Mannan oligosaccharides alleviate oxidative injury in the head kidney and spleen in grass carp(Ctenopharyngodon idella)via the Nrf2 signaling pathway after Aeromonas hydrophila infection

Background Mannan oligosaccharides(MOS)are recommended as aquaculture additives owing to their excellent antioxidant properties.In the present study,we examined the effects of dietary MOS on the head kidney and spleen of grass carp(Ctenopharyngodon idella)with Aeromonas hydrophila infection.Methods A total of 540 grass carp were used for the study.They were administered six gradient dosages of the MOS diet(0,200,400,600,800,and 1,000 mg/kg)for 60 d.Subsequently,we performed a 14-day Aeromonas hydrophila challenge experiment.The antioxidant capacity of the head kidney and spleen were examined using spectrophotometry,DNA fragmentation,qRT-PCR,and Western blotting.Results After infection with Aeromonas hydrophila,400-600 mg/kg MOS supplementation decreased the levels of reactive oxygen species,protein carbonyl,and malonaldehyde and increased the levels of anti-superoxide anion,antihydroxyl radical,and glutathione in the head kidney and spleen of grass carp.The activities of copper-zinc superoxide dismutase,manganese superoxide dismutase,catalase,glutathione S-transferase,glutathione reductase,and glutathione peroxidase were also enhanced by supplementation with 400-600 mg/kg MOS.Furthermore,the expression of most antioxidant enzymes and their corresponding genes increased significantly with supplementation of 200-800 mg/kg MOS.mRNA and protein levels of nuclear factor erythroid 2-related factor 2 also increased following supplementation with 400-600 mg/kg MOS.In addition,supplementation with 400-600 mg/kg MOS reduced excessive apoptosis by inhibiting the death receptor pathway and mitochondrial pathway processes.Conclusions Based on the quadratic regression analysis of the above biomarkers(reactive oxygen species,malondialdehyde,and protein carbonyl)of oxidative damage in the head kidney and spleen of on-growing grass carp,the recommended MOS supplementation is 575.21,557.58,531.86,597.35,570.16,and 553.80 mg/kg,respectively.Collectively,MOS supplementation could alleviate oxidative injury in the head kidney and spleen of grass carp infected with Aeromonas hydrophila.

Behavior and controlling factors of methane adsorption in Jurassic continental shale,northeastern Sichuan Basin

The behavior and controlling factors of natural gas adsorption in the Jurassic continental shale in the northeastern Sichuan Basin are studied based on the organic geochemical features,mineral compositions and pore structure parameters through a series of experiments on samples from the shale.Results show that the total gas content of the shale measured on-site is 0.1-5.3 cm^(3)/g,with an average of 0.7 cm^(3)/g.The methane isothermal adsorption curves show a trend of increasing first and then decreasing,indicating an obvious excessive adsorption.The shale has a maximum adsorption capacity(V^(L))of 0.44-3.59 cm^(3)/g,with an average of 1.64 cm^(3)/g,lower than that of marine shale in the same basin.The organic matter content and pore structure characteristics are identified as the two main factors controlling the adsorption capacity of the shale.Micropores in the shale are the main storage space for gas to be adsorbed.Due to well developed shell laminae and interlayers in the shale,calcite plays a more important role than clay minerals in affecting the adsorption of gas to the rock.The formation temperature and water content also significantly inhibit the gas adsorption to the shale.Compared with marine shale in the basin,the Jurassic continental shale is more heterogeneous and lower in TOC values.Furthermore,with a more widely developed clayey shale lithofacies and shell limy shale lithofacies as well as relatively less developed organic pores and micropores,the continental shale is inferior to marine shale in terms of gas adsorption capacity.

