Plant water stress and K starvation reduce absorption of foliar applied K by olive leaves     

Hermann Restrepo-Diaz  Manuel Benlloch  Ricardo Fernndez-Escobar 《Scientia Horticulturae》2008,116(4):409-413

Three-month-old mist-rooted ‘Picual’ olive cuttings were transplanted into 2-l plastics pots containing perlite as substrate and fertigated with a complete nutrient solution containing 0.05, 0.1 or 2.5 mM KCl depending on the experiment. In the first experiment, plants were sprayed with RbCl (Rb⁺ is a K⁺ analog) at a rate of 4% at 63 days after transplanting (DAT). Foliar Rb⁺ uptake through leaves increased with K⁺ concentration in the nutrient solution, indicating that foliar Rb⁺ uptake was lower when plants were K⁺ deficient than when they were adequate. On the contrary, it was observed that translocation of Rb⁺ from leaves to other organs of the plant was higher under K⁺ deficiency conditions. In the second and third experiments, when differences appeared on shoot length due to K⁺ nutritional status (0.05 or 2.5 mM KCl) at 63 DAT, a group of plants were subjected to water stress during 7 weeks. On the other hand, another group of plants (control plants) did not receive any water stress treatment during the experiments. After this period of 7 weeks, all plants were sprayed with RbCl at 4%. Leaf K⁺ concentration diminished in water-stressed plants independently of plants nutritional status. Foliar Rb⁺ uptake through leaves was restricted by water stress either in plants with low K⁺ (0.05 mM KCl) or plants with high K⁺ (2.5 mM KCl). Translocation of Rb⁺ from leaves was greater under water stress conditions in both K⁺ nutritional statuses. In conclusion, the results obtained could explain the irregular response in olive trees to foliar K⁺ sprays, particularly, when they grow in rainfed orchards.  相似文献   

Effectiveness of whey against zucchini squash and cucumber powdery mildew     

Wagner Bettiol  Harllen S.A. Silva  Ronielli C. Reis 《Scientia Horticulturae》2008

The effectiveness of whey against powdery mildew (Podosphaera xanthii) of cucumber and zucchini squash was tested in greenhouse experiments. Plants were sprayed once or twice a week with whey at concentrations of 0, 5, 10, 15, 20, 25, and 30% in water. Severity of powdery mildew was estimated weekly by visual assessment of individual leaves and scored as percentage of leaf area affected. Effectiveness of treatments did not differ significantly when applied weekly compared to twice a week. In each instance, powdery mildew severity correlated negatively with whey concentration. For cucumber, the rate of the disease progress in the control ranged from 0.45 to 0.75. Disease progressed more slowly in plants treated with 25–30% whey than when lower concentrations were used. The rate of disease progress varied from 0.12 to 0.33 in plants treated once a week and from 0.13 to 0.17 when applied twice a week. Similar tendencies were observed for zucchini, but disease progressed more rapidly and the final disease severity was higher than in cucumber. Effectiveness of whey applied twice a week at concentrations of 15–30% did not differ significantly among treatments; in these treatments the rate of disease progress was about 0.23 and significantly higher than the value for the water controls (about 0.80). Plants treated with 30% whey often exhibited symptoms of phytotoxicity. The data indicated that whey effectively controlled powdery mildew in cucumber and zucchini. Further studies are needed to optimize the concentration and timing of whey applications for mildew management in commercial crops.  相似文献   

Serological surveillance and factors associated with influenza A virus in backyard pigs in Southern Brazil     

Carine K. Souza  Daiane P. Oldiges  Ana Paula S. Poeta  Itabajara da S. Vaz  Rejane Schaefer  Danielle Gava  Janice R. Ciacci‐Zanella  Cludio W. Canal  Luís G. Corbellini 《Zoonoses and public health》2019,66(1):125-132

Backyard pig populations are not monitored for influenza A virus (IAV) in Brazil and there are limited data about seroprevalence and risk factors in these populations. Our goal was to assess possible factors associated with IAV seroprevalence in backyard pig populations using an indirect ELISA protocol based on a recombinant nucleoprotein. Following the IAV screening using NP‐ELISA, subtype‐specific serology based on hemagglutination inhibition (HI) assay of the ELISA‐positive pigs was conducted. The survey comprised a total of 1,667 sera samples collected in 2012 and 2014 in 479 holdings and the estimated seroprevalence was 5.3% (3.84%–7.33%) and 2.3% (1.34%–3.71%) in the respective years. In both years, H1N1pdm09 was the most prevalent subtype. The multivariable analysis showed main factors such as “age,” “sex,” “number of suckling pigs” and “neighbours raising pigs” that presented the greatest effect on IAV seroprevalence in these pig populations. These factors may be associated with the low biosecurity measures and management of backyard holdings. In addition, the low IAV seroprevalences found in these backyard pig populations could be related to a low number of animals in each pig holding and low animal movement/replacement that do not favour IAV transmission dynamics. This low frequency of H1N1pdm09 seropositive pigs could also be due to sporadic human‐to‐pig transmission of what is now a human seasonal influenza A virus; however, these factors should be explored in future studies. Herein, these results highlight the importance of IAV continued surveillance in backyard pig holdings, since it is poorly known which IAVs are circulating in these populations and the risk they could pose to public health and virus transmission to commercial farms.  相似文献   

