Accurate models and nutritional strategies for specific oxidative stress factors: Does the dose matter in swine production?

Oxidative stress has been associated with a number of physiological problems in swine,including reduced production efficiency.Recently,although there has been increased research into regulatory mechanisms and antioxidant strategies in relation to oxidative stress-induced pig production,it remains so far largely unsuccessful to develop accurate models and nutritional strategies for specific oxidative stress factors.Here,we discuss the dose and dose intensity of the causes of oxidative stress involving physiological,environmental and dietary factors,recent research models and the antioxidant strategies to provide theoretical guidance for future oxidative stress research in swine.

Establishment of an indirect immunofluorescence assay for the detection of African swine fever virus antibodies

African swine fever(ASF)continues to cause enormous economic loss to the global pig industry.Since there is no safe and effective vaccine,accurate and timely diagnosis of ASF is essential to implement control measures.Indirect immunofluorescence assay(IFA)is a gold standard serological method recommended by the World Organization for Animal Health(WOAH).In this study,we used primary fetal kidney cells to establish a wild boar cell line(BK2258)that supported the efficient replication of ASF virus(ASFV)SD/DY-I/21 and showed visible cytopathic effect(CPE).Moreover,using BK2258,we established a sensitive and specific IFA for ASFV antibody detection.To standardize and evaluate the performance of this assay,we used serum samples from pigs infected with the low virulent genotype I SD/DY-I/21 and genotype II HLJ/HRB1/20,and immunized with the vaccine candidate HLJ/18-7GD,field samples,and negative serum samples.The IFA reacted with the ASFV-positive sera and displayed bright fluorescence foci.There was no non-specific green fluorescence due to cellular senescence or other cell damage-causing factors.Compared to a commercial indirect enzyme-linked immunosorbent assay(iELISA),ASFV antibodies were detected 1–4 days earlier using our IFA.The detection limits of the IFA and iELISA for the same ASFV-antibody positive serum samples were 1:25,600 and 1:6,400,respectively,indicating that the IFA is more sensitive than iELISA.The newly established IFA was highly specific and did not cross-react with sera positive for six other important porcine pathogens(i.e.,Classical swine fever virus(CSFV),Porcine reproductive and respiratory syndrome virus(PRRSV),Porcme circovirus type 2(PCV2),Pseudorabies virus(PRV),Foot-and-Mouth disease virus type O(FMDV/O),and Porcine epidemic diarrhea virus(PEDV)).This study thus provides a sensitive,specific,and reliable detection method that is suitable for the serological diagnosis of ASF.

Call for Papers:Special issue“African Swine Fever”

African swine fever(ASF)is one of the most devastating diseasesin pigs and is caused by the ASF virus(ASFV).Since its firstdiscovery in 1921 in Kenya,ASFV has spread from Africa to otherparts of the world,causing severe economic losses to the porkindustry.Scientists have studied ASF for over 100 years,and manygovernments have tried to eradicate the disease.Nonetheless,approaches to effectively control ASF are still lacking.In recent years,ASF outbreaks have been reported in China,Belgium,Germany,Italyand many other Asian and European countries.Studies on this diseasehave gained new popularity.Under this background,we are organizingthe special issue“African swine fever”to collect the most recentknowledgeon this disease.

Application of traditional Chinese herbal medicine in the prevention and treatment of swine viral infectious diseases

This study aims to explore the current application status and development prospects of Chinese herbal medicine in preventing and treating swine viral infectious diseases over the past five years.By adopting the method of literature review,we collect,organize,and analyze relevant research literature,with the goal of summarizing and summarizing the research progress in this field.Through research,we found that swine infectious diseases have caused serious economic losses in the breeding industry and that some diseases cannot be fully protected by using vaccines.Therefore,we need new means to prevent diseases.The use of Chinese herbal medicine for the prevention and treatment of related diseases has become a reliable means.This study first briefly introduces the common infectious diseases of pigs and the risks and challenges faced by prevention and treatment,then reads the literature comparing the treatment with Western medicine and traditional Chinese medicine,proving the reliability of traditional Chinese medicine treatment and the unique advantages of Chinese herbal medicine.Afterwards,we summarized the literature on the prevention and treatment of related swine diseases with Chinese herbal medicine in the past five years,and finally made a summary and outlook,hoping to provide ideas for relevant researchers and workers.