Impacts of high temperature,relative air humidity,and vapor pressure deficit on the seed set of contrasting maize genotypes during flowering

Heat stress is a major constraint to current and future maize production at the global scale.Male and female reproductive organs both play major roles in increasing seed set under heat stress at flowering,but their relative contributions to seed set are unclear.In this study,a 2-year field experiment including three sowing dates in each year and 20 inbred lines was conducted.Seed set,kernel number per ear,and grain yield were all reduced by more than 80%in the third sowing dates compared to the first sowing dates.Pollen viability,silk emergence ratio,and anthesis-silking interval were the key determinants of seed set under heat stress;and their correlation coefficients were 0.89^(***),0.65^(***),and-0.72^(***),respectively.Vapor pressure deficit(VPD)and relative air humidity(RH)both had significant correlations with pollen viability and the silk emergence ratio.High RH can alleviate the impacts of heat on maize seed set by maintaining high pollen viability and a high silk emergence ratio.Under a warming climate from 2020 to 2050,VPD will decrease due to the increased RH.Based on their pollen viability and silk emergence ratios,the 20 genotypes fell into four different groups.The group with high pollen viability and a high silk emergence ratio performed better under heat stress,and their performance can be further improved by combining the improved flowering pattern traits.

Recent Advances in Mechanistic Understanding of Metal-Free Carbon Thermocatalysis and Electrocatalysis with Model Molecules

Metal-free carbon,as the most representative heterogeneous metal-free catalysts,have received considerable interests in electro-and thermo-catalytic reac-tions due to their impressive performance and sustainability.Over the past decade,well-designed carbon catalysts with tunable structures and heteroatom groups coupled with various characterization techniques have proposed numerous reaction mechanisms.However,active sites,key intermediate species,precise structure-activity relationships and dynamic evolution processes of carbon catalysts are still rife with controversies due to the monotony and limitation of used experimental methods.In this Review,we sum-marize the extensive efforts on model catalysts since the 2000s,particularly in the past decade,to overcome the influences of material and structure limitations in metal-free carbon catalysis.Using both nanomolecule model and bulk model,the real contribution of each alien species,defect and edge configuration to a series of fundamentally important reactions,such as thermocatalytic reactions,electrocatalytic reactions,were systematically studied.Combined with in situ techniques,isotope labeling and size control,the detailed reaction mechanisms,the precise 2D structure-activity relationships and the rate-determining steps were revealed at a molecular level.Furthermore,the outlook of model carbon catalysis has also been proposed in this work.

Preparation and Methicillin-Resistant Staphylococcus aureus Biofilm Elimination Effect of Baicalein-Loaded Hyaluronic acid/β-Cyclodextrin grafted Chitosan Nanoparticles

Methicillin-resistant Staphylococcus aureus(MRSA)is a common pathogen causing acquired infections.Antibiotics are routinely employed for bacterial infection treatment.Excessive antibiotic use for bacterial infections heightens resistance,and MRSA resistance is being prevalent[1].MRSA exhibits substantial resistance to conventional antibiotics,which is associated with its biofilm-forming capability.The bacterial biofilm serves as a barrier,restricting nutrient access and slowing internal metabolism,increasing antibiotic resistance.The bacterial biofilm forms a defensive layer,resisting antibiotic penetration while preventing nutrient entry,inducing a slow bacterial metabolism,and increasing bacterial resistance[2].Consequently,biofilm formation and the emergence of resistance to conventional antibiotics have become substantial challenges in the field of infectious diseases.The development of agents to remove biofilm barriers is urgently required because biofilms are extremely hazardous.

