An evaluation of potential dustbathing substrates for commercial broiler chickens

Provision of an appropriate dustbathing substrate may allow broiler chickens to satisfy a natural motivation and give them an opportunity to exercise. The main aim of this study was to evaluate the extent to which different substrates promote dustbathing behaviour in broilers. The trial was replicated over three production cycles in one commercial broiler house, with ~22 000 Ross broilers housed per cycle. The birds were provided with access to five experimental substrates from day 10 of the 6-week production cycle. The substrates included the following: (1) peat (P), (2) oat hulls (OH), (3) straw pellets (SP), (4) clean wood shavings (WS), and (5) litter control (C). The substrates were provided in 15 steel rings (1.1 m in diameter, three rings per substrate) dispersed throughout the house. The level of occupancy of the rings, behaviours performed in each substrate, and the effect of ring position (central or edge of house) were assessed in weeks 3, 4, 5 and 6 using scan sampling from video footage. Where substrates successfully promoted dustbathing, the length and components of the bouts (including number of vertical wing shakes and ground pecks) were also assessed. Results showed that birds used P significantly more than the remaining substrates for dustbathing (P<0.001). Oat hulls were the second most preferred substrate for dustbathing, with significantly more birds dustbathing in the OH compared with SP, WS and C (P<0.001). The least sitting inactive was also seen in the P and OH rings compared with the SP, WS and C (P<0.001). The highest levels of foraging were recorded in the P, OH and WS compared with SP and the C. Position of the rings did not affect the types of behaviours performed in any substrate, although overall more birds were counted in the central compared with edge rings (P=0.001). More detailed information on dustbathing behaviour was only recorded in the P and OH treatments, and there were no differences in the length of dustbathing bout, or components of the bout between them (P>0.05). The use of OH is likely to be more environmentally sustainable than that of P, and our results suggest that this substrate is relatively successful in promoting dustbathing. However, a preference was still observed for P and further work should investigate whether other suitable substrates could better reflect its qualities.     

Variability and periodicity of dustbathing behaviour in Japanese quail (Coturnix coturnix japonica)

The purpose of this study was to determine the amount of time invested in, and the distribution of, dustbathing behaviour over the course of a day. Amount of time spent dustbathing, preening, ingesting, and engaging in sexual/agonistic activities by individual quail was recorded for the light portion of selected photoperiods. Results indicate consistency in amounts of dustbathing exhibited by individual birds under the different photoperiods; amount of time spent dustbathing was intermediate with respect to the other behaviours recorded. A daily peak period of dustbathing was evident except under constant light conditions. These results are explained on the basis of selective pressures operating to maximize the efficiency of dustbathing.     

Regulation of dustbathing in feathered and featherless domestic chicks: the Lorenzian model revisited

In Lorenz's 'psychohydraulic model', behaviour is regulated by performance: the motivation to perform a behaviour builds up with time and can be reduced only by performance itself. However, a convincing example of Lorenzian regulation has been lacking. We studied dustbathing in featherless and feathered chicks, Gallus gallus domesticus, the latter trained to dustbathe on glass with sand underneath. In both cases the function, that is, plumage cleaning, was eliminated. In both featherless and feathered chicks dustbathing increased with time since the last performance as found in normal dustbathing, and there was a compensatory adjustment when the amount of previous dustbathing was artificially reduced. We suggest that the amount of dustbathing performed at any one time may be controlled by the cooperative action of a deprivation or timer mechanism and a counter mechanism. The timer mechanism responds to the time since the last performance, whereas the counter mechanism records the number of elements during that last dustbathing. Alternatively, there may be a single mechanism that continually records the deficit in the amount of dustbathing performed. Lorenz's model may be valid not only for dustbathing in fowl but also for other comfort behaviours. Our results suggest the existence of behavioural needs that can be satisfied only by performance. Copyright 1999 The Association for the Study of Animal Behaviour.     

Working for a dustbath: are hens increasing pleasure rather than reducing suffering?

