首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Probiotics have been applied extensively in aquaculture and demonstrated a range of benefits, but the mechanisms mediating such responses remain largely unknown. A clear illustration of the effect of probiotics on the autochthonous gut microbiota is the first step in understanding the underlying mechanisms. In this study, the autochthonous microbiota in the foregut, midgut and hindgut of juvenile grouper Epinephelus coioides following the dietary administration of probiotic Enterococcus faecium MM4 for 60?days were assessed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) with subsequent sequencing analysis. Generally similar DGGE patterns, with 15 common bands, were observed in the foregut, midgut and hindgut of fish fed the probiotic diet or the control diet, while more visible bands were present in fish fed the probiotic diet. The similarity dendrogram showed that the foregut samples formed an independent cluster distinctly different from the midgut and hindgut samples, but a high similarity (81.4%) was observed among the three gut sections. Significantly increased species richness and Shannon index were observed in the midgut and hindgut samples in the probiotic group compared with the control group, which suggested that probiotic E. faecium could elevate the autochthonous microbial diversity in the midgut and hindgut. Sequences analysis showed that probiotic E. faecium stimulated the growth of some unidentified bacteria and potentially beneficial bacteria, while exerted no apparent effect on potentially harmful Staphylococcus saprophyticus.  相似文献   

2.
Strains of lactic acid bacteria (LAB) were isolated from several different sources and evaluated in vitro for potential probiotic effects in abalones. Two isolates (Lactobacillus sp. strain a3 and Enterococcus sp. strain s6) were highly resistant to bile salt and/or gastric juice and inhibited the growth of three abalone pathogens (Listonella anguillarum, Vibrio harveyi, and V. carchariae). Each of the LAB isolates was used to supplement diet of the abalone Haliotis gigantea for a period of 3 weeks. One group of animals received Lactobacillus sp. strain a3 added to commercial dry feed, one group received Enterococcus sp. strain s6 added to the feed, and a control group received only standard commercial feed. Culturable LAB counts of gut homogenates indicate the a3 colonized in the gut of abalones. Digestive enzyme activities and the concentrations of a number of volatile short-chain fatty acids (VSCFA) were elevated in the gut of abalones receiving feed supplemented with the two LAB strains. These results indicate that dietary supplementation can enable LAB colonization or persistence in the gut of abalone species and can potentially enhance probiotic effects.  相似文献   

3.
In this study, we evaluate the use of macroalgae as vectors of probiotics bacteria into the digestive tract of abalone to improve their survival and growth. It is shown that when abalone Haliotis rufescens of different sizes were fed with a natural diet composed of fronds of the macroalga Macrocystis integrifolia supplemented with a mixture of Vibrio sp. C21‐UMA, Agarivorans albus F1‐UMA and Vibrio sp. F15‐UMA bacteria, there was a significant increase (P<0.05) in the average monthly growth rate and survival (%)in a period of 210 days, compared with the control without a probiotic supplement. The permanence of the probiotics in the digestive tract of the animals was monitored, and it was found that the number of culturable C21‐UMA and F1‐UMA bacteria decreased significantly (P<0.05) in recently weaned and adult abalone, and they almost disappeared completely on day 19 of the bioassay. However, the culturable Vibrio sp. F15‐UMA disappeared completely from the digestive tract on day 22 of the bioassay, and these were the bacteria that remained at the highest concentration compared with the other two bacterial strains over the experimental period. It is therefore shown that it is feasible to use a probiotic mixture to improve the profitability of the H. rufescens culture.  相似文献   

4.
The autochthonous microbiota in the foregut, midgut and hindgut of juvenile grouper Epinephelus coioides following the dietary administration of probiotic Bacillus clausii for 60 days were assessed using polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE). A complex and generally similar bacterial composition along the digestive tract of E. coioides was detected in the DGGE profiles, while several bacteria showed regional specialization. Similarity dendrogram revealed that the bacterial composition of the foregut was more similar to the midgut than the hindgut. Samples collected from the probiotic group and the control group showed generally similar DGGE patterns, while no significant difference in the total number of bands and Shannon index were observed between the probiotic group and the control group, suggested that probiotic B. clausii exerted no significant effect on the gut microbiota of E. coioides. However, various potentially beneficial bacteria, such as Enterococcus sp.‐like and Bacillus pumilus‐like bacterium were selectively stimulated by probiotic B. clausii, while some potential harmful species, like Staphylococcus sp.‐like and Vibrio ponticus‐like bacterium were depressed. These indicated that the gut microbiota was modified to some degree by probiotic B. clausii. Sequences analysis showed that the autochthonous gut bacteria of E. coioides could be classified into four groups, i.e. Proteobacteria, Firmicutes, Actinobacteria and unclassified bacteria.  相似文献   

