The information about toxic effects of thiamethoxam on non-target aquatic organisms is still incomplete. The semi-static toxicity test method was used to investigate the acute toxic effects of thiamethoxam on Eriocheir sinensis. The results showed that the median lethal concentration (LC50) of thiamethoxam to E. sinensis at 96 h was 510 μg/L, and the safety concentration (SC) was 51 μg/L. After 96 h exposure to thiamethoxam, the survival rates of crabs at concentrations of 0, 151.11, 226.67, 340, and 510 μg/L were 100%, 76.19%, 64.29%, 61.91%, and 46.43%, respectively. A significant (P < 0.05) decrease of the number of hemocytes was observed in thiamethoxam groups. With the increase of thiamethoxam concentration, the phagocytic activity of hemocytes, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and the activities of protease, amylase, and lipase of crabs increased firstly and then decreased, and the above indexes reached the maximum in 151.11 μg/L thiamethoxam group. Collectively, a high concentration of thiamethoxam (510 μg/L) had a great effect on the gene expression of immune metabolism-related factors in hepatopancreas and gill of crabs. These findings indicated that thiamethoxam exposure had the ability to impair immune and metabolic systems and resulted in the reduction of survival rate of crabs.
In this study,the genetic structure and variation were analyzed in pikeperch Sander lucioperca populations in Yalu River(YL)and Ulungur Lake(XJ)by mitochondrial cytochrome b gene(Cyt b)and DNA control region(D-loop).The results showed that there was significantly higher A+T contents in Cyt b(57.37％)and D-loop(66.64％)sequences than those of C+G(42.63％and 33.36％).Two mutation sites including one singleton variable site and one parsimony informative site were detected in Cyt b sequence,and 26 variation sites were detected in D-loop sequence,including 19 singleton variable sites and seven parsimony information sites.Cyt b sequence analysis showed that there were three haplotypes whose diversity(Hd)(0.032±0.031)and nucleotide diversity(π)(0.000 08±0.000 07)were lower in YL population than those in XJ population(0.467±0.043)(0.001 10±0.000 10).The ge-netic distance was less within YL population(0.000 076)than that in XJ(0.001 102),and the genetic distance between the two popu-lations was 0.000 873.The D-loop sequence analysis showed that there were 17 haplotypes whose diversity(Hd)(0.466±0.088)and nucleotide diversity(π)(0.002 41±0.000 69)were higher in YL population those in XJ population(0.435±0.100)(0.001 91± 0.000 67).The genetic distance was larger within YL population(0.002 422)than that in XJ population(0.001 919),and the genetic distance between the two populations was 0.002 269.The two populations were low haplotype diversity(Hd)and low nucleotide di-versity(π)(Hd＜0.5,π＜0.5％)based on Cyt b gene and D-loop sequences of mtDNA.The molecular variance analysis(AMOVA)of Cyt b and D-loop sequences revealed that the genetic differences in the pikeperch were primarily derived from intra populations(64.56％,97.42％)and minority from inter populations(35.44％,2.58％).The neutral test results showed that Tajima's D value and Fu's Fs value of YL and XJ populations were both negative based on D-loop sequence analysis,and the analysis of variance of XJ pop-ulation was significant,indicating that XJ population might experience population expansion.In conclusion,the YL population of pikeperch did not completely come from the XJ population,and the genetic diversity of the two populations was relatively scarce.The genetic structure characteristics of the pikeperch populations obtained in this study are of great significance for its artificial breeding and genetic diversity monitoring.
