Effect of Antimicrobial Consumption and Production Type on Antibacterial Resistance in the Bovine Respiratory and Digestive Tract

The aim of this study was to investigate the relationship between antimicrobial use and the occurrence of antimicrobial resistance in the digestive and respiratory tract in three different production systems of food producing animals. A longitudinal study was set up in 25 Belgian bovine herds (10 dairy, 10 beef, and 5 veal herds) for a 2 year monitoring of antimicrobial susceptibilities in E. coli and Pasteurellaceae retrieved from the rectum and the nasal cavity, respectively. During the first year of observation, the antimicrobial use was prospectively recorded on 15 of these farms (5 of each production type) and transformed into the treatment incidences according to the (animal) defined daily dose (TI_ADD) and (actually) used daily dose (TI_UDD). Antimicrobial resistance rates of 4,174 E. coli (all herds) and 474 Pasteurellaceae (beef and veal herds only) isolates for 12 antimicrobial agents demonstrated large differences between intensively reared veal calves (abundant and inconstant) and more extensively reared dairy and beef cattle (sparse and relatively stable). Using linear mixed effect models, a strong relation was found between antimicrobial treatment incidences and resistance profiles of 1,639 E. coli strains (p<0.0001) and 309 Pasteurellaceae (p≤0.012). These results indicate that a high antimicrobial selection pressure, here found to be represented by low dosages of oral prophylactic and therapeutic group medication, converts not only the commensal microbiota from the digestive tract but also the opportunistic pathogenic bacteria in the respiratory tract into reservoirs of multi-resistance.     

Effect of technical settings on canine semen motility parameters measured by the Hamilton-Thorne analyzer

Computerized measuring devices are needed to assess canine semen quality objectively both for research and practical purposes. As internal image settings may influence the results considerably, the effect of different technical settings and semen processing on the parameters assessed by the Hamilton-Thorne Ceros 12.1 semen analyzer (HTR Ceros 12.1) was investigated. The frame rate (15, 30 or 60 frames/s) significantly (P<0.05) influenced most of the measured motility characteristics in experiment 1 while no differences in the motility parameters were found using a different sampling duration (0.5 or 1 s, i.e. 30 or 60 frames scanned) in experiment 2. In experiment 3, an increase in sperm velocity (VAP, VSL, VCL), in linearity and in the percentage of motile and rapidly moving spermatozoa was observed with increasing sperm concentrations (25 x 10(6), 50 x 10(6) or 100 x 10(6) ml(-1)). In experiment 4, a clear effect of the diluent used was visible with higher velocity parameters (VAP, VSL, VCL) and higher percentages of motile, progressive and rapid spermatozoa for semen samples diluted in Hepes-TALP or prostatic fluid in comparison with physiological saline or egg-yolk-Tris extender. In experiment 5, significant (P<0.01) and high correlations were found between the conventional dog semen analysis methods and HTR Ceros 12.1 measurements (n=97 semen samples) for the sperm concentration (r=0.91), the motility (r=0.74) and the progressive motility (r=0.84). In experiment 6, the ejaculates from 21 proven, fertile dogs were compared with the ejaculates of a population (N: 11) of young beagles (1.5 years) but no significant differences in HTR Ceros 12.1 measurements were found between the two groups. Based on our results, diluting dog semen samples to 50 x 10(6) ml(-1) with physiological saline solution and scanning 30 frames at a frame rate of 60 frames/s (i.e. a scanning time of 0.5 s), are the set-up parameters proposed to obtain objective and standardized canine semen motility results using the HTR Ceros 12.1.     

Prey consumption by phytoseiid spider mite predators as affected by diurnal temperature variations

The consumption rate of an ectothermic predator is highly temperature-dependent and is a key driver of pest-predator population interactions. Not only average daily temperature, but also diurnal temperature variations may affect prey consumption and life history traits of ectotherms. In the present study, we evaluated the impact of temperature alternations on body size, predation capacity and oviposition rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) when presented with eggs of their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). For both predators, mean daily temperature as well as temperature alternation had a substantial impact on the number of prey consumed. At lower average temperatures, more eggs were killed under an alternating temperature regime (20 °C/5 °C and 25 °C/10 °C) than at the corresponding mean constant temperatures (15 and 20 °C). At higher average temperatures (>25 °C), however, the opposite was observed with higher numbers of prey killed at constant temperatures than at alternating temperatures. At 25 °C, temperature variation had no effect on the predation capacity. A similar trend as for the predation rates was observed for the oviposition rates of the phytoseiids. Body size of N. californicus was affected both by average daily temperature and temperature variation, with smaller adult females emerging at alternating temperatures than at constant temperatures, whereas for P. persimilis, temperature variation had no impact on its body size. Our results demonstrate that temperature variations are likely to affect biological control of T. urticae by the studied phytoseiid predators.     

Is apoptosis in bovine in vitro produced embryos related to early developmental kinetics and in vivo bull fertility?