5.
Previous studies have shown that the gut microbiota of fish differs depending on host feeding habits and these populations may also be influenced by dietary ingredients. In this study, the bacterial populations of the intestinal tract of the opportunistic omnivore jundiá Rhamdia quelen and the typical omnivore tilapia Oreochromis niloticus were investigated in two experiments. In experiment I, the levels of amylolytic, cellulolytic, lipolytic, proteolytic and total culturable bacteria were compared in the proximal, mid and distal intestine using selective agar. Higher levels of amylolytic, cellulolytic, lipolytic, proteolytic and total culturable bacteria were observed in the tilapia than jundiá, in all intestinal regions. Jundiá contained higher levels of proteolytic bacteria and lipid digesting bacteria in the distal intestinal portion as compared with the mid intestine; both fish species also presented more amylolytic bacteria in the distal intestine. In experiment II, the amylolytic intestinal microbiota between the two species was compared after administration of diets containing different carbohydrate sources. Jundiá fed broken rice presented higher total culturable bacterial levels; however, dietary cassava bagasse and ground corn significantly elevated the population of amylolytic bacteria in tilapia (P > 0.05). PCR‐DGGE was also used to assess the bacterial communities in experiment II. A Cetobacterium spp. was detected in jundiá fed diets containing broken rice, and tilapia fed cassava bagasse, dextrin, broken rice and ground corn. Microbial differentiation was further demonstrated between jundiá and tilapia, because an uncultured bacterium was unique in tilapia and an uncultured spirochete was observed only in jundiá; the presence of these bacterial species was also influenced by dietary carbohydrate sources.  相似文献   

6.
Duplicate groups of Atlantic salmon (Salmo salar L.), kept in seawater, were fed fish meal‐based cold‐pelleted diets. Diets with non‐starch polysaccharides (NSP), either cellulose, purified soybean NSP or extruded purified soybean NSP at a dietary level of 100 g kg?1, were compared with a diet without supplemental NSP and a diet with soybean meal in a 28‐day feeding trial. Isolation and characterizations were limited to culturable bacteria and population levels of aerobic and facultative aerobic heterotrophic autochthonous (adherent) and allochthonous (transient) bacteria present in the mid and distal intestines of Atlantic salmon fed the five different diets estimated using traditional bacteriological techniques. The presence of an autochthonous microbiota was demonstrated using transmission electron microscopy. No significant effects of diet composition were observed on total population levels of culturable bacteria present in the digestive tract, but the study showed that the composition of the gut microbiota (autochthonous or allochthonous) was sensitive to dietary changes. A total of 752 culturable isolates from the intestines were characterized by biochemical and physiological properties. Of these, 188 isolates were further characterized by partial sequencing the 16S rRNA genes. Among these, 146 isolates belonged to 31 phylotypes that were >94% identical to previously described species. However, 42 isolates showed similarity <94% to species available at the National Center of Biotechnology Information. Several of the phylotypes identified in the present study have not been reported previously in the gastrointestinal (GI) tract of fish, including the Gram‐negative bacteria Gelidibacter salicanalis, Pseudoalteromonas elyakovii, Psychrobacter aquimaris, Psychrobacter cibarius, Psychrobacter fozii, Psychrobacter maritimus, Psychrobacter okhotskensis and Psychrobacter psychrophilus. Among the Gram‐positive bacteria identified were Arthrobacter bergeri, Arthrobacter psychrolactophilus, Arthrobacter rhombi, Bacillus pumilus, Bacillus subtilis, Exiguobacterium spp., Microbacterium oxydans, Planococcus maritimus, Sporosarcina ginsengisoli and several bacteria that have been described as unculturable previously. In addition, we identified Carnobacterium inhibens, a lactic acid bacterium that is not frequently isolated from the GI tract of fish. Psychrobacter cibarius was the dominant bacterial species and was isolated from the digestive tract of all fish investigated.  相似文献   