Community of benthic macroinvertebrate and aquatic environmental indices were surveyed in 28 sampling sites in the whole basin of the Hulan River in summer(August),and autumn(October)of 2018 and spring(May)of 2019 to construct a benthic macroinvertebrate index of biological integrity(B-IBI),then which was used to assess the health status and the main threats of Hulan River ecosystem in the cold temperate mountainous zone.It was found that 57 species of macroinvertebrate belonging to 14 orders and 32 families.The number of Trichoptera taxonomic units,the number of EPT(Ephemeroptera,Plecoptera and Trichoptera)taxonomic units,the relative abundance of EPT,the number of pollution tolerance taxonomic units,biological index and the relative abundance of scraper individuals were filtered out as the core indicators for the Hulan River B-IBI.The health standard value was 4.42 by the ratio method.The B-IBI evaluation results indicated that the Hulan River was"fair"in the overall health status,and only 17.9％of all sur-vey sites were graded as healthy.The analysis of water quality and land use data showed that the main threat for the health of the Hulan River ecosystem were resulted from agricultural activities and urbanization in the basin.
To understand the ecological impact of Spartina alterniflora invasion on macrobenthos,6,2 and 3 survey sections were set up in May 2011,November 2017 and October 2020,respectively,with a sampling depth of 30 cm,and the macrobenthos community composition,biomass,biodiversity and functional groups were investigated according to the sampling time.A total of 151 species of macrobenthos were identified in this study,with the dominant species of the polychaete Mediomastus californiensis in 2011 and the small snail Pseudomphala latericea in 2020.Cluster analysis and Non-metric Multi-Dimensional Scaling revealed that the macrobenthic community structure in the sediments of different years of invasion of Spartina alterniflora was less similarity.The finding indicated that the species diversity of macrobenthos in the salt marsh wetlands of Lushan Bay did not change significantly over a 9-year time scale as the distribution range of Spartina alterniflora expanded in the bay,but the species composition and community structure have changed(SIMPROF,P＜0.05).
The population structure and relationships with environmental factors were investigated in water fleas Bosmina collected from 48 water bodies in the eastern plains region(EPR),Mongolian plateau(MXP),northeast China region(NCR),Yunnan-guizhou plateau(YGP)and Qinghai-Tibet plateau(QTP)in summer(July and August)of 2017,and water temperature(WT),and levels of dissolved oxygen(DO),pH,transparency(SD),ammonia nitrogen(NH4+-N),nitrite nitrogen(NO2--N),total nitrogen(TN),total phosphorus(TP)and chlorophyll a(Chl.a)were also measured.Then,correlation analyses were conducted between various species of Bosmina and environmental factors(including other crustacean zooplankton density and 9 physicochemical factors)to understand the effects of various water environmental factors on water fleas in geneus Bosmina in different regions and to provide scientific basis for the monitoring of freshwater ecosystems in summer.The results showed that no Bosmina were found in 10 water bodies in QTP,and no Bosmina coregoni except two species(i.e.B.longirostris and B.fatalis)were investigated in 35 water bodies in EPR,MXP,NCR and YGP.Pearson correlation analysis,multiple stepwise regression and RDA analysis revealed that the B.longirostris density was negatively correlated with Chl.a concentration and copepods density(P＜0.05),while B.fatalis was positively correlated with Chl.a concentration and copepods density(P＜0.05),indicating that Chl.a and copepods were two important environmental factors af-fecting B.longirostris and B.fatalis.The findings help to further understand the summer population characteristics of Bosmina in fresh-water ecosystems and its relationship with environmental factors,so as to provide reference with the biological monitoring of water quality in summer in China.
The 1-day-old D-shaped larvae[shell length of(99.5±5.8)μm]and 15-day-old metamorphosed larvae(shell length of 246.5 μm)after hatching,30 day old juveniles[shell length of(1,065±195)μm]and 60-day-old juveniles[Large size(9.15± 0.87)mm,medium size(7.01±0.71)mm and small size(4.41±0.66)mm]in surf clam Mactra veneriformis with absorption wa-ter were set on 300 mesh silk,and suspended in a 500 mL beaker(air exposure)for 120 min,3 h,10 h,and 30 h,respectively,at room temperature of 28.8℃～29.6℃,and humidity of 50％～60％to probe the response of the surf clam to air exposure.The results showed that the survival rate of the surf clam at different developmental stages was linearly decreased with the increase in the exten-sion of air exposed time(P＜0.05).The descending order of the endurance to air exposure of the surf clam in different developmental stages,based on LT50,was expressed as large 60 d juveniles(24.7 h)＞middle 60 d juveniles(17.5 h)＞small 60 d juveniles(13.8 h)＞30 d juveniles(4 h)＞metamorphosis-stage larvae(1.61 h)＞D-stage larvae(1.05 h).There was different growth of the surf clam in different developmental stages during air exposure,with significantly lower growth rate in D-stage larvae than in the control,slow growth in metamorphosis-stage larvae at the first 4 days of air exposure,and the significantly higher growth rate in each treatment group was than that in the control group with the extension of culture time,without significant difference in the growth rate between air exposure groups and the control group in 30 d juveniles.The findings will provide basic data for artificial breeding and transporting of the surf clam.
