Dietary manganese supplementation inhibits abdominal fat deposition possibly by regulating gene expression and enzyme activity involved in lipid metabolism in the abdominal fat of broilers

Excessive abdominal fat deposition seriously restricts the production efficiency of broilers.Several studies found that dietary supplemental manganese(Mn)could effectively reduce the abdominal fat deposition of broilers,but the underlying mechanisms remain unclear.The present study aimed to investigate the effect of dietary supplementation with the inorganic or organic Mn on abdominal fat deposition,and enzyme activity and gene expression involved in lipid metabolism in the abdominal fat of male or female broilers.A total of 4201-d-old AA broilers(half males and half females)were randomly allotted by body weight and gender to 1 of 6 treatments with 10 replicates cages of 7 chicks per cage in a completely randomized design involving a 3(dietary Mn addition)×2(gender)factorial arrangement.Male or female broilers were fed with the Mn-unsupplemented basal diets containing 17.52 mg Mn kg^(-1)(d 1-21)and 15.62 mg Mn kg^(-1)(d 22-42)by analysis or the basal diets supplemented with 110 mg Mn kg^(-1)(d 1-21)and 80 mg Mn kg^(-1)(d 22-42)as either the Mn sulfate or the Mn proteinate with moderate chelation strength(Mn-Prot M)for 42 d.The results showed that the interaction between dietary Mn addition and gender had no impact(P>0.05)on any of the measured parameters;abdominal fat percentage of broilers was decreased(P<0.003)by Mn addition;Mn addition increased(P<0.004)adipose triglyceride lipase(ATGL)activity,while Mn-Prot M decreased(P<0.002)the fatty acid synthase(FAS)activity in the abdominal fat of broilers compared to the control;Mn addition decreased(P<0.009)diacylglycerol acyltransferase 2(DGAT2)mRNA expression level and peroxisome proliferator-activated receptor γ(PPARγ)mRNA and protein expression levels,but up-regulated(P<0.05)the ATGL mRNA and protein expression levels in the abdominal fat of broilers.It was concluded that dietary supplementation with Mn inhibited the abdominal fat deposition of broilers possibly via decreasing the expression of PPARγand DGAT2 as well as increasing the expression and activity of ATGL in the abdominal fat of broilers,and Mn-Prot M was more effective in inhibiting the FAS acitivity.

Response of Bacterial Community and Enzyme Activity of Greenhouse Tomato under Different Irrigation Systems

The micro-sprinkler irrigation mulched(MSM)has been suggested as a novel water-saving approach in con-trolled environment agriculture.However,the effects of microbial community structure and enzyme activity in the rhizosphere soil on crop growth under MSM remain unclear.This study conducted a randomized experimen-tal design using greenhouse tomatoes to investigate changes in bacterial community structure and enzyme activity in rhizosphere soil under different irrigation frequencies(F)and amounts(I)of MSM.Thefindings revealed that with the increase of F or I,The total count of soil bacteria in tomatoesfirst rose and then fell in terms of Opera-tional Taxonomic Units(OTUs)classification.Compared to other F,the most abundance of nitrogen and phos-phorus metabolism genes and enzyme activities were observed with a 5-day F.Moreover,the diversity of soil bacterial community structure initially rose before eventually declining with the increase of the I.Applying 1.00 Epan(cumulative evaporation of a 20 cm standard pan)under MSM helped boost the abundance of nitrogen and phosphorus metabolism functional genes in soil bacteria,ensuring higher enzyme activities related to nitro-gen,carbon,and phosphorus metabolism in the rhizosphere soil of tomatoes.Tomatoes’yield initially rose before eventually declining with the increase in F or I,whereas I had a more significant effect on yield.A 1.00%increase in I yielded a minimum of 39.24%increase in tomato yield.The study showed a positive correlation between soil bacterial community,soil enzyme activity,and greenhouse tomato yield under MSM.Considering the results comprehensively,the combined irrigation mode of F of 5 d and I of 1.00 Epan was recommended for greenhouse tomatoes under MSM.This conclusion provides theoretical support for water-saving practices and yield improve-ment in facility agriculture,especially tomato cultivation.