Dustbathing is one of the major behavioural systems of domestic fowl that is constrained by commercial caging systems. Although research conducted over the last 20 years has revealed a great deal about causation of dustbathing, attempts at measuring the importance to hens of having access to dustbathing substrate have proven difficult. Various economic techniques, operant conditioning and learning trials have been used to determine whether hens have a 'need' for dustbathing substrate or 'think' about dustbathing in the absence of substrate. In this study, we measured hens' willingness to work to obtain substrate for dustbathing using a vertically swinging door to which weights could be added. Hens were trained to push through the door to enter a goal box containing peat moss. The hens were subjected to two series of trials to compare the maximum weight that they would push to open the door when living in a cage and deprived of dustbathing substrate, with the maximum weight that they would push when living in a pen furnished with litter and a dustbath (non-deprived). Of the 10 hens that opened the door for access to peat moss, six hens pushed more weight when deprived, three hens pushed more weight when non-deprived and one hen pushed an equal amount of weight. Overall, the hens tended to push more weight (860+/-95.6 vs. 682.5+/-83.3 g; P<0.10, one-tailed paired t-test) and tended to make more attempts to open the door (P<0.10) when they were deprived than when they were non-deprived. Significantly more trials resulted in dustbathing when hens were deprived (P<0.01) suggesting that following deprivation, the hens were, in fact, more motivated to dustbathe. The results of these trials indicate that although deprived hens may be more motivated to dustbathe, and that most hens may be willing to work to obtain a dusty substrate when they can see it, they are not necessarily willing to work harder when they are in a state of deprivation than when they have recently dustbathed. These results are very difficult to explain using a 'needs' model of motivation in which deprivation leads to a state of suffering. They are much more consistent with an 'opportunity' model of motivation in which performance of the behaviour, when the opportunity presents itself, leads to a state of pleasure.     

Preen gland function in layer fowls: factors affecting morphology and feather lipid levels

The effects of age and external factors on preen gland morphology and feather lipid concentrations in layer fowl (Gallus domesticus) have not previously been described. This work examines how floor substrate, whether a bird is feather pecked or not, and age influence both gross and histological morphology. Furthermore, the effects of age, beak trimming and floor substrate on feather lipid concentration (mg lipid per g feathers) are investigated. Neither absolute nor relative preen gland weight were reliably affected by floor substrate or feather pecked status. However, these parameters were strongly affected by changes in bird age and related body weight changes. The microstructures of the gland also increased consistently with age. Feather lipid concentration generally increased with age. Feather lipid was strongly influenced by the presence or absence of a dustbathing substrate. Of all the parameters tested here, the age and growth of the bird had the greatest effects on preen gland development. Feather lipid concentration is also influenced by age, and by the presence or absence of a dustbathing substrate.     

Housing and dustbathing effects on northern fowl mites (Ornithonyssus sylviarum) and chicken body lice (Menacanthus stramineus) on hens

Hen housing (cage or cage-free) did not impact overall abundances of northern fowl mites, Ornithonyssus sylviarum (Canestrini & Fanzago) (Acari: Macronyssidae), or chicken body lice, Menacanthus stramineus (Nitzsch) (Phthiraptera: Menoponidae). Cage-free hens received a dustbox with sand plus diatomaceous earth (DE), kaolin clay or sulphur. Weekly use varied from none to 100% of hens; 73% of hens used the dustbox at least once. Ectoparasite populations on dustbathing hens (users) were compared with those on non-user cage-free and caged hens. All materials reduced ectoparasites on user hens by 80-100% after 1 week of dustbox use. Diatomaceous earth and kaolin failed to reduce ectoparasites on non-user hens, and ectoparasites on user hens recovered after dustbox removal. A sulphur dustbox eliminated mites from all hens (including non-users) within 2-4 weeks. Residual sulphur controlled mites until the end of the experiment (up to 9 weeks), even after the dustbox was removed. Louse populations on hens using the sulphur dustbox were reduced in 1-2 weeks. Residual sulphur effects were less evident in lice, but the use of a sulphur dustbox by a higher proportion of hens extended louse control to all hens. This is the first experimental study to show that bird dustbathing in naturally and widely available dust materials (particularly kaolin) can suppress ectoparasites and thus the behaviour is probably adaptive.     