Meta-analysis of transarterial chemoembolization combined with cryoablation vs transarterial chemoembolization alone for≥5 cm hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma(HCC)ranks sixth globally in cancer incidence and third in mortality rates.Unfortunately,over 70% of HCC patients forego the opportunity for curative surgery or liver transplantation due to inadequate physical examinations,poor physical condition,and limited organ availability upon diagnosis.Clinical guidelines endorse transarterial chemoembolization(TACE)as the frontline treatment for intermediate to advanced-stage HCC.Cryoablation(CRA)is an emerging local ablative therapy increasingly used in HCC management.Recent studies suggest that combining CRA with TACE offers complementary and synergistic effects,potentially improving long-term survival rates.However,the superiority of combined TACE+CRA therapy over TACE alone for HCC lesions equal to or exceeding 5 cm requires further investigation.AIM To compare the efficacy and safety of TACE combined with CRA vs TACE alone in the treatment of HCC with a diameter of≥5 cm.METHODS PubMed,EMBASE,Cochrane Library,CNKI,Wanfang,and VIP databases were searched to retrieve all relevant studies on TACE and CRA up to July 2022.Meta-analysis was performed using RevMan 5.3 software.RESULTS After screening according to the inclusion and exclusion criteria,6 articles were included,including 2 randomized controlled trials and 4 nonrandomized controlled trials,with a total of 575 patients included in the meta-analysis.The results showed that the objective response rate[odds ratio(OR)=2.56,95%confidence interval(CI):1.66-3.96,P<0.0001],disease control rate(OR=3.03,95%CI:1.88-4.89,P<0.00001),1-year survival rate(OR=3.79,95%CI:2.50-5.76,P<0.00001),2-year survival rate(OR=2.34,95%CI:1.43-3.85,P=0.0008),and 3-year survival rate(OR=3.34,95%CI:1.61-6.94,P=0.001)were all superior to those of the control group;the postoperative decrease in alpha-fetoprotein value(OR=295.53,95%CI:250.22-340.85,P<0.0001),the postoperative increase in CD4 value(OR=10.59,95%CI:8.78-12.40,P<0.00001),and the postoperative decrease in CD8 value(OR=6.47,95%CI:4.44-8.50,P<0.00001)were also significantly higher than those in the TACE-alone treatment group.CONCLUSION Compared with TACE-alone treatment,TACE+CRA combined treatment not only improves the immune function of HCC patients with a diameter of≥5 cm,but also enhances the therapeutic efficacy and long-term survival rate,without increasing the risk of complications.Therefore,TACE+CRA combined treatment may be a more recommended treatment for patients with HCC with a diameter of≥5 cm.

A systematic review of the efficacy of traditional Chinese medicine retention enema in the treatment of ulcerative colitis

The objective of this study is to summarize the efficacy and safety of traditional Chinese medicine(TCM)enema in the treatment of ulcerative colitis(UC).The randomized controlled trials on TCM enema intervention in the treatment of UC were searched in seven databases:PubMed,Embase,Web of Science,CBM,CNKI,Wanfang Database,and VIP Database from January 1,2013 to June 6,2022,and the data were analyzed using RevMan 5.3 software.A total of 18 studies involving 1514 UC patients were included.Meta analysis results showed that compared with conventional Western medicine,Chinese medicine enema had a significant effect on UC,and the clinical effective rate of the experimental group using Chinese medicine enema was 4.45 times that of the control group using conventional Western medicine(odds ratio=4.45,95%confidence interval[3.27,6.06]).Therefore,Chinese medicine enema is effective in the treatment of UC,and can significantly reduce related symptoms.

Psychological experience of breastfeeding among primiparous women with lactating mastitis:A qualitative research

Objective:The objective of this study is to comprehensively understand the psychological experience of primiparous women during breastfeeding while dealing with lactating mastitis and to establish a reliable foundation for tailored support measures.Methods:Twenty primiparous mothers from a tertiary hospital in Beijing between January and March 2023 were chosen using purposive sampling for semi-structured interviews.After conducting 20 interviews,data saturation was achieved.The Colaizzi’s seven-step analytical approach was employed to analyze,summarize,and refine the identified themes.Results:Among primiparous women afflicted by lactating mastitis,the primary themes regarding breastfeeding attitudes included three key aspects:(1)uncertainty during the initial diagnosis phase,(2)intricate emotional journey during treatment,and(3)positive psychological outlook during the recovery stage.Conclusion:Primiparous women undergoing lactating mastitis experience substantial physical and psychological strain.It is crucial for medical personnel,family caregivers,and society at large to be attuned to the emotions of these patients.Tailored support measures should be offered to enhance patients’physical and mental well-being and facilitate disease recovery.