The Identification of Phenylalanine Ammonia-Lyase(PAL)Genes from Pinus yunnanensis and an Analysis of Enzyme Activity in vitro

Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes were cloned and identified from P.yunnanensis seedlings for thefirst time,namely,PyPAL-1,PyPAL-2,and PyPAL-3.Our results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 bp.Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants.In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric acid.Three PyPAL genes were expressed in different tissues in 1-year-old P.yunnanensis,and such genes had different expression patterns.This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P.yunnanensis.

Effect of ^(12)C^(6+) Ions Beam Irradiation on Seed Germination and Enzymes Activity in Seedlings of Sweet Sorghum

[ Objective] The aim was to study the effect of 12C6 ＋ ions beam irradiation to two varieties of sweet sorghum on seed germination and some enzymes activity in seedlings with different doses, and provided a theoretical foundation for sweet sorghum breeding. [ Method] After germination, the germination potential, germination fraction and enzyme activity were detected, respectively. [ Result] The results showed that with the dose increased, the germination potential of sweet sorghum increased first and then decreased, while their germination fraction presented ＂shoulder like shape＂ ; the activity of LDH, SOD, CAT and GSH-Px increased first and then decreased with doses, they presented slight differences among different enzymes. [ Conclusion] Low dose radiation could accelerate germination of sweet sorghum seeds and enzyme activity could remain at a relatively high level. Enzyme activity decreased with high doses and the growth of sweet sorghum was inhibited.

Effect of Foliar Application of Amino Acid on the Quality and Enzyme Activity of Flowering Chinese Cabbage(Brassica parachinensis Bailey)

A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage（Brassica parachinensis Bailey）.The results showed that all the application of these four amino acids could increase the yield of flowering Chinese cabbage,significantly raise the content of soluble sugar,and reduce the accumulation of nitrate.The applications of three other amino acids except alanine can increase the content of soluble proteins and decrease the accumulation of oxalic acid.However,the application of amino acid has insignificant influences on the SPAD number of chlorophyll,and causes the decrease of Vitamin C content.Meanwhile,the application of amino acid can improve the activity of nitrate reductase（NR） and glutamate dehydrogenase（GDH） as well.It shows that the application of amino acid is beneficial to improve ammonia metabolism,reduce the accumulation of nitrate and oxalic acid,increase the content of soluble sugar and soluble proteins,and improve the quality of flowering Chinese cabbage.

Mixing Alfalfa Straw and Maize Straw to Enhance Nitrogen Mineralization, Microbial Biomass and Enzyme Activity: A Laboratory Study

The quality of straw affects N release after straw retention. As straw with high C： N ratio could result in N immobilization, additional N is needed to compensate N demand of crops. However, more and more N fertilizers have been applied to the soil to improve crop yields in China, which not only increases production cost but also reduces soil quality. Therefore, reasonable application of N fertilizer becomes a key problem after straw retention. This study aimed to assess the effects of applying maize straw with high quality alfalfa straw on mineral N content, microbial biomass and enzyme activity under controlled conditions. The effect of applying maize straw with alfalfa straw was compared with that of maize straw in combination with N fertilizer under the same C： N ratio （25：1）. The laboratory incubation experiment consisted of four treatments： （1） soil with no addition （CK）; （2） soil amended with maize straw （M）; （3） soil amended with alfalfa straw and maize straw with an adjusted C： N ratio of 25：1 （MM）; （4） soil amended with inorganic nitrogen fertilizer and maize straw with an adjusted C：N ratio of 25：1 （MF）. The results showed that application of maize straw leaded to an N immobilization during the 270 d of incubation. Combined application of alfalfa and maize straw and or mineral N fertilizer alleviates the N immobilization and increase soil mineral N content. Compared to MF treatment, MM treatment prolonged N availability during the incubation. MM and MF treatments increased the soil microbial biomass carbon and nitrogen contents, and soil invertase and β-glycosidase activities. There was no difference between MM and M treatment in soil urease activity. MF treatment had significantly negative influence on soil urease activity compared with M treatment. The amount of added N significantly affected mineral N content, soil microbial biomass and enzyme activity. The mixture of alfalfa straw and maize straw sustains higher level of mineral N content, microbial biomass and enzyme activity as it had high N input compared to maize straw in combination with N fertilizer. It is concluded that alfalfa straw may be a better N source than N fertilizer in alleviating N immobilization caused by maize straw retention.

