Predicting the productivity of a young hybrid poplar clone under intensive plantation management in northern Alberta,Canada using soil and site characteristics

Site productivity of the hybrid poplar clone Brooks6 was predicted using soil and site information from 6, 4-year-old plantations in north-east Alberta. Predictions were made at both the local and microsite scales. Percent sand (R ² = 0.352, P = 0.001) was the best single predictor of hybrid poplar productivity, showing a curved relationship. Soil pH also showed a curved but weaker relationship with hybrid poplar productivity (R ² = 0.133, P = 0.100). Maximum tree productivity occurred at sand contents between 55 and 70% and pH values near 6. Other variables, including foliar nutrient concentrations, foliar δ¹³C, electrical conductivity, depth of the A horizon and total chemistry of the soil, were also related to hybrid poplar productivity at the local and microsite scales. However, all of these variables were correlated to either soil texture (percent sand) or pH. At the microsite scale within plantations, percent sand was the most important predictor of tree productivity and explained more than 50% of the variability within plantations, although the relationship varied by plantation. In plantations with fine textures, sandier microsites were associated with increased growth while in sandy plantations, finer textured microsites were more productive. As a whole, the growth of the hybrid poplar clone Brooks6 appears to be mostly influenced by a combination of soil water and nutrient availability, the former being impacted by soil texture and the latter being governed by soil pH.     

Comparative diagnosis of parasitological,serological, and molecular tests in dourine-suspected horses

Study on comparative sensitivity of parasitological, serological, and molecular tests on 237 horses originating from two dourine-suspected districts of Arsi-Bale highlands of Ethiopia was conducted to determine the prevalence of the disease and degree of agreement of the diagnostic tests. Accordingly, the prevalence of the disease was found to be 4.6%, 36.7%, and 47.6% by parasitological Woo test, RoTat 1.2 and 18S PCR tests, respectively. The seroprevalence of the disease was 27.6% in CATT/Trypanosoma evansi test. In Ethiopia, it was for the first time that trypanosomes from dourine suspected horses were demonstrated in 4.6% of the animals using Woo test. The findings of the present study disclosed that dourine is highly prevalent and one of the major diseases of horses in the area. There was no statistically significant difference (P > 0.05) in prevalence of the disease between districts, sexes, and age groups of the animals. However, there was a statistically significant difference (P < 0.05) in the prevalence of the disease between emaciated and animals with good body condition. Assessment of the degree of agreement of the diagnostic tests employed revealed low to fair ( k = 0.1 - 0.4 ) \left( {k = 0.{1} - 0.{4}} \right) with significantly higher sensitivity by PCR than other tests.     

Rheological Properties of Wheat Flour Dough and the Relationship with Bread Volume. I. Creep‐Recovery Measurements

The rheological properties of 17 pure European wheat cultivars were analyzed and evaluated in relation to the bread volume. Rheological testing included two empirical rheological methods, farinograph and alveograph, and more fundamental creep‐recovery experiments at shear stresses of 100 and 250 Pa. Principal component analysis on the farinograph and alveograph results showed that a wide range of rheological properties was present among the wheat cultivars. Correlation analysis pointed out that creep‐recovery parameters showed significant correlations with protein content, Zeleny sedimentation value, farinograph water absorption, alveograph extensibility, and bread volume. Among the rheological parameters, maximum recovery strain at a shear stress of 250 Pa showed the highest significant correlation with the bread volume (r = 0.790**). Variables were combined to predict the bread volume by multiple linear regression. A combination of protein content, farinograph water absorption, and alveograph P/L showed the best prediction (r² = 0.80). When taking into account the creep‐recovery parameters, the best prediction of the bread volume (r² = 0.74) was obtained for a combination of the maximum recovery strain at a shear stress of 250 Pa with one other quality parameter (Zeleny sedimentation value, farinograph water absorption, or alveograph W).     