Using Publicly Available Forest Inventory Data in Climate-Based Models of Tree Species Distribution: Examining Effects of True Versus Altered Location Coordinates

Species distribution models (SDMs) were built with US Forest Inventory and Analysis (FIA) publicly available plot coordinates, which are altered for plot security purposes, and compared with SDMs built with true plot coordinates. Six species endemic to the western US, including four junipers (Juniperus deppeana var. deppeana, J. monosperma, J. occidentalis, J. osteosperma) and two piñons (Pinus edulis, P. monophylla), were analyzed. The presence–absence models based on current climatic variables were generated over a series of species-specific modeling extents using Random Forests and applied to forecast climatic conditions. The distributions of predictor variables sampled with public coordinates were compared to those sampled with true coordinates using t tests with a Bonferroni adjustment for multiple comparisons. Public- and true-based models were compared using metrics of classification accuracy. The modeled current and forecast distributions were compared in terms of their overall areal agreement and their geographic mean centroids. Comparison of the underlying distributions of predictor variables sampled with true versus public coordinates did not indicate a significant difference for any species at any extent. Both the public- and true-based models had comparable classification accuracies across extent for each species, with the exception of one species, J. occidentalis. True-based models produced geographic distributions with smaller areas under current and future scenarios. The greatest areal difference occurred in the species with the lowest modeled accuracies (J. occidentalis), and had a forecast distribution which diverged severely. The other species had forecast distributions with similar magnitudes of modeled distribution shifts.     

Finite element analyses of human vertebral bodies embedded in polymethylmethalcrylate or loaded via the hyperelastic intervertebral disc models provide equivalent predictions of experimental strength

Quantitative computer tomography (QCT)-based finite element (FE) models of vertebral body provide better prediction of vertebral strength than dual energy X-ray absorptiometry. However, most models were validated against compression of vertebral bodies with endplates embedded in polymethylmethalcrylate (PMMA). Yet, loading being as important as bone density, the absence of intervertebral disc (IVD) affects the strength. Accordingly, the aim was to assess the strength predictions of the classic FE models (vertebral body embedded) against the in vitro and in silico strengths of vertebral bodies loaded via IVDs. High resolution peripheral QCT (HR-pQCT) were performed on 13 segments (T11/T12/L1). T11 and L1 were augmented with PMMA and the samples were tested under a 4° wedge compression until failure of T12. Specimen-specific model was generated for each T12 from the HR-pQCT data. Two FE sets were created: FE-PMMA refers to the classical vertebral body embedded model under axial compression; FE-IVD to their loading via hyperelastic IVD model under the wedge compression as conducted experimentally. Results showed that FE-PMMA models overestimated the experimental strength and their strength prediction was satisfactory considering the different experimental set-up. On the other hand, the FE-IVD models did not prove significantly better (Exp/FE-PMMA: R²=0.68; Exp/FE-IVD: R²=0.71, p=0.84). In conclusion, FE-PMMA correlates well with in vitro strength of human vertebral bodies loaded via real IVDs and FE-IVD with hyperelastic IVDs do not significantly improve this correlation. Therefore, it seems not worth adding the IVDs to vertebral body models until fully validated patient-specific IVD models become available.     

Predictive Models for Escherichia coli Concentrations at Inland Lake Beaches and Relationship of Model Variables to Pathogen Detection

Predictive models, based on environmental and water quality variables, have been used to improve the timeliness and accuracy of recreational water quality assessments, but their effectiveness has not been studied in inland waters. Sampling at eight inland recreational lakes in Ohio was done in order to investigate using predictive models for Escherichia coli and to understand the links between E. coli concentrations, predictive variables, and pathogens. Based upon results from 21 beach sites, models were developed for 13 sites, and the most predictive variables were rainfall, wind direction and speed, turbidity, and water temperature. Models were not developed at sites where the E. coli standard was seldom exceeded. Models were validated at nine sites during an independent year. At three sites, the model resulted in increased correct responses, sensitivities, and specificities compared to use of the previous day''s E. coli concentration (the current method). Drought conditions during the validation year precluded being able to adequately assess model performance at most of the other sites. Cryptosporidium, adenovirus, eaeA (E. coli), ipaH (Shigella), and spvC (Salmonella) were found in at least 20% of samples collected for pathogens at five sites. The presence or absence of the three bacterial genes was related to some of the model variables but was not consistently related to E. coli concentrations. Predictive models were not effective at all inland lake sites; however, their use at two lakes with high swimmer densities will provide better estimates of public health risk than current methods and will be a valuable resource for beach managers and the public.     