Effects of Different Exogenous Hormones on Rooting of Syringa microphylla Cuttings and Change in Related Enzyme Activity During the Rooting Process

[Objective] This study aimed to investigate the effects of different exoge- nous hormones on the rooting of Syringa microphylla cuttings and the change in related enzymes activity during the rooting process. [Method] Three different exoge- nous hormones IBA, NAA and ABT, each with concentrations of 500, 1 000, 1 500 and 2 000 mg/L were used to treat S. microphylla cuttings, and changes in the ac- tivities of peroxidase （POD）, poiyphenol oxidase （PPO） and indoleacetic acid oxidase （IAAO） during the rooting process were also investigated. [Result] The most appro- priate concentrations of IBA, ABT and NAA were 1 500, 1 000 and 1 000 mg/L, respectively, and the 1 500 mg/L IBA treatment exhibited the best effect on rooting. Throughout the rooting process, POD and PPO activities showed the same trends in the treatment groups as those in the control group, but the POD and PPO activi- ties in the treatment groups were increased significantly, with greater amplitude of variation; at the early stage, IAAO activity exhibited an opposite trend between the control group and the treatment groups, which increased slowly in the former, but decreased rapidly in the latter, and it was significantly lower in the treatment groups compared to the control; additionally, higher POD and IAAO activities were con- ducive to the induction of adventitious roots, and lower POD and IAAO activities fa- vored their formation and elongation. [Conclusion] This study has preliminarily clari- fied the rooting mechanism of S. microphylla cuttings.

Advances in Activity of Related Enzymes during Graft Healing Process of Citrus Paradisi Macf

The distribution and ecological characters of grapefruit were analyzed mainly,and the research trends of stock and scion selection for grafting,the healing-anatomy process and enzymology were summarized systematically.The results indicated that the range of stock and scion apolegamy decreased through the application of molecular technique.But the study on stock variety and scion selection was still in need of expanding and the key enzyme played a vital role in the healing of the stock and scion,which provided a chance for the regulation and control of healing force by hormones and also provided a theoretical basis for the regulation of gene.

Effects of Different Vegetable Planting Modes on Soil Microbial Flora and Enzyme Activity

To investigate the effects of different vegetable growing regions and planting modes on soil quality,soils in high,medium and low altitude areas of Guizhou were respectively sampled under different vegetable efficient planting modes,and the variations of soil microbial flora and enzyme activities were analyzed. The soil microbial count and total bacteria of the vegetable efficient cultivation mode were significantly higher than that of the control （traditional planting mode） in each planting area,and the microbial diversity index was also improved to varying de- grees.The soil phosphatase,catalase and urease activities of the vegetable efficient planting mode were higher than that of the control.The soil catalase and urease activities were higher than that of the control by 1.37-1.44 and 1.51-2.80 times. Application of vegetable efficient planting mode in different regions will help to im- prove the soil quality in a given period.

Study on the Correlation between Blood Enzyme Activity and Production Performance in Tibetan Yaks

Yak ( Bos grunniens ) is classified as Bovine genus,they live in Qingzang Plateau with elevation more than 3500m and it's neighbor highland,where the weather is high chilly,short of oxygen and large difference of temperature between day and night.But yak have adapted that circumstance after thousands of years' artificial and natural selection and has great anti adversity capacity.Yak is an important sustenance and means of production to Tibetan.China is a country with the largest number of yak,whose amount of livestock on hand accounts for 95% of the world and Tibet region takes the second place next to Qinghai in the number of yak.Tibetan yak has formed some groups for Tibetan's large area,complicated geological ecosystem conditions,geological isolation.The typical better groups are Yadong yak,Jiali yak and Sibu yak. Study about yak fell behind other animals due to the restriction of inconvenient transportation,difficult sampling and poor experimental technology.Study about the relationship between yak blood enzyme activities and milk production was little,only Jing (1992) studied correlation of milk production with serum amylase,esterase in Gansu Jiulong yak,Maiwa yak and no report was found in other groups.This study discussed six Jiali yak blood enzyme activities lactate dehydrogenase (LDH),alkaline phosphatases (AKP),acid phosphatase (ACP),catalase (CAT),amylase (Amy) and superoxide dismutase (SOD),and explored their relationship with milk production in Jiali yak,so as to supply with theoretical evidence by using blood enzyme activity as biochemical assisted selection marker in the breeding of Tibetan yak milk yield. This experiment investigated activity of six blood enzymes from 28 Tibetan yaks and explored its relationship to production performance.The results showed a extremely positive significant difference ( P <0.01) between activity of LDH and milk yield,CAT activity and length of belly hair respectively,while a positive significant difference ( P <0.05) was observed between AKP activity and body weight,Amy activity and body weight and a negative significant difference ( P <0.05) for SOD activity and body weight.Stepwise Regression Analysis showed that activity of LDH could be used for the prediction of milk yield,AKP,CAT,Amy for body weight,CAT,Amy for length of belly hair.So it is expected to use activity of LDH,AKP,CAT,Amy as biochemical genetic marker in the selection of milk yield,body weight and length of belly hair.

