Effect of Chromium on Oxidative Damage and Antioxidant Capacity of Ctenopharyngodon idellus

[Objective] This study aimed to investigate the effect of chromium on ox- idative damage and antioxidant capacity of Ctenopharyngodon idellus （grass carp）. [Method] The grass carps were treated with hexavalent chromium （Cr^6＋） solution at concentrations of 0, 7.23, 14.47, 28.94 mg/L, and then the content of malondialde- hyde （MDA）, the level of total antioxidative capacity （T-AOC） and the activity of gtu- tathione-S-transferase （GST） in the hepatopancreas of grass carp were determined after 96 hours in different treatment groups. [Result] The content of MDA presented increasing trend with the increase of exposure Cr^6＋ concentrations. The activity of T-AOC increased firstly, then decreased with the increasing Cr^6＋ exposure concentra- tions, showing that the level of T-AOC was induced in tow and medium concentrat ions （7.23 and 14.47 mg/L）, but inhibited in high concentrations （28.94 mg/L）. Among the exposure groups, the level of T-AOC in medium concentration group （14.47 mg/L） was significantly higher than the control （P〈0.05）. Except the low concentration groups （7.23 mg/L） of which the GST activity was slightly induced, the GST activities of the other groups all showed downward trend with increasing Cr^6＋ levels, and the activity of GST in 28.94 mg/L group was significantly lower than the control group （P〈0.05）. [Conclusion] Cr^6＋ could cause large oxidative damage in the hepatopancreas of grass carp, thus poisoning it, and Cr^6＋ may further damage the organizational structure and physiological function of grass carp.

草鱼(Ctenopharyngodon idellus)成纤维细胞生长因子8的cDNA克隆及特征分析

以草鱼(Ctenopharyngodon idellus)为实验对象,利用RACE技术克隆了草鱼成纤维细胞成长因子8(Fibro-blast Growth Factor8,FGF8)cDNA序列。实验结果显示,草鱼FGF8 cDNA序列长度为887 bp,其中5′-非翻译区长100 bp,3′-非翻译区长157 bp,开放阅读框(ORF)633 bp,编码210个氨基酸的前体蛋白,包含22个氨基酸的信号肽和188个氨基酸的成熟肽。利用已知的FGF8序列绘制系统发育树,发现草鱼与两种鲤科鱼(班马鱼、墨西哥脂鲤)聚为一簇,显示亲缘关系很近,而与其它脊椎动物如两栖类、鸟类、哺乳类的亲缘关系则相对较远,这与形态分类学的结果一致。此外,还通过生物信息学分析,揭示了草鱼FGF8的分子结构特征。

Cloning and Expression of PKR Gene of Ctenopharyngodon idellus Induced by PolyI:C in vitro

[Objective] The study aimed at cloning PKR gene from Ctenopharyngodon idellus induced by PolyI：C in vitro,so as to provide foundation for study on the anti-virus genes of C.idellus.[Method] By referring to the PKR gene sequences of zebra fish（AJ852023.1） and Carassius auratus（AY293929.1） in Genbank,three pairs of degenerate primers were designed with Primer Premier 5.0 software;in vitro C.idellus kidney cells（CIK） were treated with 100 μg/ml of Poly I：C for 12,36 and 48 h,and then total RNA of the cells treated was extracted for amplifying the PKR gene by RT-PCR.[Result] The PKR gene was amplified from the cells treated with Poly I：C for 36 and 48 h,but not from the cells treated for 12 h;in addition,the expression level increased with the processing time.Part of the amplified sequence of C.idellus shared the homology of 100% and 81.48% with the sequences of carp and zebra fish separately.[Conclusion] Part of the PKR gene sequence was cloned successfully from C.idellus.Moreover,we have proved that PolyI：C induction is effective for PKR protein expression,which will provide reference for treating viral diseases of C.idellus.

