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41.
Large tracts of land in South American native forests have been converted to monoculture for livestock production which could negatively affect soils and environmental quality. A proposed management alternative is to use agroforestry systems, but little information is available on how they affect the soils. The objective was to assess the effect of a silvopastoral chronosequence in a tropical region of Colombia on soil microbiological and physico/chemical properties. The systems (three replications) were: monoculture grass conventional pasture (CP), native forest (F), and a silvopastoral system (SS) chronosequence with ages of 3 to 6 (SS3), 8 to 10 (SS8), or 12 to 15 (SS12) years. Soil responses to these land management were determined by measuring soil chemical (total C and pH), physical (penetrometer resistance and bulk density), and microbiological properties (activities of ß-glucosidase, urease, and alkaline and acid phosphatase and microbial biomass). Because of differences in soil texture across management treatments, microbiological properties were normalized on organic C content basis. SS12 showed the highest microbial biomass and enzyme activities on a per unit C basis and was consistently and significantly different from CP. Additionally, microbiological to C ratios were significantly affected by SS establishment age (P?0.05). The low microbiological responses were consistent with high penetration resistance and bulk density of CP which indicates that the SS are improving soil quality. This study presented quantitative data that SS stimulated soil microbial biomass and enzyme activities, which indicates greater potential to carry out biogeochemical process, and that SS provides a more favorable microbial habitat. 相似文献
42.
Stability and reliability of yield and quality for 15 durum wheat genotypes (old and modern) were evaluated in a 5‐year experiment (southern Italy) in organic farming. Genotypes were grown at two N levels (0 and 80 kg/ha), with the aim of evaluating ‘genotype × environment’ (GE) interactions and their role on genotype selection in N‐limited environments. Several approaches to stability were used, within the frame of mixed models and additive main effects and multiplicative interaction analysis, and their validity in stressful conditions and organic farming was discussed. Especially for protein and gluten content, results indicate high environmental variability and the presence of crossover ‘N × environment’ interactions, which supports the need for specific breeding programmes in N‐deficient environments. The average response was strongly affected by N availability (on average, yield was 2.95 and 3.42 t/ha, protein content was 11.6% and 12.85%, gluten content was 8.55% and 9.92%, respectively, at 0 and 80 kg N/ha), and few genotypes gave high yield and quality at both fertilization levels. Only ‘Gargano’ and ‘Fortore’ showed a good inter‐year stability at both N levels. The old cultivars gave minimal responsiveness to increased N input, but gave good results in limiting conditions, indicating that they may play a role in organic farming. 相似文献
43.
Simone M. Cacciò Anna Rosa Sannella Valeria Mariano Silvia Valentini Franco Berti Fabio Tosini Edoardo Pozio 《Veterinary parasitology》2013,191(1-2):128-131
An outbreak of cryptosporidiosis occurred in a mixed sheep/cattle farm of Central Italy in October 2011. A total of 450 ovines (250 sheep and 200 lambs) and 140 bovines (130 cows and 10 calves) were housed in two separated units, at the time of the outbreak. About half of the lambs had diarrhea due to Cryptosporidium sp. with a mortality rate of 80%; calves were not infected. Genomic DNA was extracted from an archived slide and from fecal specimens, and the parasite was identified as Cryptosporidium parvum by PCR and sequence analysis at the CpA135 gene. Genotyping at the GP60 gene showed the presence of a very rare genotype, IIaA20G2R1. Shortly after the outbreak was identified, the son of the farm's owner, aged 18 months, experienced an acute gastroenteritis and was hospitalized due to recurrent episodes of diarrhea, fever, vomiting and lack of appetite. The feces tested negative for bacteria and viruses, whereas cryptosporidiosis was diagnosed by microscopy and an immunochromatographic test. Molecular typing identified the C. parvum genotype IIaA20G2R1 in the feces of the child. This is the first case of transmission of cryptosporidiosis in Italy involving lambs as source of oocysts infectious to humans. 相似文献
44.