7.
Populations of aerobic heterotrophic bacteria present in the gastrointestinal (GI) tract of healthy Atlantic cod (Gadus morhua L.) fed three different diets, fish meal, standard or a bioprocessed soybean meal (BPSBM), were estimated using the dilution plate technique. A total of 944 isolates were characterised by biochemical and physiological properties and 425 isolates were identified further by sequencing the 16S rRNA genes. Our results showed that gut microbiota were affected by dietary manipulation. The GI tract of fish fed fish meal was dominated by Gram-positive bacteria of the genera Brochothrix and Carnobacterium. The Gram-negative bacteria Chryseobacterium spp. and Psychrobacter glacincola, and Gram-positive bacteria belonging to Carnobacterium, dominated in the digestive tract of fish fed soybean meal. In contrast to these results, genus Psychrobacter dominated in the GI tract when fish were fed BPSBM.Until recently, it was generally suggested that the gut microbiota of fish were less diverse than in homoeothermic animals. However, the present study identified several “new” bacterial species isolated from the alimentary tract of Atlantic cod. These “new” bacterial species are not normally isolated from the GI tract of fish. Based on our finding we suggest that the GI tract microbiota of fish might not be as simple as believed.Antagonistic activity of carnobacteria regarding inhibition of growth of two fish pathogens (Aeromonas salmonicida ssp. salmonicida and Vibrio anguillarum) was observed. However, some difference in the antibacterial activity of Carnobacterium spp. was observed. Whether this antagonistic activity has any effect in challenge studies will be discussed, especially in relation to the finding that the digestive tract is one of the major infection routes in fish.  相似文献   

8.
The effect of dietary administration of probiotic Lactococcus lactis MM1 for 60 d on the autochthonous microbiota in the foregut, midgut and hindgut of juvenile grouper, Epinephelus coioides, was evaluated using polymerase chain reaction‐denaturing gradient gel electrophoresis (DGGE). Samples collected from the probiotic and control groups showed different DGGE patterns, while 11 common bands presented in both groups. The similarity dendrogram revealed three different clusters depending on the three sections of the gastrointestinal (GI) tract, and the probiotic triplicates in each GI section were generally clustered into one group distinctly different from the corresponding control triplicates. Increased species richness and Shannon index were observed in the foregut, midgut, and hindgut samples in the probiotic group compared with the control group, which suggested that probiotic L. lactis MM1 could improve the autochthonous microbial diversity along the GI tract of E. coioides. The growth of many potentially beneficial and unidentified bacteria was stimulated by the probiotic, whereas the growth of some potential harmful species, like Staphylococcus saprophyticus, was depressed.  相似文献   

9.
We evaluated the effects of Bacillus cereus, as an additive in water and feed, on the gut microbiota and immunological parameters of Nile tilapia (Oreochromis niloticus) fingerlings. Experiments were performed in tanks and net cages respectively. Experiment 1: Tilapia were housed in tanks for 42 days, and B. cereus was added to the water at 1.0 × 104 cfu mL?1 (Treatment 1) and 1.0 ×105 cfu mL?1 (Treatment 2) weekly. For the control, no probiotic was added. Experiment 2: Tilapia were housed in cages for 42 days, and the feed was supplemented with B. cereus at 1.0 × 107 cfu g?1 (Treatment 1) and 1.0 × 108 cfu g?1 (Treatment 2) weekly. For the control, no probiotic was added. Each treatment contained three replicates, with 50 male tilapias per replicate. The fish from the probiotic treatments in both tank and cage experiments had significantly higher serum lysozyme and peroxidase activities than the control. In the cage experiment, alkaline phosphatase and total superoxide dismutase activities in tilapia were significantly higher in probiotic treatments compared with the control. The results of polymerase chain reaction‐denaturing gradient gel electrophoresis showed that B. cereus supplementation in the feed and water affected the autochthonous gut bacteria community of tilapia and stimulated various potentially beneficial bacteria. Therefore, B. cereus, as a water or feed additive, could enhance the immune status and affect the gut microbiota of tilapia. Bacillus cereus was more effective as a feed supplement rather than a water additive for enhancing the immune status of tilapia.  相似文献   

