The effect of elemental Zn boluses on concentrations of Zn in serum and faeces of South American camelids

ABSTRACT

Aims: To monitor the effect of using long-acting Zn boluses on the Zn status of a group of South American camelids, using measurements of concentrations of Zn in faeces and serum.

Methods: As part of a facial eczema (FE) prevention programme, 15 camelids were treated with long-acting Zn boluses designed for preventing FE in sheep. Based on bodyweight, 13 alpacas (Vicugna pacos) received two boluses (26.4?g Zn/bolus) and two llamas (Lama glama) received three boluses. In order to monitor Zn status, measurements were made of concentrations of Zn in serum and faeces immediately prior to bolus treatment (Week 0) and 4, 6, 8 and 10 weeks later. Gamma glutamyl transferase (GGT) activity in serum was measured at Weeks 0 and 8.

Results: Two alpacas regurgitated the boluses; in one case the animal was quickly re-treated but this was not possible in the second animal. Mean concentrations of Zn in faeces were higher at all time points compared to Week 0 (p?<?0.001). Peak concentrations were measured at Week 8, and concentrations >120?mg/kg fresh weight (FW), suggested as being protective in calves, were only measured in all (13/13) treated camelids at Week 6. Mean concentrations of Zn in serum differed between weeks of sampling but changes were not consistent, and concentrations did not exceed 18?μmol/L following treatment. There was no evidence of a natural sporidesmin challenge during the study period and activity of GGT in serum of all animals was <45?IU/L.

Conclusions: Treatment with Zn boluses significantly increased concentrations of Zn in faeces but not in serum, but peak concentrations in faeces were only detected 8 weeks after treatment.

Clinical Relevance: The delay in achieving concentrations of Zn in faeces which were associated with protection against FE in calves, combined with the difficulties of administering boluses to camelids, means that we do not believe that Zn boluses should be used as the primary method for preventing FE in camelids. We recommend that FE prevention in camelids should focus on minimising spore production in pasture through the use of fungicides, grazing management and alternative forages, with boluses only used when it is thought that these methods are unlikely to provide sufficient protection against FE. Such use should always be under the guidance of a veterinarian and monitoring of serum GGT activity should be used to ensure that FE control is being achieved.     

Effect of β -glucanase and xylanase supplementation of barley- and rye-based diets on caecal microbiota of broiler chickens

1. The aim was to investigate the effect of grain type (barley or rye) and exogenous enzymes (β-glucanase or xylanase) on the composition of chicken caecal microbiota as examined by classical culturing and molecular techniques (fluorescent in-situ hybridisation (FISH) and terminal-restriction fragment-length polymorphism (T-RFLP)). 2. Plate counting revealed higher total numbers of anaerobic bacteria, lactic acid bacteria and yeasts in caecal contents of birds fed with rye-based diets than in birds fed with barley-based diets. 3. As assessed by FISH analysis, the most abundant bacterial groups in the broiler caeca were Clostridium coccoides-Eubacterium rectale followed by Bacteroides sp., Lactobacillus sp./Enterococcus sp., Bifidobacterium sp. and Enterobacteriaceae. For both cereal types, the enzyme supplementation significantly decreased the relative amount of Enterobacteriaceae. 4. The T-RFLP profiles indicated that the caecal microbiota of birds receiving rye-based diets was more diverse than that of birds fed on barley-based diets. 5. Irrespective of the method applied, the results indicate that the cereal type as well as the exogenous enzyme supplementation influence the microbiota in broiler chicken caeca, and may have the effect of reducing potentially pathogenic Enterobacteriaceae populations.     

Simultaneous selection for yield-related traits and susceptibility to Fusarium head blight in spring wheat RIL population

Fusarium head blight (FHB), caused by the fungal plant pathogen Fusarium, is a fungal disease that occurs in wheat and can cause significant yield and grain quality losses. The present paper examines variation in the resistance of spring wheat lines derived from a cross between Zebra and Saar cultivars. Experiments covering 198 lines and parental cultivars were conducted in three years, in which inoculation with Fusarium culmorum was applied. Resistance levels were estimated by scoring disease symptoms on kernels. In spite of a similar reaction of parents to F. culmorum infection, significant differentiation between lines was found in all the analyzed traits. Seven molecular markers selected as linked to FHB resistance QTLs gave polymorphic products for Zebra and Saar: Xgwm566, Xgwm46, Xgwm389, Xgwm533, Xgwm156, Xwmc238, and Xgwm341. Markers Xgwm389 and Xgwm533 were associated with the rate of Fusarium-damaged kernels (FDK) as well as with kernel weight per spike and thousand kernel weight in control plants. Zebra allele of marker Xwmc238 increased kernel weight per spike and thousand kernel weight both in control and infected plants, whereas Zebra allele of marker Xgwm566 reduced the percentage of FDK and simultaneously reduced the thousand kernel weight in control and infected plants.     

Assessment of genetic effects on important breeding traits in reciprocal DH populations of winter oilseed rape (Brassica napus L.)

