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1.
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2.
The effect of dietary β‐glucan on the bacterial community in the gut of common carp (Cyprinus carpio) was examined after oral application of Aeromonas hydrophila. Carp received either feed supplemented with 1% MacroGard®, a β‐1,3/1,6‐glucan, or a β‐glucan‐free diet. Fourteen days after feeding, half of the carp from each group were intubated with 109 colony‐forming units (CFU) of a pathogenic strain of A. hydrophila. Gut samples were taken 12 hr to 7 days after application and analysed using microbiological and molecular biological techniques (NGS, RT‐PCR‐DGGE). The reaction of the mucosa and the microbiota to an A. hydrophila intubation differed in carp fed with β‐glucan compared to carp from the control group. In β‐glucan fed carp, the total bacterial amount was lower but the number of bacterial species was higher. Bacterial composition was different for carp from both treatment groups. The number of mucin filled goblet cells was reduced in carp fed the β‐glucan diet. Mucus was obviously released from the goblet cells and was probably washed out of the gut together with high numbers of bacteria. This might be protective against pathogenic bacteria and, therefore, feeding with β‐glucan may provide protection against infections of the gut in carp.  相似文献   

3.
The effects of dietary β‐ (1,3) glucan and whole cell yeast (Sacharomyces uvarum) on the immune response and disease resistance to Aeromonas hydrophila were investigated in Cyprinus carpio. β‐(1,3) glucan was extracted from the yeast. Both β‐(1,3) glucan and whole yeast were incorporated into the diet at 1% level and fed to common carp C. carpio for a period of 60 days. Control and treated fish were exposed to A. hydrophila on the 30th and the 60th day of the experimental period. Dietary supplementation of glucan significantly increased the white blood cell count in fish on the 60th day (2.91±0.04 × 104), and the highest nuetrophil nitro blue tetrazolium (NBT) activity was also observed in glucan‐fed fish (30th day). A consistent increase in neutrophil (NBT) activity was also observed in whole cell fed fish until the end of the experiment. Similarly, β‐(1,3) glucan and whole cell yeast enhanced the serum lysozyme activity from the 15th day onwards but higher activity was reported on the 30th day in glucan and the 60th day in whole cell yeast‐fed fish. Suplementation of β‐(1,3) glucan protected the fish from A. hydrophila infection. Nearly 75–80% of the fish survived pathogen exposure (relative percentage survival). However, only 54–60% survival was observed in the whole cell‐fed fish. β‐(1,3) glucan and whole cell yeast protect the fish from pathogens by enhancing the cellular and humoral immune response in C. carpio.  相似文献   

4.
The goal of this study was to investigate the effects of dietary supplementation with β‐glucan and microencapsulated probiotics (Bacillus subtilis or Pediococcus acidilactici) on growth performance, body composition, haemolymph constituents, and intestinal morphology and microbiota of the Pacific white shrimp Litopenaeus vannamei. Four treatment diets [basal diet (C), β‐glucan‐containing diet (β‐glu), β‐glucan plus B. subtilis‐containing diet (β‐glu+Bs), and β‐glucan plus P. acidilactici‐containing diet (β‐glu+Pa)] were fed to L. vannamei for 90 days. Shrimp fed the β‐glu and β‐glu+Pa diets exhibited similar growth performance and body protein content, which were significantly higher than those of shrimp fed the control diet (P < 0.05). No significant differences in haemolymph triglyceride, cholesterol, protein, haemolymph urea nitrogen or chloride were detected among the experimental diets. However, dietary β‐glucan alone increased the haemolymph glucose level and osmolarity (P < 0.05). Synbiotic supplementation had greater effects on intestinal microbiota and morphology than dietary β‐glucan alone. For example, β‐glu+Bs increased the number of intestinal lactic acid bacteria and decreased the number of Vibrio spp. (P < 0.05), and β‐glu+Pa increased the height of intestinal villi.  相似文献   

