Effects of dietary supplementation of probiotic,Clostridium butyricum,on growth performance,immune response,intestinal barrier function,and digestive enzyme activity in broiler chickens challenged with Escherichia coli K88

Background： Colibacillosis caused by enterotoxigenic Escherichia coil （E. coil} results in economic losses in the poultry industry. Antibiotics are usually used to control colibacillosis, however, E. coli has varying degrees of resistance to different antibiotics. Therefore the use of probiotics is becoming accepted as an alternative to antibiotics. In this study, we evaluated the effects of Clostfidium butyricum （C. butyficum） on growth performance, immune response, intestinal barrier function, and digestive enzyme activity in broiler chickens challenged with Eschefichia coli （E. coil） K88. Methods： The chickens were randomly divided into four treatment groups for 28 days. Negative control treatment （NC） consisted of birds fed a basal diet without E. coil K88 challenge and positive control treatment （PC） consisted of birds fed a basal diet and challenged with E. coil K88. C. buO/ricum probiotic treatment （CB） consisted of birds fed a diet containing 2 x 107 cfu C. buO/ricum/kg of diet and challenged with E. coil K88. Colistin sulfate antibiotic treatment （CS） consisted of birds fed a diet containing 20 mg colistin sulfate/kg of diet and challenged with E. coil K88. Results： The body weight （BW） and average day gain （ADG） in the broilers of CB group were higher （P 〈 0.05） than the broilers in the PC group overall except the ADG in the 14-21 d post-challenge. The birds in CB treatment had higher （P 〈 0.05） concentration of tumor necrosis factor-a （TNF-a） at 3 and 7 d post-challenge, and higher （P 〈 0.05） concentration of interleukin-4 （IL-4） at 14 d post-challenge than those in the PC treatment group. The concentration of serum endotoxin in CB birds was lower （P 〈 0.05） at 21 d post-challenge, and the concentrations of serum diamine oxidase in CB birds were lower （P 〈 0.05） at 14 and 21 d post-challenge than in PC birds. Birds in CB treatment group had higher （P 〈 0.05） jejunum villi height than those in PC, NC, or CS treatment at 7, 14, and 21 d post-challenge. In comparison to PC birds, the CB birds had lower （P 〈 0.05） jejunum crypt depth during the whole experiment. The birds in CB or CS treatment group had higher （P 〈 0.05） activities of amylase and protease at 3, 7, and 14 d post-challenge, and higher （P 〈 0.05） activity of lipase at 3, 7 d post-challenge than PC birds.

Effect of water temperature on digestive enzyme activity and gut mass in sea cucumber Apostichopus japonicus (Selenka),with special reference to aestivation

The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopusjaponicus, including relative gut mass （RGM）, amylase, lipase, pepsin and trypsin activities were studied at temperatures of 7, 14, 21, and 28℃ over a period of 40 days. Results show that RGM significantly decreased after 40 days at 21 ℃ and markedly decreased over the whole experiment period at 28℃; however, no significant effect of duration was observed at 7 or 14℃. At 14℃, trypsin activity significantly decreased over 10 and 20 days, then increased; amylase and trypsin activity significantly decreased after 40 days at 28℃. However, no significant effect of duration was found on amylase, pepsin or trypsin activities in the other temperature treatment groups. At 28℃, lipase activity peaked in 20 days and then markedly decreased to a minimum at the end of the experiment. On the other hand, pepsin activity at 28℃ continuously increased over the whole experimental period. Principle component analysis showed that sea cucumbers on day 40 in the 21℃ group and in the previous 20 days in the 28℃ group were in the prophase of aestivation. At 28℃, sea cucumbers aestivated at 30-40 days after the start of the experiment. It is concluded that the effect of temperature on the digestion ofA. japonicus is comparatively weak within a specific range of water temperatures and aestivation behavior is accompanied by significant changes in RGM and digestive enzyme activities.

