Domesticated and non-domesticated animals, including wildlife, deliver significant financial and nonfinancial benefits to the human community;however, disease can have a dramatic impact on the morbidity, mortality, an...Domesticated and non-domesticated animals, including wildlife, deliver significant financial and nonfinancial benefits to the human community;however, disease can have a dramatic impact on the morbidity, mortality, and productivity of these animal populations and hence can directly and indirectly affect the human communities associated with them. This manuscript provides an overview of the important features to consider for the prevention and control of disease, with a focus on livestock diseases,and highlights the key role veterinary epidemiology plays in this endeavor. Measures of disease frequency and the type of epidemiological studies required to identify risk factors for diseases are summarized,with a focus on the use of these in the implementation of measures to control disease. The importance of biosecurity in maintaining disease-free flocks/herds is discussed and the steps taken to implement good biosecurity measures are outlined. It is concluded that a sound knowledge of veterinary epidemiology is required when developing control programs for disease and implementing biosecurity programs at a farm, regional, and national level.展开更多
The meat industry cannot respond to increases in demand by ever increasing resource use. The industry must find solutions to issues regarding animal welfare, health and sustainability and will have to do so in the fac...The meat industry cannot respond to increases in demand by ever increasing resource use. The industry must find solutions to issues regarding animal welfare, health and sustainability and will have to do so in the face of competition from emerging non-traditional meat and protein products in an increasingly complex regulatory environment. These novel meat and protein products, otherwise known as ‘artificial meat' are utilising ground breaking technologies designed to meet the issues facing the conventional meat industry. These artificial meats, in vitro or cultured meat and meat from genetically modified organisms have no real capacity to compete with conventional meat production in the present environment. However, meat replacements manufactured from plant proteins and mycoproteins are currently the biggest competitors and are gaining a small percentage of the market. Manufactured meats may push conventional meat into the premium end of the market, and supply the bulk, cheap end of the market if conventional meat products become more expensive and the palatability and versatility of manufactured meats improve. In time the technology for other artificial meats such as meat from genetic modified organisms or cultured meat may become sufficiently developed for these products to enter the market with no complexity of the competition between meat products. Conventional meat producers can assimilate agroecology ecology concepts in order to develop sustainable animal production systems. The conventional meat industry can also benefit from assimilating biotechnologies such as cloning and genetic modification technologies, using the technology to adapt to the changing environment and respond to the increasing competition from artificial meats. Although it will depend at least partly on the evolution of conventional meat production, the future of artificial meat produced from stem cells appears uncertain at this time.展开更多
Besides leaves, non-foliar green organs such as stem and spike are also considered photosynthetic organs. To assess the photosynthetic contributions of these organs, the correlations between these photosynthetic areas...Besides leaves, non-foliar green organs such as stem and spike are also considered photosynthetic organs. To assess the photosynthetic contributions of these organs, the correlations between these photosynthetic areas and single-spike weight were investigated in a winter wheat(Triticum aestivum L.) under four nitrogen and mulching treatments: N120,N150, N195, and N195 + M. Two-year repeated field experiments were conducted on the Loess Plateau of China. Non-foliar photosynthetic area, grain-filling ratio and duration,grain yield, and in particular, single-spike weight, were measured, recorded and analyzed.Under the N195 + M treatment, plants showed the largest area of photosynthetic organs(flag leaf and non-foliar organs) and the highest grain yield and single spike weight. Singlespike weight was positively correlated with the areas of all examined non-foliar photosynthetic organs, in particular with the area above the flag leaf node(R^2= 0.761*)and the area above the exposed part of the peduncle(EXP)(R^2= 0.800**). In addition, singlespike weight was highly correlated with average grain-filling ratio(R^2= 0.993**), whereas it was less highly correlated with grain-filling duration(R^2= 0.533). The morphological traits of non-foliar photosynthetic organs were also more highly correlated with average grainfilling ratio than with average grain-filling duration. The significant correlation between each of the morphological traits(area, length and width) of EXP and single-spike weight indicates that morphological traits of EXP are important in determining spike weight in the Loess Plateau environment.展开更多
Background: Three experiments were conducted to examine the overall hypothesis that addition of medium chain triglycerides(MCT) and cysteamine hydrochloride(CSH) into the diets of young and growing pigs would stimulat...Background: Three experiments were conducted to examine the overall hypothesis that addition of medium chain triglycerides(MCT) and cysteamine hydrochloride(CSH) into the diets of young and growing pigs would stimulate the endogenous somatotropic axis to improve growth and performance.Results: In Experiment 1, weaner pigs were given either a 5 d dietary supplement of 5 % MCT(n = 8) or a control diet(n = 8). MCT increased the plasma concentration of growth hormone(GH; P < 0.05) and the GH secretagogue,ghrelin(P < 0.05). Additionally, the MCT treatment reduced scouring(P < 0.05), maintained villous height in the small intestine(P < 0.05) and stabilised daily weight gain(P < 0.05), compared to the controls. Experiment 2compared the effects of 4 levels(0, 1, 3 and 6 % v/v) of MCT supplementation in grower-finisher male pigs, of approximately 35 kg live weight(n = 15 per treatment). Blood samples taken after 7 wk of treatment showed that the MCT supplementation increased circulating ghrelin(P < 0.001), GH(P < 0.01) and insulin(P < 0.05)concentrations in a dose-dependent manner. Daily weight gain, feed intake and feed conversion ratio were not affected by the MCT diets. In Experiment 3, 64 female pigs of approximately 60 kg live weight were allocated to one of three dietary treatments: control(n = 20); 6 % MCT(n = 21); and 70 mg/kg CSH(n = 21). After 3 wk of supplementation, the MCT treated pigs had a higher plasma concentration of ghrelin compared to the control and CSH pigs(P < 0.05). Plasma concentrations of GH and weight were not affected by any of the dietary treatments.Conclusions: Evidence is provided in Experiment 1 to support the use of dietary MCT supplements, perhaps acting via stimulation of somatotropic endocrine pathways, to minimise weaning-associated disorders such as slowing of growth and diarrhoea. In Experiments 2 and 3, although there was no effect on weight gain or feed conversion ratio in either experiment, MCT and CSH increased endocrine components of the somatotropic axis.展开更多
Changing markets and evolving consumer demand present new challenges for the beef and sheep industries. In response, the industry has been investing in innovations to deliver new products and management systems to con...Changing markets and evolving consumer demand present new challenges for the beef and sheep industries. In response, the industry has been investing in innovations to deliver new products and management systems to consumers. One such innovation is the Meat Standards Australia(MSA) system. This system is a Total Quality Management System, aimed at delivering an eating quality guarantee to consumers, and through this adding value to the entire supply chain. At present, it is well developed for beef and still evolving for sheepmeat. MSA has identified Critical Control Points(CCPs) in the production, pre-slaughter, processing and value-adding aspects of the supply chain that impact on consumer palatability through the large-scale taste testing of meat by untrained consumers. These CCPs are used as either(1) mandatory criteria determining eligibility for grading, and(2) inputs in a model predicting the palatability of individual combinations of muscle and different cooking methods. Through the prediction of palatability, MSA increases consumer satisfaction and is used to provide assurance for branded products and new marketing innovations in Australia and internationally. This has added significant value to the Australian beef industry, with several retail examples demonstrating consumer willingness to pay more for premium quality beef and sheepmeat products based on the MSA grading scores. This price differential at retail allows the value of the carcass to be calculated based on the eating quality as well as the volume produced, thereby delivering a financial reward for farmers producing high quality carcasses. The continuous quality scale of MSA allows producers to realise the financial gain of incremental improvements in quality, as well as the precise economic weights associated with traits such as marbling, ossification score, or breed. The use of MSA in this fashion has underpinned a new and innovative supply chain where the pricing is transparent and allows producers to make informed decisions to modify both quality and yield traits. To date, the MSA system for beef has proved to be effective in predicting beef palatability not only in Australia but also in many other countries(France, Poland, Ireland, Northern Ireland, Japan, South Korea, New-Zealand, the USA and South Africa). In Europe, results of the Pro Safe Beef and Pro Opti Beef projects as well as other national projects demonstrate the potential to develop an MSA-like international grading system for the supply chain in the EU, despite thediverse cultures and complex beef production systems within the member states. International testing in lamb has only just begun and preliminary results are discussed here.展开更多
