Agricultura y propaganda: el nitrato de Chile en España

la introducción de los abonos químicos en la agricultura española inició su tránsito hacia una agricultura industrial, en la que el control del sector químico sobre la agricultura se haría cada vez más notorio. Los abonos nitrogenados promovieron el aumento de los rendimientos en los cultivos. Entre ellos el más importante desde el siglo XIX hasta la Primera Guerra Mundial fue el nitrato de Chile. Su consumo en la agricultura obedeció no solamente a sus cualidades en los procesos de fertilización sino también a la presión sobre los agricultores, que ejercen fabricantes y comerciantes de abonos. Esta presión se plasmó en la propaganda para aumentar el consumo del nitrato y a la vez competir con su rival más importante, que era el sulfato amónico y los nacientes nitrogenados sintéticos (nitrato de cal y cianamida). La documentación empleada proviene de los fondos documentales del Permanent Nitrate Committee (PNC) en Londres, depositados en el Institute of Agricultural History de la Universidad de Reading, y en bibliografía difícil de encontrar, de los fondos bibliográficos del International Institute of Agriculture alojados en la David Lubin Library de la FAO en Roma.The introduction of chemical fertilizers in Spanish agriculture entailed a transition to industrial agriculture, which was increasingly controlled by the chemical industry. Crop yields increased due to nitrogen fertilizers. Among them, Chilean nitrate remained the most important throughout the nineteenth century and until the First World War. The use of Chilean nitrate in agriculture increased not only because of its qualities in the fertilization process but also due to the pressure exerted on farmers by fertilizer merchants and manufacturers. This was reflected in efforts at marketing that were carried out as a means of increasing the consumption of nitrate and of competing with its most important rivals, the industries producing ammonium sulphate and the emerging product of synthetic nitrogen (nitrate of lime and cyanamide). The documentation used here was deposited in the Institute of Agricultural History at the University of Reading, U.K., by the Permanent Nitrate Committee (PNC) of London. Other rare or inaccessible books consulted on this subject can be found in the library collection of the International Institute of Agriculture, housed in the David Lubin Memorial Library of the FAO, in Rome, Italy

Impact of Cryopreservation on Viability, Phenotype, and Functionality of Porcine PBMC

The use of frozen peripheral blood mononuclear cells (PBMC) is common in immunological studies. The impact of freezing PBMC has been assessed using human and mice cells, but little information is available regarding domestic animals. In the present study, the phenotype and functionality of frozen porcine PBMC were examined. In a preliminary experiment, three freezing media: fetal bovine serum plus 10% dimethyl sulfoxide, PSC cryopreservation kit, and Cryostor CS10, were compared regarding the preservation of cell viability and the response of PBMC to mitogens after thawing. After being stored one month in liquid nitrogen, cell viability was above 89% for all freezing media. The ELISPOT IFN-gamma (IFN-γ) results in response to PHA and of IgG ELISPOT in response to R848+IL-2 were similar to those obtained using fresh PBMC. In the second set of experiments, PBMC were obtained from five pigs vaccinated against Porcine reproductive and respiratory syndrome virus (PRRSV) and then frozen using Cryostor CS10. Recovered cells were phenotyped by flow cytometry using anti-CD3, CD4, CD8, and CD21 antibodies and were used to assess the PRRSV-specific responses in a proliferation experiment, an IFN-γ ELISPOT, and an IgG ELISPOT, and compared to the results obtained with fresh cells. The antigen-specific responses of frozen cells were significantly (p<0.05) impaired in the proliferation assay, particularly for CD4/CD8 double-positive T-cells and for CD21+ cells. Freezing resulted in decreased proliferation when Con A, but not PHA, was used. In ELISPOT, cryopreservation resulted in a decreased frequency of IFN-γ-secreting cells in response to PRRSV (p<0.05) but the response to PHA was not affected. No differences were observed in the IgG ELISPOT after polyclonal activation. Taken together, cryopreservation of porcine PBMC had a significant impact on the magnitude of recall antigen responses and therefore, it may affect the response of effector/memory cells but seems not to have a major impact on naïve T-cells. These results may help to the better use of frozen porcine PBMC, and to the interpretation of the results obtained from them.info:eu-repo/semantics/publishedVersio