10.
Malaysian Mahseer (Tor tambroides) has a good prospect for aquaculture because of its high market demand. However, there is a scarce information on gut microbiota associated with Malaysian Mahseer unlike other fish species. Therefore, we constructed and compared gut microbiota in different developmental stages (larval, juvenile, fingerling, yearling, and adult) using culture dependent and PCR‐DGGE fingerprinting technique for better understanding of gut microbiota composition associated with T. tambroides. Culturable gut microbiota composition in all developmental stages were composed of β‐ and γ‐Proteobacteria, and Bacilli. Biodiversity analysis of culturable gut microbiota showed that larval, juvenile, and adult stages have higher diversity than fingerling and yearling stages. Ward's linkage cluster analysis showed that culturable gut microbiota composition in larval and juvenile stages were close to adult stages, whereas fingerling and yearling stage composed same cluster. PCR‐DGGE fingerprinting technique showed that unculturable gut microbiota were constituted by α‐and γ‐Proteobacteria, and Actinobacteria. Ward's linkage cluster analysis showed that unculturable gut microbiota composition in both larval and juvenile stages were distinct from other developmental stages. Our results revealed that gut microbiota composition were varied in different developmental stages of Malaysian Mahseer and continuous shifts of gut microbiota from larval to adult stages.  相似文献   

11.
In this study, the structural changes of gut microbiota in response to abalone viscera protein hydrolysate (AVPH) were examined in alcohol induced injured mice. The gut microbiota of mice without treatment (blank), alcohol treatment (control), and alcohol+AVPH treatment (sample) were profiled with Illumina sequencing of the V4 region of 16S rDNA genes. The sequencing results revealed that 705, 654, and 888 of Operational Taxonomic Units (OTUs) were determined in the blank, control, and sample groups, respectively. Compared with the control and blank groups, the AVPH had a higher diversity index and a larger number of reads subjecting to Bacilli (class), Lactobacillales (order), Lactobacillaceae (family), and Lactobacillus (genus) levels. However, insignificant difference of beta-diversity or principal component among control, blank, and sample groups was found. This study demonstrates that the in vivo oxidation inhibition pathway in alcohol induced injured mice by AVPH was not via modulating the gut microbiota structure.  相似文献   

12.
This study evaluated the effect of two bacteria, Bacillus amyloliquefaciens and the dairy yogurt (DY) Lactobacillus sp., on improving the growth performance, feed conversion ratio (FCR) and some immunological and haematological parameters. Nile tilapia (19.1 g) were stocked in 0.42 m3 tanks at 67 fish m?3 and fed with two probiotic‐incorporated diets and a control diet for 99 days, followed by a normal diet for another 61 days. At the end of the probiotic feeding, the mean weight, FCR and production rate showed no significant difference among the treatments. However, after 61 days of feeding of the normal diet, the B. amyloliquefaciens fish showed significantly superior growth and better FCR than the control. The DY group had the lowest growth and the poorest FCR. Significantly higher serum lysozyme activity, head‐kidney superoxide dismutase, total immunoglobulin and serum bacterial agglutination titres were recorded in the probiotic groups than the control. Haematological parameters showed no difference between treatments. The B. amyloliquefaciens fed fish showed that the gut microflora was dominated by B. amyloliquefaciens even after the withdrawal of the probiotic. On the contrary, the probiotic bacterial species isolated from the dairy yoghurt did not persist longer in the gut. These results indicate the beneficial effect of administering the bacteria isolated from fish gut microflora, B. amyloliquefaciens, in improving growth, FCR and immunological parameters. The high persistence of B. amyloliquefaciens indicates that the probiotic colonization in the gut is essential for the best responses and economics.  相似文献   