Effects of Hanseniaspora opuntiae C21 on the growth and digestive enzyme activity of juvenile sea cucumber Apostichopus japonicas

The effects of a diet containing Hanseniaspora opuntiae C21 on growth and digestive enzyme activity were estimated in juvenile Apostichopus japonicus. Groups of sea cucumbers were fed diets containing H. opuntiae C21 at 0(control), 10 4, 10 5, and 10 6 CFU(colony-forming units)/g feed. Results showed that after 45 d the specific growth rate(SGR) of sea cucumbers fed a C21-supplemented diet at 10 4 CFU/g feed was significantly higher than that of the control( P < 0.05). Intestinal trypsin and lipase activities were significantly enhanced by C21 administration at 10 4 and 10 5 CFU/g feed compared with the control( P < 0.05). After feeding for 23–42 d, C21 was demonstrated by denaturing gradient gel electrophoresis to be present in the intestine of sea cucumbers. In addition, after feeding the C21-supplemented diets for 15 d, the sea cucumbers were switched to an unsupplemented diet and C21 was confirmed to be capable of colonizing the intestine for at least 31 d after cessation of feeding. In conclusion, C21 was shown to successfully colonize the intestine of juvenile A. japonicus via dietary supplementation, and improve growth and digestive enzyme activity.

Effect of dietary genistein on growth performance,digestive enzyme activity,and body composition of Nile tilapia Oreochromis niloticus

An 8-week feeding experiment was performed to evaluate the effect of dietary genistein on growth performance,body composition,and digestive enzymes activity of juvenile Nile tilapia(Oreochromis niloticus).Four isonitrogenous and isoenergetic diets were formulated containing four graded supplements of genistein:0,30,300,and 3 000 μg/g.Each diet was randomly assigned in triplicate to tanks stocked with 15 juvenile tilapia(10.47±1.24 g).The results show that 30 and 300 μg/gdietary genistein had no significant effect on growth performance of Nile tilapia,but the higher level of genistein(3 000 μg/g)significantly depressed the final body weight and specific growth rate.There was no significant difference in survival rate,feed intake,feed efficiency ratio or whole body composition among all dietary treatments.An assay of digestive enzymes showed that the diet containing 3 000 μg/ggenistein decreased stomach and hepatopancreas protease activity,and amylase activity in the liver and intestine,while a dietary level of300 μg/g genistein depressed stomach protease and intestine amylase activities.However,no significant difference in stomach amylase activity was found among dietary treatments.Overall,the results of the present study indicate that a high level of dietary genistein(3 000 μg/g,or above) would significantly reduce the growth of Nile tilapia,partly because of its inhibitory effect on the activity of major digestive enzymes.Accordingly,the detrimental effects of genistein,as found in soybean products,should not be ignored when applied as an alternative ingredient source in aquaculture.

Effects of Pseudoalteromonas sp. BC228 on Digestive Enzyme Activity and Immune Response of Juvenile Sea Cucumber(Apostichopus japonicus)

A marine bacterium, Pseudoalteromonas sp. BC228 was supplemented to feed in a feeding experiment aiming to determine its ability of enhancing the digestive enzyme activity and immune response of juvenile Apostichopus japonicus. Sea cucumber individuals were fed with the diets containing 0(control), 105, 107 and 109 CFU g-1 diet of BC228 for 45 days. Results showed that intestinal trypsin and lipase activities were significantly enhanced by 107 and 109 CFU g-1 diet of BC228 in comparison with control(P < 0.01). The phagocytic activity in the coelomocytes of sea cucumber fed the diet supplemented with 107 CFU g-1 diet of BC228 was significantly higher than that of those fed control diet(P < 0.05). In addition, 105 and 107 CFU g-1 diet of BC228 significantly enhanced lysozyme and phenoloxidase activities in the coelomic fluid of sea cucumber, respectively, in comparison with other diets(P < 0.01). Sea cucumbers, 10 each diet, were challenged with Vibrio splendidus NB13 after 45 days of feeding. It was found that the cumulative incidence and mortality of sea cucumber fed with BC228 containing diets were lower than those of animals fed control diet. Our findings evidenced that BC228 supplemented in diets improved the digestive enzyme activity of juvenile sea cucumber, stimulated its immune response and enhanced its resistance to the infection of V. splendidus.

