In this paper, the use of supercritical fluid extraction (SFE) and micellar electrokinetic capillary chromatography (MEKC) is proposed for the complete analysis of volatile nitrosamines in sausages. The extraction fluid used was CO2 and variables such as density, temperature of thimbles, extraction time, modifier, fluid flow, and kind of traps were investigated. Several experiments were carried out to obtain the most favorable conditions for analysis of volatile nitrosamines in sausages. The recoveries ranged from 21 to 82% for the five nitrosamines studied. The optimal condition of extraction was 0.2 g of sample fortified with 10 mg/kg, using dynamic extraction during 20 min and with adsorbent Florisil in the trap. The solvent selected for the elution of the analytes was methanol. 相似文献
Yield mapping technologies can help to increase the quantity and quality of agricultural production. Current systems only focus on the quantification of the harvest, but the quality has equal or greater importance in some perennial crops and impacts directly on the financial profitability. Therefore, a system was developed to quantify and relate the quality obtained in the classification line with the plants of the orchard and for decision-making. The system is comprised of hardware, which obtains the location of the harvester bag during harvesting and unloading at the unloading site, and software that processes the collected data. The cloud of real-time data contributed from the different collectors (bins) allows the construction of yield maps, considering the multi-stage harvesting system. Further, the system enables the creation of a detailed map of the plants and fruits harvested. As the harvest focuses on quality, it takes place in stages, depending on the ripening of the fruits. In addition to the yield maps, the system allows identification of the efficiency of each worker undertaking the harvest by the number of performed discharges and by the time spent. The system was developed in partnership with the Federal Technological University of Paraná and Embrapa Uva & Vinho and was tested in apple orchards in southern Brazil. Although the system was evaluated with only data from apple cultivation, monitoring the quality and quantifying other orchard fruits can positively impact the fruit sector.
This study evaluated the effects of the mode of transportation on weight and metabolism of young bulls, which are generally transported by two systems: droving and truck. This experiment consisted of two phases: transportation and refeeding and involved transportation by droving and truck. Fifty young Nellore bulls were separated in equal numbers in both groups, droving group and truck group. In the transportation phase, animals were moved, in a 640-km journey. The refeeding phase consisted of 84 days and commenced after the animals arrived at the fattening farm. The effect of the transportation system on animals’ weight, metabolic hormones, and serum biochemistry was assessed after 28, 56, and 84 days. During the transportation phase, animals in the droving group lost 10.11 kg and animals in the truck group gained 13.1 kg. The truck group showed 20.5 kg of weight gain at the end of the refeeding phase. The highest triiodothyronine (T3) and thyroxine (T4) concentrations were observed on days 0 and 60 in the transportation phase in both droving and truck groups. The serum cortisol concentration was higher in the droving group than in the truck group on day 56 of the refeeding phase. The IGF-I concentrations were higher during the refeeding phase in the droving group than in the truck group. Our results showed that transportation by droving leads to increased weight loss and reduced further weight gain compared to transportation by truck and that serum concentrations of T4, cortisol, and insulin-like growth factor (IGF-I) hormones are altered by the transportation system. 相似文献
Leptospirosis is a zoonotic disease that occurs in humans and several animal species, including cattle, pigs, and horses, and it has a worldwide distribution. In equids, leptospirosis manifests through recurrent uveitis and abortion and other reproductive disorders. The objective of the present study was to investigate the epidemiological situation of Leptospira spp. infection in equids from the Brejo Paraibano microregion in the northeast of Brazil, that is, to assess the prevalence of and identify the major risk factors for infection. For this purpose, blood samples were taken from 257 equids (204 horses, 46 mules, and 7 donkeys), and a microscopic agglutination test (MAT) was used as serological analysis, with 24 serovars of Leptospira spp. as antigens. Antibodies were observed in 16.2% of horses, 13.0% of mules, and 28.6% of donkeys. Animals between the ages of 2.5 and 11 years had a risk of infection 0.4 times lower than those younger than 2.5 years old (odds ratio, 0.4; 95% confidence interval, 0.18-0.90). Further studies are needed to identify potential wild reservoirs and the main routes of infections. 相似文献