Investigation on step overcharge to self-heating behavior and mechanism analysis of lithium ion batteries

To obtain intrinsic overcharge boundary and investigate overcharge mechanism,here we propose an innovative method,the step overcharge test,to reduce the thermal crossover and distinguish the overcharge thermal behavior,including 5%state of charge(SOC)with small current overcharge and resting until the temperature equilibrium under adiabatic conditions.The intrinsic thermal response and the self-excitation behaviour are analysed through temperature and voltage changes during the step overcharge period.Experimental results show that the deintercalated state of the cathode is highly correlated to self-heating parasitic reactions.Before reaching the upper limit of Negative/Positive(N/P)ratio,the temperature changes little,the heat generation is significantly induced by the reversible heat(endothermic)and ohmic heat,which could balance each other.Following that the lithium metal is gradually deposited on the surface of the anode and reacts with electrolyte upon overcharge,inducing selfheating side reaction.However,this spontaneous thermal reaction could be“self-extinguished”.When the lithium in cathode is completely deintercalated,the boundary point of overcharge is about 4.7 V(~148%SOC,>40℃),and from this point,the self-heating behaviour could be continuously triggered until thermal runaway(TR)without additional overcharge.The whole static and spontaneous process lasts for 115 h and the side reaction heat is beyond 320,000 J.The continuous self-excitation behavior inside the battery is attributed to the interaction between the highly oxidized cathode and the solvent,which leads to the dissolution of metal ions.The dissolved metal ions destroy the SEI(solid electrolyte interphase)film on the surface of the deposited Li of anode,which induces the thermal reaction between lithium metal and the solvent.The interaction between cathode,the deposited Li of anode,and solvent promotes the temperature of the battery to rise slowly.When the temperature of the battery reaches more than 60℃,the reaction between lithium metal and solvent is accelerated.After the temperature rises rapidly to the melting point of the separator,it triggers the thermal runaway of the battery due to the short circuit of the battery.

Dietary protein levels changed the hardness of muscle by acting on muscle fiber growth and the metabolism of collagen in sub-adult grass carp(Ctenopharyngodon idella)

Background:Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish.As a necessary nutrient for fish growth,protein accounts for the highest proportion in the fish diet and is expensive.Although our team found that the effect of protein on the muscle hardness of grass carp was probably related to an increased collagen content,the mechanism for this effect has not been deeply explored.Moreover,few studies have explored the protein requirements of sub-adult grass crap(Ctenopharyngodon idella).Therefore,the effects of different dietary protein levels on the growth performance,nutritional value,muscle hardness,muscle fiber growth,collagen metabolism and related molecule expression in grass carp were investigated.Methods:A total of 450 healthy grass carp(721.16±1.98 g)were selected and assigned randomly to six experimen-tal groups with three replicates each(n=25/replicate),and were fed six diets with 15.91%,19.39%,22.10%,25.59%,28.53%and 31.42%protein for 60 d.Results:Appropriate levels of dietary protein increased the feed intake,percentage weight gain,specific growth rate,body composition,unsaturated fatty acid content in muscle,partial free amino acid content in muscle,and muscle hardness of grass carp.These protein levels also increased the muscle fiber density,the frequency of new muscle fibers,the contents of collagen and IGF-1,and the enzyme activities of prolyl 4-hydroxylases and lysyloxidase,and decreased the activity of matrix metalloproteinase-2.At the molecular level,the optimal dietary protein increased col-lagen type Iα1(Colα1),Colα2,PI3K,Akt,S6K1,La ribonucleoprotein domain family member 6a(LARP6a),TGF-β1,Smad2,Smad4,Smad3,tissue inhibitor of metalloproteinase-2,MyoD,Myf5,MyoG and MyHC relative mRNA levels.The levels of the myostatin-1 and myostatin-2 genes were downregulated,and the protein expression levels of p-Smad2,Smad2,Smad4,p-Akt,Akt,LARP6 and Smad3 were increased.Conclusions:The appropriate levels of dietary protein promoted the growth of sub-adult grass carp and improved muscle hardness by promoting the growth of muscle fibers,improving collagen synthesis and depressing collagen degradation.In addition,the dietary protein requirements of sub-adult grass carp were 26.21%and 24.85%according to the quadratic regression analysis of growth performance(SGR)and the muscle hardness(collagen content),respectively.