Effect of dietary cottonseed meal on growth performance, physiological response, and gossypol accumulation in preadult grass carp, Ctenopharyngodon idellus

Cottonseed meal(CM) was used at up to 36.95% content in the diet(replacing 60% of dietary fish meal protein) without any negative effects on growth performance of pre-adult grass carp(initial body weight,761 g) under outdoor conditions.A culture trial was conducted in net cages installed in a large concrete pond.Seven isonitrogenous and isoenergetic diets containing a gradient of CM concentrations(0,12.2%,24.4%,36.6%,48.8%,54.8%,and 61.0%) as replacement for dietary fish meal protein(0,20%,40%,60%,80%,90%,and 100%) were formulated.Dietary non-resistant starch(from maize) was inverse to dietary CM.Growth performance and feed utilization of fish fed the diets containing CM replacing 0-40% fishmeal protein were not affected after the 6-week feeding trial.Accumulation of hepatopancreatic total gossypol in the hepatopancreas was significantly correlated with free gossypol content in the diets(HTG=88.6+1.5×DFG,R^2=0.89,P<0.05).Intestinal a-amylase and γ-glutamyl transpeptidase activities rose along with increasing dietary CM level.The structure of the mid-intestinal tissues and the ultrastructure of the enterocyte microvilli were normal when dietary CM was <36.6%(60% protein replacement).Increasing dietary CM content increased serum alanine aminotransferase levels but decreased serum alkaline phosphatase,cholesterol,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol,triglycerides,and albumin(P<0.05).

Toxic effects of meothrin on the gill ultrastructure in grass carp，Ctenopharyngodon idellus

The fingerling Grass carp. Ctenopharyngodon idellus. was exposed in differentconcentrations of meothrin nearby 24h LC_(50) and its gill morphology was examined by light and elec-tron microscopy. The results indicate that meothrin caused fish convulsions. cough, ataxia,intermittent paralysis and overtumed. Morphological examination revealved severe alterations to com-pare with control fish. These initially consisted in hypertrophy of the secondary lamellae, andfinally resulted in local telangiectasia, fusion between secondary lamellae.Ultrustiuctural changes in the gills showed the pillar cell system collapse and resulted in largenon-tissue spaces which were invaded by leucocytes. The cytoplasin of the epithelial cells appearedmany myelin figures, electron dense deposits. Chloride cells were severely damaged with a degeneratedmitochondria and nuclear membrane. Higher concentration of meothrin caused a loss of adhesion be-tween the epithelial cells. accompanied by a collapsing of the structural integrity of the primarylamellae and degenerating of epithelial and chloride cells .

Study of Embryonic and Postembryonic Development of the Hybrid(Ctenopharyngodon idellus ♀ ×Elopichthys bambusa♂)

[ Objective ] The purpose was to provide a reference for crossbreeding of grass carp. [ Method] We conducted hybridization between Ctenopharyngodon ideUus （ ♀ ） and Elopichthys bambusa ♂ ） by artificial methods. The process of embryo and postembryonic development were observed and recorded. [ Result ] The fertilization rate, hatching rate and survival rate of the hybrid F1 were （75.8 ± 6. 2）%, （41.9 ± 8.2）% and （9.3± 3.7）%, respectively. At the water temperature of 20.1 -21.6℃, the larvae was hatched for about 34 h and 25 rain after fertilization. The whole length of newly-hatched larvae of the hybrid Fl was （5.8 ± 0.12） mm. The larvae could feed rotifer and unicellular algae after 3 or 4 days hatching. Postembryonic development of the hybrid at the formation of scales, lasted for 65 days when the young was（74.0 ± 2.1 ） mm in whole length. [ Conclusion] The embryonic development of hybrid F1 was intermediate to their parents, the form of the hybrid F1 was similar to that of their female line of grass carp. The growth rate of larva was faster than that of grass carp and similar to that of their paternal fish.

Electrophoretic Analysis of Isozymes and Proteins in F_1 Hybrids of Ctenopharyngodon idellus ♀ × Elopichthys bambusa ♂

[ Objective] This study aimed to investigate the biochemical and genetic characteristics of F1 hybrids of Ctenopharyngodon idellus ♀× Elopichthys bambusa ♂ - [ Method ] By using vertical polyacrylamide gel electrophoresis technology, three isozymes （LDH, EST, MDH） in nine tissues （heart, brain, eyes, liver, kidney, spleen, fin, muscle, plasma） of F1 hybrids of C. ideUus and parents were compared. [Result] Three isozymes in F1 hybrids of ♀× E. bambusa ♀ were analyzed; differences in isozyme and proteins between F1 hybrids idellus ♀× E. bambusa ♀ exhibited varying degrees of tissue-specificity; isozymes and proteins in F, hybrids were signiticandy different from the parents. [ Conclusion] These nine differences could be used as indicators to identify F1 hybrids and parents.