The NAM-B1 gene is a member of the NAC(NAM,ATAF,and CUC)transcription factor family and plays an important role in regulating wheat grain protein content(GPC).The ancestral NAM-B1 allele has been discovered in many te...The NAM-B1 gene is a member of the NAC(NAM,ATAF,and CUC)transcription factor family and plays an important role in regulating wheat grain protein content(GPC).The ancestral NAM-B1 allele has been discovered in many tetraploid wild emmer(Triticum turgidum ssp.dicoccoides)accessions and few domesticated emmer accessions(T.turgidum ssp.dicoccum),however,it is rarely found in hexaploid bread wheat(Triticum aestivum L.).There are no systematic reports on the distribution of NAM-B1 alleles in Chinese wheat cultivars.In this study,the NAM-B1 alleles in 218 Chinese cultivars were investigated.The cultivars were collected from five major wheat regions(12 provinces),covering most of the winter wheat growing regions in China.The results showed that the NAM-B1 gene is present in 53(24.3%)cultivars and absent in the remaining 165(75.7%)cultivars.Further analysis revealed that in contrast to the wild-type allele,the NAM-B1 gene in Chinese wheat cultivars contained a 1-bp insertion in the coding region.This caused a frame-shift mutation and introduced a stop codon in the middle of the gene,rendering it non-functional.Polymorphisms were detected in DNA sequences of 21cultivars among these 53 cultivars.However,cD NA sequence analysis suggested that these variations in the exon region were not able to restore NAM-B1 gene(1-bp insertion)function.Thus,exploring the distribution of NAM-B1 gene variations(1-bp insertion and deletion)can provide some information for improving the quality of winter wheat in China and other countries.展开更多
Wheat grain yield is generally sink-limited during grain filling.The grain-filling rate(GFR)plays a vital role but is poorly studied due to the difficulty of phenotype surveys.This study explored the grain-filling tra...Wheat grain yield is generally sink-limited during grain filling.The grain-filling rate(GFR)plays a vital role but is poorly studied due to the difficulty of phenotype surveys.This study explored the grain-filling traits in a recombinant inbred population and wheat collection using two highly saturated genetic maps for linkage analysis and genome-wide association study(GWAS).Seventeen stable additive quantitative trait loci(QTLs)were identified on chromosomes 1B,4B,and 5A.The linkage interval between IWB19555 and IWB56078 showed pleiotropic effects on GFR_(1),GFR_(max),kernel length(KL),kernel width(KW),kernel thickness(KT),and thousand kernel weight(TKW),with the phenotypic variation explained(PVE)ranging from 13.38%(KW)to 33.69%(TKW).198 significant marker-trait associations(MTAs)were distributed across most chromosomes except for 3D and 4D.The major associated sites for GFR included IWB44469(11.27%),IWB8156(12.56%)and IWB24812(14.46%).Linkage analysis suggested that IWB35850,identified through GWAS,was located in approximately the same region as QGFR_(max)2B.3-11,where two high-confidence candidate genes were present.Two important grain weight(GW)-related QTLs colocalized with grain-filling QTLs.The findings contribute to understanding the genetic architecture of the GFR and provide a basic approach to predict candidate genes for grain yield trait QTLs.展开更多
An optimum method has been developed for extracting volatile organic compounds (VOCs) which contribute to the aroma of different species of citrus fruit (orange, lemon, lime, and mandarin). Headspace solid phase micro...An optimum method has been developed for extracting volatile organic compounds (VOCs) which contribute to the aroma of different species of citrus fruit (orange, lemon, lime, and mandarin). Headspace solid phase microextraction (HS-SPME) combined with gas chromatography (GC) coupled with flame ionization detection (FID) is used as a very simple, efficient and non-destructive extraction method. A three phase 50/30 μm PDV/DVB/CAR fibre was used for the extraction process. The optimal sealing time for volatiles reaching equilibrium from whole fruit in the headspace of the chamber was 20, 16, 8 and 16 hours for lemon, lime, mandarin, and orange respectively. Optimum fibre exposure times for whole fruit were 2, 4, 2 and 2 hours for lemon, lime, mandarin, and orange respectively. Three chamber volumes (500, 1000 and 2000 ml) were evaluated for the collection of VOCs with the 500 ml chamber being selected. The 500ml chamber produced the highest quality peak areas and quantity of extracted volatiles. As a result of fruit respiration, the percentage of oxygen (O2) of all citrus fruit species in 500 ml chamber decreased from 21.8% to 18.8% in the 20 hours sealing time, while carbon dioxide (CO2) contents increased to 2.9% also in the 20 hours sealing time. The results of this study showed the feasibility of this technique for identifying VOCs from four of the citrus fruit species and its potential as a routine method for physiological studies on citrus fruit or on other fruit species.展开更多
The effects of conservation agriculture (CA) practices on soil properties along with crop yields of rice-based triple cropping systems have not been adequately assessed in Bangladesh. An experiment was conducted at Ba...The effects of conservation agriculture (CA) practices on soil properties along with crop yields of rice-based triple cropping systems have not been adequately assessed in Bangladesh. An experiment was conducted at Bangladesh Agricultural Research Institute, Gazipur, Bangladesh from 2009 to 2012 to assess the effects of tillage practices and crop residue retention on soil physical properties, soil organic carbon (SOC) and crop yields in a wheat-mungbean-rice system. Treatments consisted of three tillage practices (MT: minimum tillage;CT: conventional tillage and DT: deep tillage) and eight levels of crop residue management (S0—no residues retention, Sr—retention of 30 cm rice straw, Sm—whole mungbean stover retention, SW—30 cm wheat straw retention, Smr—whole mungbean stover & 30 cm rice straw retention, Srw—30 cm rice & wheat straw retention, Smw—whole mungbean stover & 30 cm wheat straw retention and Swrm—30 cm wheat and rice straw along with whole mungbean stover retention) were applied in split plot design with three replications. Bulk density (BD) and porosity responded positively to MT and increased residue retention of all crops (p > 0.05). Minimum tillage and Swrm also significantly accumulated SOC (p < 0.05;0.38% higher than DT with no residue retention) and retained soil moisture (p < 0.05). Minimum tillage practice performed better in upland crops (p < 0.05;wheat & mungbean yields) and CT outperformed MT in wetland rice crop (p < 0.05). The grain and straw yields of wheat and rice were also influenced by previous crop residue retentions (p < 0.05). The results, therefore, suggested that increased residue retention with minimum tillage practices improved soil properties and yield of upland crops but with deeper tillage practices consistently maintained wetland rice production.展开更多
The objective of this study was to identify volatile organic compounds(VOCs)from flour,Tribolium castaneum(Herbst)and flour infested by T.castaneum separately,to confirm the difference of healthy flour and flour infes...The objective of this study was to identify volatile organic compounds(VOCs)from flour,Tribolium castaneum(Herbst)and flour infested by T.castaneum separately,to confirm the difference of healthy flour and flour infested by T.castaneum and to explore the new technique to diagnose stored flour’s quality by its VOCs change.Headspace-solid phase microextraction(HS-SPME)coupled with gas chromatography(GC)and gas chromatography–mass spectrometry(GC–MS)were used to detect the VOCs of three different samples.Totally,71 different compounds were identified in flour,T.castaneum and T.castaneum infested flour.Therefore,27 VOCs were identified from flour alone,32 VOCs from T.castaneum and 39 VOCs from T.castaneum infested flour.The compound 2-ethyl-2,5-cyclohexadiene-1,4-dione is only found in T.castaneum infested flour.This suggests that 2-ethyl-2,5-cyclohexadiene-1,4-dione can be a useful VOC for detecting T.castaneum in flour.展开更多