The broodstock of Octopus sinensis with body mass of 0.68～1.74 kg captured from the Lianjiang waters of Fujian Province was cultivated in a cement pond(6 m× 2 m× 1.5 m)for 50 days,mated and spawned naturally,and the fertilized eggs in the 8 devel-opmental stages of A,B,C,D,E,F,G and H were disposed in the sieve basin according to the following methods:each cluster of eggs was separated by 3～4 cm(control group);the cluster was separated by 3～4 cm,and washed every 1 hour by bottle-washing eggs(group 1);bunches of eggs were placed tightly in the sieve basin(group 2);bunches of eggs were placed tightly in the sieve basin,and the eggs were washed with bottle washing(group 3)at 1 hour interval every day.The fertilization hatching rate of the eggs was calculated.The juveniles hatched at the F,G and H periods of the parental care(control group)and the juveniles that were incubated separated from the parental care at the F,G,and H periods(treatment group)were reared in a 20L bucket and fed Artemia nauplii to comparate the 7-day survival rate of larvae hatched between artificial incubation and parental octopus protection.The results showed that when the fertilized eggs developed to the E stage(16 days after incubation,the embryo began to appear about 5～8 light red pig-ment spot),the newly hatching larvae were obtained by artificial incubation from the female parent.When the development to G stage(maternal care incubation 20 days,fertilized egg string is gray),the best artificial incubation effect was observed in the fertilized eggs from maternal care at whose H stage(23 d incubation,the fertilized egg strings were gray brown in color),99％of hatching rate was found in the fertilized eggs from maternal care.However,the membranes were early broken when the fertilized eggs were removed due to the stimulation of external environment,with the survival rate of only 11.7％at 7 days.In the process of artificial incubation,there was significantly higher hatching rate in sparsely arranged egg strings was than that in closely arranged egg strings.Under the same density,the hatching rate was significantly increased by blowing and washing egg strings,but the effect of blowing and washing egg strings on the hatching rate was gradually decreased as the hatching date approached.
To investigate the effect of compound Chinese herbal medicine on the growth and immune indices of juvenile Dabry's sturgeon Acipenser dabryanus,Dabry's sturgeon with body weight of(1 000±53)g was reared in a glass fiber tank with a diameter of 2 m and a water depth of 0.6 m,and fed basic diet(control group)and the diets containing four groups of compound Chinese herbal medicine consisting of 17 Chinese herbal medicines including rhubarb,isatidis,honeysuckle,and schisandra,astragalus according to the theory of Chinese medicine compatibility:group 1(Houttuynia cordata Thunb,Lonicera japonica Thunb,Rheum palmatum L,Poria,Glycyrrhiza uralensis Fisch and Astragalus mongholicus Bunge),group 2(Isatis tinctoria,Rheum palmatum L,Acanthopanar gracilistμlus W.W.Smith and Codonopsis pilosula),group 3(Lonicera japonica Thunb,Prunus armeniaca L,Cyrtomium fortune J.Sm,Baphicacanthus and Radix sophorae Tonkinensis)and group 4(Astragalus mongholicus Bunge,Phellodendron,Glycyrrhiza uralensis Fisch,Crataegus pin.nati fida Bge,Schisandra chinensis,Rheum palmatum L and Codonopsis pilosula)at a dose of 0.5 g/kg at water temperature 16 ℃～18 ℃for 14 d.The results showed that there were significantly higher serum growth hormone releasing hormone(GHRH),insulin-like growth factor 1(IGF-1),growth hormone(GH)and other indicators in the juvenile Dabry's sturgeon in group 3 and group 4(P＜0.05).The compound prescription in group 2 only had an effect on the content of insulin-like growth factor 1(IGF-1)(P＜0.05).The compound prescription in group 4 also had a significant effect on the increase of gonadotropin releasing