Effects of Spores and Crude Toxins of Helminthosporium gramineum Rabenh f.sp.echinochloae on the Activity of Defensive Enzymes in Barnyardgrass

[Objective] This study aimed to explore the effects of spores and crude toxins of Helminthosporium gramineum Rabenh f. sp. echinochloae（HGE） on the ac- tivity of defensive enzymes of barnyardgrass [Echinochloa crus-galli （L.） Beauv.]. [Method] The effects of spores and crude toxins of HGE, as well as the mixture of spores and crude toxins on the activity of defensive enzymes in barnyardgrass were determined under laboratory conditions. [Result] Spores and crude toxins of HGE had varying degrees of effects on PAL and POD activity, and no obvious effect on SOD activity in barnyardgrass. In addition, spores and toxins had some similar im- pacts on the defensive enzymes in barnyardgrass. [Conclusion] Since toxins have similar effects on the hosts as spores of fungal pathogen do, they can be a substi- tute for the fungal pathogen in studying the partial pathogenic mechanism of this pathogen due to its complexity in pathogenic process.

Effects of Cadmium Contamination on Sugarcane Growth, Soil Microorganism and Soil Enzyme Activity

[Objective] To provide a reference for exploring the relationship between Cd contamination and sugarcane growth and between Cd contamination and micro- bial properties of soil, the effects of adding different concentrations of exogenous cadmium （Cd） on the growth of sugarcane, the quantities of soil microorganisms and the activity of soil enzymes were studied. [Method] The plant height, stem di- ameter and cane yield of sugarcane, the soil microbial quantities and enzyme activi- ties were determined by using sugarcane as a material treated with different Cd concentrations （0, 25, 50, 100, 250 and 500 mg/kg） under potted conditions. IRe- suit] The results showed that the plant height, stem diameter and the yield of sug- arcane decreased with the increase of Cd concentration in the soil, and the higher the Cd concentration, the more obvious the inhibitory effect. The Cd contamination changed the enzyme activity, and the activities of urease and acid phosphatase sig- nificantly decreased with the increase of Cd concentration, especially when the Cd concentration reached 100 mg/kg. The sensitivity of the two soil enzymes to Cd ranked as urease〉acid phosphatase. Cd contamination also changed soil microbial quantities. Fungi, bacteria and actinomycetes significantly decreased at the Cd con- centration level of 100 mg/kg. There were significant and highly significant correla- tions between Cd contamination concentration and fungi, bacteria and actinomycetes, the activities of urease and acid phosphatase, plant height, stem diameter as well as cane yield. [Conclusion] Under the conditions of potted planted sugarcane, ex- ogenous Cd contamination affected the growth of sugarcane, the quantities of soil microorclanisms and soil enzyme activities to different degrees.

