Swimming crab (Portunus trituberculatus) are an important aquaculture species in eastern coastal ... more Swimming crab (Portunus trituberculatus) are an important aquaculture species in eastern coastal areas of China. To improve the understanding of P. trituberculatus culture ecosystem functioning, the dynamics of energy flow and trophic structure of a P. trituberculatus polyculture system (co-culture with white shrimp Litopenaeus vannamei and short-necked clam Ruditapes philippinarum) were investigated in this study. Three Ecopath models representing the early, middle, and late culture periods of a P. trituberculatus polyculture ecosystem, respectively, were constructed to compare ecosystem traits at different culture periods. The results demonstrated that detritus was the main energy source in this polyculture ecosystem, and most of the total system throughput occurred at trophic levels I and II. Artificial food input and consumption by the culture organisms increased from early to middle and late periods, which produced marked impacts on biomass structure and primary production. R. ...
Effects of rhythmic temperature change on the growth, body composition and energy budget of hybri... more Effects of rhythmic temperature change on the growth, body composition and energy budget of hybrid grouper (Epinephelus lanceolatus ♂ 9 E. fuscoguttatus ♀) were investigated. Nine groups of fish received repeating cycles of low-temperature manipulation (22°C) for 1, 2 and 4 days followed by recovery temperature (28°C) for (3, 7 and 11 days), (6, 14 and 22 days) and (12, 28 and 44 days) respectively, designated as L1R3, L1R7, L1R11, L2R6, L2R14, L2R22, L4R12, L4R28 and L4R44 respectively. In the control group (C), fish were reared at 28°C throughout the whole experiment. After 96-day feeding trail, the final weight, relative weight gain rate, specific growth rate, food conversion efficiency and apparent digestibility coefficient of fish in L4R28 were significantly higher than those of control (p < .05). The crude protein contents of fish in L2R14, L2R22, L4R12, L4R28 and L4R44 were significantly higher compared to the control (p < .05). According to energy budget, fish in L4R28 exhibited significantly higher proportion of food energy assimilated into growth and lower proportion consumed for excretion than the control fish (p < .05). These results indicated the occurrence of complete or over growth compensation in hybrid grouper, and the use of repeated cycles of low temperature (22°C) for 4 days followed by recovery temperature (28°C) for 28 days could obtain enhanced growth, that is overcompensation, with improved apparent digestibility coefficient, food conversion efficiency and energetic efficiency into growth. This technique would be more practically applicable in indoor culture for this species.
Abstract Pacific white shrimp (Litopenaeus vannamei) is an important aquaculture species worldwid... more Abstract Pacific white shrimp (Litopenaeus vannamei) is an important aquaculture species worldwide, and there is a growing concern over misdescribed shrimp products, particularly over their geographical origins. Shrimp samples were collected from 12 locations in northern and southern China to develop traceability methods in identifying their geographic origins. In one of the sampling sites, shrimp were collected from five farms using the same water source but feeding with different brands of feed to investigate the effect of feed on the elemental compositions of shrimp. Totally 35 elements (Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Y, U, Li, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Ag, Cd, Cs, Ba, and Pb) were detected in both shrimp and feed. Only Cd and Tb in shrimp were positively correlated with those in the feed. Moreover, 24 elements (Li, Al, V, Fe, As, Rb, Sr, Cd, Pb, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, and Y) in shrimp were significantly different between northern and southern China. Elements As, Fe, Pb, Rb, Cs, and U, selected by stepwise discriminant analysis (SDA), were used to create a new dataset (SSDAs dataset) to compare with the entire dataset (ATEs dataset) in discrimination analyses. Classification tools, including linear discriminant analysis (LDA), k-nearest neighbor (KNN), and random forest (RF) were used to create a discrimination model to authenticate shrimp provenance based on the ATEs and SSDAs datasets. The highest discrimination rate was achieved with RF using the SSDAs dataset, which achieved an overall correct discrimination rate of 100%, a cross-validation rate of 98.78%, and a predictive discrimination rate of 100%. Therefore, elemental profiling combined with chemometrics is a promising method which can be used to identify shrimp provenance.
The global shrimp industry has suffered bacterial diseases caused mainly by Vibrio species. The t... more The global shrimp industry has suffered bacterial diseases caused mainly by Vibrio species. The typical vibriosis, acute hepatopancreatic necrosis disease (AHPND), has resulted in mass mortality and devastating economic losses. Thus, therapeutic strategies are highly needed to decrease the risk of vibriosis outbreaks. Herein, we initially identified that the growth of the causative agent of AHPND, Vibrio parahaemolyticus (VP AHPND) and other vibrios in Pacific white shrimp (Litopenaeus vannamei) was inhibited by a Bacillus subtilis strain BSXE-1601. The natural products amicoumacins A, B, and C were purified from the cell-free supernatant from the strain BSXE-1601, but only amicoumacin A was demonstrated to be responsible for this anti-Vibrio activity. Our discovery provided the first evidence that amicoumacin A was highly active against shrimp pathogens, including the representative strain VP AHPND. Furthermore, we elucidated the amicoumacin A biosynthetic gene cluster by whole genome sequencing of the B. subtilis strain BSXE-1601. In addition to amicoumacin A, the strain BSXE-1601 genome harbored other genes encoding bacillibactin, fengycin, surfactin, bacilysin, and subtilosin A, all of which have previously reported antagonistic activities against pathogenic strains. The whole-genome analysis provided unequivocal evidence in support of the huge potential of the strain BSXE-1601 to produce diverse biologically antagonistic natural products, which may facilitate further studies on the effective therapeutics for detrimental diseases in shrimp.
