Prevalence of bovine tuberculosis in Jigawa State,northwestern Nigeria

We determined the prevalence of bovine tuberculosis in Jigawa State, northwestern Nigeria using the comparative intradermal tuberculin test in 22 herds consisting of 922 cattle with overall and individual prevalence of 1.08% (10/922) and 45.45% (10/22) obtained, respectively.     

A European network of long-term sites for studies on soil organic matter

In this paper we describe the GCTE global Soil Organic Matter Network (SOMNET) before focusing on the European network of long-term sites. We then select two examples from the European site network and demonstrate how such data can be used to (a) track long-term changes in soil organic matter, (b) evaluate and compare soil organic matter models, and (c) make rough estimates of the potential for carbon (C) sequestration in soils at the regional (European) level. Our simple calculations based on only two long-term experiments suggest that amendment of arable soils with 10 Mg ha⁻¹ of organic manure could lead to an increase in current total European soil C stock to 30 cm of about 4.8% over 90 yr, a scenario with limited potential for sequestering C. Similarly, afforestation through natural woodland regeneration of 30% of current arable land (surplus to requirements by 2010) could lead to an increase in current total European soil C stock of 12.4% over 100 yr. This is equivalent to 43 Tg C yr⁻¹ or 3.8% of anthropogenic CO₂–C emissions from Europe. If temporary C storage in standing woody biomass is included in the estimate, the amount of C sequestered is quadrupled and could account for 15.28% of Europe's annual CO₂–C emissions. This is equivalent to 2.8% of annual global anthropogenic CO₂–C emissions. These calculations are presented to demonstrate a simple technique for estimating rough C sequestration potentials but they do suggest some potential to sequester C in European agricultural soils. As a result, a more sophisticated approach using statistical relationships derived from a large number of long-term experiments was developed. The need for balancing the effects of these scenarios on soil C against other environmental considerations is discussed. Methods for improving estimates of the potential for soil C sequestration using the European site network are also discussed.     

Marking live feeds with inert metal oxides for fish larvae feeding and nutrition studies

Yttrium oxide (Y₂O₃), ytterbium oxide (Yb₂O₃), lanthanum oxide (La₂O₃) and dysprosium oxide (Dy₂O₃) were evaluated as potential live feed markers for feeding and nutrition studies with fish larvae, by determining the uptake and depletion of markers over time in two trials, and quantifying ingestion of Y₂O₃‐marked rotifers (Branchionus plicatilis) by Atlantic cod (Gadus morhua) in a third trial. In the first two trials, Artemia nauplii and rotifers quickly took up markers within 10 min to concentrations useful for nutrition studies (>2% dry weight). There was no significant difference (P>0.05) among temperatures in depletion of markers (10, 15, 20 °C) with Artemia or rotifers. Depletion from rotifers was not significantly different (P>0.05) between 5 and 20 min nor between 5 and 30 min for Artemia when marked at a concentration of 50 mg of marker per litre of seawater. In the second trial, rotifers and Artemia were marked with a higher concentration (250 mg L^?1) and allowed to deplete for a longer time (90 min). In the third trial, visual estimates of Artemia consumed by Atlantic cod larvae were similar to consumption estimates determined by analysis of Y₂O₃‐marked Artemia using inductively coupled plasma optical emission spectroscopy (r²=0.77).     

Conservation priorities differ at opposing species borders of a European orchid

How populations from different regions within the distribution of a species contribute to the adaptive potential and survival of that species has important implications for formulating conservation actions. We test assumptions of concepts on geographic population structure (e.g. central-marginal concept and ‘rear edge versus leading edge’ model) that could be used to inform conservation of plant species under climatic changes. We analyze a comprehensive dataset of demographic traits (e.g. population size, flowering, δ¹³C of plant leaves) of up to 32 sites of Himantoglossum hircinum (L.) Spreng. (Orchidaceae) located within six sub-regions of its European distribution range. Soil and climate parameters are employed as environmental predictors of variation in measured population traits. Climate is the main driver of demographic variability overriding central-marginal gradients that might be present. Warming of the climate at high latitudes paves the way for northward range expansion of species. Populations at the north and north-eastern range peripheries partly show exponential population growth and high genetic diversity and are likely to be the source of immigrants for colonization of newly suitable habitats as the climate continues to change. In recent times, populations at the southern range periphery have suffered from intensification of land use and decreasing rainfall, but in the case of Southern Italy are important because they contain genetically unique traits. Populations at both, ‘leading’ and ‘rear’, edges ought to be at the focus of conservation planning. Different conservation strategies are proposed at opposing species borders taking into account spatial variation in population needs on a geographic scale, projected population response to expected environmental changes and genetic characteristics.     