Background: This experiment was conducted to test the hypothesis that vitamin E(Vit E) and acetylsalicylic acid(ASA), a cyclooxygenase-2(COX-2) inhibitor, will additively reduce the production of the immunosuppressive...Background: This experiment was conducted to test the hypothesis that vitamin E(Vit E) and acetylsalicylic acid(ASA), a cyclooxygenase-2(COX-2) inhibitor, will additively reduce the production of the immunosuppressive molecule prostaglandin E_2(PGE_2) and hence reduce inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli.Methods: The experiment was conducted in a research facility with 192 individually-housed male weaner pigs(Landrace × Large White) weighing 6.6 ± 0.04 kg(mean ± SEM). The pigs were experimentally infected with an enterotoxigenic strain of E. coli and were allocated to a 2 × 3 factorial design with the respective factors being without and with 125 ppm ASA and three levels of Vit E supplementation(50, 100 or 200 IU/kg diet, dl-α-tocopheryl acetate).Results: Acetylsalicylic acid supplementation improved average daily gain(P < 0.05) and tended to improve feed:gain ratio(P < 0.10) during the first 14 d after weaning. Acetylsalicylic acid supplementation also improved(P < 0.001) amino acid utilization efficiency(as assessed by plasma urea level) and tended to decrease(P < 0.10) PGE_2 production in the liver without affecting smal intestinal histology and tight junction protein mR NA expression in the jejunal epithelium. Vitamin E supplementation greater than 100 IU/kg diet sustained both the plasma Vit E concentration(P < 0.001) and plasma haptoglobin content(P < 0.001) after weaning. However, there was no additive effects of the combined supplementation of ASA and Vit E on performance, intestinal barrier function and inflammatory responses of weaned pigs.Conclusions: Although ASA and vitamin E improved amino acid utilization efficiency and reduced acute inflammatory responses, ASA and vitamin E did not additively reduce production of PGE_2 and inflammatory responses in weaner pigs experimental y infected with an enterotoxigenic strain of E. coli.展开更多
A number of eukaryotic expression vectors have been developed for use as DNA vaccines. They showed varying abilities to initiate immune responses;however, there is little data to indicate which of these vectors will b...A number of eukaryotic expression vectors have been developed for use as DNA vaccines. They showed varying abilities to initiate immune responses;however, there is little data to indicate which of these vectors will be the most useful and practical for DNA vaccines in different species. This report examines the use of five expression vectors with different promoters and Kozak sequence to express the same hemagglutinin (HA) protein of an H6N2 avian influenza virus for DNA vaccination in chickens. Although intramuscular vaccination with seven DNA constructs elicited no or limited measurable H6 HA antibody responses in Hy-Line chickens, variable reduction in virus shedding for either oropharyngeal or cloacal swabs post-virus challenge were observed. This indicated that all DNA constructs generated some levels of protective immunity against homologous virus challenge. Interestingly, lower dose (50 or 100 μg) of plasmid DNAs consistently induced better immune response than higher dose (300 or 500 μg). In the transfection experiments there appeared to be a hierarchy in the in vitro expression efficiency in the order of pCAG-optiHAk/ pCAG-HAk > pCI-HAk > VR-HA > pCI-HA > pCI-neo-HA > pVAX-HA. Since the level of in vitro expression correlates with the level of immune response in vivo, in vitro expression levels of the DNA constructs can be used as an indicator for pre-selection of plasmid vaccines prior to in vivo assessment. Moreover, our results suggested that the Kozak sequence could be used as an effective tool for DNA vaccine design.展开更多
Background: In this experiment, intermittent suckling(IS) with or without the co-mingling(Co M) of piglets was studied as a method to stimulate solid feed intake and reduce post-weaning stress.Methods: Three weaning r...Background: In this experiment, intermittent suckling(IS) with or without the co-mingling(Co M) of piglets was studied as a method to stimulate solid feed intake and reduce post-weaning stress.Methods: Three weaning regimes using 30 multiparous sows were compared:(1) conventional weaning(CW)(n = 10 litters), where piglets had continuous access to the sow until weaning(d 0, farrowing = d-25 relative to weaning);(2) intermittent suckling(IS)(n = 10 litters), where piglets were separated from the sow for 8 h/d starting at d-7(relative to weaning); and(3) intermittent suckling with co-mingling(ISCo)(n = 10 litters) where IS started at d-7 and two litters were housed together during separation and then returned to their original sow. Ad libitum creep feed was available from d-17. At weaning pigs were housed in pens of 11 pigs, 27 pens in total. The ISCo treatment was divided in half to examine effects of different mixing strategies after weaning. Half of the ISCo litters were kept in familiar groups(ISCo F, familiar, n = 4) and the other half were mixed within treatment resulting in groups of unfamiliar pigs(ISCo NF, not familiar, n = 5), the same as IS(n = 9) and CW(n = 9) treatments.Results: The ISCo piglets ate more creep feed in the week before weaning(P < 0.01), but also showed more aggressive and manipulative behaviour on first day of Co M compared with CW piglets(P < 0.05). IS with or without Co M increased exploratory and play behaviour on the first day of treatment intervention(P < 0.001) and increased sleeping behaviour on the last day of treatment intervention compared with CW(P < 0.001). Mixing strategy at weaning had an effect on performance data with the highest growth and feed intake seen in ISCo F pigs 2 to 8 d after weaning(P <0.001). IS and ISCo NF pigs also grew faster and ate more than CW pigs 2 to 8 d after weaning(P < 0.001). Post-weaning injury scores suggested reduced aggression in ISCo as evidenced by reduced redness(skin irritation)(P < 0.05), and a tendency for ISCo to have less scratches than CW(P < 0.1). The IS pigs slept the most and displayed less manipulative behaviours on the day of weaning and plasma haptoglobin levels remained low in IS pigs after weaning(P ≤ 0.01).Conclusions: Both intermittent suckling techniques improved production indices in the immediate post-weaning period. However, the addition of co-mingling before weaning in combination with grouping familiar pigs together after weaning improved performance in an additive manner.展开更多
Timely detection of Mediterranean fruit fly (Medfly) is very important so that eradication action can be taken on time. The larvae stage of this insect is the most dangerous stage as it is within the pulp of the fruit...Timely detection of Mediterranean fruit fly (Medfly) is very important so that eradication action can be taken on time. The larvae stage of this insect is the most dangerous stage as it is within the pulp of the fruit, making it hard to detect by visual inspection. In most countries at ports of entry the inspector check a small sample of fruit by visual inspection or by cutting the produce and searching for fungus and pests. This paper will investigate a quick, reliable and sensitive method to determine the presence of fruit flies. Our research focuses on developing the technology for detecting hidden infestations by using the Head Space-Soild Phase Micro Extraction (HS-SPME) method coupled with Gas Chromatography-Mass Spectrocopy (GC-MS) technique. Five different types of fruit were infested with an early stage of Medfly Ceratitis capitata Wiedemann (Diptera: Tephidae). We investigated to detect the differences in volatile organic compounds (VOC’s) between infested and non- infested fruits by using HS-SPME with (GC-MS). The results indicated that for few chemicals no significant differences between infested and non-infested fruit can be seen, especially in the fruits with first instar. However, in case of third instar larvae infested fruits significant differences in the chemicals can be seen as compare to non infested fruits and other instar infestations. These chemicals include ethyl (Z)-2 butenoate, 2-heptanone, anisole, β-cis-ocimene, 1,3,7-nonatriene,4,8-dimethy-,ethyl octyate, isoamyl caproate and 1β,4βh,10βh- guaia-5,11-diene, in apple. Ethyl (Z)-2-butenoate, (+)-2-bornanone, (-)-trans- isopiperitenol, methyl caprate, caryophyllene and farnesene in orange. Butanoic acid, 3-methyl-,2-methylbutul acetate, sabinene, β-myrcene, octanoic acid, methyl ester, dihydrocarvone, (-)-trans-isopiperitenol and ethyl laurate in mandarin. Butyl 2-methylbutanoate, terpinen-4-ol, P-menth-8-en-2-one, E-,(3E,7E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene and dodecanoic acid, ethyl ester in lemon. Decane, 3-methyl-, p-menth-1,4(8)-diene, 1-undecene and α-cubebene in avocado. Thus, the VOC’s method could provide a possible tool for detecting tephritid larvae and this method could be adopted by industries importing and exporting fruit.展开更多
Medium-term changes in the labile nutrient pool of microbial biomass carbon (MBC) and nitrogen (MBN) resulting from organic manure application in rice (Oryza sativa L.)-based triple cropping systems have been poorly s...Medium-term changes in the labile nutrient pool of microbial biomass carbon (MBC) and nitrogen (MBN) resulting from organic manure application in rice (Oryza sativa L.)-based triple cropping systems have been poorly studied. Therefore, the effects of organic materials on the soil physico-chemical properties and microbial biomass in rice fields were investigated at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, from April 2010 to December 2012. Five treatments (control, cow dung, poultry manure, rice straw, and chemical fertilizer) were laid out in a randomized complete block design with four replications. The organic residues (2 t C ha-1) were applied 7 days before transplanting and were combined with inorganic fertilizers, following integrated plant nutrition systems. This paper presents the results from the last of the five consecutive rice growing seasons. All of the organic residues increased the pH, and organic C, N, P, and K contents of the soil. However, poultry manure was more efficient in increasing soil fertility than cow dung and rice straw, resulting in a significant increase in P from 22 mg·kg-1 to 63 mg·kg-1 at crop harvest. All of the organic residues also increased the soil water holding capacity and decreased bulk density. Furthermore, poultry manure resulted in significantly higher microbial biomass C (432 mg·kg-1;P < 0.05) and N (31.60 mg·kg-1;P < 0.05) levels in the soil at crop harvest, followed by cow dung and rice straw. These findings indicate that the regular application of organic residues and manures will help to enhance soil fertility and production sustainability.展开更多