During the farming season of 2013 and 2014, carbon dioxide (CO 2) fluxes at the water-air interfa... more During the farming season of 2013 and 2014, carbon dioxide (CO 2) fluxes at the water-air interface were determined from two typical seawater polyculture systems. The mean CO 2 fluxes of 2013 and 2014 were − 0.316 ± 0.0674 μmol m −2 s −1 and-0.173 ± 0.242 μmol m −2 s −1 in the bi-species polyculture system of swimming crab (Portunus trituberculatus) with kuruma shrimp (Marsupenaeus japonicus) (PM) and 0.249 ± 0.251 μmol m −2 s −1 and 0.426 ± 0.151 μmol m −2 s −1 in the tri-species polyculture system of swimming crab with shrimp and short-necked clam (Ruditapes philippinarum) (PMR) (Negative flux values refer to CO 2 uptake and positive values refer to CO 2 emission). During the farming season, the CO 2 budgets in PM and PMR were − 113.1 g CO 2 m −2 and 154.0 g CO 2 m −2 , respectively. Water pH seemed like a stable indicator for CO 2 flux and Chlorophyll a concentration was a key factor regulating the CO 2 flux. Subsequent decreasing in water pH and Chl a concentration was supposed to be the main contributor changing the carbon source/sink function from a CO 2 sink of PM to a CO 2 source of PMR. Under the condition of current study, pH of 8.26 could be considered to be the critical value between influxes and effluxes in seawater crab-shrimp and crab-shrimpclam polyculture systems. Aufdenkampe et al., 2011). According to the latest data, the global inland waters CO 2 evasion was estimated at 3.9 Pg C yr −1 (Drake et al., 2018). Recently, researchers (e.g., Chen et al., 2016) started to concern about the CO 2 flux of mariculture ponds, an artificial aquatic system. According to statistical data maintained by the Agriculture Ministry of China, the combined area of mariculture ponds in 2015 was 4.6 × 10 3 km 2 , nearly double the area of that in 2008, and it is very
et al., Bacillus cereus and rhubarb regulate the intestinal microbiota of sea cucumber (Aposticho... more et al., Bacillus cereus and rhubarb regulate the intestinal microbiota of sea cucumber (Apostichopus japonicus Selenka): Species-species interaction, network, and stability, aquaculture,
A novel marine origin Bacillus subtilis strain H1 isolated from a shrimp culture pond effectively... more A novel marine origin Bacillus subtilis strain H1 isolated from a shrimp culture pond effectively removed NH 4 +-N, NO − 2-N and NO − 3-N, with a maximum ammonium, nitrite and nitrate removal rate of 2.35 mg NH 4 +-N L −1 hr −1 per OD, 9.64 mg NO − 2-N L −1 hr −1 per OD and 0.75 mg NO − 3-N L −1 hr −1 respectively. The gas chromatography-isotope ratio mass spectrometry results indicated that N 2 O was emitted when 15 NH 4 Cl, Na 15 NO 2 or Na 15 NO 3 was used. Additionally, N 2 was also produced when Na 15 NO 2 was used. Single-factor experiments suggested that the optimal conditions for NH 4 +-N and NO − 2-N removal were glucose as a carbon source, C/N 15, initial pH 7.5, 30 g/L NaCl, 28°C and a shaking speed of 160 rpm. Orthogonal tests showed that the optimal conditions for NH 4 +-N removal were C/N 15, pH 9, 10 g/L NaCl and shaking speed 160 rpm when ammonium chloride was used as the substrate. The optimal conditions for NO − 2-N removal were C/N 10, pH 6, 10 g/L NaCl and a shaking speed of 160 rpm when sodium nitrite was used as the substrate. In summary, B. subtilis strain H1 had highly efficient aerobic nitrifying-denitrifying ability and high adaptability, suggesting that it is potentially valuable to marine aquaculture.
Start-up of biofilters plays crucial roles in the successful operation of recirculating aquacultu... more Start-up of biofilters plays crucial roles in the successful operation of recirculating aquaculture system, and the nature is bacterial community succession. We explored the pattern of bacterial temporal succession during the start-up process of biofilters in a commercial cold-freshwater recirculating aquaculture system (RAS). The whole succession process was divided into three distinct phases: incubation, growth and stability. Phylogenetic diversity and evenness of the bacterial community increased during the start-up process, whereas richness reached its peak at the growth phase. Seven biomarkers were identified, namely Cytophagales, Gemmatimonadales, Sphingomonadales, Sphingobacteriales, Rhizobiales, Clostridiales and Nitrospirales. The relative abundances of these functional bacteria increased, while those with a competitive growth advantage declined. The network interactions were dramatically altered from fairly simple to most complex, and then decreased in complexity during start-up. Positive relationships decreased, while competition increased. The shift in predicted function exhibited a trend from simple to diverse, and converged to idiosyncratic configuration. 1. Introduction Recirculating aquaculture systems (RAS) are an intensive form of aquaculture designed to maintain good water quality and provide safe, healthy and high-quality aquatic products. Culturing in RAS is not limited by season, water or land availability (Xiao et al., 2018), and so its use is promoted in aquaculture-heavy economies such as the United Kingdom, Ireland, Italy and Norway (Badiola et al., 2012). The most
A 42-day feeding trial was conducted to evaluate the effects of diet supplemented with various ad... more A 42-day feeding trial was conducted to evaluate the effects of diet supplemented with various additives from Clostridium butyricum (fermentation supernatant, FS; live cells, LC; cell-free extract, CE; spray-dried spores, DS; mixture of live cells and supernatant, LCS) on the growth, intestinal morphology, disease resistance, immune gene expression and mTOR signaling-related gene expression in Litopenaeus vannamai. The feeding trial showed that the final weight and specific growth rate of the shrimp were improved significantly while the feed conversion ratio were reduced significantly in LC, CE, DS and LCS groups compared to the control. The villus height and intestinal wall thickness of shrimp's mid-intestine in LC, DS and LCS group increased significantly. After challenge test to Vibrio parahaemolyticus, the cumulative mortalities of the shrimp in LC, CE, DS and LCS groups were significantly lower than that of the control. As compared to the control, the relative expression levels of superoxide dismutase, lysozyme, prophenoloxidase (proPO), Toll, Immune deficiency (Imd), Relish, TOR, 4E-BP, eIF4E1α and eIF4E2 genes in the shrimp of DS and LCS groups enhanced significantly, whereas the relative expression levels of proPO, SOD, Toll, Imd, Relish, elF4E1α and elF4E2 genes were statistically the same between FS group and the control. These results suggested that the spray-dried spores and mixture of live cells and supernatant of C. butyricum exerted better probiotic benefits in modulating immune responses of shrimp. In addition, single supernatant could not be helpful to shrimp while mixture of live cells and supernatant could better improve the immune responses of shrimp in comparison to single live cells. The integration of C. butyricum and their metabolites supplemented into feed could significantly improve growth performance, intestinal morphology, immunity capacity and resistance against V. parahaemolyticus of L. vannamei.
