Weaned piglets display low gastrointestinal digestion of pea (Pisum sativum L.) lectin and pea albumin 2

A study was conducted to investigate the biochemistry of digestion of field pea (Pisum sativum L.) albumins and globulins in the stomach and along the small intestine of weaned piglets with a particular emphasis on the respective roles of these compartments in pea protein digestion. Twenty-four piglets were weaned at 28 d of age. They were allocated to 2 diets (control and pea) and 3 slaughter times (3, 6, or 9 h after the last meal) in a 2 x3 factorial arrangement of treatments in a randomized complete block design. Pea flour provided 30% of total dietary protein in the pea diet. The diets were fed for 2 wk after weaning. After slaughter, gastrointestinal tract (GIT) compartments were weighed, digesta were collected, and pH was measured. Digesta from the stomach and cranial, middle, and caudal small intestine (SI) were extracted for soluble proteins and analyzed for specific pea proteins using SDS-PAGE, immunoblotting, and mass spectrometry. Tissue weight of the whole GIT (P = 0.015), cecum (P <0.001), and colon (P <0.001) was greater in the pea diet. Digesta pH in the stomach and caudal SI was lower (P = 0.02) in the pea diet than the control diet. In the stomach, vicilin, lectin, and pea albumin 2 were not digested, whereas legumin was only partly digested. Legumin and vicilin were totally digested in the SI in less than 3 h. A resistant peptide of 15 kDa located at the N-terminus of pea albumin 2 was transiently detected at 3 h. A protein band at 20 kDa was consistently identified as lectin. It was present in high intensity in intestinal digesta of pea-fed piglets at all times after the meal compared with those fed the control diet (P <0.001). Various proteins of, presumably, endogenous origin displayed differential digestion patterns between the control and the pea-fed piglets (P<0.05). In conclusion, differences in digestion between specific pea proteins were observed along the GIT of piglets. They could be partly explained by differences in protein digestion in the stomach.     

Cerebral Accumulation of Dietary Derivable Plant Sterols does not Interfere with Memory and Anxiety Related Behavior in Abcg5?/? Mice

Plant sterols such as sitosterol and campesterol are frequently applied as functional food in the prevention of atherosclerosis. Recently, it became clear that plasma derived plant sterols accumulate in murine brains. We questioned whether plant sterols in the brain are associated with alterations in brain cholesterol homeostasis and subsequently with brain functions. ATP binding cassette (Abc)g5-/- mice, a phytosterolemia model, were compared to Abcg5+/+ mice for serum and brain plant sterol accumulation and behavioral and cognitive performance. Serum and brain plant sterol concentrations were respectively 35-70-fold and 5-12-fold increased in Abcg5-/- mice (P<0.001). Plant sterol accumulation resulted in decreased levels of desmosterol (P<0.01) and 24(S)-hydroxycholesterol (P<0.01) in the hippocampus, the brain region important for learning and memory functions, and increased lanosterol levels (P<0.01) in the cortex. However, Abcg5-/- and Abcg5+/+ displayed no differences in memory functions or in anxiety and mood related behavior. The swimming speed of the Abcg5-/- mice was slightly higher compared to Abcg5+/+ mice (P<0.001). In conclusion, plant sterols in the brains of Abcg5-/- mice did have consequences for brain cholesterol metabolism, but did not lead to an overt phenotype of memory or anxiety related behavior. Thus, our data provide no contra-indication for nutritional intake of plant sterol enriched nutrition.     

Chemical aspects of wood modification by sol�Cgel-derived silica

It has been shown that tetraethoxysilane-derived precursors are suitable solutions for impregnating pine sapwood to improve its dimensional stability. Tailored sol?Cgel syntheses result in precursors with nano-scaled silica species which are able to penetrate into the cell walls of wood. The physical fixation of those species inside the cell walls was verified by ESEM/EDX investigations. There is evidence that the silica species are chemically bonded to wood components. Non-reacted alkoxy groups can exist in the wood composites after impregnation. The amount of these organic residues depends on the composition of the precursors, especially their condensation degree and reactivity. Treatments for finishing the composites after the impregnation step to get clean products and stable properties are discussed in this context. An explanation of the complex relationship between solids content in the impregnation solutions and percentage weight gain and bulking of the composites is given. It can be demonstrated that high WPG values (>20?%) are pre-conditions for an effective protection of the resulting composites but they only guarantee efficient improvements if connected with the incorporation of the inorganic component inside the cell walls. Therefore, the sol?Cgel syntheses have to be carried out in such a manner that very small (<2?nm) as well as reactive species are sufficiently available. This demands syntheses using sub-stoichiometric water contents (H₂O/TEOS?<?4, better <2).     