hormone(GnRH)content(P＜0.05).Significantly increase in levels of serum immunoglobulin IgG and IgM,complement C3 and C4,and antimicrobial peptides(P＜0.05)was observed in the juvenile Dabry's sturgeon in group 3 and group 4.The compound prescriptions in group 2,group 3 and group 4 led to significantly increase the serum lysozyme activity(P＜0.05),without significant change in serum interferon(IFN-r)levels in the four compound Dabry's herbal medicine test groups(P＞0.05).The findings indicated that the compound Chinese herbal medicine promoted the growth and immunity of Chinese sturgeon juveniles,in which the compounds in group 3 and group 4 had beneficial effects,especially the compound in group 4.The research results provide a scientific basis for the application and development of Chinese herbal medicine additives for Dabry's sturgeon and other sturgeons.
The primary cultured cells are maintained of r only short periods of time in vitro,and show similar biological characteristics with those cells in vivo,which are usually used as an excellent model system to investigate the normal physiological and biochemical properties of cells,as well as the effects of chemicals on cells and other aspects.The aim of the current study was to screen a suitable culture media for the grass carp muscle fiber growth under the primary culture condition.The muscle fibers of grass carp were isolated and cultured by tissue block method.Then the effects of different media on muscle fiber growth,cell morphology,migration time and first passage time were observed under an inverted microscope,the effects of different media on cell proliferation and adhesion rate were calculated by cytometry method,and the cell viability was measured by MTT method.In contrast to the DMEM and L-15,grass carp muscle fibers cultured in M199 medium showed a shorter time for tue migratios from the tissue block(P＜0.05),and a high cell adhesion rate,of(44.60±11.46)％than the cells cultured in DMEM and L-15 medium,which were(33.25±8.35)％and(22.83± 0.70)％,respectively(P＜0.05);Meanwhile,the M199 group showed a rapid cell proliferation rate,which only spent 72 h to achieve the log-growth phase,and the highest average amplification multiple of cells subcultured after 72 h(P＜0.05).Cell viability by MTT assay found that,the OD value of grass carp muscle fibers cultured in M199 medium was(1.03±0.17),which was higher than the OD values for DMEM and L-15(0.06±0.02 and 0.05±0.02),respectively(P＜0.05).To conclude,the growth and proliferation rates in M199 medium were significantly higher than those in DMEM and L-15 media,which indicated that M199 medium could pro-mote the growth of grass carp muscle fibers and could be used as a culture medium for the primary culture of grass carp muscle fibers.
In this experiment,the potential pathogenic strain with growth advantage was isolated from the diseased silver crucian carp(Carassius auratus gibelio),purified and identified morphologically,physiologically and biochemically and by 16S rRNA sequencing.The results showed that the strain was Gram-negative,positive for glucose,maltose,mannitol,and negative for hesperidin and or-nithine decarboxylase.The 16S rRNA sequence test and phylogenetic tree analysis revealed that the bacterium was identified as Vibrio aeruginosa,showing strong pathogenicity.The macro-genome sequencing test showed that the isolate carried 582 virulence genes and 216 drug resistance genes,and the in vitro co-culture and in vivo inoculation experiments between Bacillus subtilis and the bacterium showed that Bacillus subtilis potentially reduced the virulence effect of V.aeruginosa on golden crucian carp(Carassius auratus),which further explored the bacterial septicemia induced by monococcus species in golden crucian carp.The finding provides a basis for further exploration of the control of bacterial septicemia in golden crucian carp.