Trophic interaction among various biomass groups in a swimming crab Portunus trituberculatus poly... more Trophic interaction among various biomass groups in a swimming crab Portunus trituberculatus polyculture pond was investigated using carbon and nitrogen stable isotope analysis. The polycultured animal species also included white shrimp Litopenaeus vannamei, short-necked clam Ruditapes philippinarum, and redlip mullet Liza haematochila. The mean δ 13 C value for all the biomass groups in polyculture ecosystem ranged from −25.61‰ to −16.60‰, and the mean δ 15 N value ranged from 6.80‰ to 13.09‰. Significant difference in the δ 13 C value was found between particulate organic matter (POM) and sediment organic matter (SOM) (P < 0.05), indicating that these two organic matter pools have different material sources. Assuming that a 13 C-enrichment factor of 1.00‰ and a 15 N-enrichment factor of 2.70‰ existed between consumer and prey, diets of the four cultured animals were estimated using a stable isotope mixing model. The estimated model results indicated that P. trituberculatus mainly feed on Aloidis laevis; L. vannamei mainly feed on shrimp feed; while A. laevis, R. philippinarum and L. haematochelia mainly feed on POM. Shrimp feed was also an important food source of R. philippinarum and L. haematochelia. The diets of P. trituberculatus, L. vannamei, R. philippinarum, and L. haematochila showed complementary effects in this polyculture ecosystem. Our finding indicated that the polyculture of these four organisms with suitable farming density could make an effective use of most of the food sources, which can make a highly efficient polyculture ecosystem.
• Hyper-and hypo-osmotic stress induced different osmotic responses in tongue sole. • Amino acid ... more • Hyper-and hypo-osmotic stress induced different osmotic responses in tongue sole. • Amino acid metabolism played crucial roles in the osmoregulation. • Taurine and creatine accumulated in the gills of fish exposed to salinity stresses. • Transcript levels of ATP synthase in the gills increased with increasing salinity.
In order to reveal the effects of l-tryptophan (Trp) on the physiology and immune response of sea... more In order to reveal the effects of l-tryptophan (Trp) on the physiology and immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress, four density groups of sea cucumbers (i.e. 4, 8, 16 and 32 individuals per 40 L water, represented as L, ML, MH and H) were fed with diets containing 0, 1, 3 and 5% l-tryptophan respectively for 75 days. The results showed that the specific growth rates (SGR) of the sea cucumber fed with diet with 3% Trp (L, 2.1; ML, 1.76; MH, 1.2; H, 0.7) were significantly higher than those fed with basal diet without Trp supplementation (P < .05). Peak amylase activity occurred at H stress density at 3% dietary Trp. Trypsin activity was higher in diet 3% in ML and MH densities than the controls, which increased by 66.4% and 53.8%. However, the lipase activity first increased and then decreased from the stocking density L to H, with highest values of 3% Trp group showed the highest value than other groups. Compared to those fed w...
Abstract The budget of organic carbon (OC) in polyculture systems of swimming crab Portunus tritu... more Abstract The budget of organic carbon (OC) in polyculture systems of swimming crab Portunus trituberculatus , white shrimp Litopenaeus vannamei and short-necked clam Ruditapes philippinarum was studied with land-based enclosures from July 2 to October 3, 2012. Six treatments were designed, including monoculture of crab (C), polyculture of crab with shrimp (CS) and polyculture of crab with shrimp and clam (CSB 1 , CSB 2 , CSB 3 and CSB 4 ). Crab were stocked at 6 ind/m 2 in all treatments, and shrimp were stocked at 45 ind/m 2 . Short-necked clam were stocked with crab and shrimp in four different densities, i.e., 7.5 (CSB 1 ), 15 (CSB 2 ), 30 (CSB 3 ) and 60 ind/m 2 (CSB 4 ). Results showed that the yield of crab was the highest in CSB 4 system ( P 3 system ( P 4 system exhibited the best yield ( P 1 , CSB 3 and CSB 4 was significantly lower than the other systems ( P 3 showed the highest efficiency of OC utilization and followed by the CSB 4 ( P 2 , shrimp at 45 ind/m 2 , and short-necked clam at 30–60 ind/m 2 , which exhibited better ecological efficiency and economic benefit.
Starving and re-feeding trials were conducted to evaluate the effects of starvation duration and ... more Starving and re-feeding trials were conducted to evaluate the effects of starvation duration and recovery times on the growth performance and physiological characteristics of juvenile tongue sole Cynoglossus semilaevis, which included growth, body composition, intestinal morphology and digestive enzymes activities. The fish starved for one (D1), two (D2) and four (D4) days, respectively, were recovered for three (R3, R6, R12), seven (R7, R14, R28) and eleven (R11, R22, R44) folds of starvation days while the control fish were fed constantly. The experiment was conducted for 96 days. The fish individuals in D1R11, D2R14 and D2R22 caught up in weight with the control, indicating that complete compensatory growth existed in these fish individuals. The highest body weight gain and total specific growth rates were observed in D2R22. Food intake increased significantly in most treatments in comparison with that of the control except for D1R7 and D2R22 (P < 0.05). Food conversion efficiency and apparent digest coefficient in D2R22 were significantly promoted, being higher than that of the control (P < 0.05). The activities of trypsin and lipase were found to be closely related to the growth performance. The activities of liver and hindgut trypsin, also midgut and hindgut lipase in D2R22 were significantly higher than those of the control (P < 0.05). The fold height (HF) of foregut and midgut increased significantly in D2R22, and HF decreased significantly in D1R3, D2R6 and D4R12 (P < 0.05). On our findings, we may conclude that the optimum starving and re-feeding strategy is starving for 2 days and re-feeding for 22 days. And in this starving and re-feeding strategy, the compensatory growth could be mostly attributed to the promotion of food conversion efficiency and digestibility coefficiency.