Fabio A. Vannucci Dana Beckler Nicola Pusterla Samantha M. Mapes Connie J. Gebhart 《Veterinary microbiology》2013
Non-pathogenic Lawsonia intracellularis variants have been obtained through multiple passages in cell culture but there is no information regarding the number of passages necessary to attenuate a pathogenic isolate. The present study evaluated the susceptibility of pigs to L. intracellularis after 10, 20 and 40 passages in vitro. Three groups (six animals/group) were inoculated with pure culture of L. intracellularis on passage 10, 20 or 40 and one group with placebo. The animals were monitored for clinical signs, fecal shedding and serological IgG response during 28 days post-inoculation. Gross and histologic lesions and the level of infection based on the amount of L. intracellularis-specific antigen in the intestinal mucosa identified by immunohistochemistry were evaluated in two animals from each group on days 14, 21 and 28. Animals inoculated with passages 10 and 20 demonstrated proliferative lesions typical of porcine proliferative enteropathy associated with the presence of Lawsonia-specific antigen in the intestinal mucosa. Passage 40-inoculated pigs did not show proliferative lesions or presence of Lawsonia antigen at any time point throughout the study. Similar patterns of the fecal shedding were observed in passage 10 and 20-infected pigs but those infected with passage 40 shed for a short period. Serological IgG responses in passage 10 and 20-inoculated pigs were detected from day 14 post-infection but not at all in passage 40-inoculated animals. These results demonstrate attenuation of the virulence properties of L. intracellularis between 20 and 40 cell passages in vitro. This information will be valuable for design of future experimental models and for studying the mechanisms involved in the attenuation of L. intracellularis virulence. 相似文献
45.
Irina GARCIA-ISPIERTO M. Angels ROSELLó Fabio DE RENSIS Fernando LóPEZ-GATIUS 《The Journal of reproduction and development》2013,59(6):544-548
This study compared the efficiency of a five-day or standard (nine-day)
progesterone-based regimen combined with equine chorionic gonadotrophin (eCG) in a
fixed-time AI (FTAI) protocol for dairy cows. The data examined were derived from
3577 inseminations conducted in three dairy herds. Animals with no estrus signs
detected over 21 days were randomly assigned to a PRID-9 or PRID-5 group. Cows in
each group received a progesterone intravaginal device (PRID) for 9 or 5 days,
respectively, PGF2α and eCG on PRID removal, and GnRH 48 h later.
Fixed-time AI was performed 12 h after the GnRH dose. Cows artificially inseminated
following spontaneous estrus during the study period were considered as controls.
Based on the odds ratio, the likelihoods of animals in PRID-9 in the warm (conception
rate [CR] of 22.3%) and cool (32% CR) periods, and control animals in the warm period
(26.6% CR) becoming pregnant were reduced (by factors of 0.6, 0.3 and 0.4,
respectively) compared with the control animals in the cool period (CR of 43.7%). The
risk of a twin pregnancy was higher (51.4%) for cystic PRID-9 cows (by a factor of
3.6) and lower (9.9%) for cyclic PRID-5 animals (by a factor of 0.4) compared with
the PRID-9 cyclic cows. These findings indicate that the proposed protocol achieves
similar results during the cool or warm season to those obtained when AI is conducted
at spontaneous estrus during the cool season. In addition, PRID-5 reduced twin
pregnancy compared with PRID-9. 相似文献
46.
47.
Joao M. D. Sanchez Joao M. B. Vendramini Maria L. Silveira Lynn E. Sollenberger Jose C. B. Dubeux Philipe Moriel Brent Sellers James K. Yarborough Fabio C. Leite de Oliveira 《Grass and Forage Science》2019,74(3):381-388
Pintoi peanut (Arachis pintoi Krapov. & W.C. Greg.) is a warm‐season perennial legume with potential for use in grass–legume mixtures in Florida; however, limited information exists about its establishment in mixtures with bahiagrass (Paspalum notatum Flügge). The objective of this experiment was to evaluate the establishment of bahiagrass cv. “Argentine” and pintoi peanut cv. “Amarillo” as monocultures or mixture. The experiment was conducted in Ona, FL, from June to October of 2014 and 2015. Treatments were a split‐plot design of seeding strategies (bahiagrass monoculture, pintoi peanut monoculture or bahiagrass‐pintoi peanut mixtures; main plots) and two N fertilization strategies (30 or 80 kg/ha N; 30N and 80N; subplots), with four replicates. Measurements of plant density and frequency were taken every 4 weeks after seeding. Ground cover and herbage mass (HM) measurements were taken 112 days after seeding. Pintoi peanut ground cover was affected by seeding strategy × N level interaction. Ground cover was greater with 80N than 30N when pintoi was seeded in monoculture (3.6% vs 1.5% respectively) but not when it was seeded with bahiagrass (2.1%). There was no effect of seeding or N strategy on pintoi peanut proportion in HM (1.4%). Bahiagrass ground cover was not affected by seeding or N strategy (15.9%); however, its proportion in the HM was greater in 80N than 30N (12.1% vs 9.4% respectively). Mixed seeding did not negatively affect the establishment of bahiagrass and pintoi peanut and greater N fertilization levels improved some establishment parameters, with no negative effect for pintoi peanut. 相似文献
48.