Effect of synbiotics on intestinal microflora and digestive enzyme activities in rats

AIM: To investigate the effect of synbiotics, i.e. probiotics and prebiotics mixture, on the gut microbial ecology and digestive enzyme activities in rats. METHODS: Forty-eight SD rats weighing about 280 g were used in this study. Rats were divided into three groups according to the contents of probiotics and prebiotics mixture in the feed as control, low and high dose groups. The duration of the experiment was 8 wk. RESULTS: Compared with the control group, thefecal Lactobacillus and Bifidobacterium counts were significantly increased and the fecal Coliform organism counts were markedly reduced in the low and high dose groups. Concerning the digestive enzyme activity of jejunum, only lactase activity increased in low dose group. However, significant increase of lipase, lactase, sucrase, and isomaltase activities were observed in high dose group.CONCLUSION: Intake of low and high dosages of probiotics and prebiotics mixture significantly improved the ecosystem of the intestinal tract by increasing the probiotics population and digestive enzyme activities in rats.

Effect of Different Dietary Protein and Lipid Levels on the Growth,Body Composition,and Intestinal Digestive Enzyme Activities of Juvenile Yellow Drum Nibea albiflora(Richardson)

An 8-week feeding trial was conducted to determine the optimal dietary protein-to-lipid ratio for juvenile Nibea albiflora with an initial weight of(11.76 ± 0.20) g.Nine experimental diets containing different concentrations of protein(40%,47%,or 54%) and lipids(5%,9%,or 13%) in a 3 × 3 factorial experimental design were tested in triplicate groups of fish,while the protein-to-energy(P/E) ratios of the diets varied in the range of 19.74–28.32 mg k J^(-1).Results showed that fish fed diets containing 9% or 13% lipids with 54% protein exhibited significantly higher weight gains and specific growth rates than those fed other diets.The feed conversion rate of fish fed the diet with 40% protein and 5% lipids was significantly poorer than that of fish fed other diets.The protein efficiency rate of fish fed diets with 5% lipids was significantly lower than that of fish fed 9% or 13% lipid diets.Carcass lipid and energy contents were positively correlated with dietary lipid level regardless of protein level.Fish fed a 54% protein diet showed the highest trypsin activity.The intestinal lipase activity of fish fed the diet containing 13% lipids was significantly higher than that of fish fed 5% or 9% lipid diets.These results demonstrate the high protein dietary requirements of N.albiflora.A diet containing 54% protein and 9%–13% lipids with a P/E ratio of 26.2–27.81 mg protein k J^(-1) can be considered optimal for juvenile N.albiflora.

Growth performance,digestive enzyme activities and serum nonspecific immunity of the red tilapia(Oreochromis mossambicus×Oreochromis niloticus)feddiets supplemented with ultrafine powder of Enteromopha prolifera