To explore the molecular response mechanism of Na+/K+-ATPase in hybrid sturgeon(kaluga sturgeon Huso dauricus(♀)× Amur sturgeon Acipenser schrenckii(♂))under carbonate alkalinity stress,the 30-day-old"Sturgeon No.1"juveniles with body length of(133.17±16.75)mm and body weight of(12.43±3.99)g were reared in aerated tap water(alkalinity of(3.16±0.03)mmol·L-1,control group,group C),and aerated tap water with alkalinity of(7.61±0.12)(T1group),(12.10±0.05)(T2 group)and(15.30±0.85)mmol·L-1(T3 group)prepared by edible baking soda with 99％purity was.On the 30th day of rearing,the gills,skin,muscle,heart,liver,spleen,head and kidney,intestine,eye,stomach and kidney of the hybrid sturgeon in the control group and the gills of the hybrid sturgeon in the three carbonate alkalinity stress groups were collected,and the differentially expressed genes attp 1α1(Na+/K+-ATPase α1 subunit)and atp 1β1(Na+/K+-ATPase β1 subunit)were screened based on the transcriptome data of"Sturgeon No.1".The cDNA full-length se-quences of atp 1α1 gene and atp 1β1 genes were cloned by RACE technology,their sequence information was analyzed,and the tissue ex-pression differences and alkalinity exposure of Sturgeon No.1 gills were analyzed by real-time PCR.The results showed that the atp 1α1 gene had full-length cDNA sequence of 3 407 bp and encoded 1 027 amino acids(NKAα1),and the atp 1β1 gene had full-length cDNA sequence of 2 170 bp and encoded 304 amino acids(NKA β 1).The secondary structure of NKAα1 and NKAβ1 amino acid were primar-ily α-helix and irregular coil with multiple transmembrane regions.There were serine,threonine and tyrosine in the potential phosphory-lation sites in both of NKAα1 and NKAβ1 amino acid.Phylogenetic tree analysis and homologous sequence alignment showed that the NKA of the hybrid sturgeon was closest to sterlet A cipenser ruthenus.The fluorescent quantitative PCR revealed that the expression level of atp 1α1 was significantly higher in gill than that in other tissues(P＜0.05),with the maximal expression level of atp 1β1 in heart,followed by liver,intestine and gill.The expression level of atp 1α1 in gills was shown to be increased first and then decreased with the increase in alkalinity,with the maximal expression level at alkalinity of 7.61 mmol·L-1.In conclusion,there was lower expression level of atp 1α1 and atp 1β1 genes in te stress groups than that in the control group at alkalinity of over 12.10 mmol·L-1.The atp 1α1 and atp 1β1 genes of"stur-geon 1"encode respectively the subunit of NKA protein and participates in the carbonate alkalinity response.The finding provides theoret-ical basis for revealing the molecular regulation mechanism of saline-alkali tolerance in sturgeon.
Glucose transporter 4(GLUT4)directly promoted the absorption of glucose by cells and plays a vital role in glucose metabolism.In mammals,GLUT4 is mainly expressed in skeletal muscle and adipose tissue,and had been systematically research on the mechanism of regulation of the GLUT4 transport function.It has been reported that GLUT4 is involved in signal pathways related to carbohydrate metabolism,including phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt),AMP-activated protein kinase(AMPK),and protein kinase C(PKC).Since the GLUT4 is found in fish,it had been confirmed that GLUT4 in fish had high homolo-gy with mammals,with different structure and transport mode from those of mammals.The effect of insulin-dependent pathway on glucose absorption in fish was preliminarily explored.AMPK,as an important factor in the non-insulin-dependent glucose transport pathway,had been shown to affect the glucose absorption process in fish.However,PKC signaling pathway was not involved in GLUT4-mediated glucose metabolism in fish.Exploring the mechanism of glucose metabolism in fish has always been the hotspot of fish nutrition.This review would focus on the above three signal pathways by which regulate the transportation of glucose,summarizes the research on GLUT4 in fish,and provides the corresponding theoretical basis for further research of the mechanism of glucose metabolism in fish.