13.
This review addresses the dietary supplements, synbiotics and probiotics in combination with plant products or yeast/β‐glucans in aquaculture. The potential applications of synbiotics have a relatively short history in aquaculture, but have generated interest because of numerous benefits reported in endothermic animals. Since the first study was published by (Aquaculture Science in 2009) the concept has been used in aquaculture to reveal effects on growth performance, gut microbiota, gut histology, immune parameters, haematological and biochemical parameters as well as increased disease resistance. However, a limited number of probiotic bacteria (mainly Bacillus and Enterococcus) and prebiotics (mannan oligosaccharides, fructooligosaccharides, short‐chain fructooligosaccharides, galactooligosaccharides, arabinoxylan–oligosaccharides, isomaltooligosaccharide, chitosan oligosaccharide and inulin) have been used. Additionally, some studies have used plant products or yeast/β‐glucans in combination with probiotics, and these studies suggested that these dietary supplements promote growth performance and boost some immune parameters. The present review identifies evaluations of gut microbiota and gut morphology, and mucosal immune response as significant gaps in existing knowledge and suggests issues that merit further investigations to conclude the potential of dietary supplements in aquaculture.  相似文献   

14.
The present study was conducted to evaluate the effect of dietary supplementation of probiotic bacterium Bacillus licheniformis on the gut microbiota, growth and immune response in Macrobrachium rosenbergii juveniles (4.0 ± 0.02 g). Five isocaloric experimental diets supplemented with different concentrations of B. licheniformis, viz. Control (without probiotic supplementation), T1 (1.0 × 106 cfu g?1feed), T2 (1.0 × 107 cfu g?1feed), T3 (1.0 × 108 cfu g?1 feed) and T4 (1.0 × 109 cfu g?1 feed) were used for the experiment. After 60 days of feeding trial, the growth performance increases significantly in all the experimental groups compared with control, and highest weight gain, specific growth rate and lowest feed conversion ratio were recorded from T4 (P > 0.05). However, juvenile survival was not found to be significantly affected by probiotic supplementation (P > 0.05). The total bacterial count and Bacillus spp. count in the gut were significantly increased with concurrent decrease in pathogenic Aeromonas spp. and Pseudomonas spp. in all the experimental groups compared with control (P < 0.05). Compared with control, immune parameters were increased significantly in all the experimental groups (P < 0.05). Highest haemocyte count, phenol oxidase, superoxide dismutase and antibacterial activity in haemolymph were recorded from T4 (P < 0.05). When prawns were challenged with Vibrio alginolyticus, the cumulative mortality was significantly lower in T4 (P < 0.05). These results indicate that dietary supplementation of B. licheniformis can manipulate the gut microbiota and increase the growth and immune response of M. rosenbergii. In the present study, concentration response on the probiotic effect of B. licheniformis was observed which showed higher effects at a concentration of 1.0 × 109 cfu g?1 feed in the laboratory condition.  相似文献   

15.
Probiotic supplementation in fish aquaculture has significantly increased in the last decade due to its beneficial effect on fish performance. Probiotic use at early stages of fish development may contribute to better face metamorphosis and weaning stress. In the present work, we studied the influence of Shewanella putrefaciens Pdp11 supplementation on growth, body composition and gut microbiota in Senegalese sole (Solea senegalensis) during larval and weaning development. S. putrefaciens Pdp11 was incorporated using Artemia as live vector (2.5 × 107 cfu mL?1) and supplied to sole specimens in a co-feeding regime (10–86 DAH) by triplicate. Probiotic addition promoted early metamorphosis and a significantly higher growth in length at 24 DAH larvae. S. putrefaciens Pdp11 also modulated gut microbiota and significantly increased protein content and DHA/EPA ratios in sole fry (90 DAH). This nutritional enhancement is considered especially important after weaning, where significantly higher growth in length and weight was observed in probiotic fish. Moreover, a less heterogeneous fish size in length was detected since metamorphosis till the end of weaning, being of interest for sole aquaculture production. After weaning, fish showed significantly higher growth (length and weight) and less variable lengths in fish when supplemented with probiotics. Both the enhancement of nutritional condition and the decrease in size variability associated with probiotic addition are highly interesting for sole aquaculture production.  相似文献   

16.
Two bacterial strains Lactobacillus fructivorans (AS17B), isolated from adult sea bream (Sparus aurata) gut, and Lactobacillus plantarum (906), isolated from human faeces, were administered contemporaneously, during sea bream development using Brachionus plicatilis and/or Artemia salina and dry feed as vectors. The probiotic treatment influenced gut colonization: at 35 days post-hatching (p.h.) L. fructivorans was not present in the gut, but the treatment induced colonization by L. plantarum. At 66 days p.h., L. fructivorans was evident also in the control; moreover, when suitable environmental conditions appeared in the post-metamorphosis gastro-intestinal tract, competition between L. plantarum and L. fructivorans occurred. At 90 days p.h., L. plantarum was displaced by L. fructivorans that became significantly higher with respect to the control. In treated groups, probiotic administration significantly decreased larvae and fry mortality.  相似文献   