Spatial epidemiological approaches to inform leptospirosis surveillance and control: A systematic review and critical appraisal of methods     

Pandji W. Dhewantara  Colleen L. Lau  Kathryn J. Allan  Wenbiao Hu  Wenyi Zhang  Abdullah A. Mamun  Ricardo J. Soares Magalhes 《Zoonoses and public health》2019,66(2):185-206

Leptospirosis is a global zoonotic disease that the transmission is driven by complex geographical and temporal variation in demographics, animal hosts and socioecological factors. This results in complex challenges for the identification of high‐risk areas. Spatial and temporal epidemiological tools could be used to support leptospirosis control programs, but the adequacy of its application has not been evaluated. We searched literature in six databases including PubMed, Web of Science, EMBASE, Scopus, SciELO and Zoological Record to systematically review and critically assess the use of spatial and temporal analytical tools for leptospirosis and to provide general framework for its application in future studies. We reviewed 115 articles published between 1930 and October 2018 from 41 different countries. Of these, 65 (56.52%) articles were on human leptospirosis, 39 (33.91%) on animal leptospirosis and 11 (9.5%) used data from both human and animal leptospirosis. Spatial analytical (n = 106) tools were used to describe the distribution of incidence/prevalence at various geographical scales (96.5%) and to explored spatial patterns to detect clustering and hot spots (33%). A total of 51 studies modelled the relationships of various variables on the risk of human (n = 31), animal (n = 17) and both human and animal infection (n = 3). Among those modelling studies, few studies had generated spatially structured models and predictive maps of human (n = 2/31) and animal leptospirosis (n = 1/17). In addition, nine studies applied time‐series analytical tools to predict leptospirosis incidence. Spatial and temporal analytical tools have been greatly utilized to improve our understanding on leptospirosis epidemiology. Yet the quality of the epidemiological data, the selection of covariates and spatial analytical techniques should be carefully considered in future studies to improve usefulness of evidence as tools to support leptospirosis control. A general framework for the application of spatial analytical tools for leptospirosis was proposed.  相似文献   

Detection of HEV in naturally infected swine from central Argentina by an optimized HEV/MS2 duplex RT‐qPCR     

Federico Marziali  Julian Acosta  Elisa Bolatti  Santiago Mirazo  Patricia Skejich  Patricia Silva  Julie Brassard  Alejandro Costaguta  Daniela Gardiol  Ana Laura Cavatorta 《Zoonoses and public health》2019,66(7):729-738

Hepatitis E virus (HEV) is currently considered as a global health concern due to the recognition of its zoonotic transmission to humans, mainly from swine, and its association with the development of severe cases of hepatitis in human risk populations. The lack of updated data on HEV state of infection in swineherds of Argentina, and the necessity of robust technologies for its detection in complex biological samples, positions HEV as an emerging issue in public health. Here, we have optimized a RT‐qPCR with internal control for a more precise and accurate HEV RNA detection in swine stool samples. We implemented this optimized molecular tool to analyse the current epidemiological scenario of HEV infection in swine from the core region of commercial activity of Argentina. A total of 135 stool samples were collected from 16 different farms and tested for HEV presence, resulting in 11 positive cases (8.1%). Phylogenetic analysis demonstrated that all of them correspond to HEV genotype 3 and that different subtypes circulate in the region. Moreover, two of the detected strains presented a high nucleotide similarity with a previously identified isolate from human sewage discharges, suggesting the zoonotic transmission of HEV to humans. Collectively, this work provides a better understanding of HEV epidemiology in Argentina while contributes to the improvement of HEV detection technologies.  相似文献   

Prevalence of lameness and hoof lesions in all year-round grazing cattle in Brazil     

Tiago Facury Moreira  Rafael Romero Nicolino  Leandro Silva de Andrade  Elias Jorge Facury Filho  Antônio Ultimo de Carvalho 《Tropical animal health and production》2018,50(8):1829-1834

Lameness is a growing concern to the dairy industry worldwide. However, little is known about lameness and its causes in grazing cattle, especially in tropical climates. This study aimed to assess the prevalence of hoof lesions and lameness in dairy herds of all year-round grazing cattle under tropical condition, and to identify the main lesions associated with lameness. We visited 48 farms located in the Minas Gerais state, Brazil, equally divided into four groups based on daily milk production. All lactating cows in the visited farms were locomotion scored, and a representative sample was randomly chosen for hoof inspection. Among the 2267 lactating cows evaluated, 16% were scored as lame and 7% as severely lame. Nearly all cows presented at least one type of hoof lesion, of which heel horn erosion (90%), white line fissure (50%), and digital dermatitis (33%) were the most prevalent. Heel horn erosion was present in all farms and digital dermatitis was present in 96% of the farms. Sole ulcer was observed in a single animal. Additionally, digital dermatitis and white line fissure were correlated to a 2.5 times increase in the odds of a poor mobility score. Collectively, our results demonstrate that digital dermatitis and white line fissure are the main concern and the biggest cause of lameness in grazing cattle under tropical conditions.  相似文献   