Interaction of common beans cultivars of the black group with years, locations and sowing seasons

The objectives of this study were to assess which environmental factors (local, season or years) are the most important to contribute for the interactions with genotypes of common black beans and to verify the existence of genotypes with broad and/or specific adaptation to the diverse planting seasons in Central Brazil. Data of grain yields for 13 genotypes in 18 field trials used for cultivar registration were utilized, across 2?years (2003 and 2004). Analyses of variance were carried out with decomposition of the genotype x environment interactions. Firstly, data of 18 trials were used, allowing a partial isolation of factors and, subsequently, eight trials were used to allow a complete isolation of the factors. The genotype x sowing seasons (R²?=?4.2?%) and genotype x year (R²?=?4.1?%) interactions were of the greatest important, while genotype x location was less important (R²?=?3.0?%). It was concluded that is more important to conduct evaluations of genotypes in different seasons and years rather than in different locations. The majority of the genotypes tested presented specific adaptation, although it was possible to identify superior lines with wide adaptation.     

Changes induced by powdery mildew in the salicylic acid and polyamine contents and the antioxidant enzyme activities of wheat lines

Investigations were made on four wheat (Triticum aestivum L.) lines under greenhouse conditions, in order to reveal the role of stress-protective materials, namely salicylic acid, polyamines and antioxidant enzymes in the level of tolerance to powdery mildew infection caused by Blumeria graminis (DC.) Speer f.sp. tritici ém. Marchal. The four lines showed different levels of tolerance, assessed on the Saari-Prescott scoring scale: TC26 and TC33 proved to be susceptible and TC9 and TC19 resistant. In most of the lines, infection caused changes in the activities of antioxidant enzymes, especially in the case of guaiacol peroxidase. Four peroxidase isoenzymes, which responded differently to powdery mildew infection could be detected by gel electrophoresis. Infection had only a slight effect on the levels of salicylic acid (free and bound forms) in inoculated plants; while the levels of polyamines, especially spermidine and spermine increased after infection. Correlation analysis was also performed to examine how close a relationship exists between the parameters investigated. It was concluded that salicylic acid, polyamines and antioxidant enzymes have an important role in plant responses and defence mechanisms during this biotic stress and that in some cases there were significant relationships between them. However the levels of these compounds either initially or after pathogen inoculation, could not explain the degree of tolerance to powdery mildew in the four wheat lines investigated.     

Arbuscular Mycorrhizal Fungal Infectivity in Two Soils as Affected by Atmospheric Phenanthrene Pollution

Arbuscular mycorrhizal fungi (AMF) hold a crucial role in ecosystems because they are involved in nutrient cycling between soil and plants. This work aimed at evaluating the impacts that atmospheric pollution by polycyclic aromatic hydrocarbons may have on infectivity of indigenous AMF in soils. Two agricultural soils (Maconcourt, La Bouzule) were exposed for 2?weeks to ambient air (control, C) or to atmospheric phenanthrene (PHE) deposition (180???g?m^?3 air). After exposure, soils were divided into a top (0?C1?cm) and a bottom (1?C15?cm) layer fraction. AMF infectivities of soils were determined after 2?weeks of atmospheric exposition using leek (Allium porum) as bioassay plant. Atmospheric PHE was mainly recovered in the top layer of soil (500?C1,350???g?kg^?1) of both soils and did not readily diffuse into the depth. Atmospheric contamination led to decreases in AMF infectivities of the top layer in both soils and affected the growth of leeks. Our results not only report evidence that infectivity of indigenous AMF is sensitive to PHE in soils but also emphasize that AMF are primary affected by the soil layer regardless to the pollution level.     