Public policies as institutions for sustainability: potentials of the concept and findings from assessing sustainability in the European forest-based sector

It is becoming increasingly apparent that the institutional dimension is of critical importance for achieving sustainable development, which is why the view that it should be considered as a fourth dimension of sustainability is acquiring increased support. It is argued that the institutional dimension represents an important challenge to the full integration of the economic, social and environmental sustainability objectives within the necessary institutional setting. But despite its importance, the latter is often neglected when it comes to scientific assessments of sustainability performance. A fact that holds particularly true for the forestry sector. The aim of the present paper is to describe and discuss how the institutional dimension of sustainability can be incorporated into a Sustainability Impact Assessment of the European Forest-Wood-Chain (FWC) by using a policy database developed within the context of EFORWOOD. The policy database, covering all policies of key relevance to FWC-sustainability, was employed for the purpose of connecting the EFORWOOD sustainability indicators to its institutional and political background. This connection provides direct and detailed insights into the governance structures prevailing in the European forest-based sector and thereby into the institutional dimension of FWC-sustainability. The results illustrate that FWC-sustainability is governed and regulated rather inconsistently by the many political institutions involved, various types of policies in force, and different modes of governance applied. The connection between the EFORWOOD sustainability indicators and a comprehensive database of sector-related policies thus presents a feasible approach for overcoming the lack of consideration given to the institutional sphere of sustainability.     

T-2 toxin induced Salmonella Typhimurium intoxication results in decreased Salmonella numbers in the cecum contents of pigs, despite marked effects on Salmonella-host cell interactions

ABSTRACT: The mycotoxin T-2 toxin and Salmonella Typhimurium infections pose a significant threat to human and animal health. Interactions between both agents may result in a different outcome of the infection. Therefore, the aim of the presented study was to investigate the effects of low and relevant concentrations of T-2 toxin on the course of a Salmonella Typhimurium infection in pigs. We showed that the presence of 15 and 83 μg T-2 toxin per kg feed significantly decreased the amount of Salmonella Typhimurium bacteria present in the cecum contents, and a tendency to a reduced colonization of the jejunum, ileum, cecum, colon and colon contents was noticed. In vitro, proteomic analysis of porcine enterocytes revealed that a very low concentration of T-2 toxin (5 ng/mL) affects the protein expression of mitochondrial, endoplasmatic reticulum and cytoskeleton associated proteins, proteins involved in protein synthesis and folding, RNA synthesis, mitogen-activated protein kinase signaling and regulatory processes. Similarly low concentrations (1-100 ng/mL) promoted the susceptibility of porcine macrophages and intestinal epithelial cells to Salmonella Typhimurium invasion, in a SPI-1 independent manner. Furthermore, T-2 toxin (1-5 ng/mL) promoted the translocation of Salmonella Typhimurium over an intestinal porcine epithelial cell monolayer. Although these findings may seem in favour of Salmonella Typhimurium, microarray analysis showed that T-2 toxin (5 ng/mL) causes an intoxication of Salmonella Typhimurium, represented by a reduced motility and a downregulation of metabolic and Salmonella Pathogenicity Island 1 genes. This study demonstrates marked interactions of T-2 toxin with Salmonella Typhimurium pathogenesis, resulting in bacterial intoxication.     

Effects of organic selenium supplementation on growth performance, carcass measurements, tissue selenium concentrations, characteristics of reproductive organs, and testis gene expression profiles in boars