Salmonella contamination on pork carcasses: a study of critical points

The aim of the present study was to determine the frequency and distribution of Salmonella contaminations throughout the slaughtering process of pigs. The investigation was carried out in two slaughterhouses that were visited four times each on different days

Biosecurity in pig farms: a review

The perception of the importance of animal health and its relationship with biosecurity has increased in recent years with the emergence and re-emergence of several diseases difficult to control. This is particularly evident in the case of pig farming as shown by the recent episodes of African swine fever or porcine epidemic diarrhoea. Moreover, a better biosecurity may help to improve productivity and may contribute to reducing the use of antibiotics. Biosecurity can be defined as the application of measures aimed to reduce the probability of the introduction (external biosecurity) and further spread of pathogens within the farm (internal biosecurity). Thus, the key idea is to avoid transmission, either between farms or within the farm. This implies knowledge of the epidemiology of the diseases to be avoided that is not always available, but since ways of transmission of pathogens are limited to a few, it is possible to implement effective actions even with some gaps in our knowledge on a given disease. For the effective design of a biosecurity program, veterinarians must know how diseases are transmitted, the risks and their importance, which mitigation measures are thought to be more effective and how to evaluate the biosecurity and its improvements. This review provides a source of information on external and internal biosecurity measures that reduce risks in swine production and the relationship between these measures and the epidemiology of the main diseases, as well as a description of some systems available for risk analysis and the assessment of biosecurity. Also, it reviews the factors affecting the successful application of a biosecurity plan in a pig farm.info:eu-repo/semantics/publishedVersio

Effect of an acidified diet on Salmonella prevalence during the last term of fattening period

The objective of this study was to determine the effect of the acidification of pelleted feed on the carriage and seropositivity against Salmonella in finisher pigs of a commercial herd. Three different diets were assayed: 0.8% formic acid (group 1); 0.4% lactic acid plus 0.4% formic acid (group 2) and a feedstuff without additives (group 3). one thousand pigs were included in each treatment that was administered from 19 to 26 weeks of age

Control del agua y conflictividad social en la expansión del regadío: la acequia Real del Júcar, 1840-1900

The regular use of water allows the intensive agriculture in Valencia in the XIX century. The shortage of water resources led into great fight for its control, causing important tensions among public institutions and social sectors. Those tensions were resolved after long and complicated litigations which affected the whole valencian society.Si el regadío ha sido, históricamente, el fundamento del desarrollo agrario en muchas áreas mediterráneas, sólo un uso regular del agua permitía mantener el carácter intensivo de la agricultura. En condiciones de escasez de los recursos hídricos disponibles, como las que se daban en el s. XIX, ello comportaba que quienes ya tenían acceso al regadío limitaran la extensión del mismo a otras tierras. Las tensiones en torno a este problema fueron importantes e implicaron a las instituciones presentes (ayuntamientos, Agrupaciones de regantes, Estado) y a los diversos sectores sociales (cultivadores arrendatarios, propietarios acomodados locales, grandes propietarios absentistas)

Testing of umbilical cords by real time PCR is suitable for assessing vertical transmission of porcine reproductive and respiratory syndrome virus under field conditions

The objective of this study was to test the suitability of umbilical cord (UC) sampling and ear vein swabbing (EVS) as alternatives to jugular vein bleeding (JVB) for the assessment of vertical transmission of porcine reproductive and respiratory syndrome virus (PRRSV). Twelve farms suspected to be PRRSV-positive unstable were selected and the three types of samples were obtained from 21 batches of newborn piglets (n = 387). The proportions of positive results, viral loads and time spent to collect the samples were compared. UC yielded the highest detection rate, with 76 positives compared to 55 JVB- and 45 EV-positive results (P < 0.05). Average Ct values were 26.6 ± 8.5 for JVB, 30.8 ± 6.4 for EV and 32.1 ± 4.85 for UC (P < 0.01). UC was the fastest collection method (mean 24 s vs. 55 s for EV and 72 s for JVB; P < 0.05). In this study, UC testing was a faster and more sensitive alternative to JVB or EV for the detection of PRRSV in newborn piglets.info:eu-repo/semantics/acceptedVersio

