Influence of intensity and changes of physical activity on bone mineral density of immature equine subchondral bone

Reasons for performing study: Subchondral bone provides structural support to overlying articular cartilage and plays an important biomechanical role in osteochondral diseases. Mechanical features of bone correlate strongly with bone mineral density, which is directed by the loading conditions to which the tissue is subjected. Objective: To investigate the influence of physical activity levels on subchondral bone mineral density (sBMD) in foals during early development. Methods: Three groups of foals were subjected to different physical activity levels from birth until age 5 months. A proportion of these foals were subjected to euthanasia at 5 months while remaining foals were subjected to similar physical activity levels for 6 months until euthanasia at 11 months. Osteochondral specimens were collected for measurement of sBMD with peripheral quantitative computed tomography at 2 differently loaded anatomical sites of the proximal phalangeal bone at 1, 2, 3, 4 and 5 mm depth from the osteochondral junction. Results: Growth significantly increased sBMD but by a different amount depending on anatomical location and physical activity level. Significantly higher sBMD was found at the habitually loaded central area in comparison to the intermittently peak loaded marginal site. Exercise increased sBMD throughout the whole depth of analysed tissue, but changes were generally more obvious at a depth of 2 mm. Interestingly, foals subjected to additional sprint training preserved the exercise‐induced sBMD increase at the habitually loaded central area during the 6 months of the second phase of the study. Conclusions: Habitual low‐intensity loading elicits a greater response in sBMD in quantitative terms than high‐intensity low‐frequency loading at the sites investigated in this study. Future sBMD may be influenced by means of well‐tailored exercise regimens at young age. Potential relevance: Specific physical activity levels during early development may potentially reduce the prevalence of osteochondral injury later in life.     

Needle metabolome, freezing tolerance and gas exchange in Norway spruce seedlings exposed to elevated temperature and ozone concentration

Northern forests are currently experiencing increasing mean temperatures, especially during autumn and spring. Consequently, alterations in carbon sequestration, leaf biochemical quality and freezing tolerance (FT) are likely to occur. The interactive effects of elevated temperature and ozone (O(3)), the most harmful phytotoxic air pollutant, on Norway spruce (Picea abies (L.) Karst.) seedlings were studied by analysing phenology, metabolite concentrations in the needles, FT and gas exchange. Sampling was performed in September and May. The seedlings were exposed to a year-round elevated temperature (+1.3 °C), and to 1.4× ambient O(3) concentration during the growing season in the field. Elevated temperature increased the concentrations of amino acids, organic acids of the citric acid cycle and some carbohydrates, and reduced the concentrations of phenolic compounds, some organic acids of the shikimic acid pathway, sucrose, cyclitols and steroids, depending on the timing of the sampling. Although growth onset occurred earlier at elevated temperature, the temperature of 50% lethality (LT(50)) was similar in the treatments. Photosynthesis and the ratio of photosynthesis to dark respiration were reduced by elevated temperature. Elevated concentrations of O(3) reduced the total concentration of soluble sugars, and tended to reduce LT(50) of the needles in September. These results show that alterations in needle chemical quality can be expected at elevated temperatures, but the seedlings' sensitivity to autumn and spring frosts is not altered. Elevated O(3) has the potential to disturb cold hardening of Norway spruce seedlings in autumn, and to alter the water balance of the seedling through changes in stomatal conductance (g(s)), while elevated temperature is likely to reduce g(s) and consequently reduce the O(3)-flux inside the leaves.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part II: Electrostatic separation of particles

Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.     

Multiple effects of reindeer grazing on the soil processes in nutrient-poor northern boreal forests

Reindeer grazing has a great influence on the ground vegetation of nutrient-poor northern boreal forests dominated by Cladonia lichens in Fennoscandia. Grazing may influence the soil processes in these systems either by influencing the quality of plant litter, or by indirect effects through the soil microclimate. In order to investigate the mechanisms underlying the effects of reindeer on boreal forest soils, we analyzed litter decomposition, soil and microbial C and N, microbial community composition, and soil organic matter quality in three forest sites with old reindeer exclosures adjacent to grazed areas. There was no effect of grazing on soil C/N ratio, inorganic N concentrations, microbial biomass C, microbial community structure analyzed by phospholipid fatty acid (PLFA) analysis, and organic matter quality analyzed by sequential fractionation, in the soil organic layer. However, microbial N was enhanced by grazing at some of the sampling dates and was negatively correlated with soil moisture, which indicates that increased microbial N could be a stress response to drought. The effect of grazing on litter decomposition varied among the decomposition stages: during the first 1.5 months, the litter C loss was significantly higher in the grazed than the ungrazed areas, but the difference rapidly levelled out and, after one year, the accumulated litter C loss was higher in the ungrazed than the grazed areas. Litter N loss was, however, higher in the grazed areas. Our study demonstrates that herbivores may influence soil processes through several mechanisms at the same time, and to a varying extent in the different stages of decomposition.     