A Review on Tibetan Swine(a)——Carcass,Meat Quality,Basic Nutrition Component,Amino Acids,Fatty Acids,Inosine Monophosphate and Muscle Fiber

In this review, the carcass, meat quality, internal organs, basic nutrition component, amino acids （AAs）, fatty acids, inosine monophosphate （IMP） and mus- cle fiber of Tibetan swine were summarized for the first time. The formation mecha- nism of excellent features was analyzed from the aspects of physiological traits, ge- ographical environments and constraint reasons. Thereby, the outstanding features of Tibetan swine could be extended continuously, and the poor characteristics should be improved in the future.

The Lapinized Chinese Strain Vaccine Against Classical Swine Fever Virus:A Retrospective Review Spanning Half A Century

Classical swine fever （CSF）, a list A disease of Office International des Epizooties, is caused by classical swine fever virus （CSFV） belonging to the Flaviviridae family. The well-known lapinized Chinese strain of CSFV, also known as C-strain, was developed in China in the mid-1950s. In the past half a century, the vaccine has been proved to be safe and immunogenic in pigs of essentially any age. It is of high efficacy, providing immunized animals with broad-spectrum, sometimes lifelong, protection, which is contributed by both cell-mediated immunity and humoral immunity, against essentially all genotypes or subgenotypes of the virus. The maternal antibodies derived from immunized sows can confer solid protection of their offspring from disease; however, they have been proved to inhibit the successful active immunization of C-strain vaccine. The complete genomes of C-strain and dozens of established or field strains have been sequenced and annotated. Recently, the reverse genetics system of C-strain has been developed, resulting in several C- strain-derived candidate marker vaccines. Many countries manage to control or even eradicate CSF with the aid of mass vaccination with C-strain. in spite of these efforts, the eradication of the disease worldwide remains a big challenge and needs to go a long way, and provably still resorts to genetically modified C-strain vaccine. The authors present an overview of the characteristics of the vaccine, which has stood the test of half a century.

A multiplex real-time PCR assay for simultaneous detection of classical swine fever virus,African swine fever virus,and atypical porcine pestivirus

With the implementation of the C-strain vaccine,classical swine fever(CSF) has been under control in China,which is currently in a chronic atypical epidemic situation.African swine fever(ASF) emerged in China in 2018 and spread quickly across the country.It is presently occurring sporadically due to the lack of commercial vaccines and farmers’ increased awareness of biosafety.Atypical porcine pestivirus(APPV) was first detected in Guangdong Province,China,in 2016,which mainly harms piglets and has a local epidemic situation in southern China.These three diseases have similar clinical symptoms in pig herds,which cause considerable losses to the pig industry.They are difficult to be distinguished only by clinical diagnosis.Therefore,developing an early and accurate simultaneous detection and differential diagnosis of the diseases induced by these viruses is essential.In this study,three pairs of specific primers and Taq-man probes were designed from highly conserved genomic regions of CSFV(5’ UTR),African swine fever virus(ASFV)(B646L),and APPV(5’ UTR),followed by the optimization of reaction conditions to establish a multiplex real-time PCR detection assay.The results showed that the method did not cross-react with other swine pathogens(porcine circovirus type 2(PCV2),porcine reproductive and respiratory syndrome virus(PRRSV),foot-and-mouth disease virus(FMDV),pseudorabies virus(PRV),porcine parvovirus(PPV),and bovine viral diarrhea virus BVDV).The sensitivity results showed that CSFV,ASFV,and APPV could be detected as low as 1 copy μL–1;the repeatability results showed that the intra-assay and interassay coefficient of variation of ASFV,CSFV,and APPV was less than 1%.Twenty-two virus samples were detected by the multiplex real-time PCR,compared with national standard diagnostic and patented method assay for CSF(GB/T 27540–2011),ASF(GB/T 18648–2020),and APPV(CN108611442A),respectively.The sensitivity of this triple real-time PCR for CSFV,ASFV,and APPV was almost the same,and the compliance results were the same(100%).A total of 451 clinical samples were detected,and the results showed that the positive rates of CSFV,ASFV,and APPV were 0.22% (1/451),1.3%(6/451),and 0%(0/451),respectively.This assay provides a valuale tool for rapid detection and accurate diagnosis of CSFV,ASFV,and APPV.