5.
Although the improved strain HR‐5 of Pyropia haitanensis has improvement in yield and quality, it shows earlier maturation and shortened growth period. In this study, blades of HR‐5 strain were treated with 60Co‐γ ray irradiation, and a mutant strain ST‐2 was selected and characterized. The blade length of ST‐2 strain was 401.4 cm on day 70 post‐culture, which was 1.9‐fold longer than that of the parental strain HR‐5. The blades of HR‐5 strain matured earlier and most were matured on day 55, while the ST‐2 strain was not matured until day 90. When blades of HR‐5 and ST‐2 strains were firstly cultured at 23°C for 40 days and their blade discs cultured at 29°C for another 30 days, the mean length of ST‐2 strain was 2.0‐fold longer than that of HR‐5 strain. Besides, the contents of Chl. a and phycobiliprotein and the conchospore numbers in ST‐2 were comparable to that in HR‐5 strain. In summary, compared with HR‐5, we observed delayed maturation, increased length, weight and high‐temperature resistance of the blades, high content of photosynthetic pigments, and high production of conchospores in ST‐2, suggesting it might be a better strain for large‐scale production.  相似文献   

6.
The current study aimed to investigate the effects of dietary soybean β‐conglycinin on growth performance and intestine apoptosis in juvenile grass carp (Ctenopharyngodon idella). For fish fed with the 80 g β‐conglycinin/kg diet for 7 weeks, the specific growth rate and feed intake were decreased. In the proximal intestine, dietary β‐conglycinin did not induce DNA fragmentation, tended to decrease the reactive oxygen species (ROS) content, and decreased ROS‐generating enzyme (NADPH oxidase [NOX]) activity. Subsequently, in the mid‐intestine, dietary β‐conglycinin caused DNA fragmentation, tended to increase the ROS content, increased caspase‐3, caspase‐8 and caspase‐9 activities, upregulated the mRNA levels of proapoptotic molecules (apoptotic protease‐activating factor‐1 [Apaf1] and Bcl‐2‐associated X protein [BAX]) and mitogen‐activated protein kinase (MAPK)‐related signal molecules (Jun N‐terminal kinase (JNK) and p38 MAPK) and increased the protein levels of p38 MAPK and phospho‐p38 MAPK. Moreover, in the distal intestine, dietary β‐conglycinin induced DNA fragmentation, elevated NOX activity and the ROS content and increased caspase‐3, caspase‐8 and caspase‐9 activities, death ligand (TNF‐α) mRNA expression level, and p38 MAPK and phospho‐p38 MAPK protein levels. In summary, dietary soybean β‐conglycinin suppressed fish growth and inconsistently caused apoptosis among the different intestinal segments which was partially associated with ROS‐mediated MAPK signalling.  相似文献   

7.
A fibroblastic‐like cell line was established from the ornamental fish, red‐line torpedo (Puntius denisonii). The red‐line torpedo fin (RTF) cell line is being maintained in Leibovitz's L‐15 medium supplemented with 10% fetal bovine serum (FBS) for over 1 year at 28 °C on a continuous basis in normal atmosphere. The growth rate of RTF cells increased as the FBS proportion increased from 5% to 20% at 28 °C with optimum growth at the concentrations of 10% FBS. The morphology of RTF cell was predominantly fibroblastic like. Propagation of these cell lines was serum dependent, with a low plating efficiency (<15%). Karyotyping analysis of RTF cells at the 25th passage indicated that the modal chromosome number was 2n=50. The cell line was cryopreserved in liquid nitrogen at ?196 °C and could be recovered from storage after 6 months with good cell viability. Polymerase chain reaction amplification of a fragment of two mitochondrial genes, 16S rRNA and CO1, confirmed the identity of these cell lines with those reported from this animal species, confirming that the cell lines originated from P. denisonii. The bacterial extracellular products from Vibrio cholerae MTCC3904 and Aeromonas hydrophila were found to be toxic to RTF. The cell lines were not susceptible to viral nervous necrosis virus, a marine fish virus.  相似文献   