In rainfed lowlands, the beneficial effects on rice (Oryza sativa) yield from fertilizing the seedling nursery may depend on the occurrence of water and nutrient stress after transplanting into the mainfield. The aim ...In rainfed lowlands, the beneficial effects on rice (Oryza sativa) yield from fertilizing the seedling nursery may depend on the occurrence of water and nutrient stress after transplanting into the mainfield. The aim of the study was to test the effect of seedling age and nursery fertilisation on rice yield when plants experienced nutrient and water stress regimes after transplanting. The first experiment, conducted during the wet season in a low-fertility rainfed lowland field in south-east Cambodia, examined the effect of three levels of nitrogen (N), phosphorus (P) and cow manure (CM) application to the nursery and three ages of seedlings at transplanting (4, 6 and 9 weeks after sowing: WAS) on the growth of a traditional photoperiod-sensitive rice cultivar. Increasing fertilizer application to the nursery increased shoot dry weight and grain yield at each age of seedling transplanted. Shoot dry weight and grain yield from seedlings transplanted 6 WAS were 20% and 10% higher than those from the seedlings transplanted at the other ages. Seedlings transplanted at 4 WAS, which experienced a temporary submergence for 3 days after transplanting, recorded 5% greater seedling mortality from the unfertilized than fertilized nursery soil. The taller seedlings transplanted at 6 WAS experienced less mortality despite more severe submergence. The second experiment was conducted at seven rainfed lowland sites across Cambodia to test the benefit of N alone and N+P application to the nursery on rice yields in farmers’ fields. In four out of seven trials, grain yield increases averaged 13% with N+P applied to the nursery whereas N alone increased grain yield at two sites and depressed yield at two. Overall, fertilizer application in the nursery produced more vigorous seedlings with higher nutrient concentration which survived submergence and grew better with or without drought or nutrient stress after transplanting, leading to increased yields of rice. The beneficial effect of nursery fertilizer was additional to any obtained by fertilizer applied to the main field at or after transplanting.展开更多
Vetiver grass (</span><i><span style="font-family:Verdana;">Vetiveria</span></i> <i><span style="font-family:Verdana;">zizanioides</span></i>&l...Vetiver grass (</span><i><span style="font-family:Verdana;">Vetiveria</span></i> <i><span style="font-family:Verdana;">zizanioides</span></i><span style="font-family:Verdana;"> L.) is widely used for soil and water conservation, and land management. In practice, all vetiver seedlings are propagated via ramets or tillers, which cannot meet the market demand and would also destroy the original habitat. Most</span><span style="color:red;"> </span><span style="font-family:Verdana;">vetiver genotypes flower but do not produce seeds. A wild ecotype of vetiver grass originated in southern China is fertile, but the rate of seed germination is very low. This study aimed to develop a novel method to improve its seed germination and seedling establishment. In the field, the inflorescences of wild vetiver were wrapped using a transparent plastic bag with a pot containing wet soils. The effects of inflorescence bagging and Tween 80 application on seed germination and seedling growth were examined. The results showed that seed development was characterized by low seed setting rate (19.2%), uneven maturity time, easy shedding (more than 95% of spikelets shed off 20 days after flowering), therefore difficult harvest of viable seeds. Bagging the inflorescence with moist soils in pot ensured the mature seeds falling onto the nursery soil surface and absorbing water for germination while the immature seeds continued to grow on the inflorescence. Bigging not only improved seed development and maturity, saved the procedure of seed collection and storage, but also provided a humid micro-environment for seed germination and seedling growth. Tween 80 as a surfactant promoted seed water absorption, germination and seedling growth. This simple and novel method has integrated the procedures of seed collection, storage, germination and seedling establishment, and enables </span></span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">produc</span><span style="font-family:Verdana;">tion</span><span style="font-family:""> </span><span style="font-family:Verdana;">of </span><span style="font-family:Verdana;">a large </span><span style="font-family:Verdana;">number</span><span style="font-family:Verdana;"> of healthy seedlings. The possible reasons for the degeneration and disappearance of the original population were also discussed from the perspective of the disadvantages of vetiver propagation.展开更多
Natural regeneration is a critical component of forest ecosystems sustainability. Local extinction can occur without adequate regenerationor seedling recruitment prior to adult senescence. The urban and peri-urban env...Natural regeneration is a critical component of forest ecosystems sustainability. Local extinction can occur without adequate regenerationor seedling recruitment prior to adult senescence. The urban and peri-urban environment is particularly challenging for recruitment. For example, although many forest species have specific requirements involving fire events, few opportunities associated with fire exist in contemporary urban and peri-urban environments. For our study species, Eucalyptus gomphocephala, en masse recruitment can occur in ashbeds following a hot fire. However, this may not occur following low-intensity, fuel reduction burns that are prescribed for many E. gomphocephala woodlands and forests. Nevertheless, ashbeds could be created by constructing and burning coarse woody debris (CWD) piles. In a series of collaborative case studies involving community groups, NGOs and Local and State Government agencies, we investigated whether seedling recruitment could be facilitated through broadcast seeding after: a) creating CWD piles prior to a low intensity, prescribed burn;b) naturally-occurring ashbeds following a hot summer wildfire;and c) creating CWD piles and then burning the piles only. We found that regeneration of this post-fire, canopy gap regenerator can be facilitated by broadcast seeding naturally occurring or created ashbeds. However, it seems that protection from seed harvesters and herbivores is vital. These case studies provide tools that can be used to preserve the natural demographics in populations with specific regeneration requirements in a range of environments by leveraging natural recruitment processes and community involvement. Importantly, it is the conservation of these urban and peri-urban ecosystems that will be vital in maintaining connection between people and the environment into the future.展开更多
Missense mutations in the leucine rich repeat kinase 2 (LRRK2) gene are the leading genetic cause of autosomal dominant familial Parkinson’s disease. We previously reported that two mutations within the ROC domain, n...Missense mutations in the leucine rich repeat kinase 2 (LRRK2) gene are the leading genetic cause of autosomal dominant familial Parkinson’s disease. We previously reported that two mutations within the ROC domain, namely R1441C and A1442P, exhibit increased protein degradation leading to lowered steady state LRRK2 protein levels in HEK293 cells. More recently, the common WD40 domain LRRK2 haplotype, Met2397, which is a risk factor for Crohn’s disease, has been shown to lower steady state protein levels in HEK293 cells. In view of recent evidence implicating LRRK2 and inflamemation in PD, we investigated the effects of Met2397 on LRRK2 expression, and compared them to the Thr2397 variant and other LRRK2 mutants. In this study, we transfected HEK293 cells with plasmid constructs encoding the different LRRK2 variants, and analyzed the resulting protein levels by Western blot and flow cytometry. Here we found that both the Met2397 and Thr2397 haplotypes yield similar levels of LRRK2 protein expression and do not appear to impact cell viability in HEK293 cells, compared to other LRRK mutants. Thus, we have concluded that the Met2397 haplotype is unlikely to play a role in LRRK2 mediated or idiopathic PD.展开更多
文摘Domesticated and non-domesticated animals, including wildlife, deliver significant financial and nonfinancial benefits to the human community;however, disease can have a dramatic impact on the morbidity, mortality, and productivity of these animal populations and hence can directly and indirectly affect the human communities associated with them. This manuscript provides an overview of the important features to consider for the prevention and control of disease, with a focus on livestock diseases,and highlights the key role veterinary epidemiology plays in this endeavor. Measures of disease frequency and the type of epidemiological studies required to identify risk factors for diseases are summarized,with a focus on the use of these in the implementation of measures to control disease. The importance of biosecurity in maintaining disease-free flocks/herds is discussed and the steps taken to implement good biosecurity measures are outlined. It is concluded that a sound knowledge of veterinary epidemiology is required when developing control programs for disease and implementing biosecurity programs at a farm, regional, and national level.