Applicability evaluation of ERA5 wind and wave reanalysis data in the South China Sea

Wind and wave data are essential in climatological and engineering design applications.In this study,data from 15 buoys located throughout the South China Sea(SCS)were used to evaluate the ERA5 wind and wave data.Applicability assessment are beneficial for gaining insight into the reliability of the ERA5 data in the SCS.The bias range between the ERA5 and observed wind-speed data was-0.78-0.99 m/s.The result indicates that,while the ERA5 wind-speed data underestimation was dominate,the overestimation of such data existed as well.Additionally,the ERA5 data underestimated annual maximum wind-speed by up to 38%,with a correlation coefficient>0.87.The bias between the ERA5 and observed significant wave height(SWH)data varied from-0.24 to 0.28 m.And the ERA5 data showed positive SWH bias,which implied a general underestimation at all locations,except those in the Beibu Gulf and centralwestern SCS,where overestimation was observed.Under extreme conditions,annual maximum SWH in the ERA5 data was underestimated by up to 30%.The correlation coefficients between the ERA5 and observed SWH data at all locations were greater than 0.92,except in the central-western SCS(0.84).The bias between the ERA5 and observed mean wave period(MWP)data varied from-0.74 to 0.57 s.The ERA5 data showed negative MWP biases implying a general overestimation at all locations,except for B1(the Beibu Gulf)and B7(the northeastern SCS),where underestimation was observed.The correlation coefficient between the ERA5 and observed MWP data in the Beibu Gulf was the smallest(0.56),and those of other locations fluctuated within a narrow range from 0.82 to 0.90.The intercomparison indicates that during the analyzed time-span,the ERA5 data generally underestimated wind-speed and SWH,but overestimated MWP.Under non-extreme conditions,the ERA5 wind-speed and SWH data can be used with confidence in most regions of the SCS,except in the central-western SCS.

Expert consensus on diagnosis and treatment of ulcerative colitis with integrated traditional Chinese and Western medicine:A nursing perspective

Ulcerative colitis(UC)is a chronic nonspecific intestinal inflammatory disease of unclear etiology,characterized by continuous and diffuse inflammatory changes of colorectal mucosa.In recent years,the incidence rate of UC in China has increased year by year,but there is no effective cure method in Western medicine.Traditional Chinese medicine treatment based on syndrome differentiation has the unique advantages of simplicity,convenience,effectiveness,and low cost.Therefore,integration of Chinese and Western medicine has become an important strategy for UC diagnosis and treatment,and has made significant progress in UC.On the basis of learning from a number of consensuses at home and abroad,combined with Chinese research results and the actual clinical situation of traditional Chinese and Western medicine,the UC group of the Chinese Association of Integrative Medicine has formulated the expert consensus on the diagnosis and treatment of UC with integrated traditional Chinese and Western medicine.In this consensus,the pathogenesis,etiology and pathogenesis,diagnosis,integrated traditional Chinese and Western medicine treatment,and chronic disease management with integrated traditional Chinese and Western medicine for UC were recommended by experts.This article interprets the consensus from the perspective of nursing in order to provide reference basis for clinical nursing workers.

