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61.
The mode of acquisition of gastric Helicobacter spp. infection in dogs has not been determined. It is suspected that oral-oral and faecal-oral transmission may be involved. The present study sought to determine if Helicobacter spp. DNA is present in the oral cavity of healthy and vomiting dogs. Thirty-eight pet dogs (27 vomiting and 11 clinically healthy) were studied. The presence of Helicobacter spp. was determined by single and nested PCR evaluation of DNA extracted from saliva, dental plaque and gastric biopsy samples. Helicobacter spp. DNA was detected by nested PCR in 36 (94.7%) gastric biopsies, 17 (44.7%) dental plaque and 19 (50%) saliva samples out of the 38 dogs examined. Overall 27 (71.1%) dogs screened by nested PCR were found to harbour Helicobacter spp. DNA in the oral cavity (dental plaque and/or saliva). There was no significant difference in the prevalence of Helicobacter spp. DNA in the oral cavity of vomiting and healthy dogs, and the time from vomiting to oral sampling did not have significant impact. This study confirms the high prevalence of gastric Helicobacter spp. infection in dogs, and reveals that Helicobacter spp. DNA is detectable in the oral cavity of over 70% of dogs. These findings support the possibility of oral-oral transmission between dogs and that the canine oral cavity may act as source of non-pylori Helicobacter spp. infection for humans.  相似文献   
62.
To support a voluntary disease control program, this study aimed to develop an integrated scoring system for the risk assessment of bovine viral diarrhoea virus (BVDV) infection in dairy herds in Northern Italy. Sixty-two dairy herds were classified according to their BVDV serological status. Farmers were interviewed using a questionnaire on potential BVDV risk factors. Scores were used to define risk levels for factors related to (1) BVDV introduction (through livestock trade, attendance of animals at shows/exhibitions and grazing common pasture), (2) within-herd spread of BVDV and (3) the results of initial serological testing. The calculated odds ratios were significant for all categories, except for livestock trade. The application of the screening test, the questionnaire and the related risk assessment showed this to be a practical approach to predicting BVDV herd status.  相似文献   
63.
This study shows that a diet including insect-resistant Bt176 maize, fed to 53 ewes and their progeny for 3 years, did not have adverse effects on their health or performance and that no horizontal gene transfer to ruminal microorganisms or animal tissues was detected. No differences were observed regarding performance, reproductive traits, haematological parameters, antioxidant defences, lymphocyte proliferative capacity, phagocytosis and intracellular killing of macrophages, and ruminal microbial population characteristics between control and genetically modified (GM) maize-fed animals. Immune response to Salmonella abortus ovis vaccination was more efficient in GM maize fed sheep. No modifications of histological features of tissues were found; however, cytochemical analyses of ruminal epithelium by Ki67 staining provided evidence of proliferative activation of basal cells in all GM maize-fed ewes. Preliminary electron microscopy analyses of the liver and pancreas revealed smaller cell nuclei containing increased amounts of heterochromatin and perichromatin granules in GM maize-fed lambs. Meat protein content and water loss by cooking were slightly affected by the dietary treatment. No transgenic DNA was detected in tissues, blood, and ruminal fluid or ruminal bacteria. Longitudinal studies should be included in evaluation of food safety whenever possible and sheep may be a useful animal model for toxicological assessment.  相似文献   
64.
The objective of this study was to evaluate the effect of short or long day light regimes on the reproductive performance in the sow. The study comprised approximately 1300 sows and their 3400 breedings in three commercial sow pools, in which a batch farrowing of 40 sows was employed. Each batch remained in the farrowing unit for 8 weeks under either a short day (10 h light, 14 h dark) or a long day (14 h light, 10 h dark) light regime. After weaning and transportation to the central unit, all sows were kept under the long day regime until they were moved back to the farrowing unit. Production results for each individual sow were recorded. The effect of the two different light regimes on the farrowing rate (FR) and on the weaning‐to‐oestrous interval was evaluated using logistic and Poisson regression models, respectively. The light regime affected none of the parameters significantly. The FR in June, July and August did, however, drop below that in December, January and February (OR 0.7, p < 0.05). The FR was affected by the sow pool (p < 0.01). Parity two sows exhibited a lower FR (OR 0.5, p = 0.05) and higher incidence of delayed first oestrus (IRR 2.7, p < 0.01) than did older sows. This study indicates that despite an artificial light regime, sows may still react to changes in season. In conclusion, use of simple light regime to obtain complete control over reproductive performance appears to be difficult.  相似文献   
65.
Wine contains a number of biologically active compounds with beneficial effects on human health. The antibacterial action of commercial red and white wines against oral streptococci responsible for caries development and against S. pyogenes responsible for pharyngitis was studied. Its postcontact effect against S. mutans was also studied. Both wines displayed activity. The compounds responsible for such activities were succinic, malic, lactic, tartaric, citric, and acetic acid. The synthetic mixtures of the organic acids tested at the concentrations found in wine had greater antibacterial activity than the beverages, indicating that in wine they are inhibited by other components. Wine polyphenols displayed no activity against oral streptococci or S. pyogenes. Findings show that wine is active against oral streptococci and S. pyogenes and suggest that it enhances oral health.  相似文献   
66.