In order to master the plankton and fish composition structure and ecological environment status in the Weihe River,three aquatic ecological surveys were carried out in 16 sample sites in spring(April,May and June)of 2016.The SPSS statistical method and the correspondence analysis were adopted to study and analyze the community structure of the plankton and fish and their influ-encing factors in Weihe River.The results showed that there were a total of 53 phytoplankton species,belonging to 8 phyla,among which Bacillariophyta(33.9％),and Chlorophyta(43.4％)species had higher richness,and there were a total of 30 zooplankton species,belonging to 4 categories,with dominant rotifers accounting for 50.0％.There were a total of 27 fish species,belong to 8 fami-lies,with Cyprinidae accounting for the highest(55.6％).There were 13 dominant species of plankton and fish in the Weihe River,the descending order of species composition as the downstream＞the middle stream＞the upstream.The zooplankton and phytoplankton had average abundance of 4.98 ind./L and 216.9×104 cell/L,and average biomass of 0.003 mg/L and 0.422 mg/L,respectively,with the plankton Shannon-Weiner diversity index(H')of 2.48～2.56,and Pielou evenness index(J)of 0.72～0.88.The comprehensive e-valuation of water quality index(CEWI)revealed that the water quality was slightly polluted in Weihe River in spring.The canonical correspondence analysis(CCA)and redundancy analysis(RDA)showed the altitude(ALT),water temperature(WT)and total ni-trogen(TN)were the main environmental factors affecting plankton and fish communities in Weihe River in spring.The findings can provide a basis for the ecological restoration of Weihe River and for certain regional guiding significance.
Mon-rice cropping mode(CK),rice-crab co-cropping mode(RC)and rice-crab-loach co-cropping(RCL)modes were set up in nine rice field units in Suihua National Rice Fishery Integrated Planting and Breeding Demonstration Area,Heilongjiang Province.The characteristics and effects of microbial community structure and diversity in paddy soil were evaluated under different co-cropping patterns in cold region.Each mode has three replicates,and each rice field unit has an area of 300 m2.The rice variety is"Suijing 4".The Chinese mitten crab(Eriocheir sinensis)with body mass of(21.45±1.45)g was reared at stocking density of 500 ind./667 m2 in RC mode,and harvested on September 20,2020.The Chinese mitten crab with body mass of(21.45±1.45)g was reared at stocking density of 350 ind./667 m2,co-cultured with loach(Misgurnus anguillicaudatus)with body mass of(0.47±0.07)g/ind.at stocking density of 2,223 ind./667 m2 and harvested on September 20,2020 in RCL mode.During the culture period,formu-lated diet was fed,and the same management process was conducted in all the rice field units.The results showed that the 9 soil sam-ples of different models contained 6,404 OTUs,belonging to 59 phyla,1,093 genera and 2,245 species.The Venn diagram showed that the specific OTU number was 375 for CK,359 for RC and 453 for RCL.Chloroflexi,Actinobacteria,Bacteroidota,Proteobacteria,Fir-micutes,Acidobacteria and Desulfobacterota were of the main dominant bacteria in the three modes.There were higher ACE index,Chao index and Shannon index of soil bacteria in RC and RCL than those in CK,without significant difference(P＞0.05).PCoA re-vealed that RC,RCL and CK were clustered in different regions.The findings indicated that rice-crab co-cropping and rice-crab-loach co-cropping led to change the soil bacterial community structure and to increase the richness and diversity of soil bacteria.
In order to understand biological characteristics of the feeding habits of fairy shrimp Branchinella kugenumaensis in wild,the DNA metabarcoding technology was adopted to identify food items in the intestine of the fairy shrimp sampled in ponds in Jiadeng Village,Duyun City,Guizhou Province.The results showed that a total of 151 species were observed in the intestinal tract,belonging to 10 phyla including Arthropoda,Cnidaria,Chordata,Nematoda,Mollusca,Hemichordata,Annelida,Platyhelminthes,Angiospermae,and Chlorophyta,with the most abundant Arthropoda in food,with a total of 83 species,accounting for 70％of the total food items;followed by the species of Chordate,with 27 species,accounting for 11％,and the least Chlorophyta,only 0.3％.It was found that B.kugenumaensis actively filtered organic particles in the water body,without food selectivity.The organic particles were primarily de-rived from water fleas Daphnia magna,Daphnia pulex,Hydra vulgaris,A cromyrmex echinatior and Harpegnathos saltator.