Nursing perspective of expert consensus for diagnosis and treatment of gastric cancer with integrated traditional Chinese and Western medicine

Gastric cancer is a common and highly malignant tumor of the digestive system,which seriously threatens human health.The benefit of surgical treatment is limited.The effect of radiotherapy and chemotherapy is not significant,and the toxic and side effects are large.Although the diagnosis and treatment modes of molecular targeting and multidisciplinary cooperation have also been further developed and applied,a relatively unified comprehensive treatment standard scheme has not been formed.Traditional Chinese medicine(TCM),as complementary and alternative medicine,has unique advantages in the development of diagnosis and treatment of diseases in China.Therefore,the Chinese Association of Integrative Medicine formed“Expert Consensus for Diagnosis and Treatment of Gastric Cancer with Integrated Traditional Chinese and Western Medicine”on the basis of clinical practice and experience.In this article,the consensus is interpreted from the perspective of nursing,focusing on the pathogenesis,high‑risk factors,characteristic therapies of TCM,and nursing of integrated traditional Chinese and Western medicine for gastric cancer,to provide a reference for front‑line medical personnel in the roots in the future nursing care of gastric cancer.

Operating procedures of moxibustion technology

Moxibustion therapy is a treatment and health-care method that originated from China.It is a kind of therapy for preventing and treating diseases by stimulating meridians and acupoints using heat to regulate the viscera and enhance immunity.This article introduces the definition and mechanism of moxibustion technology,clinical operation technics,and precautions of moxibustion in practice,and demonstrates plenty of iconic cases of application of moxibustion in the treatment of insomnia,dysmenorrhea,urinary retention,knee arthritis,chronic eczema,etc.,so as to provide a reference for the wide application of moxibustion technology.

Technical operation specification for pricking-cupping therapy

Pricking-cupping therapy is a Traditional Chinese Medicine(TCM)nursing technology that can adjust the viscera of the human body,make the meridians smooth,and Yin and Yang balanced mainly by means of relieving heat and detoxification,harmonizing Qi and blood,promoting blood circulation and removing blood stasis,dredging meridians and activating collaterals,reducing swelling and pain,purging heat and calming shock,clearing heat,and opening orifices.Pricking-cupping therapy has a long history and wide application.After thousands of years of development,it has made great progress.They are widely used to treat lumbar disc herniation,herpes zoster,acute arthritis,migraine,and other diseases in China.Through the clinical practice and theoretical exploration of physicians of past dynasties,the therapeutic mechanism and application scope of pricking-cupping therapy have been greatly enriched.Modern TCM practitioners have conducted in-depth researches on the operation norms of the therapy on the basis of the ancients,hoping to grasp the essence of the disease more accurately and make the rational use of the operation technology of the therapy.

Operating procedures of traditional Chinese medicine breast massage

Traditional Chinese medicine breast massage,also known as breast Tuina or manual expression of breast milk,is a technique of using certain manipulations to act on specific positions or acupoints of the breast to promote blood and lymphatic circulation of breast and facilitate the discharge of stagnant milk.This technique is widely used in China to treat breastfeeding problems such as breast engorgement,mastitis,and postpartum hypogalactia.In this article,we introduce the definition and standardization process of breast massage,elaborate the operating procedures of breast massage in detail,and summarize and discuss the current situation of its clinical application,so as to provide a reference for its wide application and in‑depth research.

Early warning systems for enteral feeding intolerance in patients with stroke

Objective:The objective of this study was to construct an early warning system(EWS)to facilitate risk assessment,early identification,and appropriate treatment of enteral nutrition feeding intolerance(FI)in patients with stroke,so as to provide a reference for risk classification standards and interventions toward a complete EWSs for nursing care of stroke.Materials and Methods:Based on evidence and clinical nursing practice,a structured expert consultation method was adopted on nine experts over two rounds of consultation.Statistical analysis was used to determine the early warning index for FI in patients with stroke.Results:The expert authority coefficient was 0.89;the coefficients of variation for the two rounds of consultation were 0.088-0.312 and 0.096-0.214,respectively.There were significant differences in the Kendall’s concordance coefficient(P<0.05).Finally,22 items in five dimensions of patient age,disease,treatment,biochemical,and enteral nutrition-related factors were identified.Conclusion:The early warning index for FI in patients with a history of stroke is valid and practical.It provides a reference for the early clinical identification of FI risk.