17.
The concept of the use of probiotic organisms or prebiotic compounds to modify the fish gut microflora is becoming a popular topic for investigation. A major flaw in many such studies is a failure to consider fully the nature of the established microflora, which is to be modified pre-, or probiotically. Since it is widely accepted that a large proportion of bacteria are non-culturable, the use of conventional bacteriological (culture) techniques alone to investigate fish intestinal microflora may be expected to bias results. We report a study designed to investigate the normal intestinal microflora of rainbow trout (Oncorhynchus mykiss) using both conventional bacteriological and molecular methods.Over an 18 month period, the intestinal microflora of a single population of laboratory-raised rainbow trout was investigated. Bacteria isolated using bacteriological techniques were identified using the BiOLOG system and 16S rRNA gene sequencing. Dominant bacteria consistently were Aeromonas sp. and Carnobacterium piscicola, demonstrating that the microflora is stable in fish kept in defined conditions. Restriction Fragment Length Polymorphism (RFLP) and 16S rRNA gene sequence analysis was used to investigate anaerobic and non-culturable bacteria. An obligate anaerobe, Clostridium gasigenes, was shown to be among the dominating intestinal microflora.  相似文献   

18.
Dried distiller's grain (DDG) is considered as an alternative ingredient of dietary feed due to its high contents of protein, fibre and fat. In this study, 60 g kg‐1 of DDG was used to feed grass carp (Ctenopharyngodon idella), bluntnose black bream (Megalobrama amblycephala), gibel carp (Carassius gibelio) and black carp (Mylopharyngodon piceus) for 8 weeks, and its effect on fish production and gut allochthonous microbiota was investigated for the development of a suitable fish feed high in nutrients and low in cost for polyculture freshwater fish. DDG supplementation resulted in the less weight gain and higher feed conversion ratio of black carp (P < 0.05), but had no significant effects on other fish or parameters. PCR–denaturing gradient gel electrophoresis (DGGE) analysis indicated that all four fish species had some common and unique bacteria in their digestive tracts, and the gut microbiota of bluntnose black and gibel carp fed the control diet and DDG diets were very similar (Cs > 91%); of them, the total counts of intestinal bacteria studied by qPCR increased in grass carp (P < 0.05) and depressed in black carp (P < 0.05) when fed dietary DDG. Thus, we assumed that dietary DDG modulated production and gut microbiota of fish in a host‐specific way.  相似文献   

19.
The dietary supplementation of prebiotics, probiotics and symbiotic in hybrid surubins (a Pseudoplatystoma corruscans and P. fasciatum cross) was evaluated for the effects on their autochthonous intestinal microbiota and on haematological and immunological parameters. A total of 160 fish were divided into four treatment groups with four replicates each. The treatment groups were fed with the following diets for 15 days: control diet without supplementation; 0.5% inulin (prebiotic) supplementation; Weissella cibaria (CPQBA 001‐10 DRM 02) (7.87 ± 0.2 log CFU g?1) supplementation; or 0.5% inulin and W. cibaria supplementation (symbiotic group). The midgut intestines of the fish with the symbiotic diet supplementation had higher concentrations of lactic acid bacteria (7.07 ± 1.11 log CFU g?1) and low levels of Vibrio spp (1.90 ± 0.60 log CFU g?1) and Pseudomonas spp (2.23 ± 1.48 log CFU g?1). In addition, increased erythrocytes and reduced circulating neutrophils were observed in this group. No differences in blood glucose, serum protein or lysozyme levels were detected between treatment groups. However, a higher concentration of total immunoglobulin was observed in fish fed with the probiotic and symbiotic diets. The addition of 0.5% inulin (prebiotic) thus W. cibaria (probiotic) to the diet of Pseudoplatystoma hybrid surubins reduce the number of pathogenic bacteria and stimulate the beneficial intestinal microbiota and may possibly alter their immune defence system.  相似文献   

20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号