The present study evaluated ef fects of ultrafine powder of the green macroalgae E nteromopha prolifera as dietary supplement on growth performance, digestive enzyme activities and serum nonspecific immune responses of the red tilapia(O reochromis mossambicus × Oreochromis niloticus). The red tilapia were fed five diets supplemented with different levels of E. prolifera ultrafine powder as well as a control diet containing no E. prolifera for seven weeks(Diets 0–6 contained 0(control), 10, 20, 30, 40 and 50 g/kg of E. prolifera ultrafine powder, respectively). The results showed that diets supplemented with E. prolifera ultrafine powder generally improved growth, immunity and digestive enzyme activities of the red tilapia. In particular, the fish fed the diet incorporated 50 g/kg (5%) E. prolifera ultrafine powder(Diet 5) achieved the highest percentage weight gain, specific growth rate and the condition factor(increased by 15.4%, 8.0% and 5.7%, respectively when compared to the control). Feeding the diet also led to significantly increases( P <0.05) in serum nonspecific immune responses, including total superoxide dismutase, acid phosphatase, alkaline phosphatase, lysozyme activities and serum total protein(increased by 19.4%, 48.1%, 29.5%, 30.3% and 8.7%, respectively) as well as digestive enzyme activities of erepsin, gastric amylase, gastric lipase, pepsin, intestinal amylase and gastric lipase(increased by 15.7%, 33.3%, 16.3%, 21.3%, 52.3% and 28.2%, respectively) than those of the control. Based on these results, it is recommended that the inclusion level of E. prolifera ultrafine powder in the diet of the red tilapia should be 50 g/kg(or 5%).

Effects of Dihydromyricetin Extracted from Ampelopsis grossedentata on Visceral Organ Indexes and Intestinal Digestive Enzyme Activities of Chickens

To provide a reference basis for reasonable development and utilization of Ampelopsis grossedentata resource and its application in production,we added 0.025%,0.05% and 0.1% dihydromyricetin（DMY）extracted from A.grossedentata into the basal diets of Yaoshan chickens,and studied the effects of DMY on visceral organ indexes and digestive enzyme activities of 40-day-old healthy Yaoshan chickens.Supplementation of DMY in basal diets influenced visceral organ weight,organ index,length and digestive enzyme activity of small intestine of chickens.Among them,0.05% DMY was the most appropriate volume for supplementation.Compared with control group（without DMY）,0.05% DMY reduced lung weight and index（P〉0.05）,significantly reduced liver weight（P〈0.05）,extremely reduced stomach weight and stomach index（P〈0.01）,increased activity of amylase in small intestine（P〉0.05）,significantly increased length of small intestine and activity of protease（P〈0.05）.Supplementation of 0.05% DMY reduced the visceral organ weight and organ index,enhanced digestion and absorption ability of gastrointestinal tract,thereby improving feed utilization rate and promoting the growth of chickens.

Effects of Dietary Carbohydrate-lipid Ratio on Growth, Body Composition and Digestive Enzyme Activities of Juvenile Peanut Worm,Sipunculus nudus

[Objective] This study was conducted to investigate the effects of dietary carbohydrate-lipid( C / L) ratios on growth performance,body composition and digestive enzyme activities of juvenile peanut worm. [Methods]Juvenile peanut worm with average body weight of( 16. 77 ± 0. 40) mg were fed with five isonitrogenous and isoenergetic diets formulated to contain different carbohydrate / lipid( C / L) ratios( 0. 68,1. 02,1. 62,2. 61 or 4. 35) for 8 weeks. [Results] The dietary C / L ratios had no significant effects on survival of juvenile peanut worm( P 】 0. 05). With the increasing of dietary C / L ratios,weight growth rate( WGR)and specific growth rate( SGR) increased when dietary C / L ratios were between 0. 68 and 2. 61,and then decreased significantly with dietary C / L ratio further increased. When the dietary C / L ratio was 2. 61( carbohydrate level was 20. 64%,lipid level was 7. 92%) both WGR and SGR produced the maximum value,they were 451. 78 ± 16. 85% and 3. 41 ± 0. 06 % / d,respectively. The dietary C / L ratios had significant effects on body moisture,body protein content and body lipid content( P 【 0. 05),but no significant effects on body ash content of juvenile peanut worm( P 】 0. 05). Different C / L ratios had significant effects on amylase activity and lipases activity of juvenile peanut worm( P 【 0. 05),but no significant effects on protease activity( P 】 0. 05). [Conclusion]The regression model analysis showed that the most suitable dietary C / L ratio which can make juvenile peanut worm acquire the best weight growth rate is 2. 42.