The Study of Enzymology Characterization of Ctenopharyngodon idellus LDH Isozyme

LDH-A_4,B_4,and C_4 were isolated and purified from Ctenopharyngodon idellus tissues by means ofaffinity chromatography.The purity,amino acid content and kinetics were analyzed.The anti-LDH-A_4,B_4,and C_4 antibodies were prepared from rabbit sensitized by LDH-A_4,B_4,and C_4respectively.The LDH patterns of some freshwater fish and marine fish were identified by theantigen-antibody precipitation reaction.The homology between LDH isozyme molecules fromdifferent sources and the immunological homology of different LDH isozymes were discussed.

Cd-Zn对草鱼(Ctenopharyngodon idellus)的联合毒性及对肝脏超氧化物歧化酶(SOD)活性的影响

以草鱼(Ctenopharyngodon idellus)为实验材料,研究并比较了重金属镉(Cd)与锌(Zn)对草鱼的单一与联合毒性.在此基础上,根据水生毒理联合效应指数相加法原理,利用生物测定计数型机值分析得到毒性单位浓度LC50值进行判断.结果表明,Cd对草鱼的毒性大于Zn.Cd、Zn对草鱼96h的半致死浓度分别为26.87和33.14mg·L-1;Cd与Zn对草鱼的联合毒性在48h为拮抗作用,在96h表现为协同作用.以草鱼肝脏组织超氧化物歧化酶(SOD)活性影响为指标,Cd与Zn的联合作用与Cd、Zn的暴露剂量和暴露时间都有密切关系:草鱼肝脏SOD活性应激反应对低浓度Zn(0.4TU)暴露较敏感,对高浓度Cd(0.8TU)的暴露较敏感,SOD活性能迅速产生应激性升高;48h时Cd与Zn的联合毒性显示为拮抗作用,96h时Cd与Zn的联合毒性显示为协同作用.

Different metabolomic responses of grass carp(Ctenopharyngodon idellus)to dietary tannin and rapeseed meal

In order to study the metabolomic responses of rapeseed meal on grass carp and the role that tannin plays in those responses,grass carp were fed four diets for an eight week trial.Two were practical diets:FM diet contained 10%fishmeal without rapeseed meal,RM diet contained 50%rapeseed meal without fishmeal;the other two were semi-purified diets without(T0)or with 1.25%(T1)of supplemental hydrolysable tannin.The tannin content in the RM diet was close to that of T1.The rate of weight gain for RM was significantly lower than FM,while the feed conversion ratio in the T1 was significantly higher than T0.The muscle lipid and protein content was significantly lower and glycogen higher in the RM and T1 compared to the other treatments.The percent of muscle-saturated fatty acid(SFA)in the RM and T1 groups was significantly lower than FM and T0 groups,respectively,while the mono-unsaturated fatty acid(MUFA)in the RM group was significantly higher than FM.The hepatic activities of alanine aminotransferase and aspartate aminotransferase were lower and the hepatic glycogen and malonaldehyde were higher in the T1 and RM than the other treatments.The total serum protein,globulin,and triglycerides were significantly higher in T1 and RM;the alanine aminotransferase in the T1 was significantly higher than T0;and the aspartate aminotransferase in the RM and T0 groups were significantly higher than the other treatments.In a metabolomic assay,29 differential metabolites were identified between T0 and T1,23 metabolites were downregulated,and 6 metabolites were upregulated in T1 compared to T0.Ninety-two differential metabolites were identified between FM and RM,31 metabolites were downregulated,and 61 metabolites were upregulated in RM compared to FM.These indicated that lipid utilization and carbohydrate metabolism might be improved,while the protein metabolism was suppressed by rapeseed meal.The abnormal protein and lipid metabolism may be partly caused by tannin in the rapeseed meal,as the tannin contained within the rapeseed meal seemed to bring different effects that the tannin additive.

