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1.
High dilution rates have been documented as detrimental for boar spermatozoa, shortening their lifespan (Centurion et al. 2003, Biol Reprod 69: 640–646). Addition of seminal plasma (SP) to semen extenders, or selenium (Se) and vitamin E (VE) in diet of boars could increase motility of highly diluted spermatozoa (HDS). The aim of this work was to evaluate the effect of seminal plasma on sperm motility of HDS from boars feed with Se and VE. Sixteen 12 month-old boars were designed to one of four dietary treatments: (i) control, Se 0 ppm–VE 0 IU/kg; (ii) Se 0–VE 250; (iii) Se 0.5–VE 250 and (iv) Se 0.5–VE 0. Boars were treated for 8 weeks before semen collection. Sperm rich fractions from each boar were diluted to 5 × 106 sperm/ml in PBS medium and incubated at 37°C with or without 10% SP. The measurements were done at 0, 2 or 5 h. Data were analyzed as a mixed model for a factorial design [2 (Se) × 2 (VE) × 2 (SP) × 3 (h)]. Percentage of sperm motility (PSM) increases significantly (p < 0.001) with addition of Se (81.3 ± 1.52), VE (81.0 ± 1.62) and SP (81.5 ± 1.57) vs control (73.4 ± 1.61). There was significant interaction Se × VE (p < 0.001) and Se × VE × SP (p < 0.05) in PSM. However, PSM was affected significantly by time (0 h 83.4 ± 1.92; 2 h 80.7 ± 1.92 and 5 h 67.9 ± 1.92; p < 0.001). There was significant interaction SP × Time (p < 0.05) in PSM. These results indicate that Se, VE and SP improve seminal viability. Addition of 10% of SP maintains PSM at least during 5 hours.  相似文献   
2.
We attempted to determine whether weaning is required for induction of diarrhea in pigs with postweaning enterotoxigenic Escherichia coli infection. Three-week-old newly weaned pigs and their suckling littermates were inoculated with the K88+ enterotoxigenic E coli strain M1823B. Fourteen of 21 weaned and 12 of 20 suckling pigs were genetically resistant to intestinal adhesion by the K88+ strain of E coli; they remained healthy, and gained weight at similar rates. Both groups of K88-resistant pigs gained weight faster, and shed fewer bacteria of strain M1823B in their feces, than did their K88-susceptible counterparts. Diarrhea developed in K88-susceptible pigs in the weaned (6 of 7 pigs) and suckling (4 of 8 pigs) groups, and 1 of the 4 affected suckling pigs died from complications resulting from diarrhea. The incidences of diarrhea, weight gain rates, and the numbers of strain M1823B shed in feces of susceptible weaned and suckling pigs were not significantly (P greater than 0.05) different. Diarrhea scores of susceptible weaned pigs were significantly (P less than 0.02) higher than those of susceptible suckling pigs on the second day after inoculation. In this experimental model, it was concluded that weaning is not required for induction of diarrhea, but may modestly increase its severity.  相似文献   
3.
Bacterial apical necrosis (BAN), caused by the bacterium Pseudomonas syringae pv. syringae (Pss), is currently the most limiting disease affecting the mango crop in the Mediterranean area. The copper‐based compound Bordeaux mixture (BM) is considered to be the conventional treatment against BAN, but it does not act as a bactericide. Alternative experimental treatments to BM that are compatible with organic farming were tested for their ability to control BAN disease. Field trials were conducted over six seasons in different mango orchards with natural infestation of Pss. The experimental treatments included applications of Silicon gel (a commercial formulation of aqueous potassium silicate), dicalcium phosphate, Kaolinite, and Ulmasud B® (bentonite, powder); BM was applied as the conventional treatment. During the first two seasons (small‐scale trial, 2002–2004), all these experimental compounds were applied in order to select those treatments providing the greatest reduction of BAN symptoms. In the next three seasons (2005–2008), a semi‐commercial scale trial was carried out with the best‐performing treatments, resulting in the selection of Silicon gel. Finally, Silicon gel was tested in a commercial scale trial during the last season (2008–2009). Trees treated with Silicon gel showed significantly fewer necrotic buds and leaves, reaching disease levels very similar to those using the conventional treatment with BM. However, minor differences in P. syringae‐like population levels were observed, as has been described in previous studies. The possible mode of action of the Silicon gel is discussed. Currently, the Silicon gel compound is undergoing the registration process for its commercial use in mango management in Spain.  相似文献   
4.