8.
To explore the role of β‐glucan (0, 0.05%, 0.1% and 0.2%) in resisting bacteria, rainbow trout (Oncorhynchus mykiss) was challenged with Aeromonas salmonicida after 42‐day β‐glucan administration, and then sampled at 0, 2, 4 and 6 days post infection (dpi). The data showed that 0.2% β‐glucan reduced the accumulated mortality rates compared with the ICG (infected control group) (p < .05). The white blood cells, red blood cells and haemoglobin were higher in the 0.2% β‐glucan group (BG) than the ICG (p < .05). 0.1% and 0.2% β‐glucan elevated serum total antioxidative capability and glutathione activity but alleviated the increase of serum alkaline phosphatase activity and glucose concentration (p < .05) during infection. Serum TNF‐α, IL‐1β, IL‐8 and IgM in three BGs elevated remarkably on 6 dpi compared with the ICG (p < .05). Expression of tnf, il1b and cxcl8 of the head kidney in the 0.1% and 0.2% BGs was higher than the ICG on 4 dpi while ighm expression in the 0.2% BG was higher than in the ICG on 2 and 6 dpi (p < .05). 0.1% and 0.2% β‐glucan increased the expression of tlr5m, tlr5s, tmek and myd88 in the spleen after infection (p < .05). Similarly, 0.2% β‐glucan up‐regulated the expression of tmek, myd88, oncmyk‐dab and c3 in head kidney (p < .05). Overall, 0.2% dietary β‐glucan effectively decreased accumulated mortality rate by modulating the biochemistry process, cytokines, and activating TLR and ERK signalling pathways during A. salmonicida infection.  相似文献   

9.
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10.
A cell line (PaF) derived from the fin tissue of silver pomfret (Pampus argenteus) was established and characterized in this study. The cell line has been subcultured for more than 50 times in Dulbecco's modified Eagle's medium (DMEM) containing 15% foetal bovine serum (FBS) since the initial primary culture. PaF cells grew well at temperatures from 24°C to 28°C in DMEM supplemented with 15% FBS. Partial amplification and sequence analysis of the cytochrome B gene indicated that PaF originated from silver pomfret. Cytogenetic analysis demonstrated that the modal chromosome number was 48. A significant cytopathic effect was observed in PaF cells during viral haemorrhagic septicaemia virus (VHSV) infection, and the VHSV replication was confirmed by qRT‐PCR and viral titre assays. In contrast, PaF cells were resistant to red‐spotted grouper nervous necrosis virus infection. Moreover, PaF cells could respond to VHSV and lipopolysaccharide treatments, as indicated by the expression of immune‐related genes, TLR5 and TLR9. In conclusion, the establishment of PaF cell line will provide an appropriate in vitro tool for the study of mechanisms of pathogen–silver pomfret interaction.  相似文献   

11.
To determine the dietary β‐glucan and vitamin C levels that would enable the fish to cope with different stress, 252 tilapia (16.86 ± 0.24 g) were distributed in thirty six 250‐L aquaria and fed experimental diets for 60 d. Diets were supplemented with β‐glucan (0.1, 0.2, 0.4, and 0.8%) and vitamin C (400 and 600 mg/kg diet) and distributed in a factorial design that included a control diet (0 β‐glucan/125 mg vitamin C/kg). After growth performance analyses, a group of 108 fish were subjected to cold‐induced stress and another to Aeromonas hydrophila infection. Hematological and immunological parameters were determined before and after the stress. Growth performance was not affected. Red blood cells, hematocrit, mean corpuscular volume, total plasma protein, albumin : globulin ratio and leukocytes, lymphocytes, neutrophils, and monocytes were affected (P < 0.05) by stress and/or diets. The control diet resulted in higher post‐infection cortisol (P < 0.05). Liver vitamin C was directly proportional to dietary vitamin C (P < 0.05). The production of hydrogen peroxide and nitric oxide was also affected by diets and/or bacterial challenge (P < 0.05). In total, 0.1–0.2% β‐glucan and 600 mg/kg vitamin C increased fish resistance to stress and 0.8% β‐glucan resulted in reduced immune responses regardless of the vitamin C supplementation level.  相似文献   