月饱食度对草鱼幼鱼生长性能、体组成、免疫能力及水质的影响

为探讨月饱食度对草鱼(Ctenopharyngodon idellus)幼鱼的摄食、生长、免疫能力和养殖水体水质的影响,选取初始体重(18.10±0.09)g的草鱼幼鱼为试验对象,试验期为60 d。设计4个月饱食度,分别为月饱食量的70%、80%、90%和100%。结果表明,①试验鱼的增重率和特定生长率与月饱食度呈显著性正相关,月饱食度为100%的处理组表现出最佳的特定生长率(2.02%/d),但与月饱食度90%的处理组之间无显著差异(P>0.05);试验鱼的饲料系数与月饱食度呈显著性负相关,月饱食度为90%的处理组饲料系数最低(1.16±0.04),而月饱食度为70%的处理组饲料系数最高(1.43±0.07)。②不同月饱食度对试验鱼的存活率和形态学指标有一定的影响,其中月饱食度为100%的处理组存活率最低,但其肝体比和肥满度最高。③不同月饱食度对试验鱼肌肉营养组成成分无显著影响(P>0.05),而随着月饱食度的增加,全鱼粗脂肪含量越高(P<0.05)。④养殖水体氨氮、硝态氮和磷酸盐含量与试验鱼的月饱食呈显著性正相关(P<0.05),但养殖水体的亚硝态氮和试验鱼的血清抗氧化指标不受月饱食度变化的影响而显著性变化(P>0.05)。

一株草鱼源荧光假单胞菌的分离鉴定及其耐药特性分析

为探究临沂市某草鱼养殖场发生病害的原因,从患病的草鱼(Ctenopharyngodon idellus)肝脏和肾脏混合组织中分离得到一株优势致病菌G-13,通过细菌形态学观察、革兰氏染色、生理生化特征、16S rRNA基因测序,以及系统发育分析等完成菌株鉴定,并测定其耐药特性。形态特征显示G-13是一种短杆状的革兰氏阴性菌,在LB固体平板上形成乳白色、圆形、整体呈隆起状、边缘较为整齐、表面光滑湿润的菌落;16S rRNA系统发育进化分析发现G-13与荧光假单胞菌(Pseudomonas fluorescens)聚在一支,序列同源性高达100%;生理生化试验显示葡萄糖、精氨酸双水解酶、鸟氨酸脱羧酶、赖氨酸脱羧酶、氧化酶、无盐和3%NaCl胰胨水等7项指标为阳性,与假单胞菌属特征相近,确定分离株G-13为P.fluorescens。药敏试验结果显示菌株G-13对丁胺卡那、多西环素、四环素、新霉素、环丙沙星、氧氟沙星等13种抗生素敏感,对氨苄西林、头孢拉定、克林霉素、呋喃唑酮等7种抗生素耐药。

饲喂蚕豆的草鱼肠道细菌群落的PCR-DGGE分析

为探讨饲喂蚕豆(Vicia faba)对草鱼(Ctenopharyngodon idellus)肠道菌群的影响,采用PCR-DGGE技术比较了饲喂蚕豆的草鱼(脆肉鲩组)及饲喂配合饲料的草鱼(普通草鱼组)肠道微生物菌群的异同。结果显示,DGGE图谱上出现了20条明显条带,表明脆肉鲩组及普通草鱼组肠道中均存在大量细菌群落。对这20条条带测序后,获得了其中17条条带的序列,这17条条带中有9条是尚未被培养的细菌。经分析发现,这17条条带分属于变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)及未分类的细菌,其中变形菌门为两组肠道的优势菌。实验还发现,饲喂蚕豆对肠内容物菌群的影响大于对肠壁菌群的影响。结果表明,饲喂蚕豆不改变草鱼肠道菌群的种类,但对肠道菌群的相对丰度有一定影响。

两株草鱼呼肠孤病毒江西株的分离与鉴定

对从江西省南昌县莲塘镇的患病草鱼鱼种池塘采集到草鱼出血病疑似病样材料分离出的两株病毒株进行了鉴定。结果显示:用除菌过滤后的患病鱼肝脏、脾脏、肾脏组织浆滤液腹腔注射感染8～10 cm健康草鱼鱼种,5 d后试验鱼发病,可复制出自然发病症状,死亡率达50%以上,对照组未有死亡。用病样滤液接种草鱼肾细胞系(CIK),可产生细胞病变效应(CPE),病毒的TCID50分别为10-8.3/0.1 mL和10-8.0/0.1 mL。理化特性研究结果显示:氯仿、乙醚处理组病毒的感染力和对照组相比变化不显著。病毒基因组RT-PCR反应可扩增出目的片段,序列测定与分析结果表明,其与GenBank中GCRV(登录号为AF403392,AF239175)相应序列的同源性达99%以上。