Comparison of Digestive Enzyme Activities in Normal and Growth Retarded Japanese Eels(Anguilla japonics)

[ Objective] This experiment was conducted to compare the activity difference of digestive enzymes in Japanese eels Anguilla japonics and growth retarded eels under different reaction temperature. [Method] Both 20 normal Japanese eels （Weight from 126.4 to 140.2 g per eel） and 20 growth retarded eels （Weight from 3.5 to 8.6 g per eel） were selected, then, the protease, amylase, lipase activities in hepatopancreas, intestine and stomach under the reaction temperature 5, 10, 15, 25, 30, 35, 40, 45 and 55℃ were measured. [ Result] The protease activities in hepatopancreas, intestine and stomach all reached the highest value for both normal eels and growth retarded eels, and the order of protease activities was intestine 〉 stomach 〉 hepatopancreas except the protease activities of growth retarded eels at the temperature of 5, 15, 55℃ The protease activities in hepatopancreas, intestine and stomach of growth retarded eels were 29.5%, 15.7% and 25.2% of those of normal eels（ P 〈0. 05）. The amylase activities of both normal and growth retarded eels reached the highest value at the temperature of 30 ~C. The amylase activity or- der of normal eels was hepatopancreas 〉 intestine 〉 stomach expect the amylase activity at the temperature of 5 ~C, while the amylase activity order of growth retarded eels is intestine 〉 hepatopancreas 〉 stomach. The amylase activities in hepatopancreas, intestine and stomach of growth retarded eels were 42.4%, 73.7% and 43.8% of those of normal eels （ P 〈 0.05）. The lipase activities of both normal and growth retarded eels reached the highest value at the temperature of 35 ~C. The lipase activity order of normal eels was hepatopancreas 〉 stomach 〉 intestine, while the lipase activity order of growth retarded eels was hepatopancreas 〉 intestine 〉 stomach expect the lipase activity at the temperature of 35 ~C. The lipase activities in hepatopancreas, intestine and stomach of growth retarded eels were 41.5%, 45.6% and 23.2% of those of normal eels（ P 〈0.05）. [ Conclusion] The protease, amylase, lipase activities in hepatopancreas, intestine and stomach of growth retarded Japanese eels were significantly lower than those of normal Japanese eels, therefore, its growth was affected directly.

Impact of Different Diets on Adult Tri-Spine Horseshoe Crab,Tachypleus tridentatus

Effective culture and management of adult tri-spine horseshoe crab,Tachypleus tridentatus can ensure that stock enhancement programs and aquaculture systems are maintained.To explore suitable feed for animals during the breeding season,Pacific oyster(Ostrea gigas)(oyster group;OG)and frozen sharpbelly fish(Hemiculter leucisculus)(frozen fish group;FG)were selected to feed 20 T.tridentatus male and female pairs,respectively.At the end of the experiment,intestinal samples were obtained to measure digestive enzymes activities.The intestinal flora were determined by 16S r DNA sequencing.No eggs were observed in the FG and one T.tridentatus adult died.No animals died in the OG,and 9.7×10;eggs were obtained.These results show that oysters are more suitable for the development and reproduction of adult T.tridentatus than frozen fish.Additionally,the digestive enzyme activity analysis revealed that animals in the OG exhibited higher protein digestibility than those in the FG,but no significant differences in lipid and carbohydrate uptake were observed between the groups.Furthermore,the intestinal flora analysis showed that operational taxonomic units(OTUs)and the Chao1 index were significantly higher in the OG than in the FG,but no significant difference was observed in the Shannon or Simpson indices between the groups.Our data indicate that the oyster diet improved the intestinal microbial diversity of T.tridentatus.We hypothesize that nutrients,such as oyster-based taurine,proteins,and highly unsaturated fatty acids,improve protease activity in the T.tridentatus digestive tract,alter the intestinal floral structure,and improve the reproductive performance of T.tridentatus.