Concentrating methods generally affect the vitality of the microalgae and may alter its feeding a... more Concentrating methods generally affect the vitality of the microalgae and may alter its feeding and environmental effect. This article studied the concentrating methods (centrifugation and settlement) on primary productivity of the microalgae Cylindrotheca fusiformis. The effects of free settled C. fusiformis, centrifuged C. fusiformis and macroalgae Sargassum polycystum on growth of the sea cucumber, farming water and sediment quality under two light intensities (1500 lx and 500 lx) were studied by a six-week rearing experiment. The results showed that the primary productivity of free settled C. fusiformis was 3-4 times higher than that of those centrifuged, indicating centrifugation inhibited the photosynthesis process. In the rearing experiment, feed, light intensities and their interactions significantly affected the specific growth rate (SGR) of the animals (P < 0.01). The animals reared in higher light intensity also had higher SGR, but only those fed free settled C. fusiformis reached a significant level (P < 0.05). The group also had the highest SGR (P < 0.05), suggesting that the photosynthesis ability of C. fusiformis directly contributed to the growth of the animals. During the experiment, the soluble inorganic nitrogen, reactive phosphorus in farming water, total nitrogen and total organic carbon in the sediment gradually increased in all treatments. The S. polycystum group had slightly higher level of nutrients in water and sediment at the end of the experiment for its high organic content. These results provide evidence that the harvesting methods of C. fusiformis directly affect its vitality, which consequentially alter the feeding and environmental effect, especially under higher light densities.
The present study determined the changes in the fatty acid (FA) profiles of juvenile sea cucumber... more The present study determined the changes in the fatty acid (FA) profiles of juvenile sea cucumber Apostichopus japonicus in response to the varied water temperature. Sea cucumbers with similar size (4.02±0.11g) were cultured for 8 weeks at 14°C, 18°C, 22°C and 26°C, respectively. At the end of the experiment, the specific growth rate (SGR) and the profiles of FAs in neutral lipids and phospholipids of the juvenile sea cucumbers cultured at different temperatures were determined. The SGRs of the sea cucumbers cultured at 26°C significantly decreased 46.3% compared to thos cultured at 18°C. Regression analysis showed that the SGR-temperature (T) relationship can be expressed as SGR=-0.0073T(2)+0.255T -1.0231 (R(2)=0.9936) and the highest SGR was predicted at 17.5°C. For the neutral lipids, the sum of saturated FAs (SFAs), monounsaturated FAs (MUFAs) or polyunsaturated FAs (PUFAs) of the sea cucumbers that were cultured at the water temperature from 18°C-26°C did not change significant...
Environmental pollution (Barking, Essex : 1987), Jan 8, 2016
The CO2 and CH4 fluxes at the water-air interface were measured in shrimp (Marsupenaeus japonicus... more The CO2 and CH4 fluxes at the water-air interface were measured in shrimp (Marsupenaeus japonicus) monoculture ponds (S) with feed supply and shrimp-sea cucumber (Apostichopus japonicus) polyculture ponds (SS) without feed supply. During farming seasons of the whole year, cumulated CO2-C fluxes were -5.69 g m(-2) (S) and 11.23 g m(-2) (SS), respectively. The cumulated CO2 emissions from S and SS did not differ significantly. The cumulated CH4-C emissions from S (0.57 g m(-2)) were significantly higher than those from SS (0.068 g m(-2)). S absorbed C from the atmosphere with a mean absorption rate of -5.12 g m(-2), whereas SS emitted C to the atmosphere with a mean emission rate of 11.30 g m(-2). Over 20-year horizon, the compressive global warming potentials (cGWPs) were 33.55 (S) and 47.71 (SS), respectively, indicating both feeding and no-feeding mariculture ponds could promote global warming.
A 60-day feeding trial was conducted to investigate the effects of dietary Chinese herbal medicin... more A 60-day feeding trial was conducted to investigate the effects of dietary Chinese herbal medicine (rhubarb, Rheum officinale Bail), probiotic (Bacillus cereus BC-01), prebiotic (yeast polysaccharide), and antibiotic (florfenicol) supplementation on the growth, intestinal morphology, and immune responses of juvenile sea cucumbers (Apostichopus japonicus Selenka; initial weight, 4.67 ± 0.06 g). The control treatment was fed only the basal diet (CT treatment), whereas four other treatments were fed the basal diet supplemented with rhubarb (RH treatment), B. cereus BC-01 (BC treatment), yeast polysaccharide (PO treatment), or florfenicol (FL treatment). Groups of ten sea cucumbers were housed in separate tanks, and each diet was fed to five randomly selected groups. The specific growth rates of the individuals in the RH and BC treatments were significantly higher than those in the CT, PO, and FL treatments. The apparent digestibility coefficient of crude protein in the RH and BC treatments was significantly higher than that of crude protein in the CT and PO treatments. The alkaline phosphatase activity of the coelomocytes in the RH and BC treatments was significantly higher than that in the CT and FL treatments. Coelomocytes in the PO treatment had the highest acid phosphatase activity. Higher than average lysozyme activity was observed in the PO and FL treatments. Fold and enterocyte heights in the mid-intestinal tract of sea cucumbers in the CT and RH treatments were lower than those in the BC, PO, and FL treatments. Microvillus height was greatest in the RH treatment and lowest in the FL treatment. Scanning electron microscopy revealed remarkable atrophy of microvilli and apoptosis of intestinal epithelial cells in the FL treatment. These results suggest that dietary rhubarb, B. cereus, and yeast polysaccharide & Xiangli Tian
Swimming crab (Portunus trituberculatus) are an important aquaculture species in eastern coastal ... more Swimming crab (Portunus trituberculatus) are an important aquaculture species in eastern coastal areas of China. To improve the understanding of P. trituberculatus culture ecosystem functioning, the dynamics of energy flow and trophic structure of a P. trituberculatus polyculture system (co-culture with white shrimp Litopenaeus vannamei and short-necked clam Ruditapes philippinarum) were investigated in this study. Three Ecopath models representing the early, middle, and late culture periods of a P. trituberculatus polyculture ecosystem, respectively, were constructed to compare ecosystem traits at different culture periods. The results demonstrated that detritus was the main energy source in this polyculture ecosystem, and most of the total system throughput occurred at trophic levels I and II. Artificial food input and consumption by the culture organisms increased from early to middle and late periods, which produced marked impacts on biomass structure and primary production. R. ...