草鱼和银鲫肠道产消化酶细菌的研究

检测了分别从草鱼(Ctenopharyngodon idellus)和银鲫(Carassius auratus gibelio)肠道中分离的180株细菌的蛋白酶、脂肪酶、淀粉酶和纤维素酶的产酶能力。结果显示,两种鱼肠道内可分泌胞外消化酶的细菌包括Aero-monas(气单胞菌属,Aer.)、Vibrio(弧菌属,Vib.)、Bacillus(芽孢杆菌属,Bac.)、Pseudomonas(假单胞菌属,Pse.)四个种属的细菌,Aer.在其中占主要优势,45.71%的Aer.可分泌胞外消化酶。草鱼可分泌上述四种胞外消化酶的菌株共有33株,占肠道菌总数的36.67%;银鲫43株,占47.78%。产酶菌的分布上,草鱼中肠内产消化酶细菌数量显著多于前肠和后肠(P<0.05),前、中、后肠分别是6株、20株和7株;银鲫中肠和后肠数量差异不显著,前肠分布最少。草鱼分泌蛋白酶、脂肪酶、淀粉酶和纤维素酶的菌株分别有21株(23.33%)、10株(11.11%)、30株(33.33%)和16株(17.78%)。银鲫肠道内未检测到可分泌纤维素酶的细菌,蛋白酶、脂肪酶和淀粉酶菌株的数量分别是21株、37株和17株。可见鱼类肠道细菌对食饵消化有重要作用。

酸化剂对草鱼生长和非特异性免疫能力的影响

为考察不同类型酸化剂对草鱼生长及生理机能的影响,在基础饲料(对照组)中分别添加0.21%磷酸、柠檬酸、乳酸和复合酸,饲养初始体重为(10.33±0.03)g草鱼(Ctenopharyngodon idellus)8周。结果表明:(1)与对照组相比,饲料中添加0.21%柠檬酸、乳酸和复合酸均显著提高草鱼的增重率、特定生长率,降低饲料系数(P<0.05);(2)与对照组相比,饲料中添加酸化剂对草鱼全鱼营养成分和P、K、Na含量无显著影响(P>0.05),磷酸组Mg和Cu,柠檬酸组Mg、Mn、Fe和Cu,乳酸组Mg、Fe和Cu,复合酸组Ca、Mg、Fe、Mn、Cu和Zn含量显著提高(P<0.05);(3)饲料中添加酸化剂均显著提高草鱼肠道和肝胰脏蛋白酶活性,添加复合酸显著提高肠道和肝胰脏淀粉酶和脂肪酶活性,添加乳酸和柠檬酸显著提高肝胰脏脂肪酶和淀粉酶活性(P<0.05);(4)饲料中添加酸化剂显著提高草鱼血清超氧化物歧化酶、谷胱甘肽过氧化物酶和溶菌酶活性,添加乳酸和复合酸显著提高了血清碱性磷酸酶活性,添加复合酸显著降低血清丙二醛含量(P<0.05)。结论:饲料中添加酸化剂能够促进草鱼生长,增强其消化、抗氧化和免疫能力,其中柠檬酸和乳酸效果优于磷酸,复合酸效果最好。

四氯乙烯和对二氯苯对草鱼的联合毒性

采用水生污染暴露试验和水生毒理联合效应相加指数法,研究了四氯乙烯(PCE)和对二氯苯(P-DCB)对草鱼(Ctenopharyngodon idellus)的单一毒性与联合毒性.结果表明,PCE和P-DCB的单一毒性均为高毒,且P-DCB的毒性大于PCE.PCE和P-DCB对草鱼的联合染毒在浓度1:1时,暴露时间为24,48,72,96h的相加指数(AI)分别为0.26,0.37,0.78,0.98,联合毒性为相加作用.PCE与P-DCB对草鱼的联合染毒在毒性1:1时,暴露时间为24,48,72,96h的AI分别为-0.15,0.24,0.83,1.30,联合毒性主要是相加作用,但是随着染毒时间的延长,联合毒性由相加作用向协同作用转变.