12.
β‐glucan binding protein (βGBP), a pattern recognition protein was purified from the haemolymph of freshwater prawn Macrobrachium rosenbergii by heparin affinity chromatography that showed a single band in native gradient PAGE. The β‐glucan binding property of the purified protein was confirmed in a phenoloxidase (PO) assay, where addition of βGBP along with β‐glucan increased the specific PO activity compared with that of β‐glucan alone. The molecular weight of the βGBP was found to be ~316 kDa on gel filtration chromatography. In SDS‐PAGE, βGBP molecule was reduced to one polypeptide chain of molecular weight ~113 kDa. Thus the βGBP in M. rosenbergii is possibly a homotrimeric molecule. The purified sample run on unreduced condition in SDS‐PAGE also revealed a similar size band (~113 kDa) and hence, the polypeptide chains of βGBP are held by non‐covalent interactions. The purified βGBP samples run in native PAGE was stained positively with alcian blue for carbohydrates and Sudan black for lipids indicating the βGBP to be a glycolipoprotein. With rabbit polyclonal anti‐βGBP serum developed, an indirect ELISA was standardized and the normal βGBP concentration in adult M. rosenbergii serum was quantified to be ~2 mg mL?1. Furthermore, the applicability of the developed ELISA is discussed.  相似文献   

13.
The objective of this study was conducted to research the effects of β‐conglycinin in the diets on the growth performance, immunity function, antioxidant capacity and intestinal health of juvenile golden crucian carp (Carassius auratus). Five diets contained respectively (0, 20, 40, 60 and 80 g/kg) β‐conglycinin, and were used to feed juvenile golden crucian carp for 56 days. Final weight, weight gain and specific growth rate were significantly reduced by dietary β‐conglycinin (20–80 g/kg). Feed efficiency and protein efficiency were significantly reduced by dietary β‐conglycinin (40–80 g/kg). In hepatopancreas, the activities of T‐SOD, ACP, ALT and T‐AOC were significantly suppressed by dietary β‐conglycinin (20–80 g/kg). The activities of LZM, AKP, CAT and GPx were significantly reduced by dietary β‐conglycinin (40–80 g/kg). The activities of protease were significantly reduced and the content of MDA was significantly increased by dietary β‐conglycinin (60–80 g/kg). In proximal intestines, the activities of protease and CAT were significantly decreased by dietary β‐conglycinin (40–80 g/kg). In mid and distal intestines, the activities of protease and CAT were significantly inhibited by dietary β‐conglycinin (20–80 g/kg). In intestines, T‐AOC and GPx were significantly declined by dietary β‐conglycinin (20–80 g/kg). In proximal and mid intestines, the content of MDA were significantly increased by dietary β‐conglycinin (40–80 g/kg). In distal intestines, the content of MDA was significantly increased by dietary β‐conglycinin (20–80 g/kg). The expression of IGF‐I was significantly decreased and the expression of IL‐1β and TNF‐α was significantly increased by dietary β‐conglycinin (20–80 g/kg). The structural integrity of intestinal tissues were damaged by dietary β‐conglycinin (20–80 g/kg), the part of intestinal villus were shed, the part of epithelial cells were separated from lamina propria. Ultimately, these results suggested dietary β‐conglycinin should be <20 g/kg in formula feed of golden crucian carp.  相似文献   

14.
To assess the effects of A3α‐peptidoglycan (A3α‐PG) extracted from Bifidobacterium sp. on the immune response and disease resistance of sea cucumber, different concentrations (0, 0.5, 5 and 50 mg mL?1) of A3α‐PG suspensions were used to perform hypodermic injection on Apostichopus japonicus, followed by a Vibrio splendidus challenge. Total coelomocyte count (TCC), phagocytosis activity and activities of four immunological enzymes in both cell‐free coelomic fluid (extra‐cellular, EC) and coelomocyte lysate supernatant (intracellular, IC), including acid phosphatase (ACP), alkaline phosphatase (ALP), superoxide dismutase (SOD) and peroxidase (POD), were measured at 2, 6, 14 and 24 h post injection (hpi). The TCC was not significantly affected (P > 0.05) by A3α‐PG, ranging from 1.84 × 106 to 3.53 × 106 cells mL?1. The coelomocyte phagocytosis activity was significantly activated (P < 0.05) in all the A3α‐PG treatments, whereas no significant difference was observed between them except 24 hpi (P > 0.05). The EC‐ACP activity in the 5.0 mg mL?1 treatment increased significantly (P < 0.05) at all sampling times, while the IC‐ACP activity in the 50 mg mL?1 treatment increased significantly (P < 0.05) at 2 hpi. Also, the 5.0 mg mL?1 treatment had significant (P < 0.05) increase in the EC‐ALP activity within 14 hpi and the EC‐POD activity at 2 hpi, respectively, while significantly (P < 0.05) enhanced IC‐ALP and IC‐POD activities were observed in the 50 mg mL?1 treatment within 6 hpi and at 2 hpi, respectively. Only the 5.0 mg mL?1 treatment showed significant (P < 0.05) increase in the EC‐SOD activity at 2 hpi and IC‐SOD activity within 14 hpi, respectively. The challenge test showed that the animals treated with 50 mg mL?1 of A3α‐PG had notably lower cumulative mortality after 14 days following V. splendidus exposure. All together, these results suggest that A3α‐PG could positively enhance immune response that effectively promotes the health status of A. japonicus against V. splendidus infection.  相似文献   