Technical operation specification for cupping therapy

Cupping,as one of the characteristic therapies of traditional Chinese medicine,has been applied for more than 2000 years and has a unique curative effect in clinic.With the evolution of the times,the types and operation techniques of cupping method are also iterating.In the process of its inheritance and development,cupping technology is also known by more and more people.Starting from the development and efficacy of cupping method,this paper introduces the clinical operation steps and precautions of cupping method in detail,and lists the representative diseases such as lumbar muscle strain,herpes zoster,and ankylosing spondylitis,to provide reference for clinical application.

Relationship between Muscle Strength, Muscle Mass and BMD in Postmenopausal Female of Zhuang in Guangxi Province of China

Objective: To explore the correlation between muscle strength, muscle mass and bone mineral density (BMD) in Zhuang female population, body composition analysis and grip strength, and to analyze the possible influencing factors of BMD. Methods: 182 postmenopausal women were selected from Guangxi Province of China. Broadband ultrasound attenuation (BUA) was used to evaluate BMD. Grip dynamometer to assess muscle strength. Height, weight and muscle mass of each part were measured by body composition measuring instrument. Body mass index (BMI), skeletal muscle mass index (SMI) and limb skeletal muscle mass (SM) were calculated according to the measurement results. Results: BUA, grip strength and SMI in postmenopausal women of Zhuang nationality showed a decreasing trend with age (p p p r = 0.305, p Conclusion: With the increase of age, the decline rate of muscle strength of postmenopausal Zhuang women in Guangxi is slower than that of BMD and muscle mass. SM can better reflect the BMD level of the body than SMI, and the LSM is the main influencing factor of BMD.

The relationship between dietary methionine and growth,digestion,absorption,and antioxidant status in intestinal and hepatopancreatic tissues of sub-adult grass carp(Ctenopharyngodon idella)

Background: Methionine is an essential amino acid for fish. The present study was conducted to investigate the effects of dietary methionine on growth performance, digestive and absorptive ability, as well as antioxidant capacity in the intestine and hepatopancreas of sub-adult grass carp(Ctenopharyngodon idella).Results: Dietary methionine deficiency significantly decreased percentage weight gain(PWG), feed intake, feed efficiency and protein efficiency ratio, as well as activities of hepatopancreatic glutamate-oxaloacetate transaminase and muscle glutamate-pyruvate transaminase in sub-adult grass carp(P < 0.05). Furthermore, methionine deficiency significantly reduced activities of trypsin, lipase and amylase in the intestine, Na^+/K^+-ATPase, alkaline phosphatase and γ-glutamyl transpeptidase in three intestinal segments, and creatine kinase(CK) in the proximal intestine(P < 0.05). However, an unexplained and significant increase in CK activity in the mid intestine was associated with dietary methionine deficiency. Malondialdehyde and protein carbonyl contents in the intestine and hepatopancreas were significantly increased by methionine deficiency(P < 0.05), whereas anti-hydroxyl radical capacity in the hepatopancreas and intestine, and anti-superoxide anion capacity in the intestine, were significantly decreased by methionine deficiency(P < 0.05). Moreover, methionine deficiency significantly decreased superoxide dismutase and glutathione reductase activities, glutathione contents in the hepatopancreas and intestine, as well as glutathione peroxidase activity in the intestine(P < 0.05), whereas it significantly increased activities of catalase in the hepatopancreas and glutathione-S-transferase in the hepatopancreas and intestine(P < 0.05).(Continued on next page)(Continued from previous page)Conclusions: The present results demonstrated that dietary methionine deficiency induced poor growth, and decreased digestive and absorptive function and antioxidant capacity in the hepatopancreas and intestine of sub-adult grass carp. Methionine requirements for sub-adult grass carp(450-1, 170 g) based on PWG, intestinal trypsin, and hepatopancreatic anti-hydroxyl radical activities were estimated to be 6.12 g/kg diet(21.80 g/kg protein),6.99 g/kg diet(24.90 g/kg protein) and 5.42 g/kg diet(19.31 g/kg protein), respectively, in the presence of 1.50 g cysteine/kg(5.35 g/kg protein).