基金supported by the Murdoch University, Meat and Livestock Australia and Institut National de la Recherche Agronomique (INRA)
文摘The meat industry cannot respond to increases in demand by ever increasing resource use. The industry must find solutions to issues regarding animal welfare, health and sustainability and will have to do so in the face of competition from emerging non-traditional meat and protein products in an increasingly complex regulatory environment. These novel meat and protein products, otherwise known as ‘artificial meat' are utilising ground breaking technologies designed to meet the issues facing the conventional meat industry. These artificial meats, in vitro or cultured meat and meat from genetically modified organisms have no real capacity to compete with conventional meat production in the present environment. However, meat replacements manufactured from plant proteins and mycoproteins are currently the biggest competitors and are gaining a small percentage of the market. Manufactured meats may push conventional meat into the premium end of the market, and supply the bulk, cheap end of the market if conventional meat products become more expensive and the palatability and versatility of manufactured meats improve. In time the technology for other artificial meats such as meat from genetic modified organisms or cultured meat may become sufficiently developed for these products to enter the market with no complexity of the competition between meat products. Conventional meat producers can assimilate agroecology ecology concepts in order to develop sustainable animal production systems. The conventional meat industry can also benefit from assimilating biotechnologies such as cloning and genetic modification technologies, using the technology to adapt to the changing environment and respond to the increasing competition from artificial meats. Although it will depend at least partly on the evolution of conventional meat production, the future of artificial meat produced from stem cells appears uncertain at this time.
基金the financial support of the National Basic Research Program of China (2015CB150402)National Natural Science Foundation of China (51479189)+1 种基金Open Foundation of State Key Laboratory, Institute of Water and Soil Conservation, Chinese Academy of Sciences, Ministry of Water Resources (A314021402-1610)Key Research Foundation of Baoji University of Arts and Sciences (ZK16066)
文摘Besides leaves, non-foliar green organs such as stem and spike are also considered photosynthetic organs. To assess the photosynthetic contributions of these organs, the correlations between these photosynthetic areas and single-spike weight were investigated in a winter wheat(Triticum aestivum L.) under four nitrogen and mulching treatments: N120,N150, N195, and N195 + M. Two-year repeated field experiments were conducted on the Loess Plateau of China. Non-foliar photosynthetic area, grain-filling ratio and duration,grain yield, and in particular, single-spike weight, were measured, recorded and analyzed.Under the N195 + M treatment, plants showed the largest area of photosynthetic organs(flag leaf and non-foliar organs) and the highest grain yield and single spike weight. Singlespike weight was positively correlated with the areas of all examined non-foliar photosynthetic organs, in particular with the area above the flag leaf node(R^2= 0.761*)and the area above the exposed part of the peduncle(EXP)(R^2= 0.800**). In addition, singlespike weight was highly correlated with average grain-filling ratio(R^2= 0.993**), whereas it was less highly correlated with grain-filling duration(R^2= 0.533). The morphological traits of non-foliar photosynthetic organs were also more highly correlated with average grainfilling ratio than with average grain-filling duration. The significant correlation between each of the morphological traits(area, length and width) of EXP and single-spike weight indicates that morphological traits of EXP are important in determining spike weight in the Loess Plateau environment.
基金supported by the Co-operative Research Centre for an Internationally Competitive Pork IndustryPork CRC Ltd(ACN:113 703 174)P.O.Box 466,Willaston,South Australia,5118,Australia
文摘Background: Three experiments were conducted to examine the overall hypothesis that addition of medium chain triglycerides(MCT) and cysteamine hydrochloride(CSH) into the diets of young and growing pigs would stimulate the endogenous somatotropic axis to improve growth and performance.Results: In Experiment 1, weaner pigs were given either a 5 d dietary supplement of 5 % MCT(n = 8) or a control diet(n = 8). MCT increased the plasma concentration of growth hormone(GH; P < 0.05) and the GH secretagogue,ghrelin(P < 0.05). Additionally, the MCT treatment reduced scouring(P < 0.05), maintained villous height in the small intestine(P < 0.05) and stabilised daily weight gain(P < 0.05), compared to the controls. Experiment 2compared the effects of 4 levels(0, 1, 3 and 6 % v/v) of MCT supplementation in grower-finisher male pigs, of approximately 35 kg live weight(n = 15 per treatment). Blood samples taken after 7 wk of treatment showed that the MCT supplementation increased circulating ghrelin(P < 0.001), GH(P < 0.01) and insulin(P < 0.05)concentrations in a dose-dependent manner. Daily weight gain, feed intake and feed conversion ratio were not affected by the MCT diets. In Experiment 3, 64 female pigs of approximately 60 kg live weight were allocated to one of three dietary treatments: control(n = 20); 6 % MCT(n = 21); and 70 mg/kg CSH(n = 21). After 3 wk of supplementation, the MCT treated pigs had a higher plasma concentration of ghrelin compared to the control and CSH pigs(P < 0.05). Plasma concentrations of GH and weight were not affected by any of the dietary treatments.Conclusions: Evidence is provided in Experiment 1 to support the use of dietary MCT supplements, perhaps acting via stimulation of somatotropic endocrine pathways, to minimise weaning-associated disorders such as slowing of growth and diarrhoea. In Experiments 2 and 3, although there was no effect on weight gain or feed conversion ratio in either experiment, MCT and CSH increased endocrine components of the somatotropic axis.