The objective was to compare growth and physiological responses in boars fed diets supplemented with organic or inorganic sources of Se. At weaning, crossbred boars (n = 117; 8.3 kg of BW) were placed in nursery pens (3 boars/pen) and assigned within BW blocks to receive on an ad libitum basis 1 of 3 dietary treatments: I) basal diets with no supplemental Se (controls), II) basal diets supplemented with 0.3 mg/kg of organic Se, and, III) basal diets supplemented with 0.3 mg/kg of sodium selenite (13 pens/dietary treatment). Average daily gain (470 g/d), ADFI (896 g/d), and G:F (0.54) were similar among groups. Blood Se concentrations were greater (P < 0.01) for boars consuming organic Se (107.5 ± 4.8 μg/L) or sodium selenite (114.7 ± 4.8 μg/L) compared with controls (28.4 ± 4.8 μg/L). Intact pens of boars (11 pens/dietary treatment) were moved to a grow-finish barn and continued to receive appropriate diets on an ad libitum basis. Average daily gain (1,045 g/d) and ADFI (2,716 g/d) were similar among groups. Gain:feed was affected by treatment (P = 0.02) and was greater (P < 0.06) for boars fed organic Se (0.378 ± 0.004) compared with boars fed sodium selenite (0.368 ± 0.004) or controls (0.363 ± 0.004). Blood Se concentrations were greater (P < 0.01) in grow-finish boars consuming organic Se (198.9 ± 5.5 μg/L) than boars consuming sodium selenite (171.4 ± 5.4 μg/L) or controls (26.7 ± 5.4 μg/L). Treatment did not affect (P > 0.15) HCW, dressing percent, carcass length, LM area, standardized fat-free lean, lean percentage, backfat thickness, visual color, firmness, marbling, or Minolta loin color scores. Selenium supplementation did not affect (P > 0.17) testis or accessory sex gland sizes. Concentrations of Se in loin, liver, kidney, testis, cauda epididymis, and accessory sex glands were greatest (P < 0.01) in boars receiving organic Se, intermediate in boars receiving sodum selenite, and least in control boars. Microarray analysis of testis gene expression did not detect differences (P > 0.05) due to dietary treatment. Testis gene expression of glutathione peroxidase 4, as determined using quantitative PCR, was increased (P < 0.01) in boars fed organic Se compared with those fed sodium selenite. In summary, dietary supplementation of boars with organic Se failed to alter ADG or ADFI but enhanced G:F during grow-finish. More research is needed to discern the mechanism by which organic Se improves feed efficiency in boars.     

Selected persistent organic pollutants (POPs) in the rhizosphere of sewage sludge-treated soil: implications for the biodegradability of POPs

The impact of regular application of sewage sludge or farmyard manure on the organic contaminant loads in soil was assessed in a model rhizobox experiment. Two soils originating from a long-term field crop rotation and fertilizer experiment running since 1996 were used. The total polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), organochlorinated pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) contents were determined in the rhizosphere and bulk soil. The results showed low but still detectable contents of PCBs and OCPs in the soil, substances which were banned a few decades ago. Among the OCPs, dichlorodiphenyltrichloroethane (DDT) and its metabolites reaching up to 18.2 µg kg^?1 of the soil even exceeded the preventive levels for these compounds in agricultural soils, i.e. 7.5 µg kg^?1 of soil. For PBDEs, PFOA, and PFOS, their contents in the soil significantly increased with sewage sludge application. The enhancement of the potential biodegradability of the POPs in the rhizosphere was confirmed only for hexachlorocyclohexane (γ-HCH), where, the level of γ-HCH increased significantly in the rhizosphere soil compared to bulk soil. Thus, natural attenuation of POPs in the soil-plant system seems to be insufficient for most of the investigated compounds.     

Mutual relationships of biochar and soil pH,CEC, and exchangeable base cations in a model laboratory experiment

Purpose

The majority of biochar studies use soils with only a narrow range of properties making generalizations about the effects of biochar on soils difficult. In this study, we aimed to identify soil properties that determine the performance of biochar produced at high temperature (700 °C) on soil pH, cation exchange capacity (CEC), and exchangeable base cation (Ca²⁺, K⁺, and Mg²⁺) content across a wide range of soil physicochemical properties.

Materials and methods

Ten distinct soils with varying physicochemical properties were incubated for 12 weeks with four rates of biochar application (0.5, 2, 4, and 8% w/w). Soil pH, CEC, and exchangeable base cations (Ca²⁺, K⁺, and Mg²⁺) were determined on the 7th and 84th day of incubation.