Understanding of the trophic level and feeding habits of various aquatic organisms is one of the basic goals of modern ecolo-gy.Traditional research methods are featured by the disadvantages of low detection sensitivity,and limited by time and space.Stable isotope ratios can represent the long-term accumulation of different biological trophic data in time and space,and then distinguish the small differences in trophic levels of different species in the food web.This paper describes the application principle of stable isotope technology,discusses the effects of food source composition,proportion and metabolic process of aquatic animals on the composition and distribution of stable isotope,and analyzes specific cases of food source,food web structure,nutritional grade and migration route in aquatic animal food research to provide theoretical data support for aquatic animal domestication,habitat protection and fishery re-sources monitoring.
A high-density genetic linkage map was constructed in 107 samples in a full-sib F1 family of mirror carp(Cyprinus carpio)F1 population of six months old using SLAF-seq high-throughput sequencing technology,and the QTL of four growth-related traits in-cluding body weight,body length,body thickness and body depth of the mirror carp were locally analyzed by means of interval map-ping method of Map QTL5.0 to detect SNP genotypes.A total of 29 QTL intervals affecting growth-related traits were detected among 11 linkage groups(LG3、LG5、LG6、LG7、LG12、LG16、LG30、LG38、LG44、LG46 and LG47)with LOD values ranging from 2.50 to 4.09 and explained 9.0％～24.2％of the phenotypic variations,with the maximal PVE in QTL6_5 explaining 24.2％PVE in body weight and 24.1％PVE in body length,which can be considered main effect on QTL and thus apparent effect on the traits.Several QTLs affecting different traits clustered together at the identical or close regions of the same linkage group,such as there are six QTLs distribution on LG5,LG6 and LG38,respectively.It was found that 17 QTLs were shared among different growth-related traits,and that the other 12 QTLs were only related to one trait.12 candidate genes were identified from these QTL intervals.The findings pro-vide a basis for elucidating genetic mechanism of growth-related traits and will promote the growth to higher production through mark-er-assisted breeding in mirror carp.
For acute toxic experiments of alkalinity and salinity indoor on two sizes of juveniles of Leuciscus idus at a water tempera-ture of 23.12℃～24.35℃,healthy 1-month-old juveniles with body weight of(3.36±0.24)g were exposed to NaCl salinities of 2.1 g·L-1,4.0 g·L-1,6.1 g·L-1,8.0 g·L-1,10.0 g·L-1,12.1 g·L-1 and 14.0 g·L-1 in a set of temperature-controlled aquaria;Meantime,the same size above and 3-month-old juveniles with body weight of(17.1±0.05)g were exposed to NaHCO3 alkalinities of 10.3 mmol· L-1,20.1 mmol·L-1,30.4 mmol·L-1,41.8 mmol·L-1,50.8 mmol·L-1,60.4 mmol·L-1,69.2 mmol·L-1,81.4 mmol·L-1,and 90.8 mmol·L1 in another set of temperature-controlled aquaria.According to LC50 of a single salinity or alkalinity toxicity test,double combination tests of alkalinities