15.
Poly‐β‐hydroxybutyrate (PHB) is microbial carbon and energy storage polymer, which can be degraded into water‐soluble β‐hydroxybutyric acid in the gastrointestinal tract of aquatic animals. A 60‐day culture experiment was performed using Chinese mitten crab, Eriocheir sinensis (Milne‐Edwards) juveniles with an average initial body weight of 0.74 ± 0.06 g which were fed a diet supplemented with 0%, 0.5%, 1%, 3% or 5% PHB. A PHB dietary supplementation of 1% and 3% significantly improved the body weight gain, moulting frequency and concomitantly reduced 2nd–3rd moulting intervals of the crabs (P < 0.05). The dietary PHB level positively related to hepatopancreatic pepsin, trypsin and lipase activity (P < 0.05). Increasing the dietary PHB also improved total superoxide dismutase activity, but reduced alkaline phosphatase and acid phosphatase activity in the serum of hemolymph (P < 0.05). A 16S rRNA gene analysis by denaturing gradient gel electrophoresis indicated that PHB supplementation led to a significantly higher range‐weighted richness, diversity and evenness of the gut bacterial community when dosed at 3% in the feed. The beneficial effects of PHB are discussed in terms of immune defense, metabolism and gut microbiota of the crabs.  相似文献   

16.
A 4‐week growth trial was conducted to compare the effects of different feeding strategies of dietary immunostimulants on the growth, immunity and resistance against Vibrio splendidus of sea cucumbers Apostichopus japonicus (Selenka). Six feeding strategies were set, including feeding immunostimulants‐free diet continuously (control), feeding dietary β‐glucan (1.25 g kg?1 diet) continuously, feeding dietary mannan‐oligosaccharides (MOS; 2.00 g kg?1 diet) continuously, feeding β‐glucan 2 days followed by MOS 5 days alternately, feeding β‐glucan 5 days followed by MOS 2 days alternately and feeding β‐glucan 7 days followed by MOS 7 days alternately. The sea cucumbers fed immunostimulants showed higher specific growth rate (SGR) and lower cumulative mortality than control (P < 0.05). When sea cucumbers were fed with β‐glucan continuously, total coelomocytes counts and superoxide anion were significantly higher than control on the 4th day (P < 0.05). However, these two immune parameters were not significantly higher than those in control after the 18th day (P > 0.05). While sea cucumbers continuously fed MOS, these two immune parameters were not significantly higher than control until the 15th day. All immune parameters of the sea cucumbers fed with β‐glucan and MOS alternately were significantly higher than those in control during the experiment (P < 0.05). The sea cucumbers fed with β‐glucan 7 days followed MOS 7 days alternately showed the highest SGR and second lowest cumulative mortality. It was suggested that this feeding strategy is most suitable for sea cucumbers.  相似文献   

17.
The effects of six 1,3;1,6‐β‐D‐glucooligo‐ and polysaccharides with different structures (ranging from 1 to 10 kDa in molecular mass and containing 10–25% of β‐1,6‐linked glucose residues) from brown algae, Saccharina cichorioides, on development of the chum salmon, Oncorhynchus keta (Walbaum), were evaluated. Exposure of chum salmon eggs to 1,3;1,6‐β‐D‐glucans with a molecular mass of more than 2 kDa increased the survival of embryos and juveniles and their resistance to Saprolegnia infection by up to 2.5‐fold, leading to a weight gain in juveniles of 40–55% compared with The control chum salmons. The 1,3;1,6‐β‐D‐glucans with molecular mass of 6–8 kDa and used at a at concentration of 0.5 mg mL?1 rendered the best stimulative effect.  相似文献   