Variation of Enzyme Activity in Flue-cured Tobacco-growing Soil Planted with Different Lastseason Crops

The rice soil （last crop was rice） and arid red soil （last crop was corn） were used as a test material for the pot experiment. The variation of enzyme activi-ty in flue-cured tobacco-growing soil planted with different last-season crops was in-vestigated at different growth stages in this study. The results showed the activity variation of the 3 enzymes differed in the 2 soils at different growth stages. The catalase activity in the arid red soil trended to decrease overal from the vigorous growing stage to harvesting stage; while it decreased gradual y in the rice soil until the harvesting stage. The phosphatase activity in the 2 soils al increased with the proceeding of growth period. The urease activity in the arid red soil decreased gradual y at different growth stages, but the variation of urease activity in rice soil was irregular. During the growth of flue-cured tobacco, the catalase and urease ac-tivity in the arid red soil increased first and then decreased, and the phosphatase activity increased gradual y. ln rice soil, the catalase activity increased first and then decreased; the phosphatase activity decreased first and then increased; the urease activity increased first, then decreased and increased last. The activity of al the en-zymes in the 2 soils showed significant differences compared to the control except some enzymes at the vigorous growing stage. lt was suggested the planting of flue-cured tobacco would affect greatly the soil enzyme activities.

Impact of Vanadium on Enzyme Activity and Microbial Biomass in Soils

[Objective] This study aimed to investigate the impact of vanadium at dif- ferent concentration on enzyme activity and microbial biomass in soils. [Method] Us- ing pot experiments in the growth cabinet, we would like to investigate the changes of the soil enzyme activity and microbial biomass at different growing stages of rape （Brassica juncea L.） at different soil vanadium concentrations （soil background value was 147 mg/kg, spiked with 0, 50, 100, 150, 250 and 500 mg/kg of exogenous vanadium）. [Result] Among all enzymes examined, polyphenol oxidase was most sensitive to soil vanadium. Addition of 50 mg/kg vanadium decreased its activity up to 56% of the control probably due to the vanadium toxicity. In comparison, the ac- tivities of sucrase, urease and catalase was less affected by soil vanadium. Surpris- ingly, the activity of sucrase, urease and catalase at the rape seedling stage differed significantly from at the maturity stage, highlighting the potential impact of plant growth on the vanadium-soil enzyme interaction. Different soil vanadium concentra- tions led to increases of microbial biomass to different extents. However, the corre- lation between soil microbial biomass carbon and phosphorus with vanadium con- centrations was insignificant. This revealed that the presence of additional factors （eg. plant） affected soil microbial biomass carbon and phosphorus aside from soil vanadium. [Conclusion] Polyphenol oxidase may be considered as an indicator of soil vanadium contamination. Due to the highly complicated interaction between vanadium and soil biological activities during plant growth, more investigations are required to reveal the mechanisms beyond our findings here.

Responses of soil stoichiometry and soil enzyme activities in the different distance around opencast coal mine of the Hulun Buir Grassland of China

The objectives of this study were to explore the changes in soil stoichiometry and enzyme activities at different distances from an opencast coal mine in the Hulun Buir Grassland of China. Four transects were established on north and east sides of the opencast coal mining area, and samples were collected at 50 m, 550 m, and 1550 m from the pit on each transect. Control samples were collected from a grassland station 8 km from the opencast coal mining area that was not disturbed by mining. Four replicate soil samples were collected at each point on the four transects. Soil physicochemical properties and enzyme activities were determined, and correlations between soil properties and stoichiometric ratios and enzyme activities were explored using redundancy analysis. The increase in distance from mining did not significantly affect soil properties, although soil urease activity was significantly lower than that of the control area. Soil properties 1550 m from the mine pit were similar to those at the grassland control. In addition, soil total nitrogen had the greatest effect on soil stoichiometry, and soil total potassium had the greatest effect on soil enzyme activities. Coal dust from opencast mining might be the main factor affecting soil stoichiometry and enzyme activities. The results of this study provide direction for the next step in studying the influence of mining areas on soil properties and processes.

Bacterial communities and enzyme activities during litter decomposition of Elymus nutans leaf on the Qinghai-Tibet Plateau