Bovine fetal wastage in Southwestern Nigeria: a survey of some abattoirs

As a result of inadequate veterinary services and indiscriminate slaughter of animals in most Nigerian abattoirs, pregnant animals are often slaughtered resulting in wastage of scarce protein made available to the people. To this end, an evaluation of the volume of pregnant cows slaughtered at some abattoirs in Southwestern Nigeria between 2005 and 2007 based on meat inspection records was carried out with a view to determining the level of fetal wastage in this part of the country. A total of 321,448 cows were slaughtered, out of which, 16,092 (5.01%) were pregnant. The fetal wastages across the four seasons of the study period were statistically significant (P < 0.05); the late dry season showing the highest percentage. There was a downward trend across the years, and this was considerably lower in 2007 than the other 2 years which were not statistically different from each other (X _A2005 = 224.33; X _A2006 = 216.38; X _B2007 = 126.38). Our results indicated a considerable level of slaughtering of pregnant cows in the abattoirs studied. Hence, we advocate stepping up routine veterinary checks and interventions among trade animals in order to salvage the high level of fetal wastage in the region and the country at large.     

Litter carbon inputs to the mineral soil of Japanese Brown forest soils: comparing estimates from the RothC model with estimates from MODIS

The level of organic carbon found in soil is the result of the balance between litter input to the soil and decomposition. Litter input to the soil is closely related to net primary production (NPP); at equilibrium, the NPP is equal to the litter input to soil. Plant litter input to a depth of 30 cm in the mineral soil was estimated for Japanese forest using the Rothamsted Carbon model (RothC) and an average value of soil organic carbon (SOC) content, and was compared with estimated litter inputs from the NPP dataset from Moderate Resolution Imaging Spectroradiometer (MODIS). A Monte Carlo uncertainty analysis of the input SOC was also conducted in order to reveal the sensitivity and uncertainty of the model to input SOC. The litter carbon input calculated using RothC and that derived from MODIS NPP were positively correlated, but the mean estimated litter input from RothC was 17.2% smaller than that estimated from MODIS. Mapping the normalized difference revealed spatial biases in the difference. The discrepancy was probably because of the different temperature controls for the MODIS algorithm and the RothC model, and also our simple assumption in the RothC calculation. This comparison reveals a close link between litter inputs estimated from SOC data and litter inputs estimated from satellite-based NPP data. The discrepancies between the estimates merit further study.     

Production of alpha 1,3-galactosyltransferase-deficient pigs

The enzyme alpha1,3-galactosyltransferase (alpha1,3GT or GGTA1) synthesizes alpha1,3-galactose (alpha1,3Gal) epitopes (Galalpha1,3Galbeta1,4GlcNAc-R), which are the major xenoantigens causing hyperacute rejection in pig-to-human xenotransplantation. Complete removal of alpha1,3Gal from pig organs is the critical step toward the success of xenotransplantation. We reported earlier the targeted disruption of one allele of the alpha1,3GT gene in cloned pigs. A selection procedure based on a bacterial toxin was used to select for cells in which the second allele of the gene was knocked out. Sequencing analysis demonstrated that knockout of the second allele of the alpha1,3GT gene was caused by a T-to-G single point mutation at the second base of exon 9, which resulted in inactivation of the alpha1,3GT protein. Four healthy alpha1,3GT double-knockout female piglets were produced by three consecutive rounds of cloning. The piglets carrying a point mutation in the alpha1,3GT gene hold significant value, as they would allow production of alpha1,3Gal-deficient pigs free of antibiotic-resistance genes and thus have the potential to make a safer product for human use.     

Analysis of immune responses induced by avian pathogenic Escherichia coli infection in turkeys and their association with resistance to homologous re-challenge

Avian pathogenic Escherichia coli (APEC) cause severe respiratory and systemic disease in poultry yet the nature and consequences of host immune responses to infection are poorly understood. Here, we describe a turkey sub-acute respiratory challenge model and cytokine, cell-mediated and humoral responses associated with protection against homologous re-challenge. Intra-airsac inoculation of turkeys with 10⁵ colony-forming units of APEC O78:H9 strain χ7122nal^R induced transient and mild clinical signs of colibacillosis followed by clearance of the bacteria from the lungs and visceral organs. Upon re-challenge with 10⁷ χ7122nal^R, primed birds were solidly protected against clinical signs and exhibited negligible bacterial loads in visceral organs, whereas age-matched control birds exhibited high lesion scores and bacterial loads in the organs. Levels of mRNA for signature cytokines suggested induction of a Th1 response in the lung, whereas a distinct anti-inflammatory cytokine profile was detected in the liver. Proliferative responses of splenocytes to either Concanavalin A or soluble χ7122nal^R antigens were negligible prior to clearance of bacteria, but APEC-specific responses were significantly elevated at later time intervals and at re-challenge relative to control birds. Primary infection also induced significantly elevated χ7122nal^R-specific serum IgY and bile IgA responses which were bactericidal against χ7122nal^R and an isogenic Δrfb mutant. Bactericidal activity was observed in the presence of immune, but not heat-inactivated immune serum, indicating that the antibodies can fix complement and are not directed solely at the lipopolysaccharide O-antigen. Such data inform the rational design of strategies to control a recalcitrant endemic disease of poultry.