Effects of rhythmic temperature change on the growth, body composition and energy budget of hybri... more Effects of rhythmic temperature change on the growth, body composition and energy budget of hybrid grouper (Epinephelus lanceolatus ♂ 9 E. fuscoguttatus ♀) were investigated. Nine groups of fish received repeating cycles of low-temperature manipulation (22°C) for 1, 2 and 4 days followed by recovery temperature (28°C) for (3, 7 and 11 days), (6, 14 and 22 days) and (12, 28 and 44 days) respectively, designated as L1R3, L1R7, L1R11, L2R6, L2R14, L2R22, L4R12, L4R28 and L4R44 respectively. In the control group (C), fish were reared at 28°C throughout the whole experiment. After 96-day feeding trail, the final weight, relative weight gain rate, specific growth rate, food conversion efficiency and apparent digestibility coefficient of fish in L4R28 were significantly higher than those of control (p < .05). The crude protein contents of fish in L2R14, L2R22, L4R12, L4R28 and L4R44 were significantly higher compared to the control (p < .05). According to energy budget, fish in L4R28 exhibited significantly higher proportion of food energy assimilated into growth and lower proportion consumed for excretion than the control fish (p < .05). These results indicated the occurrence of complete or over growth compensation in hybrid grouper, and the use of repeated cycles of low temperature (22°C) for 4 days followed by recovery temperature (28°C) for 28 days could obtain enhanced growth, that is overcompensation, with improved apparent digestibility coefficient, food conversion efficiency and energetic efficiency into growth. This technique would be more practically applicable in indoor culture for this species.
Abstract Pacific white shrimp (Litopenaeus vannamei) is an important aquaculture species worldwid... more Abstract Pacific white shrimp (Litopenaeus vannamei) is an important aquaculture species worldwide, and there is a growing concern over misdescribed shrimp products, particularly over their geographical origins. Shrimp samples were collected from 12 locations in northern and southern China to develop traceability methods in identifying their geographic origins. In one of the sampling sites, shrimp were collected from five farms using the same water source but feeding with different brands of feed to investigate the effect of feed on the elemental compositions of shrimp. Totally 35 elements (Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Y, U, Li, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Ag, Cd, Cs, Ba, and Pb) were detected in both shrimp and feed. Only Cd and Tb in shrimp were positively correlated with those in the feed. Moreover, 24 elements (Li, Al, V, Fe, As, Rb, Sr, Cd, Pb, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, and Y) in shrimp were significantly different between northern and southern China. Elements As, Fe, Pb, Rb, Cs, and U, selected by stepwise discriminant analysis (SDA), were used to create a new dataset (SSDAs dataset) to compare with the entire dataset (ATEs dataset) in discrimination analyses. Classification tools, including linear discriminant analysis (LDA), k-nearest neighbor (KNN), and random forest (RF) were used to create a discrimination model to authenticate shrimp provenance based on the ATEs and SSDAs datasets. The highest discrimination rate was achieved with RF using the SSDAs dataset, which achieved an overall correct discrimination rate of 100%, a cross-validation rate of 98.78%, and a predictive discrimination rate of 100%. Therefore, elemental profiling combined with chemometrics is a promising method which can be used to identify shrimp provenance.
The global shrimp industry has suffered bacterial diseases caused mainly by Vibrio species. The t... more The global shrimp industry has suffered bacterial diseases caused mainly by Vibrio species. The typical vibriosis, acute hepatopancreatic necrosis disease (AHPND), has resulted in mass mortality and devastating economic losses. Thus, therapeutic strategies are highly needed to decrease the risk of vibriosis outbreaks. Herein, we initially identified that the growth of the causative agent of AHPND, Vibrio parahaemolyticus (VP AHPND) and other vibrios in Pacific white shrimp (Litopenaeus vannamei) was inhibited by a Bacillus subtilis strain BSXE-1601. The natural products amicoumacins A, B, and C were purified from the cell-free supernatant from the strain BSXE-1601, but only amicoumacin A was demonstrated to be responsible for this anti-Vibrio activity. Our discovery provided the first evidence that amicoumacin A was highly active against shrimp pathogens, including the representative strain VP AHPND. Furthermore, we elucidated the amicoumacin A biosynthetic gene cluster by whole genome sequencing of the B. subtilis strain BSXE-1601. In addition to amicoumacin A, the strain BSXE-1601 genome harbored other genes encoding bacillibactin, fengycin, surfactin, bacilysin, and subtilosin A, all of which have previously reported antagonistic activities against pathogenic strains. The whole-genome analysis provided unequivocal evidence in support of the huge potential of the strain BSXE-1601 to produce diverse biologically antagonistic natural products, which may facilitate further studies on the effective therapeutics for detrimental diseases in shrimp.