The dominant plant litter plays a crucial role in carbon(C)and nutrients cycling as well as ecosystem functions maintenance on the Qinghai-Tibet Plateau(QTP).The impact of litter decomposition of dominant plants on edaphic parameters and grassland productivity has been extensively studied,while its decomposition processes and relevant mechanisms in this area remain poorly understood.We conducted a three-year litter decomposition experiment in the Gansu Gannan Grassland Ecosystem National Observation and Research Station,an alpine meadow ecosystem on the QTP,to investigate changes in litter enzyme activities and bacterial and fungal communities,and clarify how these critical factors regulated the decomposition of dominant plant Elymus nutans(E.nutans)litter.The results showed that cellulose and hemicellulose,which accounted for 95%of the initial lignocellulose content,were the main components in E.nutans litter decomposition.The litter enzyme activities ofβ-1,4-glucosidase(BG),β-1,4-xylosidase(BX),andβ-D-cellobiosidase(CBH)decreased with decomposition while acid phosphatase,leucine aminopeptidase,and phenol oxidase increased with decomposition.We found that both litter bacterial and fungal communities changed significantly with decomposition.Furthermore,bacterial communities shifted from copiotrophic-dominated to oligotrophic-dominated in the late stage of litter decomposition.Partial least squares path model revealed that the decomposition of E.nutans litter was mainly driven by bacterial communities and their secreted enzymes.Bacteroidota and Proteobacteria were important producers of enzymes BG,BX,and CBH,and their relative abundances were tightly positively related to the content of cellulose and hemicellulose,indicating that Bacteroidota and Proteobacteria are the main bacterial taxa of the decomposition of E.nutans litter.In conclusion,this study demonstrates that bacterial communities are the main driving forces behind the decomposition of E.nutans litter,highlighting the vital roles of bacterial communities in affecting the ecosystem functions of the QTP by regulating dominant plant litter decomposition.

Effects of desert plant communities on soil enzyme activities and soil organic carbon in the proluvial fan in the eastern foothills of the Helan Mountain in Ningxia,China

It is of great significance to study the effects of desert plants on soil enzyme activities and soil organic carbon(SOC)for maintaining the stability of the desert ecosystem.In this study,we studied the responses of soil enzyme activities and SOC fractions(particulate organic carbon(POC)and mineral-associated organic carbon(MAOC))to five typical desert plant communities(Convolvulus tragacanthoides,Ephedra rhytidosperma,Stipa breviflora,Stipa tianschanica var.gobica,and Salsola laricifolia communities)in the proluvial fan in the eastern foothills of the Helan Mountain in Ningxia Hui Autonomous Region,China.We recorded the plant community information mainly including the plant coverage and herb and shrub species,and obtained the aboveground biomass and plant species diversity through sample surveys in late July 2023.Soil samples were also collected at depths of 0–10 cm(topsoil)and 10–20 cm(subsoil)to determine the soil physicochemical properties and enzyme activities.The results showed that the plant coverage and aboveground biomass of S.laricifolia community were significantly higher than those of C.tragacanthoides,S.breviflora,and S.tianschanica var.gobica communities(P<0.05).Soil enzyme activities varied among different plant communities.In the topsoil,the enzyme activities of alkaline phosphatase(ALP)andβ-1,4-glucosidas(βG)were significantly higher in E.rhytidosperma and S.tianschanica var.gobica communities than in other plant communities(P<0.05).The topsoil had higher POC and MAOC contents than the subsoil.Specifically,the content of POC in the topsoil was 18.17%–42.73%higher than that in the subsoil.The structural equation model(SEM)indicated that plant species diversity,soil pH,and soil water content(SWC)were the main factors influencing POC and MAOC.The soil pH inhibited the formation of POC and promoted the formation of MAOC.Conversely,SWC stimulated POC production and hindered MAOC formation.Our study aimed to gain insight into the effects of desert plant communities on soil enzyme activities and SOC fractions,as well as the drivers of SOC fractions in the proluvial fan in the eastern foothills of the Helan Mountain and other desert ecosystems.

Microplastic Can Decrease Enzyme Activities and Microbes in Soil

An in vitro study was conducted to investigate the impacts of microplastics on enzyme activities and soil bacteria. The study included four different treatments of microplastics including a control. Different levels of microplastics were applied to the soil ranging from 0% to 5%, to assess the impacts of microplastics on soil enzymes and subsequent soil bacteria. After 30 days of incubation, the soil samples were collected and growth parameters of bacteria were assessed. Activities of β-glucosidase, urease and dehydrogenase enzymes were also determined. Our results showed that the presence of microplastics in the soil significantly reduced bacterial population together with bacterial strains. The activities of β-glucosidase, urease and dehydrogenase enzymes were reduced significantly to approximately 32%, 40% and 50% in microplastics treated soils respectively. Concentration of microplastic has a role to play towards this direction;the higher the concentration of microplastic the greater is the impact on enzymes and soil bacteria. The present study on the microbial soil health vis-à-vis microplastic application indicates that the material can have negative effect on the soil bacterial population of and thus ultimately may jeopardize soil health and crop production.