Distribution of protozoa in scots pine mycorrhizospheres

The distribution of heterotrophic flagellates, naked amoebae, testate amoebae and ciliates was investigated in habitats created by Scots pine-Paxillus involutus and -Suillus bovinus ectomycorrhizospheres. The protozoa living on plant and fungal surfaces preferred the non-mycorrhizal pine roots over mycorrhizal roots or external mycelium. The testate amoebae were more abundant on external mycelium than on mycorrhizae regardless of the mycorrhizal fungal species. Numbers of protozoa were higher in the different habitats provided by S. bovinus mycorrhizospheres when compared with P. involutus mycorrhizospheres. Interestingly, the quality of the bacterial flora as food for the protozoa was affected by the mycorrhizal fungi even in the soils adjacent to non-mycorrhizal root tips of pine. These results demonstrate that mycorrhizal fungi create habitats differently suitable for protozoa living in boreal forest soil.     

Characterization of phenolic compounds from lingonberry (Vaccinium vitis-idaea)

Phenolic compounds from the lingonberry (Vaccinium vitis-idaea) were identified using LC-TOFMS, LC-MS/MS, and NMR experiments. The compounds were extracted from the plant material using methanol in an ultrasonicator and further isolated and purified using solid-phase extraction and preparative liquid chromatographic techniques. A total of 28 phenolic compounds were at least tentatively identified, including flavonols, anthocyanidins, catechins and their glycosides, and different caffeoyl and ferulic acid conjugates. This is apparently the first report of coumaroyl-hexose-hydroxyphenol, caffeoyl-hexose-hydroxyphenol, coumaroyl-hexose-hydroxyphenol, quercetin-3-O-alpha-arabinofuranoside, kaempferol-pentoside, and kaempferol-deoxyhexoside in the plant, and the flavonol acylglycosides quercetin-3-O-[4' '-(3-hydroxy-3-methylglutaroyl)]-alpha-rhamnose and kaempferol-3-O-[4' '-(3-hydroxy-3-methylglutaroyl)]-alpha-rhamnose are presented here for the first time ever. In addition, more detailed structure in comparison to earlier reports is described for some compounds previously known to exist in lingonberry.     

Effect of feed supplementation with Satureja khuzistanica essential oil on performance and physiological parameters of broilers fed on wheat- or maize-based diets

1. The aim of this study was to evaluate various levels of Satureja khuzistanica essential oil (SKEO) on performance and physiological parameters of broilers fed on wheat- or maize-based diets.

2. Treatments consisted of two cereals (maize- or wheat-based diets) and three levels of SKEO)0, 250 and 500 mg/kg).

3. Feed intake (FI) and body weight gain (BWG) decreased in broilers fed on the wheat-based diets compared to the control diet. Dietary supplementation of 500 mg/kg SKEO increased FI and BWG. Dietary SKEO supplementation was effective in improving FI and BWG only in wheat-based diets and was effective in improving feed conversion ratio (FCR) in both diets.

4. Dietary supplementation of 500 mg/kg SKEO caused a significant decrease in plasma cholesterol and triglycerides. Also, plasma low-density lipoprotein concentration was decreased in broilers fed on 250 and 500 mg/kg of SKEO. Plasma cholesterol levels in birds fed on the wheat-based diets were lower than in those fed on maize-based diets.

5. Dietary supplementation of 500 mg/kg SKEO increased caecal population of Lactobacillus and reduced total bacterial and Escherichia coli count. Caecal population of Lactobacillus decreased in broilers fed on the wheat-based diets.

6. Digesta viscosity was increased in broilers fed on the wheat-based diets and decreased in broilers fed on 500 mg/kg SKEO compared to the control diet. Dietary SKEO supplementation was effective in reducing digesta viscosity values only in wheat-based diets.

7. Villus height of the duodenum and jejunum decreased in broilers fed on the wheat-based diets. Dietary supplementation of 500 mg/kg SKEO increased villus height and villus height-to-crypt depth ratios and decreased crypt depth of the duodenum compared to the control diet.

8. It can be concluded that dietary SKEO supplementation was effective in improving FI, BWG and FCR values in wheat-based diets.     

Susceptibility of silver birch (Betula pendula) to herbivorous insects is associated with the size and phenology of birch – implications for climate warming

Susceptibility of trees to herbivorous insects is often associated with the tree growth and phenology, both of which are sensitive to a warming climate. Therefore, changes in these traits may affect the intensity of herbivory on trees in the future. We grew silver birch (Betula pendula) populations differing in their growth and phenology in a common garden experiment, and studied the effect of these plant traits on the leaf herbivory, insect herbivore density and community composition of herbivores in two consecutive years, 2011 and 2012. Differences in size and the timing of growth cessation among the birch genotypes were related to differences in herbivore community compositions and herbivory. In 2011, the most intensive herbivore damage was observed on birch genotypes of small size, late bud burst and early growth cessation, and these genotypes originated from high-latitude populations. The differences among birch genotypes in their susceptibility to herbivore damage may lead to differences in their competitive abilities. While climate warming will affect phenology and growth of plants, our study shows, that it may indirectly affect herbivory and herbivore communities as well.