 200, 400, 600, 800, and 1000 mg/kg) were fed to 540 grass carp over 60 days. To examine the immune response and potential mechanisms of MOS supplementation on the intestine, a challenge test was conducted using injections of Aeromonas hydrophila for 14 days. Results of the study on the optimal supplementation with MOS were found as follows (1) MOS enhances immunity partly related to increasing antibacterial substances content and antimicrobial peptides expression; (2) MOS attenuates inflammatory response partly related to regulating the dynamic balance of intestinal inflammatory cytokines; (3) MOS regulates immune barrier function may partly be related to modulating TLRs/MyD88/NFκB and TOR/S6K1/4EBP signalling pathways. Finally, the current study concluded that MOS supplementation could improve fish intestinal immune barrier function under Aeromonas hydrophila infected conditions.

Dietary Mannan Oligosaccharides Enhance the Non-Specific Immunity, Intestinal Health, and Resistance Capacity of Juvenile Blunt Snout Bream (Megalobrama amblycephala) Against Aeromonas hydrophila.

Mannan oligosaccharides (MOS) have been studied and applied as a feed additive, whereas their regulation on the growth performance and immunity of aquatic animals lacks consensus. Furthermore, their immunoprotective effects on the freshwater fish Megalobrama amblycephala have not been sufficiently studied. Thus, we investigated the effects of dietary MOS of 0, 200, and 400 mg/kg on the growth performance, non-specific immunity, intestinal health, and resistance to Aeromonas hydrophila infection in juvenile M. amblycephala. The results showed that the weight gain rate of juvenile M. amblycephala was not significantly different after 8 weeks of feeding, whereas the feed conversion ratio decreased in the MOS group of 400 mg/kg. Moreover, dietary MOS increased the survival rate of juvenile M. amblycephala upon infection, which may be attributed to enhanced host immunity. For instance, dietary MOS increase host bactericidal and antioxidative abilities by regulating the activities of hepatic antimicrobial and antioxidant enzymes. In addition, MOS supplementation increased the number of intestinal goblet cells, and the intestine was protected from necrosis of the intestinal folds and disruption of the microvilli and junctional complexes, thus maintaining the stability of the intestinal epithelial barrier. The expression levels of M. amblycephala immune and tight junction-related genes increased after feeding dietary MOS for 8 weeks. However, the upregulated expression of immune and tight junction-related genes in the MOS supplemental groups was not as notable as that in the control group postinfection. Therefore, MOS supplementation might suppress the damage caused by excessive intestinal inflammation. Furthermore, dietary MOS affected the richness and composition of the gut microbiota, which improved the gut health of juvenile M. amblycephala by increasing the relative abundance of beneficial gut microbiota. Briefly, dietary MOS exhibited significant immune protective effects to juvenile M. amblycephala, which is a functional feed additive and immunostimulant.

Inclusion of Mannan-Oligosaccharides in Diets for Tropical Gar Atractosteus tropicus Larvae: Effects on Growth, Digestive Enzymes, and Expression of Intestinal Barrier Genes

Mannan-oligosaccharides (MOS) are non-digestible carbohydrates, and their use in aquaculture as prebiotics is well documented. The objective of this work was to test whether MOS supplemented in the diet of A. tropicus larvae (2, 4, and 6 g kg−1) influence growth parameters, the activity of digestive enzymes, and the expression of genes related to the intestinal barrier. The highest total length was observed in larvae fed 6 g kg−1 MOS compared to control larvae. Trypsin activity increased with the addition of MOS to the diets, but leucine aminopeptidase activity only increased with 6 g kg−1 MOS. Lipase and α-amylase activities increased in larvae fed with 2 and 4 g kg−1 MOS. The expression of zo-2 was higher with the 6 g kg−1 MOS treatment. The cl-3 transcripts were lower with 2 g kg−1 MOS but higher with 6 g kg−1 MOS. All tested concentrations of MOS increased the expression of muc-2. In this study, incorporating mannan-oligosaccharides into the diet of A. tropicus larvae had a positive effect, and the concentration of 6 g kg−1 produced the best results. Therefore, including this prebiotic in the diets for the culture of A. tropicus larvae is suitable.

An Antioxidant Supplement Function Exploration: Rescue of Intestinal Structure Injury by Mannan Oligosaccharides after Aeromonas hydrophila Infection in Grass Carp (Ctenopharyngodon idella).