Colonization and Probiotic Effect of Metschnikowia sp. C14 in the Intestine of Juvenile Sea Cucumber, Apostichopus japonicus

Viable cell count was used to determine whether Metschnikowia sp.C14 can colonize the intestine of juvenile sea cucumber Apostichopus japonicus.Sea cucumber individuals were divided into two groups,which were fed the control diet for 38 days or the C14-supplemented diet at 105 cells g−1 diet for 28 days,then the control diet from day 29 to day 38.The number of C14 cells in the intestine of sea cucumber fed the C14-supplemented diet significantly increased from day 7 to day 28,and decreased from day 29 to day 38.Sea cucumber fed with the diet containing C14 showed a significant increase in trypsin activity and lipase activity from day 21 to day 33 compared with the control.Feeding C14 significantly improved the phagocytic activity and respiratory burst in coelomocytes from day 21 to day 35 and from day 14 to day 38,respectively.In addition,there was an obvious enhancement in lysozyme activity(from day 21 to day 38 or day 33),phenoloxidase activity(from day 21 to day 28)and total nitric oxide synthase activity(from day 14 to day 38)in coelomic fluid supernatant and/or coelomocyte cell lysate supernatant compared with the control.There were significant positive correlations between the number of C14 cells colonizing the intestine and trypsin activity of the intestine,lysozyme activity of the coelomic fluid supernatant and coelomocyte lysate supernatant from sea cucumber.These data suggested that the number of C14 cells should be maintained at 105 cfu(colony-forming units)g−1 intestine material for the maximum benefit.

Short-Term Biochemical Impacts in Cyphoderus javanus Borner (Collembola) as Potential Biomarkers of Fly Ash and Heavy Metal Pollution in Tropical Lateritic Soil

The detritivorous soil microarthropods are ideal models for environmental health assessment, but only scant information is available on their biomarker potentials against xenobiotics in the tropical edaphic conditions. This microcosm study has estimated short-term biochemical changes with respect to tissue nutrient levels and digestive enzyme activities in a near cosmopolitan Collembola Cyphoderus javanus Borner exposed to coal fly ash amended lateritic cropland soil (5% and 20% w/w i.e. 50 or 200 t ·ha-1), and cadmium sulphate (200 mg/kg soil)/lead acetate (200 mg/kg soil) treated sterile river sand. The levels of total tissue carbohydrates, proteins, free amino acids, and lipids decrease within 7 days in the specimens of fly ash (P α-amylase, cellulase and protease activities are also down regulated by fly ash and heavy metals (P < 0.05). It is also observed the enzyme: protein ratios increase in fly ash treated sets and decrease in lead and cadmium treated specimens. Specimens in treated sets accumulate high levels of lead and cadmium within 15 days, which decrease subsequently probably due to elimination through frequent moulting. These short-term biochemical effects in Collembola have applied importance in C. javanus, as biomarkers for quick ecotoxicological assessments in the tropical agricultural soils.

Effect of Fermentation Bed with Spent Mushroom Substrate of Pleurotus eryngii on Weaning Piglets