主养草鱼池塘底泥微生物群落多样性研究

为研究主养草鱼池塘底泥微生物多样性,采用细菌通用引物27F和1492R扩增了湖北石首一草鱼(Cteno-pharyngodon idellus)养殖池塘底泥细菌16S rDNA片段,构建了底泥细菌16S rDNA克隆文库,并对该文库中的微生物群落进行了分析。结果显示,该文库的Shannon多样性指数(H')为3.85,Schao1丰富度指数为185,Evenness均匀度指数(E)为0.96。池塘底泥中主要的细菌类群为:变形菌门(Proteobacteria)(53.66%)、厚壁菌门(Firmi-cutes)(14.63%)、酸杆菌门(Acidobacteria)(7.32%)、拟杆菌门(Bacteroidetes)(7.32%)、绿弯菌门(Chloroflexi)(3.66%)、放线菌门(Actinobacteria)(3.66%)、浮霉菌门(Planctomycetes)(2.44%)和分类地位未知(Unclassifiedbacteria)(7.32%)的种类。其中,变形菌门中的γ-变形菌纲(γ-Proteobacteria)是明显的优势类群(21.95%)。草鱼养殖池塘底泥中微生物种类丰富,而磷代谢功能菌Enterobacter cloacae和鱼类病原菌Acinetobacter lwoffii的出现表明池塘底泥既是生态修复功能菌的资源库,也是鱼类细菌性疾病的病原库。

不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响

以鱼粉和豆粕为蛋白源，鱼油和豆油等比例混合油为脂肪源，共配制4个蛋白水平（20％、25％、30％、35％），每一蛋白水平设4个脂肪水平（4．5％、8％、11．5％、15％），共16组饲料。每组设3个重复，在水温23～29℃下，连续投喂初始体重为（16．84±0．28）g的草鱼（Ctenopharyngodonidellus）10周，研究不同蛋白能量比饲料对草鱼幼鱼消化酶活性的影响。结果显示：肠道蛋白酶的活性随着饲料蛋白含量的升高而显著升高（P〈0．05），饲料蛋白水平在20％～30％时，饲料中的脂肪水平对蛋白酶活性影响不显著（P〉0．05），蛋白水平在35％时，高脂肪抑制了蛋白酶活性，肝胰脏的蛋白酶变化规律类似于肠道；肠道和肝胰脏淀粉酶活性在饲料蛋白含量相同的情况下，随着脂肪含量的升高呈现显著的下降趋势（P〈0．05），但饲料中蛋白（30％，35％）和脂肪（8％，11．5％，15％）含量较高时，淀粉酶活性较稳定；肠道和肝胰脏的脂肪酶活性在饲料蛋白含量相同的情况下，随着脂肪含量的升高，呈显著上升的趋势（P〈0．05），但在蛋白含量（30％，35％）和脂肪含量（8％、11．5％，15％）的6个试验组之间差异不显著（P〉0．05）；在脂肪含量分别为4．5％、8％和11．5％时，饲料的蛋白含量对肠道的脂肪酶活性无显著性影响（P〉0．05），当脂肪含量为15％时，随着蛋白含量的升高，肠道的脂肪酶活性显著降低（P〈0．05）。结果表明，草鱼饲料中蛋白含量为30％和脂肪为8％（即蛋白能量比21．7mg／kJ）的试验组草鱼获得较高的消化酶活性。

草鱼肠道微生物对食物改变适应性变化的研究

对草鱼(Ctenopharyngodon idellus)先饲喂人工饲料再饲喂苏丹草,运用PCR-DGGE的方法,比较了食物改变引起的草鱼肠道微生物菌群结构的变化过程。结果显示,饲喂同种饲料的草鱼后肠与前、中肠样品间菌群结构存在显著差异(TH0-F0=-2.268,P<0.05;TH0-M0=-2.470,P<0.05),饲喂不同种食物的相同肠段样品间菌群结构也存在着显著差异(P<0.05)。微生物多样性指数显示,后肠样品Shannon指数H'一般不低于4.25,而前、中肠样品H'均未超过4.25。对后肠样品进一步研究发现,食物改变11 d之后,后肠微生物菌群基本达到稳定。结果表明,草鱼肠道不同部位内容物菌群结构不同,后肠样品具有更高的微生物多样性,并且食物的改变会对草鱼肠道微生物菌群产生快速而显著的影响。