Coffee brew is a widely consumed beverage with multiple biological activities due both to naturally occurring components and to the hundreds of chemicals that are formed during the roasting process. Roasted coffee extract possesses antibacterial activity against a wide range of microorganisms, including Staphylococcus aureus and Streptococcus mutans, whereas green coffee extract exhibits no such activity. The naturally occurring coffee compounds, such as chlorogenic acids and caffeine, cannot therefore be responsible for the significant antibacterial activity exerted by coffee beverages against both bacteria. The very low minimum inhibitory concentration (MIC) found for standard glyoxal, methylglyoxal, and diacetyl compounds formed during the roasting process points to these alpha-dicarbonyl compounds as the main agents responsible for the antibacterial activity of brewed coffee against Sa. aureus and St. mutans. However, their low concentrations determined in the beverage account for only 50% of its antibacterial activity. The addition of caffeine, which has weak intrinsic antibacterial activity, to a mixture of alpha-dicarbonyl compounds at the concentrations found in coffee demonstrated that caffeine synergistically enhances the antibacterial activity of alpha-dicarbonyl compounds and that glyoxal, methylglyoxal, and diacetyl in the presence of caffeine account for the whole antibacterial activity of roasted coffee.  相似文献   
67.
Changes of terpenes in black currant juice induced by the action of heat were investigated in the present study. Limonene, alpha-terpinene, linalool, alpha-terpineol, 4-terpineol, and menthol added to either black currant juice or a model system were thermally treated at 90 degrees C for 30 min. Similar heat-induced decreases in the concentration of the terpenes were observed in the two systems. The concentration of a range of terpene hydrocarbons and oxygenated terpenes increased, alpha-terpineol being a main conversion product of most of the examined compounds. In the main, the measured loss of compounds exceeded the detected concentrations of products formed. In addition, determination of glycosidically bound terpenes in the juice was carried out by two methods of enzymatic hydrolysis, namely, addition of beta-glucosidase to an Amberlite XAD-2 isolate or directly to black currant juice. The two methods gave the same patterns of seven released volatile aglyconic terpenes. However, none of the released terpenes are important for the odor of black currant juice.  相似文献   
68.
Early forecasting of fruit orchard yield is important for market planning and for growers and exporters to plan labour, bins, storage and purchase of packing materials. Large variations in tree yield pose a challenge for accurate yield estimation. We evaluated a three-level systematic sampling procedure for unbiased estimation of fruit number for yield forecasts. In the Spring of 2009 we estimated the total number of fruit in several rows of each of 14 commercial fruit orchards growing apple (11 groves), kiwifruit (two groves), and table grapes (one grove) in central Chile. Survey times were 10–100 min for apples (depending on vigour), 85 min for the table grapes, and 85 and 150 min for the kiwifruit. During harvest in the Fall, the fruit were counted to obtain the true number. Yields ranged from lows of several thousand (grape bunches), to highs of more than 40 000 fruit (apples, kiwifruit). Absolute true errors (defined as the absolute difference between the estimate and the true value, divided by the true value) were less than 5% in six orchards, between 5 and 10% in a further five orchards and 13% in one orchard. In two apple orchards we obtained absolute true errors of about 20%. Error analysis based on systematic sub-sampling across each sampling stage was used to determine how to distribute sampling effort to achieve a total coefficient of error of 10%. We discuss the extension of the procedure for yield estimation at the full orchard scale for any target precision.  相似文献   
69.
Landscape dynamics increasingly challenge agronomists to explain how and why agricultural landscapes are designed and managed by farmers. Nevertheless, agronomy is rarely included in the wide range of disciplines involved in landscape research. In this paper, we describe how landscape agronomy can help explain the relationship between farming systems and agricultural landscape dynamics. For this, we propose a conceptual model of agricultural landscape dynamics that illustrates the specific contribution of agronomy to landscape research. This model describes the relationship between three elements: farming practices, landscape patterns and natural resources. It can stimulate agronomists to deal with research issues in agricultural landscape dynamics and enhance the interdisciplinary integration of farming systems in wider landscape research. On these premises, we discuss the main research issues that will benefit from an active involvement of agronomy, to understand, but also to assess landscape dynamics and to design relevant decision support systems.  相似文献   
70.
The in vitro permissivity to infection with homologous and heterologous bovine viral diarrhoea virus (BVDV) strains of bovine peripheral blood mononuclear cells (PBMCs) from eight na?ve and eight BVDV-1b immune animals was studied. Four reference strains (BVDV-1a NADL, BVDV-1b NY-1, BVDV-2 125 and BVDV-2 890) were selected, based on genotype, prevalence and biotype. Virus neutralizing antibody titres were determined at bleeding and the viral loads were measured in PBMCs by end point titration in cell culture and by real-time PCR. PBMCs from both na?ve and immune animals became infected by all BVDV strains tested, although virus titres were lower for immune heifers than na?ve ones; the differences were significant for NADL (P<0.05) and 890 (P<0.001) strains. The in vitro model used in this study showed that PBMCs from immune animals are susceptible to re-infection with both homologous and heterologous BVDV strains, albeit at a lower extent than na?ve cattle.  相似文献   
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