During the farming season of 2013 and 2014, carbon dioxide (CO 2) fluxes at the water-air interfa... more During the farming season of 2013 and 2014, carbon dioxide (CO 2) fluxes at the water-air interface were determined from two typical seawater polyculture systems. The mean CO 2 fluxes of 2013 and 2014 were − 0.316 ± 0.0674 μmol m −2 s −1 and-0.173 ± 0.242 μmol m −2 s −1 in the bi-species polyculture system of swimming crab (Portunus trituberculatus) with kuruma shrimp (Marsupenaeus japonicus) (PM) and 0.249 ± 0.251 μmol m −2 s −1 and 0.426 ± 0.151 μmol m −2 s −1 in the tri-species polyculture system of swimming crab with shrimp and short-necked clam (Ruditapes philippinarum) (PMR) (Negative flux values refer to CO 2 uptake and positive values refer to CO 2 emission). During the farming season, the CO 2 budgets in PM and PMR were − 113.1 g CO 2 m −2 and 154.0 g CO 2 m −2 , respectively. Water pH seemed like a stable indicator for CO 2 flux and Chlorophyll a concentration was a key factor regulating the CO 2 flux. Subsequent decreasing in water pH and Chl a concentration was supposed to be the main contributor changing the carbon source/sink function from a CO 2 sink of PM to a CO 2 source of PMR. Under the condition of current study, pH of 8.26 could be considered to be the critical value between influxes and effluxes in seawater crab-shrimp and crab-shrimpclam polyculture systems. Aufdenkampe et al., 2011). According to the latest data, the global inland waters CO 2 evasion was estimated at 3.9 Pg C yr −1 (Drake et al., 2018). Recently, researchers (e.g., Chen et al., 2016) started to concern about the CO 2 flux of mariculture ponds, an artificial aquatic system. According to statistical data maintained by the Agriculture Ministry of China, the combined area of mariculture ponds in 2015 was 4.6 × 10 3 km 2 , nearly double the area of that in 2008, and it is very
et al., Bacillus cereus and rhubarb regulate the intestinal microbiota of sea cucumber (Aposticho... more et al., Bacillus cereus and rhubarb regulate the intestinal microbiota of sea cucumber (Apostichopus japonicus Selenka): Species-species interaction, network, and stability, aquaculture,
A novel marine origin Bacillus subtilis strain H1 isolated from a shrimp culture pond effectively... more A novel marine origin Bacillus subtilis strain H1 isolated from a shrimp culture pond effectively removed NH 4 +-N, NO − 2-N and NO − 3-N, with a maximum ammonium, nitrite and nitrate removal rate of 2.35 mg NH 4 +-N L −1 hr −1 per OD, 9.64 mg NO − 2-N L −1 hr −1 per OD and 0.75 mg NO − 3-N L −1 hr −1 respectively. The gas chromatography-isotope ratio mass spectrometry results indicated that N 2 O was emitted when 15 NH 4 Cl, Na 15 NO 2 or Na 15 NO 3 was used. Additionally, N 2 was also produced when Na 15 NO 2 was used. Single-factor experiments suggested that the optimal conditions for NH 4 +-N and NO − 2-N removal were glucose as a carbon source, C/N 15, initial pH 7.5, 30 g/L NaCl, 28°C and a shaking speed of 160 rpm. Orthogonal tests showed that the optimal conditions for NH 4 +-N removal were C/N 15, pH 9, 10 g/L NaCl and shaking speed 160 rpm when ammonium chloride was used as the substrate. The optimal conditions for NO − 2-N removal were C/N 10, pH 6, 10 g/L NaCl and a shaking speed of 160 rpm when sodium nitrite was used as the substrate. In summary, B. subtilis strain H1 had highly efficient aerobic nitrifying-denitrifying ability and high adaptability, suggesting that it is potentially valuable to marine aquaculture.
Start-up of biofilters plays crucial roles in the successful operation of recirculating aquacultu... more Start-up of biofilters plays crucial roles in the successful operation of recirculating aquaculture system, and the nature is bacterial community succession. We explored the pattern of bacterial temporal succession during the start-up process of biofilters in a commercial cold-freshwater recirculating aquaculture system (RAS). The whole succession process was divided into three distinct phases: incubation, growth and stability. Phylogenetic diversity and evenness of the bacterial community increased during the start-up process, whereas richness reached its peak at the growth phase. Seven biomarkers were identified, namely Cytophagales, Gemmatimonadales, Sphingomonadales, Sphingobacteriales, Rhizobiales, Clostridiales and Nitrospirales. The relative abundances of these functional bacteria increased, while those with a competitive growth advantage declined. The network interactions were dramatically altered from fairly simple to most complex, and then decreased in complexity during start-up. Positive relationships decreased, while competition increased. The shift in predicted function exhibited a trend from simple to diverse, and converged to idiosyncratic configuration. 1. Introduction Recirculating aquaculture systems (RAS) are an intensive form of aquaculture designed to maintain good water quality and provide safe, healthy and high-quality aquatic products. Culturing in RAS is not limited by season, water or land availability (Xiao et al., 2018), and so its use is promoted in aquaculture-heavy economies such as the United Kingdom, Ireland, Italy and Norway (Badiola et al., 2012). The most
A 42-day feeding trial was conducted to evaluate the effects of diet supplemented with various ad... more A 42-day feeding trial was conducted to evaluate the effects of diet supplemented with various additives from Clostridium butyricum (fermentation supernatant, FS; live cells, LC; cell-free extract, CE; spray-dried spores, DS; mixture of live cells and supernatant, LCS) on the growth, intestinal morphology, disease resistance, immune gene expression and mTOR signaling-related gene expression in Litopenaeus vannamai. The feeding trial showed that the final weight and specific growth rate of the shrimp were improved significantly while the feed conversion ratio were reduced significantly in LC, CE, DS and LCS groups compared to the control. The villus height and intestinal wall thickness of shrimp's mid-intestine in LC, DS and LCS group increased significantly. After challenge test to Vibrio parahaemolyticus, the cumulative mortalities of the shrimp in LC, CE, DS and LCS groups were significantly lower than that of the control. As compared to the control, the relative expression levels of superoxide dismutase, lysozyme, prophenoloxidase (proPO), Toll, Immune deficiency (Imd), Relish, TOR, 4E-BP, eIF4E1α and eIF4E2 genes in the shrimp of DS and LCS groups enhanced significantly, whereas the relative expression levels of proPO, SOD, Toll, Imd, Relish, elF4E1α and elF4E2 genes were statistically the same between FS group and the control. These results suggested that the spray-dried spores and mixture of live cells and supernatant of C. butyricum exerted better probiotic benefits in modulating immune responses of shrimp. In addition, single supernatant could not be helpful to shrimp while mixture of live cells and supernatant could better improve the immune responses of shrimp in comparison to single live cells. The integration of C. butyricum and their metabolites supplemented into feed could significantly improve growth performance, intestinal morphology, immunity capacity and resistance against V. parahaemolyticus of L. vannamei.