of 40 mmol·L-1 and 50 mmol·L-1 mixed with salinities of 4 g·L-1,6 g·L-1,8 g·L-1 and 10 g·L-1 respectively were al-so performed.The results showed that the LC50 values of alkalinity was found to be 78.93 mmol·L-1 at 12 h,71.47 mmol·L-1 at 24 h,67.33 mmol·L-1 at 48 h,63.38 mmol·L-1 at 72 h,and 61.46 mmol·L-1 at 96,with safety concentration of 17.93 mmol·L-1 by probal·ility unit method,and 68.73 mmol·L-1 at 12 h,65.59 mmol·L-1 at 24 h,63.72 mmol·L-1 at 48 h,60.74 mmol·L-1 at 72 h,and 58.51 mmol L-1 at 96 h with safety concentration of 18.04 mmol·L-1 by linear regression for 1-month-old juveniles,and 89.46 mmol·L-1 at 12 h,78.13 mmol·L-1 at 24 h,72.11 mmol·L-1 at 48 h,68.25 mmol·L-1 at 72 h,68.25 mmol·L-1 at 96 h,with safety concentration of 18.43 mmol·L-1 by probability unit method,and 73.09 mmol·L-1 at 12 h,67.64 mmol·L-1 at 24 h,65.33 mmol·L-1 at 49 h,61.63 mmol·L-1 at 72 h,61.63 mmol·L-1 at 96 h by linear regression for 3-month-old.The statistical t-test showed that there was no significant difference in the LC50 values calculated by different methods for different sizes of juveniles at the same stress period,although the LC50 values were found to be lower in 1-month old than those in 3-month-old.Similarly,using the same calculation methods as alkalinity,the LC50 values of salinity were 14.03 g·L-1,12.71 g·L-1,12.43 g·L-1,11.52 g·L-1,11.24 g·L-1 and 11.54 g·L-1,10.79 g·L-1,10.24 g·L-1,10.11 g· L-1,9.89 g·L-1 for 1-month-old juveniles,respectively,with SC values of 2.71 g·L-1 and 2.77 g·L-1.The combined toxicity of alkalinity and salinity on the two different sizes of juveniles within 96 h showed antagonistic effect,and the descending order of toxic effects were expressed as alkali-saline mixture＞alkalinity＞salinity.In conclusion,the L.idus has strong alkali and saline tolerance and is an excellent variety for bicarbonate alkali-saline water culture with medium alkalinity(10～30 mmol·L-1).
sRNA in bacteria is a gene expression regulator with a length of 40～500 nucleotides that can quickly respond to the external environment and help pathogens adapt to adversity conditions and infect the host.At present,the sRNA of mammalian pathogens has been studied in-depth,but the research on the sRNA of aquatic pathogens has just started,so the related research is of great signifi-cance.In this paper,the mechanism of sRNA regulating gene expression and its research progress in common aquatic pathogenic bac-teria such as Vibrio alginolyticus and Edwardsiella piscicida were reviewed,to provide new ideas for the study of sRNA involved in bacterial virulence.
为评价三种复合微生态制剂联用在稻田养殖中华绒螯蟹(Eriocheir sinensis)中的应用效果,5月中旬,在天津三缘宝地农业科技有限公司的6块约80 m2的稻田养成蟹池中,投放同批次的"光合1号"中华绒螯蟹,密度为6 g·m-2.其中3个平行对照组稻田投喂中华绒螯蟹全价饲料;另3块平行试验稻田投喂拌有三种复合微生态制剂的全价饲料(微生态制剂组).这些复合微生态制剂包括:①水产专用复合预混饲料"营养快线"氨基酸电解质多维;②混合型饲料添加剂复合微生物"利多精"(含1.0×109 CFU·g-1的枯草芽孢杆菌和破壁花粉);③水产用复合预混饲料"LY-生命素"(主要成分为低聚壳聚糖、复合维生素、DL-蛋氨酸、泛酸钙、啤酒酵母粉).5个月养殖结果表明:饲喂复合微生态制剂对蟹的生长和基本营养成分与对照组没有显著差异(P>0.05),但能显著提高蟹蒸煮后的感官品质(P<0.05),提高生殖腺肥满度、蟹肉鲜甜度和香味,使蟹壳红度增加.微生态制剂降低了底泥和水中的微生物多样性和丰富度,改变了物种组成,使水体中具有氮、磷、硫降解能力的菌-丛毛单胞菌科的比例从23.96％上升到30.82％,但也使底泥中水稻病原菌黄单胞菌目从3.02％上升到7.98％.研究结果可为稻-蟹共生模式中复合微生态制剂的应用和开发提供参考.