Using commercial ELISAs to assess humoral response in sows repeatedly vaccinated with modified live porcine reproductive and respiratory syndrome virus

Background Sows in breeding herds are often mass vaccinated against porcine reproductive and respiratory syndrome (PRRS) every few months using modified live vaccines (MLV). Field veterinarians repeatedly report that multiple vaccinated sows test negative in ELISA. Obviously, this creates uncertainty when assessing the compliance of vaccination and the status of sows. Methods In the present study, four commercial ELISAs were used to assess the serological PRRS status in gilts and sows of three farms that were PRRS MLV vaccinated every four months. Animals were tested before vaccination (BV) and postvaccination (PV). Total and neutralising antibodies and cell-mediated responses were also measured in animals that yielded negative results in all ELISAs. Results The proportion of seronegative animals BV varied depending on the farm and the ELISA used. When samples were analysed using only one ELISA, a substantial number of negative results obtained BV remained as negative afterwards. Five animals were negative BV and PV with all the examined ELISAs. Those animals also yielded negative results in all the other immunological assays. Conclusion Our findings suggest that the use of ELISA for monitoring multiple PRRS MLV vaccinated sows is very limited due to the variability of the humoral responses and the moderate agreement between tests.info:eu-repo/semantics/acceptedVersio

Development of pig conventional dendritic cells from bone marrow hematopoietic cells in vitro

In recent years, porcine dendritic cells (DCs) have been identified from pig tissues. However, studying the interaction of porcine DCs with pathogens is still difficult due to the scarcity of DCs in tissues. In the present work, the Flt3-ligand (Flt3L)-based in vitro derivation system was further characterized and compared with other cytokine derivation models using a combination of factors: stem cell factor (SCF), GM-CSF, and IL-4. The method using Flt3L alone or combined with SCF supported the development of pig bone marrow hematopoietic cells into in vivo equivalent conventional DCs (cDCs). The equivalent cDC1 (the minor population in the cultures) were characterized as CADM1+CD14-MHC-II+CD172a-/lo CD1-CD163- DEC205+CD11R3 lo CD11R1+CD33+CD80/86+. They expressed high levels of FLT3, ZBTB46, XCR1, and IRF8 mRNA, were efficient in endocytosing dextran and in proliferating allogenic CD4+CD8+ T cells, but were deficient in phagocyting inactivated Staphylococcus aureus (S. aureus). Also, after poly I:C stimulation, they predominantly produced IL-12p40a and matured as indicated by the increase of MHC-I, MHC-II, and CD80/86. The equivalent cDC2 (the main population) were CADM1+CD14-MHC-II+C D172a+CD1+CD163-/lo DEC205 lo CD11R3+CD11R1+CD33+CD80/86+; meanwhile, they overexpressed FcεR1α and IRF4 mRNA. They showed high efficiency in the endocytosis of dextran, but weak in phagocytosing bacteria. They supported allogenic CD4+CD8-/CD4+CD8+ T cell proliferation and were high producers of IL-12p40 (upon TLR7 stimulation) and IL-10 (upon TLR7 stimulation). TLR ligand stimulation also induced their maturation. In addition, a CD14+ population was identified with the phenotype CADM1+CD14+MHC-II+CD172a+ CD1+CD163+DEC205-CD11R3+CD11R1+CD33-/lo CD80/86+. They shared some functional similarities with cDC2 and were distinguishable from macrophages. This CD14+ population was efficient in phagocyting S. aureus but showed less maturation upon TLR ligand stimulation than cDC1 or cDC2. The alternative methods of DC derivation including GM-CSF and/or IL-4 produced mostly CADM1- cells that did not fulfill the canonical phenotype of bona fide porcine DCs. Our study provides an exhaustive characterization of Flt3L-derived DCs with different methods that can help the in vitro study of the interaction of DCs with porcine-relevant pathogens.info:eu-repo/semantics/publishedVersio