N-rich (C:N=27) and N-poor (C:N=130) wheat straw, labelled with 14C and 15N, was incubated for 2 yr in two major ecosystems of the upper elevation belt of cultivation in the high Andes: the moist Paramo (precipitation=1329 mm, altitude=3400 m asl, Andes of Merida, Venezuela) and the dry Puna (precipitation=370 mm, altitude=3800 m asl, Central Altiplano, Bolivia). The experiment was installed in young (2 yr) and old (7 yr) fallow plots. The following soil analyses were performed at nine sampling occasions: soil moisture, total-14C and -15N, and Microbial Biomass (MB)-14C and -15N. The measured data were fitted by the MOMOS-6 model (a process based model, with five compartments: labile and stable plant material, MB, and labile (HL) and stable humus (HS)) coupled with the SAHEL model (soil moisture prediction) using daily measured and/or predicted meteorological data. The aim was to understand how (1) the climatic conditions, (2) the quality of plant material, (3) the fallow age and (4) the soil properties affect the cycling of C and N within the soil organic matter system.The fallow age (2 and 7 yr) did not affect the measured data or the model predictions, indicating that in these systems the decomposition potential is not affected by fallow length. During the short initial active decomposition phase, the labile plant material was quickly exhausted, enabling a build up of MB and of HL. During the low activity phase, that covered 4/5 of the time of exposure, the MB size decreased slowly and the HL pool was progressively exhausted as it was reused by the MB as substrate. The HL compartment was directly or indirectly the major source for the inorganic 15N production. If the C:N ratio of the added plant material increased, the model predicted (1) a reduction of the decomposition rates of the plant material (essentially the stable plant material) and (2) an increased mortality of the MB which increased the production of HL (microbial cadavers and metabolites). Thus the essential effect of the slower decomposition due to the N-poor plant material was a higher accumulation of C and N in the HL and its slower recycling by the MB during the low activity phase. The labelling experiment allows to understand the higher soil native organic matter content in Paramo soils compared to Puna. The large sequestration of organic matter generally observed in the Paramo soils can be explained by two abiotic factors: the unfavourable soil microstructure and the accumulation of free aluminium linked to the climatic and acid soil conditions, inhibiting the microbial activity physically and chemically.  相似文献   
5.
ObjectiveTo determine the anaesthetic and cardiorespiratory effects of a constant rate infusion of fentanyl in sheep anaesthetized with isoflurane and undergoing orthopaedic surgery.Study designProspective, randomised, ‘blinded’ controlled study.AnimalsTwenty healthy sheep (weight mean 41.1 ± SD 4.5 kg).MethodsSheep were sedated with intravenous (IV) dexmedetomidine (4 μg kg−1) and morphine (0.2 mg kg−1). Anaesthesia was induced with propofol (1 mg kg−1 minute−1 to effect IV) and maintained with isoflurane in oxygen and a continuous rate infusion (CRI) of fentanyl 10 μg kg−1 hour−1 (group F) or saline (group P) for 100 minutes. The anaesthetic induction dose of propofol, isoflurane expiratory fraction (Fe’iso) required for maintenance and cardiorespiratory measurements were recorded and blood gases analyzed at predetermined intervals. The quality of recovery was assessed. Results were compared between groups using t-tests or Mann–Whitney as relevant.ResultsThe propofol induction dose was 4.7 ± 2.4 mg kg−1. Fe’iso was significantly lower (by 22.6%) in group F sheep than group P (p = 0). Cardiac index (mean ± SD mL kg−1 minute−1) was significantly (p = 0.012) lower in group F (90 ± 15) than group P (102 ± 35). Other measured cardiorespiratory parameters did not differ statistically significantly between groups. Recovery times and recovery quality were statistically similar in both groups.Conclusions and clinical relevanceFentanyl reduced isoflurane requirements without clinically affecting the cardiorespiratory stability or post-operative recovery in anaesthetized sheep undergoing orthopaedic surgery.  相似文献   
6.