Results and discussion

Our results indicate that the highest biochar application rate (8%) was more effective at altering soil properties than lower biochar rates. Application of 8% biochar increased pH significantly in all incubated soils, with the increment ranging up to 1.17 pH unit. Biochar induced both an increment and a decline in soil CEC ranging up to 35.4 and 7.9%, respectively, at a biochar application rate of 8%. Similarly, biochar induced increments in exchangeable Ca²⁺ up to 38.6% and declines up to 11.4%, at an 8% biochar application rate. The increment in CEC and exchangeable Ca²⁺ content was found in soils with lower starting exchangeable Ca²⁺ contents than the biochar added, while decreases were observed in soils with higher exchangeable Ca²⁺ contents than the biochar. The original pH, CEC, exchangeable Ca²⁺, and texture of the soils represented the most crucial factors for determining the amount of change in soil pH, CEC, and exchangeable Ca²⁺ content.

Conclusions

Our findings clearly demonstrate that application of a uniform biochar to a range of soils under equivalent environmental conditions induced two contradicting effects on soil properties including soil CEC and exchangeable Ca²⁺ content. Therefore, knowledge of both biochar and soil properties will substantially improve prediction of biochar application efficiency to improve soil properties. Among important soil properties, soil exchangeable Ca²⁺ content is the primary factor controlling the direction of biochar-induced change in soil CEC and exchangeable Ca²⁺ content. Generally, biochar can induce changes in soil pH, CEC, and exchangeable Ca²⁺, K⁺, and Mg²⁺ with the effectiveness and magnitude of change closely related to the soil’s original properties.

     

Propagation of trembling aspen and hybrid poplar for agroforestry: potential benefits of elevated CO2 in the greenhouse

We examined the usefulness of elevated CO₂ in the greenhouse to aid in early selection of genotypes and in the propagation of Populus tremuloides Michaux (aspen) and hybrid poplars for agroforestry, afforestation, or reclamation. Growth in elevated (800 ppm) vs ambient (375 ppm) CO₂ for 95 days resulted in greater height (14%), stem caliper (16%), overall biomass, and proportional allocation of biomass to roots as well as elevated net assimilation and water-use-efficiency. Aspen clones selected for superior growth (based on phenotypic selection) broke bud significantly earlier than unselected clones under both CO₂ levels; superior clones were also taller with greater stem caliper under both CO₂ treatments (but not significant). Under ambient CO₂ male aspen were taller than females while under elevated CO₂ female aspen were taller than males and also had greater caliper (but not significant). Hybrid poplar grown under elevated (vs ambient) CO₂ broke bud significantly earlier and had significantly greater net assimilation and water-use efficiency; they were also taller with greater caliper (but not significant). Differences in performance among the eight hybrid clones were enhanced by growth under elevated CO₂. Under ambient CO₂, P38P38 was the clone that broke bud earliest, was tallest with greater caliper and had a lower shoot:root biomass ratio. Sargentii, on the other hand, was the shortest with the smallest caliper. The implications of these results need to be considered in the context of using aspen and hybrid poplar for large-scale agroforestry, afforestation and reclamation across Canada. This revised version was published online in August 2006 with corrections to the Cover Date.     

Bacterial killing activity and lysozymes: A stable defence mechanism in stallion seminal plasma?

During insemination, bacterial contamination of the ejaculate can lead to reduced sperm quality and transmission of pathogens to the female, thus should be avoided. The semen of a variety of animal taxa possess antimicrobial properties against a wide range of bacterial species through antimicrobial molecules, such as lysozyme, but their variance and the factors influencing it are unknown for most species. In this study, the antibacterial defence (bacterial killing activity (BKA) against Escherichia (E.) coli and Staphylococcus (S.) aureus as well as lysozyme concentration) was studied in seminal fluid from two consecutive ejaculates of 18 stallions. All ejaculates showed BKA against the tested bacteria, which correlated between the two consecutive ejaculates (r_S = 0.526, p = .025 for E. coli and r_S = 0.656, p = .003 for S. aureus) and appeared to be stable over the tested period. The lysozyme concentration (LC) showed no significant correlation between the consecutive ejaculates (r_S = 0.161, p = .681). However, LC had a positive correlation to the ratio of apoptotic spermatozoa within the ejaculates (r_S = 0.426, p = .019). In contrast to other livestock (e.g., boar, bull), the BKA in stallion semen did not correlate significantly with the age of the animal nor sperm quality characteristics.