A complex combination of adult health-related disorders can originate from developmental events that occurin utero. The periconceptional period may also be programmable. We report on the effects of restricting the supply of specific B vitamins (i.e., B₁₂and folate) and methionine, within normal physiological ranges, from the periconceptional diet of mature female sheep. We hypothesized this would lead to epigenetic modifications to DNA methylation in the preovulatory oocyte and/or preimplantation embryo, with long-term health implications for offspring. DNA methylation is a key epigenetic contributor to maintenance of gene silencing that relies on a dietary supply of methyl groups. We observed no effects on pregnancy establishment or birth weight, but this modest early dietary intervention led to adult offspring that were both heavier and fatter, elicited altered immune responses to antigenic challenge, were insulin-resistant, and had elevated blood pressure–effects that were most obvious in males. The altered methylation status of 4% of 1,400 CpG islands examined by restriction landmark genome scanning in the fetal liver revealed compelling evidence of a widespread epigenetic mechanism associated with this nutritionally programmed effect. Intriguingly, more than half of the affected loci were specific to males. The data provide the first evidence that clinically relevant reductions in specific dietary inputs to the methionine/folate cycles during the periconceptional period can lead to widespread epigenetic alterations to DNA methylation in offspring, and modify adult health-related phenotypes.

Cow genes dictate environmentally friendly microbiomes: a step towards reducing greenhouse gas emissions.

We sought to explore the interactions between roots and soil without disturbance and in four dimensions (i.e. 3-D plus time) using X-ray micro-computed tomography. The roots of tomato Solanum lycopersicum 'Ailsa Craig' plants were visualized in undisturbed soil columns for 10 consecutive days to measure the effect of soil compaction on selected root traits including elongation rate. Treatments included bulk density (1.2 vs. 1.6 g cm(-3)) and soil type (loamy sand vs. clay loam). Plants grown at the higher soil bulk density exploited smaller soil volumes (P < 0.05) and exhibited reductions in root surface area (P < 0.001), total root volume (P < 0.001) and total root length (P < 0.05), but had a greater mean root diameter (P < 0.05) than at low soil bulk density. Swelling of the root tip area was observed in compacted soil (P < 0.05) and the tortuosity of the root path was also greater (P < 0.01). Root elongation rates varied greatly during the 10-d observation period (P < 0.001), increasing to a maximum at day 2 before decreasing to a minimum at day 4. The emergence of lateral roots occurred later in plants grown in compacted soil (P < 0.01). Novel rooting characteristics (convex hull volume, centroid and maximum width), measured by image analysis, were successfully employed to discriminate treatment effects. The root systems of plants grown in compacted soil had smaller convex hull volumes (P < 0.05), a higher centre of mass (P < 0.05) and a smaller maximum width than roots grown in uncompacted soil. Soil compaction adversely affects root system architecture, influencing resource capture by limiting the volume of soil explored. Lateral roots formed later in plants grown in compacted soil and total root length and surface area were reduced. Root diameter was increased and swelling of the root tip occurred in compacted soil.

The objective of this study was to investigate whether measurement of methane emissions by individual dairy cows during milking could provide a useful technique for monitoring on-farm methane emissions. To quantify methane emissions from individual cows on farm, we developed a novel technique based on sampling air released by eructation during milking. Eructation frequency and methane released per eructation were used to estimate methane emission rate. For 82 cows, methane emission rate during milking increased with daily milk yield (r = 0.71), but varied between individuals with the same milk yield and fed the same diet. For 12 cows, methane emission rate recorded during milking on farm showed a linear relationship (R² = 0.79) with daily methane output by the same cows when housed subsequently in respiration chambers. For 42 cows, the methane emission rate during milking was greater on a feeding regimen designed to produce high methane emissions, and the increase compared with a control regimen was similar to that observed for cows in respiration chambers. It was concluded that, with further validation, on-farm monitoring of methane emission rate during milking could provide a low-cost reliable method to estimate daily methane output by individual dairy cows, which could be used to study variation in methane, to identify cows with low emissions, and to test outcomes of mitigation strategies.

Soil tillage practices have a profound influence on the physical properties of soil and the greenhouse gas (GHG) balance. However there have been very few integrated studies on the emission of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and soil biophysical and chemical characteristics under different soil management systems. We recorded a significantly higher net global warming potential under conventional tillage systems (26-31% higher than zero tillage systems). Crucially the 3-D soil pore network, imaged using X-ray Computed Tomography, modified by tillage played a significant role in the flux of CO2 and CH4. In contrast, N2O flux was determined mainly by microbial biomass carbon and soil moisture content. Our work indicates that zero tillage could play a significant role in minimising emissions of GHGs from soils and contribute to efforts to mitigate against climate change.