Effects of dietary supplementation of probiotic,Clostridium butyricum,on growth performance,immune response,intestinal barrier function,and digestive enzyme activity in broiler chickens challenged with Escherichia coli K88

Background： Colibacillosis caused by enterotoxigenic Escherichia coil （E. coil} results in economic losses in the poultry industry. Antibiotics are usually used to control colibacillosis, however, E. coli has varying degrees of resistance to different antibiotics. Therefore the use of probiotics is becoming accepted as an alternative to antibiotics. In this study, we evaluated the effects of Clostfidium butyricum （C. butyficum） on growth performance, immune response, intestinal barrier function, and digestive enzyme activity in broiler chickens challenged with Eschefichia coli （E. coil） K88. Methods： The chickens were randomly divided into four treatment groups for 28 days. Negative control treatment （NC） consisted of birds fed a basal diet without E. coil K88 challenge and positive control treatment （PC） consisted of birds fed a basal diet and challenged with E. coil K88. C. buO/ricum probiotic treatment （CB） consisted of birds fed a diet containing 2 x 107 cfu C. buO/ricum/kg of diet and challenged with E. coil K88. Colistin sulfate antibiotic treatment （CS） consisted of birds fed a diet containing 20 mg colistin sulfate/kg of diet and challenged with E. coil K88. Results： The body weight （BW） and average day gain （ADG） in the broilers of CB group were higher （P 〈 0.05） than the broilers in the PC group overall except the ADG in the 14-21 d post-challenge. The birds in CB treatment had higher （P 〈 0.05） concentration of tumor necrosis factor-a （TNF-a） at 3 and 7 d post-challenge, and higher （P 〈 0.05） concentration of interleukin-4 （IL-4） at 14 d post-challenge than those in the PC treatment group. The concentration of serum endotoxin in CB birds was lower （P 〈 0.05） at 21 d post-challenge, and the concentrations of serum diamine oxidase in CB birds were lower （P 〈 0.05） at 14 and 21 d post-challenge than in PC birds. Birds in CB treatment group had higher （P 〈 0.05） jejunum villi height than those in PC, NC, or CS treatment at 7, 14, and 21 d post-challenge. In comparison to PC birds, the CB birds had lower （P 〈 0.05） jejunum crypt depth during the whole experiment. The birds in CB or CS treatment group had higher （P 〈 0.05） activities of amylase and protease at 3, 7, and 14 d post-challenge, and higher （P 〈 0.05） activity of lipase at 3, 7 d post-challenge than PC birds.

Changes in enzymes activity, substrate utilization pattern and diversity of soil microbial communities under cadmium pollution

Heavy metal pollution has received increasing attention in recent years mainly because of the public awareness of environmental issues. In this study we have evaluated the effect of cadmium （Cd） on enzymes activity, substrate utilization pattern and diversity of microbial communities in soil spiked with 0, 20, 40, 60, 80, and 100 mg/kg Cd, during 60 d of incubation at 25℃. Enzyme activities determined at 0, 15, 30, 45, and 60 d after heavy metal application（DAA） showed marked declines for various Cd treatments, and up to 60 DAA, 100 mg/kg Cd resulted in 50.1%, 47.4%, and 39.8% decreases in soil urease, acid phosphatase and dehydrogenase activities, respectively to control. At 60 DAA, substrate utilization pattern of soil microbial communities determined by inoculating Biolog ECO plates indicated that Cd addition had markedly inhibited the functional activity of soil microbial communities and multivariate analysis of sole carbon source utilization showed significantly different utilization patterns for 80 and 100 mg/kg Cd treatments. The structural diversity of soil microbial communities assessed by PCR-DGGE method at 60 DAA, illustrated that DGGE patterns in soil simplified with increasing Cd concentration, and clustering of DGGE profiles for various Cd treatments revealed that they had more than 50% difference with that of control.