Trophic interaction among various biomass groups in a swimming crab Portunus trituberculatus poly... more Trophic interaction among various biomass groups in a swimming crab Portunus trituberculatus polyculture pond was investigated using carbon and nitrogen stable isotope analysis. The polycultured animal species also included white shrimp Litopenaeus vannamei, short-necked clam Ruditapes philippinarum, and redlip mullet Liza haematochila. The mean δ 13 C value for all the biomass groups in polyculture ecosystem ranged from −25.61‰ to −16.60‰, and the mean δ 15 N value ranged from 6.80‰ to 13.09‰. Significant difference in the δ 13 C value was found between particulate organic matter (POM) and sediment organic matter (SOM) (P < 0.05), indicating that these two organic matter pools have different material sources. Assuming that a 13 C-enrichment factor of 1.00‰ and a 15 N-enrichment factor of 2.70‰ existed between consumer and prey, diets of the four cultured animals were estimated using a stable isotope mixing model. The estimated model results indicated that P. trituberculatus mainly feed on Aloidis laevis; L. vannamei mainly feed on shrimp feed; while A. laevis, R. philippinarum and L. haematochelia mainly feed on POM. Shrimp feed was also an important food source of R. philippinarum and L. haematochelia. The diets of P. trituberculatus, L. vannamei, R. philippinarum, and L. haematochila showed complementary effects in this polyculture ecosystem. Our finding indicated that the polyculture of these four organisms with suitable farming density could make an effective use of most of the food sources, which can make a highly efficient polyculture ecosystem.
• Hyper-and hypo-osmotic stress induced different osmotic responses in tongue sole. • Amino acid ... more • Hyper-and hypo-osmotic stress induced different osmotic responses in tongue sole. • Amino acid metabolism played crucial roles in the osmoregulation. • Taurine and creatine accumulated in the gills of fish exposed to salinity stresses. • Transcript levels of ATP synthase in the gills increased with increasing salinity.
In order to reveal the effects of l-tryptophan (Trp) on the physiology and immune response of sea... more In order to reveal the effects of l-tryptophan (Trp) on the physiology and immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress, four density groups of sea cucumbers (i.e. 4, 8, 16 and 32 individuals per 40 L water, represented as L, ML, MH and H) were fed with diets containing 0, 1, 3 and 5% l-tryptophan respectively for 75 days. The results showed that the specific growth rates (SGR) of the sea cucumber fed with diet with 3% Trp (L, 2.1; ML, 1.76; MH, 1.2; H, 0.7) were significantly higher than those fed with basal diet without Trp supplementation (P < .05). Peak amylase activity occurred at H stress density at 3% dietary Trp. Trypsin activity was higher in diet 3% in ML and MH densities than the controls, which increased by 66.4% and 53.8%. However, the lipase activity first increased and then decreased from the stocking density L to H, with highest values of 3% Trp group showed the highest value than other groups. Compared to those fed w...
Abstract The budget of organic carbon (OC) in polyculture systems of swimming crab Portunus tritu... more Abstract The budget of organic carbon (OC) in polyculture systems of swimming crab Portunus trituberculatus , white shrimp Litopenaeus vannamei and short-necked clam Ruditapes philippinarum was studied with land-based enclosures from July 2 to October 3, 2012. Six treatments were designed, including monoculture of crab (C), polyculture of crab with shrimp (CS) and polyculture of crab with shrimp and clam (CSB 1 , CSB 2 , CSB 3 and CSB 4 ). Crab were stocked at 6 ind/m 2 in all treatments, and shrimp were stocked at 45 ind/m 2 . Short-necked clam were stocked with crab and shrimp in four different densities, i.e., 7.5 (CSB 1 ), 15 (CSB 2 ), 30 (CSB 3 ) and 60 ind/m 2 (CSB 4 ). Results showed that the yield of crab was the highest in CSB 4 system ( P 3 system ( P 4 system exhibited the best yield ( P 1 , CSB 3 and CSB 4 was significantly lower than the other systems ( P 3 showed the highest efficiency of OC utilization and followed by the CSB 4 ( P 2 , shrimp at 45 ind/m 2 , and short-necked clam at 30–60 ind/m 2 , which exhibited better ecological efficiency and economic benefit.
Starving and re-feeding trials were conducted to evaluate the effects of starvation duration and ... more Starving and re-feeding trials were conducted to evaluate the effects of starvation duration and recovery times on the growth performance and physiological characteristics of juvenile tongue sole Cynoglossus semilaevis, which included growth, body composition, intestinal morphology and digestive enzymes activities. The fish starved for one (D1), two (D2) and four (D4) days, respectively, were recovered for three (R3, R6, R12), seven (R7, R14, R28) and eleven (R11, R22, R44) folds of starvation days while the control fish were fed constantly. The experiment was conducted for 96 days. The fish individuals in D1R11, D2R14 and D2R22 caught up in weight with the control, indicating that complete compensatory growth existed in these fish individuals. The highest body weight gain and total specific growth rates were observed in D2R22. Food intake increased significantly in most treatments in comparison with that of the control except for D1R7 and D2R22 (P < 0.05). Food conversion efficiency and apparent digest coefficient in D2R22 were significantly promoted, being higher than that of the control (P < 0.05). The activities of trypsin and lipase were found to be closely related to the growth performance. The activities of liver and hindgut trypsin, also midgut and hindgut lipase in D2R22 were significantly higher than those of the control (P < 0.05). The fold height (HF) of foregut and midgut increased significantly in D2R22, and HF decreased significantly in D1R3, D2R6 and D4R12 (P < 0.05). On our findings, we may conclude that the optimum starving and re-feeding strategy is starving for 2 days and re-feeding for 22 days. And in this starving and re-feeding strategy, the compensatory growth could be mostly attributed to the promotion of food conversion efficiency and digestibility coefficiency.