[Objective] The paper was to investigate effects on fermentation bed temperature,growth performance,diarrhea rate and digestive en-zyme activity of weaning piglets by using spent mushroom substrate of Pleurotus eryngii as padding.[Method] A total of 120 weaning piglets（Duroc × Landrace ×Yorkshire） with average initial body weight of（8.0 ±0.5）kg were allocated to five dietary treatments in a randomized complete block design for 42 d,each of which was replicated three times with eight piglets per replicate（half male,half female）.The padding for control group was（50% sawdust ＋50% rice husk）;experimental group Ⅰ 100% spent mushroom substrate;experimental group Ⅱ（15% sawdust ＋15% rice husk ＋70% spent mushroom substrate）;experimental group Ⅲ（25% sawdust ＋25% rice husk ＋50% spent mushroom substrate）;experimental group Ⅳ（35% sawdust ＋35% rice husk ＋30% spent substrate）.[Result] There was no significant difference in surface temperature of fermentation bed between experimental groups and control group（P〉0.05）.Compared with the control group,the temperature under 20 cm of fermentation bed in ex-perimental groups I,Ⅱ and Ⅲ increased significantly（P〈0.05）.Except for experimental group Ⅳ,other three experimental groups had higher aver-age daily gain（P〈0.05） and experimental group Ⅰ had higher average daily feed intake（P〈0.05） compared to the control group.The diarrhea rate and mortality of weaning piglets in experimental groups Ⅱ,Ⅲ and Ⅳ were significantly decreased compared with the control group（P〈0.05）.Compared with the control group,other three experimental groups had higher digestive enzyme activity in duodenal contents except for experimental group Ⅳ（P〈0.05）.[Conclusion] Spent mushroom substrate of P.eryngii can be used as fermentation bed padding,and the optimal proportion was experimental group Ⅲ.

Comparisons of blood biochemical parameters,digestive enzyme activities and volatile fatty acid profile between Meishan and Yorkshire piglets

This study was conducted to compare physiological characteristics between Meishan and Yorkshire piglets in their early lives. Six healthy purebred Meishan sows and Yorkshire sows with close farrowing dates were used in this research. The piglets sucked their respective sow’s milk for 14 days, then they were slaughtered to collect samples of blood, pancreas, contents of stomach, jejunum, cecum, colon as well as feces for analysis of blood biochemical parameters, digestive enzymes, and volatile fatty acid(VFA). The results showed that Yorkshire piglets had higher concentrations of high-density lipoprotein cholesterol(HDL-C) and total cholesterol(TC)(P < 0.05). Gastric lipase activity was higher in Meishan piglets but Yorkshire piglets had higher lactase activity(P < 0.05). The total VFA together with acetate and propionate in cecum and colon were higher in Meishan piglets than in Yorkshire piglets(P < 0.05),but acetate in jejunum and ratio of acetate to propionate in colon were lower in Meishan piglets than in Yorkshire piglets(P < 0.05). In conclusion, in early suckling period, significant differences exist in host metabolism and intestinal microbial metabolism between Meishan and Yorkshire piglets.

Potential probiotic and health fostering effect of host gut-derived Enterococcus faecalis on freshwater prawn,Macrobrachium rosenbergii

The present study investigated the potential probiotic effect of Enterococcus faecalis against a pathogenic microorganism,Vibrio harveyi occurring in the giant freshwater prawn(Macrobrachium rosenbergii).V.harveyi was isolated from the intestine of M.rosenbergii through biochemical tests and PCR-based molecular assays.An in-vitro challenge was conducted by mixing isolated probiotic(5.12 log CFU/g)and V.harveyi(3.09 log CFU/g).Feeds incorporated with E.faecalis(9.02 log CFU/g)were applied to the treatment group during in vivo test in the aquarium and earthen pond(70 m^(2),1 m depth).Pathogenic bacteria were found to be reduced after 8 h(from 5.02 to 3.62 log CFU/g)and 60 days(from 5.44 to 2.15 log CFU/g)of probiotic administration in the in vitro and in vivo test,respectively.The E.faecalis mixed feed also showed higher weight gain(WG%,481.22%±17.71%;SGR%,2.93%±0.18%)and digestive enzymes activities(amylase,1.26±0.08 unit/mg;protease,2.78±0.02 unit/mg)compared to control group(WG%,371.31%±13.35%;SGR%,2.30%±0.32%;amylase,0.7±0.03 unit/mg;protease,1.82±0.02 unit/mg).Furthermore,the probiotic also improved the immune response by augmenting NGH(from 73.33%±0.23%to 74.63%±0.11%)and SGH(from 22.24%±0.06%to 23.13%±0.08%)in the treatment group.Therefore,E.faecalis could be recommended to use against bacterial infections of the M.rosenbergii.