18.
A family of antimicrobial peptides (AMPs) derived from the β‐subunit of haemoglobin was recently isolated from channel catfish, Ictalurus punctatus, infected with Ichthyophthirius multifiliis (ich), an important freshwater fish parasite that causes ichthyophthiriosis. We previously discovered that one of these AMPs, HbβP‐1, had strong cidal activity against ich as well as another ectoparasite, Tetrahymena pyriformis. HbβP‐1 toxicity was specific, primarily affecting the trophozoite (trophont) stage of ich. Here, we show that HbβP‐1 acts more rapidly to kill smaller (presumably less mature) trophonts of ich, taking almost twice as long to kill larger trophonts (P < 0.0001). It acts more rapidly than an unrelated AMP, piscidin 1, which is haemolytic and also lethal to ich trophonts. HbβP‐1 is potently and selectively lethal to the trophont stage of the dinoflagellate ectoparasite, Amyloodinium ocellatum, one of the most important pathogens of warmwater marine fish. HbβP‐1 has no effect on the fish gill cell line feeder layer (G1B cells) used to propagate Amyloodinium, further suggesting a highly selective action. These findings suggest that HbβP‐1 or related AMPs might function in protecting marine as well as freshwater fish and that HbβP‐1 has highly selective activity against specific life stages of important fish ectoparasites.  相似文献   

19.
This study was conducted to investigate the effects of dietary synthetic β‐carotene on growth performance, haematological and immunological parameters, energy reserves and antioxidant status of juvenile fish Piaractus mesopotamicus. Two hundred and ten fish (12.24 ± 2.98 g) were fed with a control extruded feed (CEF) and the same diet supplemented with β‐carotene (BEF) for 90 days. A higher weight gain and specific growth rate were found in fish fed BEF in comparison with those fed CEF. In addition, BEF‐fed fish showed lower liver somatic index and a higher percentage of eosinophils. No statistical differences were found in energy reserves, except for plasma triglycerides which decreased in fish fed with BEF. Regarding oxidative stress markers, decreased activities of antioxidant enzymes were found in intestine and gills of BEF‐fed fish (SOD and GST, respectively). In the liver, both LPO levels and CAT activity decreased in fish fed with BEF. Additionally, lower brain LPO levels without changes in the antioxidant enzymes were observed in BEF‐fed fish. The inclusion of dietary synthetic β‐carotene improved growth and antioxidant status, and had a plasma triglyceride‐lowering effect in juvenile P. mesopotamicus.  相似文献   

20.
The white shrimp Litopenaeus vannamei, fed immunostimulant‐free, 0.2%β‐glucan and 0.06% glycyrrhizin diets for 18 days, respectively, were challenged with Vibrio alginolyticus at 6.4 × 104 CFU shrimp?1. The total haemocyte count (THC), phenoloxidase (PO) activity, respiratory burst (RB) and superoxide dismutase (SOD) activity changes for a 120‐h period were investigated, and shrimp mortality was also recorded. The results showed that PO activity, RB and SOD activity were significantly higher in shrimp fed the two immunostimulant diets after 18 days than those in shrimp fed immunostimulant‐free diets. The THC and SOD activity decreased significantly from 0 to 24 h post challenge, and then reverted to normal levels at 96 and 72 h respectively. The values for PO activity and RB increased from 0 to 48 h post challenge. Compared with those fed the control diets, shrimp fed immunostimulants had significantly higher PO activity and RB values at 120 h post challenge. Mortalities after challenge with V. alginolyticus were significantly lower in shrimp fed with β‐glucan or glycyrrhizin than in those fed with a diet without immunostimulants. It was concluded that dietary β‐glucan and glycyrrhizin increased the shrimp immunity. Furthermore, β‐glucan caused an increase in some immune parameters 12 h earlier than glycyrrhizin after V. alginolyticus challenge.  相似文献   

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