Although several studies have indicated a paternal effect on bovine embryo development, no conclusive data exist on the effect of in vivo bull fertility on apoptosis. Therefore, it was the main objective of this study to compare the apoptotic cell ratio (ACR) in embryos originating from bulls with different in vivo fertility. However, since it is has been demonstrated before that bulls with different in vivo fertility differ in timing of first cleavage, it was necessary to investigate first the effect of timing of development on apoptosis in vitro in order to get an unbiased insight in the contribution of in vivo bull fertility on apoptosis in bovine blastocysts. In the first experiment, bovine embryos (n = 939) were allocated to different groups according to cleavage rate at 30, 36 and 48 hpi and blastocysts were selected at 7 and 8 dpi. The blastocyst rate at 7 dpi was significantly lower in embryos which had first cleaved at 48 hpi than in embryos from the 30 and 36 hpi group (P < 0.05). The ACR after TUNEL in day 7 blastocyst was significantly lower in the 30 hpi group in comparison with the 36 and 48 hpi group (P < 0.05) and lower in day 7 blastocysts than in day 8 blastocysts. In the second experiment, sperm of eight bulls with different non return rates was used for in vitro bovine embryo production (n = 3820 oocytes). Cleavage rates (30, 36 and 48 hpi) and blastocyst rate (7 dpi) were determined. Only very low negative correlations could be found between in vivo and in vitro bull fertility and ACR did not differ between groups derived from sires with either low or normal fertility (P > 0.05). Further research in serum free conditions is needed to confirm that the lower ACR in early cleaved embryos could be mediated by the cooperative interaction of embryos of good quality cultured in group. In vivo bull fertility could hardly be correlated with in vitro blastocyst yield and could not be correlated with appearance of apoptosis.     

Individualistic responses of forest herb traits to environmental change

• Intraspecific trait variation (ITV; i.e. variability in mean and/or distribution of plant attribute values within species) can occur in response to multiple drivers. Environmental change and land‐use legacies could directly alter trait values within species but could also affect them indirectly through changes in vegetation cover. Increasing variability in environmental conditions could lead to more ITV, but responses might differ among species. Disentangling these drivers on ITV is necessary to accurately predict plant community responses to global change.
• We planted herb communities into forest soils with and without a recent history of agriculture. Soils were collected across temperate European regions, while the 15 selected herb species had different colonizing abilities and affinities to forest habitat. These mesocosms (384) were exposed to two‐level full‐factorial treatments of warming, nitrogen addition and illumination. We measured plant height and specific leaf area (SLA).
• For the majority of species, mean plant height increased as vegetation cover increased in response to light addition, warming and agricultural legacy. The coefficient of variation (CV) for height was larger in fast‐colonizing species. Mean SLA for vernal species increased with warming, while light addition generally decreased mean SLA for shade‐tolerant species. Interactions between treatments were not important predictors.
• Environmental change treatments influenced ITV, either via increasing vegetation cover or by affecting trait values directly. Species’ ITV was individualistic, i.e. species responded to different single resource and condition manipulations that benefited their growth in the short term. These individual responses could be important for altered community organization after a prolonged period.

     

Spatially combining wood production and recreation with biodiversity conservation

Pine plantations established on former heathland are common throughout Western Europe and North America. Such areas can continue to support high biodiversity values of the former heathlands in the more open areas, while simultaneously delivering ecosystem services such as wood production and recreation in the forested areas. Spatially optimizing wood harvest and recreation without threatening the biodiversity values, however, is challenging. Demand for woody biomass is increasing but other pressures on biodiversity including climate change, habitat fragmentation and air pollution are intensifying too. Strategies to spatially optimize different ecosystem services with biodiversity conservation are still underexplored in the research literature. Here we explore optimization scenarios for advancing ecosystem stewardship in a pine plantation in Belgium. Point observations of seven key indicator species were used to estimate habitat suitability using generalized linear models. Based on the habitat suitability and species’ characteristics, the spatially-explicit conservation value of different forested and open patches was determined with the help of a spatially-explicit conservation planning tool. Recreational pressure was quantified by interviewing forest managers and with automated trail counters. The impact of wood production and recreation on the conservation of the indicator species was evaluated. We found trade-offs between biodiversity conservation and both wood production and recreation, but were able to present a final scenario that combines biodiversity conservation with a restricted impact on both services. This case study illustrates that innovative forest management planning can achieve better integration of the delivery of different forest ecosystem services such as wood production and recreation with biodiversity conservation.     