Erika Di Iorio Claudio Colombo Ruggero Angelico Roberto Terzano Carlo Porfido Fabio Valentinuzzi Youry Pii Tanja Mimmo Stefano Cesco 《植物养料与土壤学杂志》2019,182(6):921-933
In soil, iron (Fe) solubility depends on complex interactions between Fe minerals and organic matter, but very little is known about plant availability of Fe present in Fe oxides associated with humic substances. For this purpose, this study investigates the effect of Fe mineral crystallinity in the presence of humic acids (HA) on Fe availability to plants. Four Fe–HA mineral coprecipitates were prepared, either in the presence or absence of oxygen, i.e., two goethite (G)‐HA samples containing large amounts of Fe as nanocrystalline goethite and ferrihydrite mixed phases, and two magnetite (M)‐HA samples containing crystalline magnetite. Bioavailability studies were conducted in hydroponic systems on cucumber plants (Cucumis sativus L.) grown under Fe deficient conditions and supplied with the Fe–HA coprecipitates containing goethite or magnetite. Results showed that plants grown in the presence of Fe–HA coprecipitates exhibited a complete recovery from Fe deficiency, albeit less efficiently than plants resupplied with Fe‐chelate fertilizer used as control (Fe‐diethylene triamine penta acetic acid, Fe‐DTPA). However, the supply with either G‐ or M–HA coprecipitates produced different effects on plants: G–HA‐treated plants showed a higher Fe content in leaves, while M–HA‐treated plants displayed a higher leaf biomass and SPAD (Soil–Plant Analysis Development) index recovery, as compared to Fe‐DTPA. The distribution of macronutrients in the leaves, as imaged by micro X‐ray fluorescence (µXRF) spectroscopy, was different in G–HA and M–HA‐treated plants. In particular, plants supplied with the poorly crystalline G–HA coprecipitate with a lower Fe/HA ratio showed features more similar to those of fully recovered plants (supplied with Fe‐DTPA). These results highlight the importance of mineral crystallinity of Fe–HA coprecipitates on Fe bioavailability and Fe uptake in hydroponic experiments. In addition, the present data demonstrate that cucumber plants can efficiently mobilize Fe, even from goethite and ferrihydrite mixed phases and magnetite, which are usually considered unavailable for plant nutrition. 相似文献
49.
Mazzotti F Di Donna L Maiuolo L Napoli A Salerno R Sajjad A Sindona G 《Journal of agricultural and food chemistry》2008,56(1):63-67
A high-throughput mass spectrometric method is presented for the simultaneous detection of Sudan I, II, III, IV, and Para-Red azodyes in foodstuff. The method is based on the use of deuterium-labeled internal standards and atmospheric pressure chemical ionization (APCI) in a triple-quadrupole instrument. The gas-phase breakdown pattern of each labeled and unlabeled analogue displays the naphthoic moiety as a common fragment. The search for the parents of this common species (parent ion scans) allows, by flow injection and in a single run, the evaluation of the presence of each polluting species spiked in typical foodstuffs. A detailed assay of each azodye was performed by LC-APCI and isotope dilution method, through the multiple reaction monitoring approach, using deuterium-labeled internal standards. Sudan dyes can be quantified above the threshold of 10 ppb except for Sudan Para-Red, for which the limit of quantification was 20 ppb, likely due to the different ionization efficiency. 相似文献
50.
The principal applications of high-resolution solid-state NMR spectroscopy, in the field of food science, are reviewed, after a short general introduction, mainly focusing on the potential of these investigations, which are, today, routine tools for resolving technological problems. Selected examples of the applications in the field of food science of high-resolution solid-state NMR spectroscopy both in (13)C and in (1)H NMR particularly illustrative of the results obtainable are reported in some detail. 相似文献