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111.
High in vitro oxygen (O2) tensions are associated with enhanced levels of reactive oxygen species and cumulus oocyte complex (COC) apoptosis. The objective of this study was to determine the influence of O2 tension on cumulus cell (CC) viability from canine oocytes. Cumulus oocyte complexes were distributed into three groups (CG, T20 and T5) and two O2 tension levels (20% and 5%). The control group (CG) was matured in vitro in a humidified atmosphere with 5% CO2 in air in TCM199 with 26.19 m m sodium bicarbonate, 10% (v/v) foetal calf serum (FCS), 0.10 m m gentamicin, 0.20 m m pyruvic acid, 20 μg/ml oestradiol, 0.5 μg/ml follicle-stimulating hormone, 0.03 IU/ml human chorionic gonadotropin, and 1.0 μg/ml human somatotropin. Groups T20 and T5 were matured under 20% or 5% O2 tensions respectively in a high-glucose medium, without FCS. T20 and T5 were as CG, and supplemented with 0.1% Polyvinyl Alcohol, and 5.5 m m glucose. After 48 h of IVM, CCs from COCs were stained with propidium iodide (1.50 m m ). The results showed that viability of CCs (cytoplasmic features and nuclear morphological integrity) was different for the three groups. Rates of apoptosis were at 57.9% (521/900) for CG, 54.4% (490/900) for T20 and 38.9% (350/900) for T5 (p < 0.001). Predominant features in apoptotic cells (n = 1361) were DNA nuclear fragments (94.0%). It was concluded that CCs of canine COCs cultured in high-glucose medium showed significantly less apoptosis than those cultured in medium with FCS. Low O2 tension was efficient in reducing apoptosis in canine CCs.  相似文献   
112.
The aim of this study was to evaluate the efficacy of Cervidil®, a prostaglandin E2 (PgE2)-releasing vaginal insert used for induction of cervical ripening and labour in women, to enhance the ease of transcervical artificial insemination (TCAI) in anestrous ewes (June). It was hypothesized that the use of Cervidil® prior to AI would cause dilation of the cervix, and thus alleviate the difficulty associated with traversing the cervix for semen deposition in sheep. Cervidil® was inserted 12 h before insemination in six Rideau-Arcott ewes; six ewes served as untreated controls.Semen was deposited into the uterus of all six treated ewes but TCAI was possible only in four of the six control ewes. It can be concluded that Cervidil® facilitated transcervical semen deposition in anestrous ewes. The treatment with Cervidil® has the promise of a technique to improve transcervical AI and to enable non-invasive embryo transfer procedures in sheep.  相似文献   
113.
The global dairy industry, the predominant pathogens causing mastitis, our understanding of mastitis pathogens and the host response to intramammary infection are changing rapidly. This paper aims to discuss changes in each of these aspects. Globalisation, energy demands, human population growth and climate change all affect the dairy industry. In many western countries, control programs for contagious mastitis have been in place for decades, resulting in a decrease in occurrence of Streptococcus agalactiae and Staphylococcus aureus mastitis and an increase in the relative impact of Streptococcus uberis and Escherichia coli mastitis. In some countries, Klebsiella spp. or Streptococcus dysgalactiae are appearing as important causes of mastitis. Differences between countries in legislation, veterinary and laboratory services and farmers' management practices affect the distribution and impact of mastitis pathogens. For pathogens that have traditionally been categorised as contagious, strain adaptation to human and bovine hosts has been recognised. For pathogens that are often categorised as environmental, strains causing transient and chronic infections are distinguished. The genetic basis underlying host adaptation and mechanisms of infection is being unravelled. Genomic information on pathogens and their hosts and improved knowledge of the host's innate and acquired immune responses to intramammary infections provide opportunities to expand our understanding of bovine mastitis. These developments will undoubtedly contribute to novel approaches to mastitis diagnostics and control.  相似文献   
114.
Arrowsmith is a unique computer-assisted strategy designed to assist investigators in detecting biologically-relevant connections between two disparate sets of articles in Medline. This paper describes how an inter-institutional consortium of neuroscientists used the UIC Arrowsmith web interface http://arrowsmith.psych.uic.edu in their daily work and guided the development, refinement and expansion of the system into a suite of tools intended for use by the wider scientific community.  相似文献   
115.
The practice of harvesting forest residues is rapidly increasing due to rising demand for renewable energy. However, major concerns have been raised about the sustainability of this practice and its net impact on productivity, in particular through negative effects on the growth of subsequent tree crops. We measured height, diameter at breast height (DBH) and tree spacing density on 23-year-old second rotation stands of Sitka spruce (Picea sitchensis), following whole tree harvesting (WTH—of all above ground biomass, by cable crane) or conventional stem-only harvesting (CH) of the first rotation crop. Overall, WTH reduced tree DBH by 10.3% (p = 0.017), with weaker evidence that it may have reduced height (by 8.2%, p = 0.164) and stand basal area (by 15.3%, p = 0.101). However, treatment effects differed greatly between individual blocks and, analysed separately by block, significant differences (WTH plot trees smaller than CH plot trees) were most notable in the two more exposed south-facing blocks (where, in both cases, p < 0.01 for height and p < 0.05 for basal area). Variation in productivity between the experimental plots cannot simply be attributed to preharvesting site environment – no correlation was found between first rotation and second rotation productivity – nor was treatment effect explained by differences in tree spacing density. Treatment effects can be attributed to the removal of three to four times larger quantities of N, P and K in the tree biomass by WTH than by CH of the first rotation crop, combined with greater competition with tree natural regeneration and other vegetation in WTH plots during the early stages of the second rotation. Soil moisture was higher in WTH plots but there was no evidence that WTH increased soil acidity or aluminium mobility nor that it decreased soil organic matter. The results also highlight the complexities of predicting the effect of harvesting treatment on future productivity, even within single-age, single-species forests. The study demonstrates the risk that WTH can reduce second rotation productivity of conifer forests in acidic upland sites, and that this practice will only be sustainable with appropriate interventions to overcome shortage of nutrients and high levels of vegetation competition.  相似文献   
116.