Environmental factors that influence milk production of Pantaneiro ewes and the weight gain of their lambs during the pre-weaning period     

M. L. Longo  F. M. Vargas Junior  K. Cansian  M. R. Souza  P. C. Burim  A. L. A. Silva  C. M. Costa  L. O. Seno 《Tropical animal health and production》2018,50(7):1493-1497

The main objective of this research was to conduct an exploratory study of the lactation curve in order to characterize the productive potential of Pantaneiro ewes and lambs. Fifty ewes were bred using four rams in two different mating seasons. The ewes were kept with their lambs on pasture of Brachiaria brizantha. Ewe body score, ewe weight, and lamb weight were evaluated. Milk sampling was performed every week. In the morning for milk collections, the ewes were treated with 1 UI of oxytocin (intramuscular) for complete milking. Lambs were separated from the ewes for 4 h and milk collections were performed. The total milk production over 24 h was estimated by multiplying the production of this period (4 h) by 6. The data were analyzed using the MIXED procedure (P?<?0.05) in SAS. Milk production data were fitted to the curve using the incomplete gamma function of Wood, and lamb growth data were fitted using the Gompertiz equation. The average milk production of the ewes was 1.03 kg/day^?1. Younger ewes had the lowest milk production (18?=?798?±?330, 24?=?1001?±?440, 36?=?1100?±?490, and 48?=?1106?±?490 g/day^?1). Ewe body score at lambing affected initial milk production (1.0?=?816?±?660, 1.5?=?1089?±?105, and 2.0?=?1424?±?1600 g/day^?1). Lambs were weaned with an average weight of 20.3 kg. Daily weight gain from birth to weaning was 181 g. Locally adapted Pantaneiro ewes showed a linear decreasing lactation curve, with reduced production from the second week of lactation. Overall, evaluation of the dairy production and lamb performance revealed great variation, denoting potential for selection.  相似文献   

Low occurrence of pathogenic Yersinia enterocolitica in pig tonsils at slaughter in Southern Brazil     

Wildemann  Paula  Gava  Danielle  Sfaciotte  Ricardo Antônio Pilegi  Melo  Fernanda Danielle  Ferraz  Sandra Maria  da Costa  Ubirajara Maciel  Vaz  Eliana Knackfuss 《Tropical animal health and production》2018,50(3):671-675

Tropical Animal Health and Production - Yersinia enterocolitica is a foodborne pathogen and pigs are the main reservoir of it in their tonsils. As Brazil is a large producer and exporter of pork...  相似文献   

Morphological description of male genital organs of Marca's marmoset (Mico marcai)          下载免费PDF全文

Gustavo Henrique Lima de Siqueira  Felipe Ennes Silva  Marcelo Ismar Silva Santana 《Anatomia, histologia, embryologia》2018,47(4):372-384

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Non-phytate phosphorus requirement for broilers from 8 to 21 days of age under heat stress conditions     

Evandro Ferreira Cardoso  Juarez Lopes Donzele  Rita Flávia Miranda de Oliveira Donzele  Bruna Leite Sufiate  Amanda Dione Silva  Tarciso Tizziani 《Tropical animal health and production》2018,50(2):317-325

Two trials were conducted to determine the non-phytate phosphorus (nPP) requirement for broiler under heat stress. In both trials, birds were distributed in a completely randomized 4 × 2 factorial design with four nPP concentrations: 0.25, 0.35, 0.45, and 0.55%, and two Ca supply techniques: Ca fixed at 0.899% (CaF) or varying along with nPP aiming a 2:1 Ca to nPP ratio (CaV). Both trials had eight pens/treatment, with nine and five birds/pen for exp. 1 and exp. 2, respectively. nPP concentration had no effect on feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), nor fat deposition ratio (FDR). nPP levels showed a linear effect on protein deposition ratio (PDR) only for CaF diets. The nPP levels had a significant effect, regardless the technique adopted, on tibia phosphorus (TibP), which varied quadratically, on tibia calcium (TibCa) that increased quadratically and linearly, respectively, on CaF and CaV diets, and on tibia ash (TibAsh) that showed a quadratic effect for both. No effect was observed on Ca to P ratio in the tibia (TibCa:TibP). The nPP levels showed a linear increase effect over phosphorus intake (PI), phosphorus excreted (PE), and phosphorus retained (PR), and a linear decrease effect on phosphorus retention coefficient (PRC). Therefore, the nPP requirement for broilers from 8 to 21 days of age that provided better performance and bone variables were 0.250 and 0.484%, respectively, for CaF diets and 0.250 and 0.511%, respectively, for CaV diets.  相似文献