基金the Sheep Cooperative Research Centre(CRC)for Sheep Industry Innovation,and associated organisations for funding and data collection support
文摘Changing markets and evolving consumer demand present new challenges for the beef and sheep industries. In response, the industry has been investing in innovations to deliver new products and management systems to consumers. One such innovation is the Meat Standards Australia(MSA) system. This system is a Total Quality Management System, aimed at delivering an eating quality guarantee to consumers, and through this adding value to the entire supply chain. At present, it is well developed for beef and still evolving for sheepmeat. MSA has identified Critical Control Points(CCPs) in the production, pre-slaughter, processing and value-adding aspects of the supply chain that impact on consumer palatability through the large-scale taste testing of meat by untrained consumers. These CCPs are used as either(1) mandatory criteria determining eligibility for grading, and(2) inputs in a model predicting the palatability of individual combinations of muscle and different cooking methods. Through the prediction of palatability, MSA increases consumer satisfaction and is used to provide assurance for branded products and new marketing innovations in Australia and internationally. This has added significant value to the Australian beef industry, with several retail examples demonstrating consumer willingness to pay more for premium quality beef and sheepmeat products based on the MSA grading scores. This price differential at retail allows the value of the carcass to be calculated based on the eating quality as well as the volume produced, thereby delivering a financial reward for farmers producing high quality carcasses. The continuous quality scale of MSA allows producers to realise the financial gain of incremental improvements in quality, as well as the precise economic weights associated with traits such as marbling, ossification score, or breed. The use of MSA in this fashion has underpinned a new and innovative supply chain where the pricing is transparent and allows producers to make informed decisions to modify both quality and yield traits. To date, the MSA system for beef has proved to be effective in predicting beef palatability not only in Australia but also in many other countries(France, Poland, Ireland, Northern Ireland, Japan, South Korea, New-Zealand, the USA and South Africa). In Europe, results of the Pro Safe Beef and Pro Opti Beef projects as well as other national projects demonstrate the potential to develop an MSA-like international grading system for the supply chain in the EU, despite thediverse cultures and complex beef production systems within the member states. International testing in lamb has only just begun and preliminary results are discussed here.
基金supported by the National Natural Science Founding of China (31401378)the Major Scientific and Technological Innovation Project of Shandong Academy of Agricultural Sciences, China (2014CXZ10)+2 种基金the Youth Foundation of Shandong Academy of Agricultural Sciences, China (2014QNZ02)the Program for Youth Talent of Shandong Academy of Agricultural Sciences, China (118005)the Science & Technology Development Plan of Shandong Province, China (2014GSF121001)
文摘The NAM-B1 gene is a member of the NAC(NAM,ATAF,and CUC)transcription factor family and plays an important role in regulating wheat grain protein content(GPC).The ancestral NAM-B1 allele has been discovered in many tetraploid wild emmer(Triticum turgidum ssp.dicoccoides)accessions and few domesticated emmer accessions(T.turgidum ssp.dicoccum),however,it is rarely found in hexaploid bread wheat(Triticum aestivum L.).There are no systematic reports on the distribution of NAM-B1 alleles in Chinese wheat cultivars.In this study,the NAM-B1 alleles in 218 Chinese cultivars were investigated.The cultivars were collected from five major wheat regions(12 provinces),covering most of the winter wheat growing regions in China.The results showed that the NAM-B1 gene is present in 53(24.3%)cultivars and absent in the remaining 165(75.7%)cultivars.Further analysis revealed that in contrast to the wild-type allele,the NAM-B1 gene in Chinese wheat cultivars contained a 1-bp insertion in the coding region.This caused a frame-shift mutation and introduced a stop codon in the middle of the gene,rendering it non-functional.Polymorphisms were detected in DNA sequences of 21cultivars among these 53 cultivars.However,cD NA sequence analysis suggested that these variations in the exon region were not able to restore NAM-B1 gene(1-bp insertion)function.Thus,exploring the distribution of NAM-B1 gene variations(1-bp insertion and deletion)can provide some information for improving the quality of winter wheat in China and other countries.
基金supported by the National Natural Science Foundation of China (31971936)the Science &Technology Projects of Shandong Province, China (2019YQ028, 2020CXGC010805, 2019B08, 2019YQ014 and ZR2020MC093)
文摘Wheat grain yield is generally sink-limited during grain filling.The grain-filling rate(GFR)plays a vital role but is poorly studied due to the difficulty of phenotype surveys.This study explored the grain-filling traits in a recombinant inbred population and wheat collection using two highly saturated genetic maps for linkage analysis and genome-wide association study(GWAS).Seventeen stable additive quantitative trait loci(QTLs)were identified on chromosomes 1B,4B,and 5A.The linkage interval between IWB19555 and IWB56078 showed pleiotropic effects on GFR_(1),GFR_(max),kernel length(KL),kernel width(KW),kernel thickness(KT),and thousand kernel weight(TKW),with the phenotypic variation explained(PVE)ranging from 13.38%(KW)to 33.69%(TKW).198 significant marker-trait associations(MTAs)were distributed across most chromosomes except for 3D and 4D.The major associated sites for GFR included IWB44469(11.27%),IWB8156(12.56%)and IWB24812(14.46%).Linkage analysis suggested that IWB35850,identified through GWAS,was located in approximately the same region as QGFR_(max)2B.3-11,where two high-confidence candidate genes were present.Two important grain weight(GW)-related QTLs colocalized with grain-filling QTLs.The findings contribute to understanding the genetic architecture of the GFR and provide a basic approach to predict candidate genes for grain yield trait QTLs.
文摘An optimum method has been developed for extracting volatile organic compounds (VOCs) which contribute to the aroma of different species of citrus fruit (orange, lemon, lime, and mandarin). Headspace solid phase microextraction (HS-SPME) combined with gas chromatography (GC) coupled with flame ionization detection (FID) is used as a very simple, efficient and non-destructive extraction method. A three phase 50/30 μm PDV/DVB/CAR fibre was used for the extraction process. The optimal sealing time for volatiles reaching equilibrium from whole fruit in the headspace of the chamber was 20, 16, 8 and 16 hours for lemon, lime, mandarin, and orange respectively. Optimum fibre exposure times for whole fruit were 2, 4, 2 and 2 hours for lemon, lime, mandarin, and orange respectively. Three chamber volumes (500, 1000 and 2000 ml) were evaluated for the collection of VOCs with the 500 ml chamber being selected. The 500ml chamber produced the highest quality peak areas and quantity of extracted volatiles. As a result of fruit respiration, the percentage of oxygen (O2) of all citrus fruit species in 500 ml chamber decreased from 21.8% to 18.8% in the 20 hours sealing time, while carbon dioxide (CO2) contents increased to 2.9% also in the 20 hours sealing time. The results of this study showed the feasibility of this technique for identifying VOCs from four of the citrus fruit species and its potential as a routine method for physiological studies on citrus fruit or on other fruit species.
文摘The effects of conservation agriculture (CA) practices on soil properties along with crop yields of rice-based triple cropping systems have not been adequately assessed in Bangladesh. An experiment was conducted at Bangladesh Agricultural Research Institute, Gazipur, Bangladesh from 2009 to 2012 to assess the effects of tillage practices and crop residue retention on soil physical properties, soil organic carbon (SOC) and crop yields in a wheat-mungbean-rice system. Treatments consisted of three tillage practices (MT: minimum tillage;CT: conventional tillage and DT: deep tillage) and eight levels of crop residue management (S0—no residues retention, Sr—retention of 30 cm rice straw, Sm—whole mungbean stover retention, SW—30 cm wheat straw retention, Smr—whole mungbean stover & 30 cm rice straw retention, Srw—30 cm rice & wheat straw retention, Smw—whole mungbean stover & 30 cm wheat straw retention and Swrm—30 cm wheat and rice straw along with whole mungbean stover retention) were applied in split plot design with three replications. Bulk density (BD) and porosity responded positively to MT and increased residue retention of all crops (p > 0.05). Minimum tillage and Swrm also significantly accumulated SOC (p < 0.05;0.38% higher than DT with no residue retention) and retained soil moisture (p < 0.05). Minimum tillage practice performed better in upland crops (p < 0.05;wheat & mungbean yields) and CT outperformed MT in wetland rice crop (p < 0.05). The grain and straw yields of wheat and rice were also influenced by previous crop residue retentions (p < 0.05). The results, therefore, suggested that increased residue retention with minimum tillage practices improved soil properties and yield of upland crops but with deeper tillage practices consistently maintained wetland rice production.