Effects of Integrated Chinese Herbs and Western Medicine on Swine Toxoplasmosis

[ Objective] To evaluate the efficacy of integrated Chinese herbs and western medicine on the treatment of swine toxoplasmosis, in order to increase cure rate and lower recurrence rate. [ Method] Pigs artificially infected by Toxoplasma gondii were treated with compound suffonamide and a self-designed Chinese herbs formula, and the quantities of toxoplasma in ascites were determined. Animal regression experiment was per- formed after mice were inoculated with pathological samples of the pigs infected with toxoplasma. After treatment with integrated Chinese herbs and western medicine, the clinical manifestations of pigs were observed and the level of circulating antigen （CAg） in sera was detected. Curative effect indexes of integrated Chinese herbs and western medicine-treated group were compared with that of Chinese herbs-treated group, western medi- cine-treated group and positive control group. [ Result] All the toxoplasma trophozoites were killed by integrated and westem medicine. Regression expedment results showed that toxoplasma appeared only in one mouse that was inoculated with brain of pig. The treated pigs had nonsignificant clinical symptoms; the peak of serum CAg was lower than that of the positive control group and CAg turned negative faster than that of Chinese herbs-treated group, westem medicine-treated group, and positive control group. [ Conclusion] The integrated Chinese herbs and western medicine has good effect on the treatment of swine toxoplasmosis.

Study on Environmental and Economic Benefits of Rice and Wheat Rotation with Swine Manure-Straw Returning

[Objective] The aim was to investigate the application effect of swine manure-straw returning and to determine the best mode. [Method] A field experiment under rice and wheat rotation with different swine manure-straw treatments was con- ducted to study the growth characters and output of rice and wheat, calculate the economic benefit and carbon dioxide emission reduction, and analyze the best mode of swine manure applying-straw returning. [Result] The swine manure-straw returning was conducive to the growth of crop, the highest outputs of rice and wheat were on the treatment of ＂30% swine manure and 20% straw and 50% chemical fertiliz- er＂, they were 7 874.57 and 6 427.00 kg/hm^2, and saved cost about 5 146.35 Yuan/hm^2, increased input 5 312.56 and 3 931.93 Yuan/hm^2, the greenhouse gas e- mission reduction was 1.30 t/hm^2 （calculated according to carbon dioxide on a dry basis）. [Conclusion] The treatment of ＂30% swine manure and 20% straw and 50% chemical fertilizer＂ was the best mode of swine manure-straw returning.

Cloning and Sequence Analysis on IGF-1 Gene of Hubei White Swine

[Objective] The study aimed at cloning and analyzing the insulin-like growth factor-1 （IGF-1） gene from liver of Hubei white swine. [Method] The total RNA was extracted by using Trizol from the liver of Hubei white swine and used as template to amplify IGF-1 gene cDNA by RT-PCR. The cDNA product was cloned into pCRII vector, screened with blue-white colonies, digested with double enzymes and sequenced. [Result] The sequencing result indicated that the IGF-1 gene consisted of 607 nucleotides, containing 5＇-untranslated region at nucleotides 1-145, a complete ORF at nucleotides 146-538 encoding 130 amino acids, and 3＇-untranslated region at nucleotides 539-607. It shared 100% homology with the porcine IGF-1 gene reported by Muller et al. [Conclusion] The successful cloning and sequencing of the Hubei white swine IGF-1 gene confirmed that IGF-I gene was highly conserved, which provided technical basis for the use of transgenic technology for breeding of Hubei white swine.