Here we present a study on the genetic effects of agronomic and seed quality traits in double haploid (DH) populations, which were developed by microspore culture from reciprocal F₁ hybrids produced between cultivar Californium and DH W-15. Each of the populations consisted of 25 DH lines. The field experiments were conducted in a randomized complete block design with three replications during three growing seasons. Field observations were recorded on seed yield and its structure: the number of branches and pods per plant, the number of seeds per pod, the 1000-seed weight, the content of fat in the seeds, and three unsaturated fatty acids (oleic, linoleic, linolenic) in the seed oil. In order to investigate the influence of cross direction on the studied traits, parental effects were evaluated on the basis of differences between reciprocal DH populations. The maternal effect was revealed on the number of seeds per pod and the effect of the paternal form on linolenic acid content. The occurrence of transgression effects also depended on the direction of crossing and this was particularly noticeable in terms of the number of seeds per pod. The use of multivariate statistical methods allowed for the simultaneous characterization and grouping of tested lines in terms of several traits. Graphic images of the distribution of DH lines in the space of the two first canonical variates showed a great variation between the two reciprocal populations, both in terms of yield and its components, as well as fat and those unsaturated fatty acids.     

Temperature and surface-ocean water balance of the mid-holocene tropical western pacific

Skeletal Sr/Ca and 18O/16O ratios in corals from the Great Barrier Reef, Australia, indicate that the tropical ocean surface approximately 5350 years ago was 1 degrees C warmer and enriched in 18O by 0.5 per mil relative to modern seawater. The results suggest that the temperature increase enhanced the evaporative enrichment of 18O in seawater. Transport of part of the additional atmospheric water vapor to extratropical latitudes may have sustained the 18O/16O anomaly. The reduced glacial-Holocene shift in seawater 18O/16O ratio produced by the mid-Holocene 18O enrichment may help to reconcile the different temperature histories for the last deglaciation given by coral Sr/Ca thermometry and foraminiferal oxygen-isotope records.     

Genotype-by-environment interaction of barley DH lines infected with Fusarium culmorum (W.G.Sm.) Sacc.

Infection of plants by pathogens is a biotic environmental stress. Barley plants are infected, among others, by Fusarium culmorum—a pathogen affecting seedling, head, root and stem. The infection can result in reduced yield and grain quality. The aim of the study was to compare the reaction of inoculated and non-inoculated barley doubled haploids (DHs) with F. culmorum in various environments. Thirty-four genotypes were inoculated with an isolate of F. culmorum. The experiment was carried out over 6 years. Kernel weight per spike, 1000-kernel weight and percentage of plump kernels were observed in control and inoculated plants. Genotype-by-environment (GE) interaction and its structure with reference to the environments and genotypes were analysed. Additional information about the sensitivity of healthy and infected genotypes to environments was determined by the regression analysis. Statistical computation was made using the SERGEN software. Lines were considered as unstable when their GE interaction was significant at P = 0.05. Unstable genotypes were classified as intensive or extensive according to the results of the regression analysis. It was found that infection with Fusarium decreased the stability of barley lines in different environments. Interaction of unstable infected genotypes with environments, most often, could not be explained by the regression—their response to various environmental conditions appeared to be unpredictable. Selection of lines less susceptible to biotic and abiotic stresses was possible due to comparison of classification of healthy and infected lines, which was made based on their main effects and GE interaction.     

Intraregional and inter‐regional variability of herbicide sensitivity in common arable weed populations

The question on intraregional versus inter‐regional variability in herbicide sensitivity for weed populations is of major importance, both in extrapolation of model parameters and in herbicide zonal approval procedures. We hypothesised that inter‐regional variability in herbicide sensitivity for field populations would be the same as intraregional variability for regions with similar climatic conditions. Seeds of field weed populations were collected in a Danish, German and Polish region. Herbicide sensitivity was tested in dose–response experiments in the glasshouse with flufenacet and iodosulfuron (Apera spica‐venti), florasulam and tribenuron (Tripleurospermum inodorum), diflufenican, diflufenican + flurtamone and pendimethalin (Viola arvensis). ED₅₀ values and variance components of the ED₅₀ values were estimated to describe the influence of region, year and population. The regions accounted for a maximum of 26% of the variance and always less than the variance accounted for by individual populations. Sensitivity indices (SI₅₀) were calculated as the ratio between ED₅₀ of the test population and a reference population. There was considerable intraregional variability in SI₅₀ values and SI₅₀ values from a single region did not consistently differ from other regions. The large intraregional variability in herbicide sensitivity between populations, with no evidence of resistance, is of interest both for zonal evaluation of herbicides and resistance research. For practical weed management, we conclude that dose–response functions can be transferred between the study regions, for example for the common use in decision support systems with proper insurance for the control of less sensitive populations.     

The influence of alternative plant propagation and stand establishment techniques on survival and growth of eastern cottonwood (Populus deltoides Bartr.) clones

Four eastern cottonwood clones, including standard operational clone ST66 and three advanced clonal selections were produced and included in a test utilizing five different plant propagation methods. Despite relatively large first-year growth differences among clones, all clones demonstrated similar responses to the treatments and clone × cutting treatment interactions were generally non-significant. The effects of changing cutting lengths are consistent with previous studies which indicated the potential for increased plant survival and growth with increased cutting lengths. Differences in stored carbohydrate reserves alone do not appear to completely control first-year growth and development of cuttings. First-year growth of 51 cm long cuttings planted 30.5 cm deep was greater than the same cuttings planted 48 cm deep. Stem form of plants derived from whip-tip propagation did not differ from plants derived from standard, unrooted cuttings. This propagation method offers the potential of far greater production capacity from a cutting orchard and rapid bulk-up of new or limited clones. Stand uniformity assessments suggest that surviving trees of each individual cutting treatment exhibit similar levels of growth variation. Optimization of plantation establishment techniques has the potential to increase growth of young Populus plantations.