Data from twenty‐two digestibility trials were compiled to examine the relationship between faecal N concentration and organic matter (OM) digestibility (OMD), and between faecal N excretion and OM intake (OMI) by wethers fed tropical or temperate forages alone or with supplements. Data set was grouped by diet type as follows: only tropical grass (n =204), only temperate grass (n =160), tropical grass plus supplement (n =216), temperate grass plus supplement (n =48), tropical grass plus tropical legume (n =60) and temperate grass with ruminal infusion of tannins (n =16). Positive correlation between OMD and either total faecal N concentration (Nfc, % of OM) or metabolic faecal N concentration (Nmetfc, % of OM) was significant for most diet types. Exceptions were the diet that included a tropical legume, where both relationships were negative, and the diet that included tannin extract, where the correlation between OMD and Nfc was not significant. Pearson correlation and linear regressions between OM intake (OMI, g/day) and faecal N excretion (Nf, g/day) were significant for all diet types. When OMI was estimated from the OM faecal excretion and Nfc‐based OMD values, the linear comparison between observed and estimated OMI values showed intercept different from 0 and slope different from 1. When OMI was estimated using the Nf‐based linear regressions, the linear comparison between observed and estimated OMI values showed neither intercept different from 0 nor slope different from 1. Both linear comparisons showed similar R2 values (i.e. 0.78 vs. 0.79). In conclusion, linear equations are suitable for directly estimating OM intake by wethers, fed only forage or forage plus supplements, from the amount of N excreted in faeces. The use of this approach in experiments with grazing wethers has the advantage of accounting for individual variations in diet selection and digestion processes and precludes the use of techniques to estimate forage digestibility. 相似文献
Summary Random amplified polymorphic DNA (RAPD) analysis was carried out to evaluate polymorphism and genetic similarity between 39 Mediterranean mandarin genotypes. One hundred eleven amplification products were identified using 21 random primers. An average of 2.2 RAPD markers was obtained for each primer, corresponding to 42% of the amplification products. Genotype-specific RAPD markers were also found, mainly in known hybrids. UPGMA cluster analysis revealed the low level of genetic variation between accessions of Mediterranean mandarins, whereas their hybrids with other Citrus species showed greater genetic dissimilarity. Twenty accessions yielded very similar patterns, suggesting either that they could be a single clone, or that the technique was not able to detect genomic variation. However, for the other specimens genetic polymorphism can easily be detected by RAPD, although the genetic variation between accessions was quite low. The large number of hybrids and the low polymorphism between accessions support the hypothesis that Mediterranean mandarins are all true hybrid of Common mandarins (Citrus reticulata Blanco). 相似文献
The goal of this research was to study the introgression of the high regeneration capacity of Lycopersicon pimpinellifolium Mill line WV-700, in recalcitrant tomato cultivars (L. esculentum Mill cvs. Petomech, Santa Rita and VFN-8) using backcrossing. Hypocotyl explants of in vitro germinated seeds were cultivated in half strength MS medium supplemented with 5mg/l 6-BA to assess their shoot regeneration
capacity. The apical shoot of the in vitro germinated seeds were cultured on a separate medium. Apical shoots from genotypes showing high regeneration rates were acclimated
in a glasshouse and used as pollen donors for the next backcrossing. After four backcrossings, the material showed a similar
mean fruit weight for the cultivated tomato and a high regeneration capacity similar to the wild species. It is shown that
L. pimpinellifolium can be used with success as donor parent to introgress in vitro regeneration capacity to recalcitrant tomato cultivars.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
AbstractNew studies are needed to optimize the nitrogen (N) amount that can be applied to utilize the Azospirillum brasilense benefits. In addition, information regarding the interaction between the urease inhibitor and biological nitrogen fixation (BNF) and how they affect the macronutrients accumulation are also needed. We evaluate the effect of N sources and doses associated with A. brasilense regarding the macronutrients accumulation in straw and grains and wheat grain yield in tropical conditions. A randomized block experimental design was used with four replications in a 2?×?5?×?2 factorial arrangement as follows: two N sources (urea and urea with urease enzyme inhibitor NBPT; five N doses (0, 50, 100, 150, and 200?kg ha?1) applied in topdressing; with and without A. brasilense inoculation. We found that an increase in N doses positively influenced the accumulation of macronutrients in straw and grains and the wheat grain yield. N sources have similar effects. Inoculation with A. brasilense increased accumulation of Mg and S in straw and P, Ca, and Mg in grains, regardless of the N dose. The inoculation with A. brasilense associated with 140?kg ha?1 of N increased wheat grain yield. The inoculation can contribute in a more sustainable way to wheat nutrition and optimizing N fertilization. 相似文献