Mannan oligosaccharides (MOS) are a type of functional oligosaccharide which have received increased attention because of their beneficial effects on fish intestinal health. However, intestinal structural integrity is a necessary prerequisite for intestinal health. This study focused on exploring the protective effects of dietary MOS supplementation on the grass carp’s (Ctenopharyngodon idella) intestinal structural integrity (including tight junction (TJ) and adherent junction (AJ)) and its related signalling molecule mechanism. A total of 540 grass carp (215.85 ± 0.30 g) were fed six diets containing graded levels of dietary MOS supplementation (0, 200, 400, 600, 800 and 1000 mg/kg) for 60 days. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila for 14 days. We used ELISA, spectrophotometry, transmission electron microscope, immunohistochemistry, qRT-PCR and Western blotting to determine the effect of dietary MOS supplementation on intestinal structural integrity and antioxidant capacity. The results revealed that dietary MOS supplementation protected the microvillus of the intestine; reduced serum diamine oxidase and d-lactate levels (p < 0.05); enhanced intestinal total antioxidant capacity (p < 0.01); up-regulated most intestinal TJ and AJ mRNA levels; and decreased GTP-RhoA protein levels (p < 0.01). In addition, we also found several interesting results suggesting that MOS supplementation has no effects on ZO-2 and Claudin-15b. Overall, these findings suggested that dietary MOS supplementation could protect intestinal ultrastructure, reduce intestinal mucosal permeability and maintain intestinal structural integrity via inhibiting MLCK and RhoA/ROCK signalling pathways.

Evaluation of the prophylactic potential of non-enterotoxigenic Escherichia coli (non-ETEC) vaccine immunization and dietary mannan oligosaccharide competitive exclusion benefits against ETEC infections in weaned pigs

Enterotoxigenic Escherichia coli (ETEC) strains expressing F4 and F18 fimbriae are the most common causative agents of post-weaning diarrhoea (PWD) in pigs. The growing global restriction on the use of antibiotics in food animals has encouraged research into the development of nutritional and feeding strategies as well as vaccination against PWD. The aim of this study was to evaluate the efficacy of a live oral F4ac+ F18ac+ non-ETEC vaccine candidate (VAC) to stimulate gut and systemic cellular immunity in 4-week old pigs over 5 weeks following immunization. The onset and duration of protective immunity against on-farm occurring PWD, growth performance, diarrhoea scoring and mortality, as well as the phenotypic proportions of immune cells, were determined. Faecal and ileal samples were taken for determining the microbial composition or phenotyping of naïve/memory T cells. Also, the effect of prebiotic supplement mannan oligosaccharide (MOS) in the prevention of small intestinal colonization by ETEC, and its potential adjuvanticity in combination with the vaccine (VAC+MOS) were assessed. The pigs supplemented with MOS or that received VAC had significantly higher body weight (BW) (P&lt;0.05) on Day 14, whereas the VAC+MOS treated pigs had significantly lower BW on Day 35. Treatment with VAC+MOS resulted in considerably reduced clinical PWD, in particular the incidence and severity of diarrhoea and mortality. The total bacterial load in the ileum was much lower in the pigs from all 3 principal groups (MOS, VAC, and VAC+MOS) than in the control (CON) group (19 x 107, 17 x 107 and 12 x 107 vs. 23 x 108 CFU/mL, respectively) on Day 35. The pigs from the principal groups had significantly higher proportions of tested immune cells (P&lt;0.05) on Days 28 and 35. The localization and frequency of naive CD45RA+ and memory CD45RC+ T lymphocytes indicated their different distribution patterns within particular tissue structures, such as the villi, crypts, epithelium, lamina propria and areas (interfollicular follicular and Peyer’s patches) of ileal mucosa. This may indicate their different functions in intestinal immune responses to intraluminal microbes and their products, vaccinal immunogens and/or immunomodulators/adjuvants. To conclude, active mucosal immunity is needed to protect pigs against PWD. Hence, oral vaccination of pigs against both F4 and F18 ETEC, in combination with prebiotic supplementation represents a sustainable, practical and effective approach in PWD control.

Effect of dietary mannan oligosaccharide (MOS) on growth, digestive enzymes activity, innate immunity and disease resistance against virulent Aeromonas hydrophila in peninsular carp Barbodes carnaticus (Jerdon, 1849)

Effect of dietary mannan oligosaccharide (MOS) on growth, digestive enzymes activity, innate immunity and disease resistance against virulent Aeromonas hydrophila in peninsular carp Barbodes carnaticus (Jerdon, 1849)