文摘The objective of this study was to identify volatile organic compounds(VOCs)from flour,Tribolium castaneum(Herbst)and flour infested by T.castaneum separately,to confirm the difference of healthy flour and flour infested by T.castaneum and to explore the new technique to diagnose stored flour’s quality by its VOCs change.Headspace-solid phase microextraction(HS-SPME)coupled with gas chromatography(GC)and gas chromatography–mass spectrometry(GC–MS)were used to detect the VOCs of three different samples.Totally,71 different compounds were identified in flour,T.castaneum and T.castaneum infested flour.Therefore,27 VOCs were identified from flour alone,32 VOCs from T.castaneum and 39 VOCs from T.castaneum infested flour.The compound 2-ethyl-2,5-cyclohexadiene-1,4-dione is only found in T.castaneum infested flour.This suggests that 2-ethyl-2,5-cyclohexadiene-1,4-dione can be a useful VOC for detecting T.castaneum in flour.
基金support by Australian Cooperative Research Centre for High Integrity Australian Pork(Award number 2C-110 1213)
文摘Background: This experiment was conducted to test the hypothesis that vitamin E(Vit E) and acetylsalicylic acid(ASA), a cyclooxygenase-2(COX-2) inhibitor, will additively reduce the production of the immunosuppressive molecule prostaglandin E_2(PGE_2) and hence reduce inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli.Methods: The experiment was conducted in a research facility with 192 individually-housed male weaner pigs(Landrace × Large White) weighing 6.6 ± 0.04 kg(mean ± SEM). The pigs were experimentally infected with an enterotoxigenic strain of E. coli and were allocated to a 2 × 3 factorial design with the respective factors being without and with 125 ppm ASA and three levels of Vit E supplementation(50, 100 or 200 IU/kg diet, dl-α-tocopheryl acetate).Results: Acetylsalicylic acid supplementation improved average daily gain(P < 0.05) and tended to improve feed:gain ratio(P < 0.10) during the first 14 d after weaning. Acetylsalicylic acid supplementation also improved(P < 0.001) amino acid utilization efficiency(as assessed by plasma urea level) and tended to decrease(P < 0.10) PGE_2 production in the liver without affecting smal intestinal histology and tight junction protein mR NA expression in the jejunal epithelium. Vitamin E supplementation greater than 100 IU/kg diet sustained both the plasma Vit E concentration(P < 0.001) and plasma haptoglobin content(P < 0.001) after weaning. However, there was no additive effects of the combined supplementation of ASA and Vit E on performance, intestinal barrier function and inflammatory responses of weaned pigs.Conclusions: Although ASA and vitamin E improved amino acid utilization efficiency and reduced acute inflammatory responses, ASA and vitamin E did not additively reduce production of PGE_2 and inflammatory responses in weaner pigs experimental y infected with an enterotoxigenic strain of E. coli.
文摘A number of eukaryotic expression vectors have been developed for use as DNA vaccines. They showed varying abilities to initiate immune responses;however, there is little data to indicate which of these vectors will be the most useful and practical for DNA vaccines in different species. This report examines the use of five expression vectors with different promoters and Kozak sequence to express the same hemagglutinin (HA) protein of an H6N2 avian influenza virus for DNA vaccination in chickens. Although intramuscular vaccination with seven DNA constructs elicited no or limited measurable H6 HA antibody responses in Hy-Line chickens, variable reduction in virus shedding for either oropharyngeal or cloacal swabs post-virus challenge were observed. This indicated that all DNA constructs generated some levels of protective immunity against homologous virus challenge. Interestingly, lower dose (50 or 100 μg) of plasmid DNAs consistently induced better immune response than higher dose (300 or 500 μg). In the transfection experiments there appeared to be a hierarchy in the in vitro expression efficiency in the order of pCAG-optiHAk/ pCAG-HAk > pCI-HAk > VR-HA > pCI-HA > pCI-neo-HA > pVAX-HA. Since the level of in vitro expression correlates with the level of immune response in vivo, in vitro expression levels of the DNA constructs can be used as an indicator for pre-selection of plasmid vaccines prior to in vivo assessment. Moreover, our results suggested that the Kozak sequence could be used as an effective tool for DNA vaccine design.
基金Financial support by Australian Cooperative Research Centre for High Integrity Australian Pork
文摘Background: In this experiment, intermittent suckling(IS) with or without the co-mingling(Co M) of piglets was studied as a method to stimulate solid feed intake and reduce post-weaning stress.Methods: Three weaning regimes using 30 multiparous sows were compared:(1) conventional weaning(CW)(n = 10 litters), where piglets had continuous access to the sow until weaning(d 0, farrowing = d-25 relative to weaning);(2) intermittent suckling(IS)(n = 10 litters), where piglets were separated from the sow for 8 h/d starting at d-7(relative to weaning); and(3) intermittent suckling with co-mingling(ISCo)(n = 10 litters) where IS started at d-7 and two litters were housed together during separation and then returned to their original sow. Ad libitum creep feed was available from d-17. At weaning pigs were housed in pens of 11 pigs, 27 pens in total. The ISCo treatment was divided in half to examine effects of different mixing strategies after weaning. Half of the ISCo litters were kept in familiar groups(ISCo F, familiar, n = 4) and the other half were mixed within treatment resulting in groups of unfamiliar pigs(ISCo NF, not familiar, n = 5), the same as IS(n = 9) and CW(n = 9) treatments.Results: The ISCo piglets ate more creep feed in the week before weaning(P < 0.01), but also showed more aggressive and manipulative behaviour on first day of Co M compared with CW piglets(P < 0.05). IS with or without Co M increased exploratory and play behaviour on the first day of treatment intervention(P < 0.001) and increased sleeping behaviour on the last day of treatment intervention compared with CW(P < 0.001). Mixing strategy at weaning had an effect on performance data with the highest growth and feed intake seen in ISCo F pigs 2 to 8 d after weaning(P <0.001). IS and ISCo NF pigs also grew faster and ate more than CW pigs 2 to 8 d after weaning(P < 0.001). Post-weaning injury scores suggested reduced aggression in ISCo as evidenced by reduced redness(skin irritation)(P < 0.05), and a tendency for ISCo to have less scratches than CW(P < 0.1). The IS pigs slept the most and displayed less manipulative behaviours on the day of weaning and plasma haptoglobin levels remained low in IS pigs after weaning(P ≤ 0.01).Conclusions: Both intermittent suckling techniques improved production indices in the immediate post-weaning period. However, the addition of co-mingling before weaning in combination with grouping familiar pigs together after weaning improved performance in an additive manner.
文摘Timely detection of Mediterranean fruit fly (Medfly) is very important so that eradication action can be taken on time. The larvae stage of this insect is the most dangerous stage as it is within the pulp of the fruit, making it hard to detect by visual inspection. In most countries at ports of entry the inspector check a small sample of fruit by visual inspection or by cutting the produce and searching for fungus and pests. This paper will investigate a quick, reliable and sensitive method to determine the presence of fruit flies. Our research focuses on developing the technology for detecting hidden infestations by using the Head Space-Soild Phase Micro Extraction (HS-SPME) method coupled with Gas Chromatography-Mass Spectrocopy (GC-MS) technique. Five different types of fruit were infested with an early stage of Medfly Ceratitis capitata Wiedemann (Diptera: Tephidae). We investigated to detect the differences in volatile organic compounds (VOC’s) between infested and non- infested fruits by using HS-SPME with (GC-MS). The results indicated that for few chemicals no significant differences between infested and non-infested fruit can be seen, especially in the fruits with first instar. However, in case of third instar larvae infested fruits significant differences in the chemicals can be seen as compare to non infested fruits and other instar infestations. These chemicals include ethyl (Z)-2 butenoate, 2-heptanone, anisole, β-cis-ocimene, 1,3,7-nonatriene,4,8-dimethy-,ethyl octyate, isoamyl caproate and 1β,4βh,10βh- guaia-5,11-diene, in apple. Ethyl (Z)-2-butenoate, (+)-2-bornanone, (-)-trans- isopiperitenol, methyl caprate, caryophyllene and farnesene in orange. Butanoic acid, 3-methyl-,2-methylbutul acetate, sabinene, β-myrcene, octanoic acid, methyl ester, dihydrocarvone, (-)-trans-isopiperitenol and ethyl laurate in mandarin. Butyl 2-methylbutanoate, terpinen-4-ol, P-menth-8-en-2-one, E-,(3E,7E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene and dodecanoic acid, ethyl ester in lemon. Decane, 3-methyl-, p-menth-1,4(8)-diene, 1-undecene and α-cubebene in avocado. Thus, the VOC’s method could provide a possible tool for detecting tephritid larvae and this method could be adopted by industries importing and exporting fruit.