The mechanisms linking soil respiration to climate and soil physical properties are important for modelling transformation and sequestration of C and N in the soil. We investigated them by incubating 14C and 15N labelled straw in soils of the dry puna (Bolivian altiplano, semi‐arid shrubland at 3789 m above sea level) and the humid paramo (Venezuelan tropical alpine vegetation at 3400 m). These two ecosystems of the high Andes are comparable in terms of altitude, mean temperature and land use, but are very different regarding organic matter content, rainfall patterns and soil physical properties. Total 14C and 15N, microbial‐biomass 14C and 15N, soil moisture and meteorological data were recorded over 2 years. Daily soil moisture was predicted from a water balance model. The data from the paramo site were used to calibrate MOMOS‐6, a model of organic matter decomposition based on microbial activity and requiring only kinetic constant parameters to describe: (i) inputs to microbial biomass from plant debris and microbial metabolites, and (ii) losses from the biomass by mortality and respiration (respiration coefficient and microbial metabolic quotient qCO2). The simulated qCO214C agrees well with qCO214C and qCO2 measured at the calibration site and with published data. To apply MOMOS‐6 to the puna site, only the respiration coefficient of the biomass was re‐estimated. The dynamics of 14C and 15N were very different in the two systems. In the puna, the transformation processes stop during the long dry periods, though total annual mineralization is greater than in the paramo. The change in the value of the respiration coefficient enables us to predict that the amount of C and N sequestered in the stable humus is greater in the paramo than in the puna. The data in this paper can be used to estimate values of the respiration coefficient so that MOMOS‐6 can be applied to other systems.  相似文献   
7.
Near infrared reflectance spectroscopy (NIRS) was used to predict the water-soluble and total extractable polyphenolics of plant material. Different life forms (forbs, grasses, shrubs, giant rosettes), organs (leaves, stems, roots) and decomposition stages (biomass, necromass and decomposing plant material) were studied. Prediction was good, with a R2 in validation ranging from 0.91 to 0.93 and in prediction from 0.88 to 0.94. Various standard error ratios were used to assess the quality of the models, which are generally very good, being the model for predicting the water-soluble polyphenolics in the decomposing plant material the slightly less good. Because it is a cheap and rapid method, it would allow to perform a large screening for studies concerning (i) polyphenolics control on decomposition process and (ii) phenolics implication in herbivory.  相似文献   
8.
The effect of titanium applied as titanium ascorbate (Titavit®) on the lipoxygenase (LOX) pathway of tomato and red pepper seedlings was studied. Seeds were germinated in solutions containing titanium at 5 and 10 ppm. The uptake of titanium was significant and occurred at a similar amount for both tomato and red pepper. LOX and hydroperoxide decomposing (HPD) activities were determined in the crude extracts. The results showed that LOX activity in the extract of Titavit‐germinated seedlings was significantly higher than that of the control, whereas no effect was observed on the activity of HPD enzymes. It is suggested that activation of LOX by Titavit was due to a chemical interaction of titanium within the reaction mixture than to an induction of the biosyntheis of the enzyme.  相似文献   
9.
Western flower thrips (WFT) is one of the most economically important pest insects of many crops worldwide. Recent EU legislation has caused a dramatic shift in pest management strategies, pushing for tactics that are less reliable on chemicals. The development of alternative strategies is therefore an issue of increasing urgency. This paper reviews the main control tactics in integrated pest management (IPM) of WFT, with the focus on biological control and host plant resistance as areas of major progress. Knowledge gaps are identified and innovative approaches emphasised, highlighting the advances in ‘omics’ technologies. Successful programmes are most likely generated when preventive and therapeutic strategies with mutually beneficial, cost‐effective and environmentally sound foundations are incorporated. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   
10.
As ecologically and socially oriented food initiatives proliferate, the significance of these initiatives with respect to conventional food systems remains unclear. This paper addresses the transformative potential of alternative food networks (AFNs) by drawing on insights from recent research on food and embodiment, diverse food economies, and more-than-human food geographies. I identify several synergies between these literatures, including an emphasis on the pedagogic capacities of AFNs; the role of the researcher; and the analytical and political value of using assemblage and actor-network thinking to understand the far-reaching forces and power disparities confronting proponents of more ethical and sustainable food futures.  相似文献   
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