Epidemiological investigations in regard to porcine reproductive and respiratory syndrome (PRRS) in Quebec, Canada. Part 2: prevalence and risk factors in breeding sites

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major threat for swine industry and understanding factors involved in its epidemiology is undoubtedly essential for disease control. As a part of a larger project, a cross-sectional study was performed on breeding sites in a moderate density area of swine production in Quebec to estimate the prevalence of PRRSV infected sites and to evaluate if characteristics of sites and biosecurity practices, either as specific measures or as a global score, were associated with PRRSV status. A questionnaire and diagnostic procedures were performed on 54 breeding sites between September 2006 and August 2008. A biosecurity score that had been previously computed using two-step clustering procedure was used, classifying breeding sites into two biosecurity patterns (high vs. low) according to 21 specific biosecurity measures. The apparent prevalence of PRRSV infected sites was 74.0% (95% CI, 60.3-85.0). Univariable and multivariable logistic regression models with robust standard errors adjusting for potential clustering of sites due to same ownership were computed. In a first multivariable model evaluating characteristics of sites and specific biosecurity variables, four main effects were significantly associated (P<0.05) with PRRSV positive status: large pig inventory (OR: 10.7), proximity to closest pig site (OR: 7.3), absence of shower (OR: 8.7) and free access to the main entrance of the site by the rendering truck (OR: 7.0). In a second multivariable model including a global biosecurity score as a surrogate for a specific pattern of biosecurity measures, this score was not retained in the final model. The adjusted population attributable fractions were 16% for the proximity to closest pig site variable, 27% for the absence of shower variable, and 10% for the free access to main entrance of the site by the rendering truck. These two latter biosecurity measures, manageable directly on the site, should be prioritized and be part of any intervention strategy designed for PRRSV control.     

A simple stem taper model with mixed effects for boreal black spruce

We simplified Kozak’s taper model by setting the inflection point at 1.3 m (dbh) without losing accuracy and precision. The simplification was required to facilitate the estimation of the covariance parameters when using a mixed-effects method. This method was necessary to take into account the correlation among multiple diameter measurements on an individual stem. The simple stem taper model was fitted to an extended data set collected across the province of Quebec, Canada. Comparison of the predicted stem taper and the derived stem volume with those obtained using existing models showed a comparable predictive power for the simple model. Including a prediction of the tree random effects based on supplementary diameter measurements of the bole improves the predictive ability of the model around the extra diameter observation. This model offers welcome simplicity as a means of predicting tree taper at coarse resolution for planning tree harvesting.     

Time course differential gene expression in response to porcine circovirus type 2 subclinical infection

This study was aimed at characterizing the potential differences in gene expression in piglets inoculated with Porcine circovirus type 2 (PCV2), the essential causative agent of postweaning multisystemic wasting syndrome. Seven-day-old caesarean-derived, colostrum-deprived piglets were distributed into two groups: control (n = 8) and pigs inoculated with 10^5.2 TCID₅₀ of the Burgos PCV2 isolate (n = 16). One control and three inoculated pigs were necropsied on days 1, 2, 5, and 8 post-infection (p.i.). The remaining pigs (four of each group) were sequentially bled on days 0, 7, 14, 21, and 29 p.i. (necropsy). Total RNA from the mediastinal lymph node (MLN) and lysed whole blood (LWB) samples were hybridized to Affymetrix Porcine GeneChip^®. Forty-three probes were differentially expressed (DE) in MLN samples (FDR < 0.1, fold change > 2) and were distributed into three clusters: globally down-regulated genes, and up-regulated genes at early (first week p.i.) and late (day 29 p.i.) stages of infection. In LWB samples, maximal differences were observed at day 7 p.i., with 54 probes DE between control and inoculated pigs. Main Gene Ontology biological processes assigned to up-regulated genes were related to the immune response. Six common genes were found in both types of samples, all of which belonged to the interferon signaling antiviral effector pathway. Down-regulated genes were mainly related to cell adhesion and migration in MLN, and cellular organization and biogenesis in LWB. Microarray results were validated by quantitative real-time PCR. This study provides, for the first time, the characterization of the early and late molecular events taking place in response to a subclinical PCV2 infection.