Bioinformatics Analysis on MSTN Gene of Swine

[Objective] The aim was to make bioinformatics analysis on MSTN gene in swine. [Method] In the research, coding sequences （CDS） of MSTN gene in swine, rat, mouse, dog, sheep, goat, cattle, chimpanzee, human, horse, chicken and zebra fish were loaded to Megalign of DNAstar for analysis of phyletic evolution. In addi- tion, we also made analysis on basic information, restriction map, secondary struc- ture of coding protein, signal peptide, transmembrane domain and protein subcellular localization. [Result] Closely related to rat, mouse, dog, sheep, goat, cattle, chim- panzee, human and horse, MSTN genes in swine included many enzyme cutting sites and the encoding protein was unstable in hydrophobicity. The molecular weight was 42 791.3 u, isoelectric point was 6.98, and the gene included 375 amino acid residues. In addition, the secondary structure of protein contained 20.53% of c^-Helix, 4% of 15-Turn, 53.07% of Coil, 22.4% of extenden strand and one transmembrane domain. The extracellular protein was probably being signal peptide. [Conclusion] The research provided references for further study on MSTN genes of swine.

Swine Wastewater Treatment with Struvite Precipitation Technology

[Objective] This study aimed to determine the optimal technical parameters for the swine wastewater treatment by struvite precipitation. [Method] Central composite design （CCD） and response surface method （RSM） were employed to study the effects of struvite precipitation on removing the ammonia nitrogen in the swine wastewater. Quadratic model was developed to describe the mathematical relationships between the investigated factors of pH value, reaction time, magnesium to nitrogen molar ratio （Mg/P）, nitrogen to phosphorus molar ratio （N/P）, the investigated indicators of NH 4 -N removal efficiency and residual PO 4 3 -P concentration. Contour overlay plot was proposed to predict the optimal experimental conditions with the NNH 4 -N removal efficiency of 75% and residual PO 4 3-P concentration of 3.0 mg/L as the desired values. [Result] At pH of 10.0, mixing time of 30 min, Mg/N of 1.11, N/P of 1.14, the NH 4 -N removal efficiency （Y 1 ） was the maximum of 79.0% , and the residual PO 4 3-P concentration （Y 2 ） at this time was 0.35 mg/L. The verification test of the optimal conditions proved that the verification data and model predictions agreed well. [Conclusion] The optimized parameters for the chemical struvite precipitation used to treat swine wastewater with central composite experimental design and response surface method are scientific, rational and efficient.

不变与变:从“SARS”到“Swine Influenza”的中文译名谈起

SARS与Swine Influenza为发生在本世纪初的两场重大传染疾病,其中SARS的中文译名一直未变,译为"非典";Swine Influenza则从开始的"猪流感"更名为"甲型H1N1流感"。本文尝试从翻译与传播的视角探讨这两种疾病中文译名的不变与变,分析背后的原因,并提出SARS中文译名的改进译法。

一株猪流感病毒A/swine/Shanghai/01/2019(H1N1)的分离鉴定及遗传进化分析

为鉴定上海地区猪流感病毒的流行株及其分子生物学特征,本研究从上海地区养殖场采集疑似流感症状的猪咽拭子样品40份,采用套式PCR结合鸡胚分离鉴定方法,从中分离到1株H1N1亚型猪流感病毒(SIV),命名为A/swine/Shanghai/01/2019(H1N1)。经全基因组测定和遗传进化分析结果显示该分离株的8个基因节段与欧亚类禽H1N1 SIV同源性最高,其PB2、PB1、PA基因节段可能来源于A/swine/Jiangsu/49/2012(H1N1)病毒,NA、NP和M基因节段可能来源于A/swine/Shanghai/3/2014(H1N1)病毒。该分离病毒的HA蛋白裂解位点为PSIQSR↓GLFGAI,为低致病性流感病毒的分子特征。该分离株NA蛋白未出现与神经氨酸酶抑制剂相关的氨基酸突变,M2蛋白S31N突变表明该病毒可能对金刚烷胺类药物具有一定的耐药性。PA蛋白224S和PB2蛋白701N突变提示该分离株对哺乳动物的适应性增强,可能导致其致病性增强,需要加强对此类SIV的监测。结合近年来的监测表明,上海地区猪群中H1N1亚型SIV持续存在,需要持续跟踪监测SIV变异趋势。本研究为防控猪流感提供实验依据。