Concentrating methods generally affect the vitality of the microalgae and may alter its feeding a... more Concentrating methods generally affect the vitality of the microalgae and may alter its feeding and environmental effect. This article studied the concentrating methods (centrifugation and settlement) on primary productivity of the microalgae Cylindrotheca fusiformis. The effects of free settled C. fusiformis, centrifuged C. fusiformis and macroalgae Sargassum polycystum on growth of the sea cucumber, farming water and sediment quality under two light intensities (1500 lx and 500 lx) were studied by a six-week rearing experiment. The results showed that the primary productivity of free settled C. fusiformis was 3-4 times higher than that of those centrifuged, indicating centrifugation inhibited the photosynthesis process. In the rearing experiment, feed, light intensities and their interactions significantly affected the specific growth rate (SGR) of the animals (P < 0.01). The animals reared in higher light intensity also had higher SGR, but only those fed free settled C. fusiformis reached a significant level (P < 0.05). The group also had the highest SGR (P < 0.05), suggesting that the photosynthesis ability of C. fusiformis directly contributed to the growth of the animals. During the experiment, the soluble inorganic nitrogen, reactive phosphorus in farming water, total nitrogen and total organic carbon in the sediment gradually increased in all treatments. The S. polycystum group had slightly higher level of nutrients in water and sediment at the end of the experiment for its high organic content. These results provide evidence that the harvesting methods of C. fusiformis directly affect its vitality, which consequentially alter the feeding and environmental effect, especially under higher light densities.
The present study determined the changes in the fatty acid (FA) profiles of juvenile sea cucumber... more The present study determined the changes in the fatty acid (FA) profiles of juvenile sea cucumber Apostichopus japonicus in response to the varied water temperature. Sea cucumbers with similar size (4.02±0.11g) were cultured for 8 weeks at 14°C, 18°C, 22°C and 26°C, respectively. At the end of the experiment, the specific growth rate (SGR) and the profiles of FAs in neutral lipids and phospholipids of the juvenile sea cucumbers cultured at different temperatures were determined. The SGRs of the sea cucumbers cultured at 26°C significantly decreased 46.3% compared to thos cultured at 18°C. Regression analysis showed that the SGR-temperature (T) relationship can be expressed as SGR=-0.0073T(2)+0.255T -1.0231 (R(2)=0.9936) and the highest SGR was predicted at 17.5°C. For the neutral lipids, the sum of saturated FAs (SFAs), monounsaturated FAs (MUFAs) or polyunsaturated FAs (PUFAs) of the sea cucumbers that were cultured at the water temperature from 18°C-26°C did not change significant...
Environmental pollution (Barking, Essex : 1987), Jan 8, 2016
The CO2 and CH4 fluxes at the water-air interface were measured in shrimp (Marsupenaeus japonicus... more The CO2 and CH4 fluxes at the water-air interface were measured in shrimp (Marsupenaeus japonicus) monoculture ponds (S) with feed supply and shrimp-sea cucumber (Apostichopus japonicus) polyculture ponds (SS) without feed supply. During farming seasons of the whole year, cumulated CO2-C fluxes were -5.69 g m(-2) (S) and 11.23 g m(-2) (SS), respectively. The cumulated CO2 emissions from S and SS did not differ significantly. The cumulated CH4-C emissions from S (0.57 g m(-2)) were significantly higher than those from SS (0.068 g m(-2)). S absorbed C from the atmosphere with a mean absorption rate of -5.12 g m(-2), whereas SS emitted C to the atmosphere with a mean emission rate of 11.30 g m(-2). Over 20-year horizon, the compressive global warming potentials (cGWPs) were 33.55 (S) and 47.71 (SS), respectively, indicating both feeding and no-feeding mariculture ponds could promote global warming.
A 60-day feeding trial was conducted to investigate the effects of dietary Chinese herbal medicin... more A 60-day feeding trial was conducted to investigate the effects of dietary Chinese herbal medicine (rhubarb, Rheum officinale Bail), probiotic (Bacillus cereus BC-01), prebiotic (yeast polysaccharide), and antibiotic (florfenicol) supplementation on the growth, intestinal morphology, and immune responses of juvenile sea cucumbers (Apostichopus japonicus Selenka; initial weight, 4.67 ± 0.06 g). The control treatment was fed only the basal diet (CT treatment), whereas four other treatments were fed the basal diet supplemented with rhubarb (RH treatment), B. cereus BC-01 (BC treatment), yeast polysaccharide (PO treatment), or florfenicol (FL treatment). Groups of ten sea cucumbers were housed in separate tanks, and each diet was fed to five randomly selected groups. The specific growth rates of the individuals in the RH and BC treatments were significantly higher than those in the CT, PO, and FL treatments. The apparent digestibility coefficient of crude protein in the RH and BC treatments was significantly higher than that of crude protein in the CT and PO treatments. The alkaline phosphatase activity of the coelomocytes in the RH and BC treatments was significantly higher than that in the CT and FL treatments. Coelomocytes in the PO treatment had the highest acid phosphatase activity. Higher than average lysozyme activity was observed in the PO and FL treatments. Fold and enterocyte heights in the mid-intestinal tract of sea cucumbers in the CT and RH treatments were lower than those in the BC, PO, and FL treatments. Microvillus height was greatest in the RH treatment and lowest in the FL treatment. Scanning electron microscopy revealed remarkable atrophy of microvilli and apoptosis of intestinal epithelial cells in the FL treatment. These results suggest that dietary rhubarb, B. cereus, and yeast polysaccharide & Xiangli Tian
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