117.
Wheat streak mosaic virus, vectored by the wheat curl mite Aceria tosichella Keifer, is a major limiting factor in wheat production in the Texas Panhandle. It is the most frequently encountered virus in the region, affecting both shoot and root biomass, and consequently it can drastically reduce both forage and grain yield, and water-use efficiency of the plant. In light of the continuing decline of water levels in the Ogallala Aquifer, its effect on water-use efficiency has significant implications for irrigated fields, especially with regard to energy costs for pumping water. This article estimates the potential economic losses from the virus infection. To achieve this objective, partial budgeting techniques, based primarily on data from field experiments, were used. Results indicate that Wheat streak mosaic virus causes grain and forage yield losses that significantly affect profits from wheat production. In addition, irrigated wheat producers are more negatively affected by the disease due to the economic losses from reduced water-use efficiency of infected plants. The economic insights from this article provide important implications for wheat management and research priority-setting.  相似文献   
118.
Oxidative stress represents a challenge during sperm manipulation. We have tested the effect of increasing hydrogen peroxide (H2O2) levels on red deer spermatozoa after cryopreservation, and the role of male‐to‐male variation in that response. In a first experiment, eight thawed samples were submitted to 0, 25, 50, 100 and 200 μm H2O2 for 2 h at 37°C. Intracellular reactive oxygen species (H2DCFDA‐CM) increased with H2O2 concentration, but we only detected a decrease in sperm function (motility by CASA and chromatin damage by sperm chromatin structure assay) with 200 μm . Lipoperoxidation assessed by the thiobarbituric acid reactive substance (TBARS) method increased slightly with 50 μm H2O2 and above. In a second experiment, samples from seven males were submitted to 0 and 200 μm H2O2 for 2 h, triplicating the experiment within each male. Males differed at thawing and regarding their response to incubation and H2O2 presence. We found that the kinematic parameters reflected male‐to‐male variability, whereas the response of the different males was similar for lipid peroxidation and viability. A multiparametric analysis showed that males grouped differently if samples were assessed after thawing, after incubation without H2O2 or after incubation with H2O2. Red deer spermatozoa are relatively resilient to H2O2 after thawing, but it seems to be a great male‐to‐male variability regarding the response to oxidative stress. The acknowledgement of this individual variability might improve the development of optimized sperm work protocols.  相似文献   
119.
Our objective was to compare the effects of feeding steam-flaked, high-oil corn with normal steam-flaked corn to which yellow grease was added to equalize dietary fat on performance and carcass characteristics of finishing beef steers, and palatability, retail case life, and fatty acid composition of strip loins. Angus steers (n = 120; initial BW = 288 kg) were allotted to dietary treatments consisting of 1) normal mill-run, steam-flaked corn plus added fat (NMR) or 2) high-oil, steam-flaked corn (HOC) and assigned randomly to pens (12 pens/treatment with 5 steers/pen). Performance (ADG, DMI, and G:F) was measured over time, and cattle were shipped to a commercial abattoir for collection of carcass data after 165 d on feed. Carcass data were collected at 48 h postmortem on all carcasses, and 2 carcasses from each pen were selected randomly for collection of strip loins (IMPS #180A). At 14 d postmortem, 4 steaks (2.54 cm thick) were removed for retail display, trained sensory panel analysis, Warner-Bratzler shear force determination, and fatty acid analysis. Daily BW gain was greater (P = 0.03) and G:F was increased 8.4% (P = 0.01) for steers fed NMR compared with HOC, but DMI was not affected (P > 0.10) by treatment. No treatment differences were observed (P > 0.10) for HCW, 12th-rib fat, KPH, and yield grade. Marbling scores were greater (P = 0.01) for NMR than for HOC, and LM area tended (P = 0.07) to be greater in NMR than in HOC carcasses. The proportion of carcasses grading USDA Choice did not differ (P = 0.77) between treatments, but a greater (P = 0.04) proportion of carcasses graded in the upper two-thirds of Choice for NMR vs. HOC. Trained sensory panel traits and Warner-Bratzler shear force values did not differ between treatments (P > 0.10), and no differences (P > 0.10) were detected for purge loss or fatty acid composition. Overall, ADG and G:F were less and marbling score was decreased, but there were no differences between treatments in beef palatability, retail case life, or concentrations of fatty acids in strip loins.  相似文献   
120.
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