A review of the effects of dietary organic acids fed to swine

Animal production depends on nutrient utilization and if done there is an accelerated momentum towards growth with a low cost to feed ratio Public concern over the consumption of pork with antibiotic residues of the animals fed with antibiotic growth promoters （AGP） has paved the way to use other additives like herbs and their products, probiotics, prebiotics etc. Numerous feed additives are in vogue for achieving this target and one such classical example is the usage of organic acids and their salts. Usage of organic acids was in progress for over four decades. Early weaned piglets are （3-4 weeks age） exposed to stress with a reduced feed intake, little or no weight gain. This post weaning lag period is due to a limited digestive and absorptive capacity due to insufficient production of hydrochloric acid, pancreatic enzymes and sudden changes in feed consistency and intake. Lowering dietary pH by weak organic acids was found to overcome these problems. The main activity of organic acids is associated with a reduction in gastric pH converting the inactive pepsinogen to active pepsin for effective protein hydrolysis. Organic acids are both bacteriostatic and bactericidal. Lactic acid has been reported to reduce gastric pH and delay the multiplication of an enterotoxigenic E. coil These acids are the intermediary products in Kreb＇s cycle and thus act as an energy source preventing the tissue breakdown resulting from gluconeogenesis and lipolysis. Excretion of supplemental minerals and nitrogen are minimized with organic acids as these form complexes with minerals and aids for their bio-availability. Short chain fatty cids like acetic, propionic and n-butyric acid produced by microbial fermentation of dietary fibre in the large intestines may increase the proliferation of epithelial cells and have stimulatory effects on both endocrine and exocrine pancreatic secretions in pigs. Organic acids also enhances apparent total tract digestibility and improves growth performance. It is concluded that organic acids and their salts increase the protein utilization especially in weaner pigs and improves production indices.

猪流感病毒分离株A/Swine/Fujian/F1/2001(H5N1)表面蛋白基因序列分析

对猪流感病毒株A/Swine/Fujian/F1/2001(H5N1)(简称SW/FJ/F1/01)的表面蛋白基因进行序列测定,并与GenBank中的A型流感病毒H5N1亚型毒株参考序列进行比较。遗传进化分析表明,猪流感病毒SW/FJ/F1/01的血凝素基因(HA)和神经氨酸酶基因(NA)均与2000年浙江鸭源毒株A/Duck/Zhejiang/52/2000(H5N1)(简称DK/ZJ/52/00)的亲缘关系最近,其HA蛋白的裂解位点为-RRKKR*G-,受体结合位点226位为Q,228位为G,识别唾液酸-α2,3-半乳糖,与人流感病毒H3亚型的受体结合位点不同,分析表明该病毒来源于禽源流感病毒。

H9N2亚型猪流感病毒A/Swine/Shandong/1/02分离株的基因序列分析

从有肺炎症状的病猪中分离到1株H9N2亚型猪流感病毒（SIV）A／Swine／Shandong／1／02，对其进行了全病毒基因序列分析。结果表明，该毒株8个基因片段的核苷酸序列均来自禽流感病毒（AIV），与我国目前家禽中流行的H9N2亚型AIV毒株具有很高的同源性，与A／Duck／Hong Kong／Y280／97（H9N2）的同源性为94．1％～98．9％，与A／Chicken／Beijing／1／94（H9N2）的同源性为94．5％～98．2％；推导的其血凝素（HA）裂解位点处的氨基酸序列为P—A-R—S-S-R，完全符合H9亚型AIV欧亚分支中的类A／Chicken／Beijing／1／94亚分支的特征；基因分析结果表明，该分离株的所有基因片段均来源于H9N2亚型AIV，它可直接感染猪，并导致发病，但它并未在猪体内发生重组。

Recovery of Nitrogen and Phosphorous as Struvite From Swine Waste Biogas Digester Effluent