文摘Medium-term changes in the labile nutrient pool of microbial biomass carbon (MBC) and nitrogen (MBN) resulting from organic manure application in rice (Oryza sativa L.)-based triple cropping systems have been poorly studied. Therefore, the effects of organic materials on the soil physico-chemical properties and microbial biomass in rice fields were investigated at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, from April 2010 to December 2012. Five treatments (control, cow dung, poultry manure, rice straw, and chemical fertilizer) were laid out in a randomized complete block design with four replications. The organic residues (2 t C ha-1) were applied 7 days before transplanting and were combined with inorganic fertilizers, following integrated plant nutrition systems. This paper presents the results from the last of the five consecutive rice growing seasons. All of the organic residues increased the pH, and organic C, N, P, and K contents of the soil. However, poultry manure was more efficient in increasing soil fertility than cow dung and rice straw, resulting in a significant increase in P from 22 mg·kg-1 to 63 mg·kg-1 at crop harvest. All of the organic residues also increased the soil water holding capacity and decreased bulk density. Furthermore, poultry manure resulted in significantly higher microbial biomass C (432 mg·kg-1;P < 0.05) and N (31.60 mg·kg-1;P < 0.05) levels in the soil at crop harvest, followed by cow dung and rice straw. These findings indicate that the regular application of organic residues and manures will help to enhance soil fertility and production sustainability.
文摘In rainfed lowlands, the beneficial effects on rice (Oryza sativa) yield from fertilizing the seedling nursery may depend on the occurrence of water and nutrient stress after transplanting into the mainfield. The aim of the study was to test the effect of seedling age and nursery fertilisation on rice yield when plants experienced nutrient and water stress regimes after transplanting. The first experiment, conducted during the wet season in a low-fertility rainfed lowland field in south-east Cambodia, examined the effect of three levels of nitrogen (N), phosphorus (P) and cow manure (CM) application to the nursery and three ages of seedlings at transplanting (4, 6 and 9 weeks after sowing: WAS) on the growth of a traditional photoperiod-sensitive rice cultivar. Increasing fertilizer application to the nursery increased shoot dry weight and grain yield at each age of seedling transplanted. Shoot dry weight and grain yield from seedlings transplanted 6 WAS were 20% and 10% higher than those from the seedlings transplanted at the other ages. Seedlings transplanted at 4 WAS, which experienced a temporary submergence for 3 days after transplanting, recorded 5% greater seedling mortality from the unfertilized than fertilized nursery soil. The taller seedlings transplanted at 6 WAS experienced less mortality despite more severe submergence. The second experiment was conducted at seven rainfed lowland sites across Cambodia to test the benefit of N alone and N+P application to the nursery on rice yields in farmers’ fields. In four out of seven trials, grain yield increases averaged 13% with N+P applied to the nursery whereas N alone increased grain yield at two sites and depressed yield at two. Overall, fertilizer application in the nursery produced more vigorous seedlings with higher nutrient concentration which survived submergence and grew better with or without drought or nutrient stress after transplanting, leading to increased yields of rice. The beneficial effect of nursery fertilizer was additional to any obtained by fertilizer applied to the main field at or after transplanting.
文摘Vetiver grass (</span><i><span style="font-family:Verdana;">Vetiveria</span></i> <i><span style="font-family:Verdana;">zizanioides</span></i><span style="font-family:Verdana;"> L.) is widely used for soil and water conservation, and land management. In practice, all vetiver seedlings are propagated via ramets or tillers, which cannot meet the market demand and would also destroy the original habitat. Most</span><span style="color:red;"> </span><span style="font-family:Verdana;">vetiver genotypes flower but do not produce seeds. A wild ecotype of vetiver grass originated in southern China is fertile, but the rate of seed germination is very low. This study aimed to develop a novel method to improve its seed germination and seedling establishment. In the field, the inflorescences of wild vetiver were wrapped using a transparent plastic bag with a pot containing wet soils. The effects of inflorescence bagging and Tween 80 application on seed germination and seedling growth were examined. The results showed that seed development was characterized by low seed setting rate (19.2%), uneven maturity time, easy shedding (more than 95% of spikelets shed off 20 days after flowering), therefore difficult harvest of viable seeds. Bagging the inflorescence with moist soils in pot ensured the mature seeds falling onto the nursery soil surface and absorbing water for germination while the immature seeds continued to grow on the inflorescence. Bigging not only improved seed development and maturity, saved the procedure of seed collection and storage, but also provided a humid micro-environment for seed germination and seedling growth. Tween 80 as a surfactant promoted seed water absorption, germination and seedling growth. This simple and novel method has integrated the procedures of seed collection, storage, germination and seedling establishment, and enables </span></span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">produc</span><span style="font-family:Verdana;">tion</span><span style="font-family:""> </span><span style="font-family:Verdana;">of </span><span style="font-family:Verdana;">a large </span><span style="font-family:Verdana;">number</span><span style="font-family:Verdana;"> of healthy seedlings. The possible reasons for the degeneration and disappearance of the original population were also discussed from the perspective of the disadvantages of vetiver propagation.
文摘Natural regeneration is a critical component of forest ecosystems sustainability. Local extinction can occur without adequate regenerationor seedling recruitment prior to adult senescence. The urban and peri-urban environment is particularly challenging for recruitment. For example, although many forest species have specific requirements involving fire events, few opportunities associated with fire exist in contemporary urban and peri-urban environments. For our study species, Eucalyptus gomphocephala, en masse recruitment can occur in ashbeds following a hot fire. However, this may not occur following low-intensity, fuel reduction burns that are prescribed for many E. gomphocephala woodlands and forests. Nevertheless, ashbeds could be created by constructing and burning coarse woody debris (CWD) piles. In a series of collaborative case studies involving community groups, NGOs and Local and State Government agencies, we investigated whether seedling recruitment could be facilitated through broadcast seeding after: a) creating CWD piles prior to a low intensity, prescribed burn;b) naturally-occurring ashbeds following a hot summer wildfire;and c) creating CWD piles and then burning the piles only. We found that regeneration of this post-fire, canopy gap regenerator can be facilitated by broadcast seeding naturally occurring or created ashbeds. However, it seems that protection from seed harvesters and herbivores is vital. These case studies provide tools that can be used to preserve the natural demographics in populations with specific regeneration requirements in a range of environments by leveraging natural recruitment processes and community involvement. Importantly, it is the conservation of these urban and peri-urban ecosystems that will be vital in maintaining connection between people and the environment into the future.
文摘Missense mutations in the leucine rich repeat kinase 2 (LRRK2) gene are the leading genetic cause of autosomal dominant familial Parkinson’s disease. We previously reported that two mutations within the ROC domain, namely R1441C and A1442P, exhibit increased protein degradation leading to lowered steady state LRRK2 protein levels in HEK293 cells. More recently, the common WD40 domain LRRK2 haplotype, Met2397, which is a risk factor for Crohn’s disease, has been shown to lower steady state protein levels in HEK293 cells. In view of recent evidence implicating LRRK2 and inflamemation in PD, we investigated the effects of Met2397 on LRRK2 expression, and compared them to the Thr2397 variant and other LRRK2 mutants. In this study, we transfected HEK293 cells with plasmid constructs encoding the different LRRK2 variants, and analyzed the resulting protein levels by Western blot and flow cytometry. Here we found that both the Met2397 and Thr2397 haplotypes yield similar levels of LRRK2 protein expression and do not appear to impact cell viability in HEK293 cells, compared to other LRRK mutants. Thus, we have concluded that the Met2397 haplotype is unlikely to play a role in LRRK2 mediated or idiopathic PD.