Climate warming and atmospheric deposition affect seed viability of common juniper (<Emphasis Type="Italic">Juniperus communis</Emphasis>) via their impact on the nutrient status of the plant

Global environmental change is increasingly affecting species worldwide. One of the emblematic casualties among plants in several European countries is common juniper (Juniperus communis). Many populations of common juniper throughout its distribution range are declining. The relative lack of viable seed production, resulting in low probabilities for successful natural regeneration, is one of the main reasons for this decline. Climate warming and elevated atmospheric depositions have been shown to negatively affect seed viability of common juniper, but our understanding of the underlying mechanisms remains scarce. One possible pathway is via changes in the plant nutrient status that, in turn, may affect seed viability. Here we took advantage of large-scale gradients in climate and atmospheric depositions between central Sweden and northern Spain, and analysed foliar nutrient concentrations and stoichiometry and seed viability in 20 juniper populations spread across Europe. Our results show that increasing temperatures can negatively affect needle N and P concentrations while enhanced potentially acidifying depositions resulted in lower foliar N and Ca concentrations. Needle C:N ratios increased with higher temperature, acidifying depositions and precipitation. By linking these patterns to seed viability, we found that low needle P, Ca and Mg concentrations were related to low seed viability. Thus, a shortage of these key elements during seed development and seed nutrient storage, can lead to anomalies and seed abortion. These findings help to explain the low seed viability of juniper in Europe and may help to assist land managers to take urgently needed conservation actions.     

Effectiveness of the sperm quality analyzer (SQA-Vp) for porcine semen analysis

The Sperm Quality Analyzer (SQA-Vp) was evaluated for assessing concentration and motility of porcine semen. Both fresh and diluted semen from 50 different boars from a commercial artificial insemination (AI) centre were investigated. For the fresh ejaculate, the concentration obtained with SQA-Vp was compared with a photometer and a haemocytometer. For the diluted samples, the concentration and motility were compared with computer assisted semen analysis (CASA) and visual sperm analysis. The agreement between methods was studied with Bland-Altman plots and the repeatability with coefficient of variation (CV) as well as Bland-Altman plots. The sperm concentration (x10⁶/ml) obtained with SQA-Vp (379.3 ± 134.9) for fresh ejaculates agreed well with concentration by the photometer (447.2 ± 154.2; difference= -67.9 x 10⁶/ml; difference + 2SD = 55.3 x 10⁶/ml; difference - 2SD = -191.1 x 10⁶/ml) and with the haemocytometer (332.8 ± 141.11; d = 92.8; d + 2SD = 448.6; d - 2SD = -263). For diluted semen, the agreement between the concentration (x10⁶/ml) assessed with SQA-Vp (20.4 ± 4.3) was good with CASA (23.2 ± 5.8; d = -2.8; d + 2SD = 6.2; d - 2 SD = -11.8) but poor with the haemocytometer (18.8 ± 5.0; d = 1.6; d+ 2SD = 12.2; d - 2SD = -9). The % motile spermatozoa assessed by SQA-Vp (65.8 ± 10.0) in diluted semen agreed well with CASA (72.2 ± 13.7; d = -6.4; d+ 2SD = 20; d - 2SD = -32.8) and with visual assessment (64.1 ± 11.6; d = 1.7; d+ 2SD = 30.9; d - 2SD = -27.5). The SQA-Vp showed a good repeatability (CV; repeatability coefficient) for measuring the concentration of both fresh (3.9%; d = 10.7; d + 2SD = 30.9; d - 2SD = -9.5) and diluted semen (2.6%; d = 1.0; d + 2SD = 2.38; d - 2SD = -0.42) and for motility (3.2%; d = 0.9; d + 2SD = 8.5; d - 2SD = -6.7). The mean SQA-Vp values fell between the other methods′ results for both fresh and diluted semen. Moreover the repeatability was acceptable. Therefore SQA-Vp can be used as a valid device for sperm quality analysis in pigs.     

Negative effects of temperature and atmospheric depositions on the seed viability of common juniper (Juniperus communis)

Background and Aims

Environmental change is increasingly impacting ecosystems worldwide. However, our knowledge about the interacting effects of various drivers of global change on sexual reproduction of plants, one of their key mechanisms to cope with change, is limited. This study examines populations of poorly regenerating and threatened common juniper (Juniperus communis) to determine the influence of four drivers of global change (rising temperatures, nitrogen deposition, potentially acidifying deposition and altering precipitation patterns) on two key developmental phases during sexual reproduction, gametogenesis and fertilization (seed phase two, SP2) and embryo development (seed phase three, SP3), and on the ripening time of seeds.

Methods

In 42 populations throughout the distribution range of common juniper in Europe, 11 943 seeds of two developmental phases were sampled. Seed viability was determined using seed dissection and related to accumulated temperature (expressed as growing degree-days), nitrogen and potentially acidifying deposition (nitrogen plus sulfur), and precipitation data.

Key Results

Precipitation had no influence on the viability of the seeds or on the ripening time. Increasing temperatures had a negative impact on the viability of SP2 and SP3 seeds and decreased the ripening time. Potentially acidifying depositions negatively influenced SP3 seed viability, while enhanced nitrogen deposition led to lower ripening times.

Conclusions

Higher temperatures and atmospheric deposition affected SP3 seeds more than SP2 seeds. However, this is possibly a delayed effect as juniper seeds develop practically independently, due to the absence of vascular communication with the parent plant from shortly after fertilization. It is proposed that the failure of natural regeneration in many European juniper populations might be attributed to climate warming as well as enhanced atmospheric deposition of nitrogen and sulfur.