Objective To investigate the feasibility of nitrogen and phosphorus recovery from swine waste biogas digester effluent and the effects of pH and NH4^＋： Mg2^＋： PO4^3- molar ratio on its precipitation. Methods Precipitation experiments with swine waste biogas digester effluent were conducted at pH 7.5, 8.0, 8.5, and 9.0 together with NH4^＋： Mg^2＋： PO4^3- molar ratios 1： 0.2： 0.08, 1： 1： 1, and 1： 1.5： 1.5. Chemical and X-ray diffraction （XRD） analysis were done to determine the composition of the precipitate. Results The highest removal and recovery of NH4^＋ and PO4^3- were achieved at pH 9.0 in each experiment. The elevation of pH to 9.0 alone could decrease the initial PO4^3- concentration from 42 mg L^-1 to 4.7 mg L-1 and 89.2% PO4^3- recovery was achieved. The pH-molar ratio combination 9.0-1： 1.5： 1.5 effected 76.5% NH4^＋ and 68.5% PO4^3- recovery. The molar ratio of 1： 1： 1 together with pH elevation to 9.0 was determined to be the optimum combination for both NH4＋ and PO4^3- removal as it recovered over 70% and 97% of the initial NH4^＋ and PO4^3-, respectively. Conclusions Nitrogen and phosphorus can be recovered from biogas digester effluent as struvite.

Pharmacokinetics of Mequindox and Its Metabolites in Swine

The present study was carried out to investigate the pharmacokinetics of mequindox （MEQ）, a new synthetic quinoxaline 1,4-dioxide derivative and its two main metabolites M1 [2-isoethanol mequinoox], M2 [2-isoethanol 1-desoxymequindox] in healthy swine. MEQ （10 mg kg-1 body weight） was administered to nine healthy cross-bread swine via oral, intramuscular, and intravenous routes in a randomized 3x3 crossover design with a 1-wk washout period. A sensitive high-performance liquid chromatography （HPLC） method was used for the determination of plasma concentrations of MEQ and its metabolites M1 and M2. Plasma concentration versus time profiles of MEQ and its metabolites, M1 and M2, were analyzed by noncompartmental analysis using WinNonlin 5.2 software. The mean maximum concentrations （Cmax） of M1 and M2 after intravenous administration of MEQ were （5.27±1.59） lag mL-1 at 1.78 h and （1.01±0.29） μg mL-1 at 0.92 h, respectively. The mean maximum concentrations （Cmax） ofMEQ, M1, and M2 were found to be （6.96±3.23）, （6.61±1.56）, and （0.78 ±0.25） lag mL-1 respectively at 0.15, 1.61, and 1.30 h after intramuscular administration of MEQ, respectively and （0.75±0.45）, （6.90±1.52）, and （0.62±0.21） lag mL-1, respectively at 0.40, 1.57, and 2.00 h, respectively after oral administration of MEQ. The apparent elimination half-lives （b2） ofMEQ, M1, and M2 were （0.84±0.35）, （7.57±3.93）, and （9.56±6.00） h, respectively after intravenous administration of MEQ; （0.50±0.25）, （6.30±3.00）, and （5.94±2.54） h, respectively after intramuscular administration of MEQ; and （1.64± 1.17）, （5.59±1.93）, and （16.25±10.27） h, respectively after oral administration of MEQ. The mean areas under the plasma concentration-time curve （AUC0-∝） of MEQ, M1, and M2 were （4.88±1.54）, （36.93±17.50）, and （5.16±94） μg h mL-1, respectively after intravenous administration of MEQ; （4.18±0.76）, （48.25±20.82）, and （4.88±2.21） μg h mL-1 , respectively after intramuscular administration of MEQ; and （1.01±0.40）, （48.83±20.71）, and （5.54±2.23） μg h mL-1, respectively after oral administration of MEQ. MEQ was rapidly absorbed and metabolized in swine after oral, intramuscular, and intravenous administration. Further studies are required to investigate the double-peak phenomenon observed in the plasma concentration-time profile after oral administration and the pharmacokinetics of other metabolites of MEQ.

Enhancing treatment efficiency of swine wastewater by effluent recirculation in vertical-flow constructed wetland

Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragraites Typhia are planted, respectively; each stage has a dimension of 4 m^2 （2 m × 2 m）. Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m^3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand （BOD5） and suspended solids（SS） obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen（DO） and oxidation-reduction potential（ORP） of inflow and outflow reveal that the adoption of effluent recirculation is benefi- cial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients （R2 〉0.93） are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.