Drivers of Solidago species invasion in Central Europe—Case study in the landscape of the Carpathian Mountains and their foreground

AimThe invasion process is a complex, context‐dependent phenomenon; nevertheless, it can be described using the PAB framework. This framework encompasses the joint effect of propagule pressure (P), abiotic characteristics of the environment (A), and biotic characteristics of both the invader and recipient vegetation (B). We analyzed the effectiveness of proxies of PAB factors to explain the spatial pattern of Solidago canadensis and S. gigantea invasion using invasive species distribution models.LocationCarpathian Mountains and their foreground, Central Europe.MethodsThe data on species presence or absence were from an atlas of neophyte distribution based on a 2 × 2 km grid, covering approximately 31,200 km² (7,752 grid cells). Proxies of PAB factors, along with data on historical distribution of invaders, were used as explanatory variables in Boosted Regression Trees models to explain the distribution of invasive Solidago. The areas with potentially lower sampling effort were excluded from analysis based on a target species approach.ResultsProxies of the PAB factors helped to explain the distribution of both S. canadensis and S. gigantea. Distributions of both species were limited climatically because a mountain climate is not conducive to their growth; however, the S. canadensis distribution pattern was correlated with proxies of human pressure, whereas S. gigantea distribution was connected with environmental characteristics. The varied responses of species with regard to distance from their historical distribution sites indicated differences in their invasion drivers.Main conclusionsProxies of PAB are helpful in the choice of explanatory variables as well as the ecological interpretation of species distribution models. The results underline that human activity can cause variation in the invasion of ecologically similar species.     

Staphylococcus aureus Growth Boundaries: Moving towards Mechanistic Predictive Models Based on Solute-Specific Effects

The formulation of shelf-stable intermediate-moisture products is a critical food safety issue. Therefore, knowing the precise boundary for the growth-no-growth interface of Staphylococcus aureus is necessary for food safety risk assessment. This study was designed to examine the effects of various humectants and to produce growth boundary models as tools for risk assessment. The molecular mobility and the effects of various physical properties of humectants, such as their glass transition temperatures, their membrane permeability, and their ionic and nonionic properties, on S. aureus growth were investigated. The effects of relative humidity (RH; 84 to 95%, adjusted by sucrose plus fructose, glycerol, or NaCl), initial pH (4.5 to 7.0, adjusted by HCl), and potassium sorbate concentration (0 or 1,000 ppm) on the growth of S. aureus were determined. Growth was monitored by turbidity over a 24-week period. Toxin production was determined by enterotoxin assay. The 1,792 data points generated were analyzed by LIFEREG procedures (SAS Institute, Inc., Cary, N.C.), which showed that all parameters studied significantly affected the growth responses of S. aureus. Differences were observed in the growth-no-growth boundary when different humectants were used to achieve the desired RH values in both the absence and the presence of potassium sorbate. Sucrose plus fructose was most inhibitory at neutral pH values, while NaCl was most inhibitory at low pH values. The addition of potassium sorbate greatly increased the no-growth regions, particularly when pH was <6.0. Published kinetic growth and survival models were compared with boundary models developed in this work. The effects of solutes and differences in modeling approaches are discussed.     

The combined effect of nitrogen,phosphorus and iron on the growth of Selenastrum gracile reinsch

Mathematical regression models are given which describe the dependence of the growth of the alga Selenastrum gracile Reinsch on the available concentrations of nitrogen, phosphorus and iron. From these models the optimum concentrations of these elements were obtained. The culture growth in its phases is affected by phosphorus and iron and by their interaction effect, while in later phases growth is accelerated by nitrogen and phosphorus and by their interaction effect.     

Construction of Predictive Models to Describe Apparent and Complex Viscosity Values of O/W Model System Meat Emulsions Using Adaptive Neuro – Fuzzy Inference System (ANFIS) and Artificial Neural Networks (ANN)

This paper introduces an adaptive neuro ?C fuzzy inference system (ANFIS) and artificial neural networks (ANN) models to predict the apparent and complex viscosity values of model system meat emulsions. Constructed models were compared with multiple linear regression (MLR) modeling based on their estimation performance. The root mean square error (RMSE), mean absolute error (MAE) and determination coefficient (R ²) statistics were performed to evaluate the accuracy of the models tested. Comparison of the models showed that the ANFIS model performed better than the ANN and MLR models to estimate the apparent and complex viscosity values of the model system meat emulsions. Coefficients of determination (R ²) calculated for estimation performance of ANFIS modeling to predict apparent and complex viscosity of the emulsions were 0.996 and 0.992, respectively. Similar R ² values (0.991 and 0.985) were obtained when estimating the performance of the ANN model. In the present study, use of the constructed ANFIS models can be suggested to effectively predict the apparent and complex viscosity values of model system meat emulsions.     

Characterization of novel wheat NBS domain-containing sequences and their utilization,in silico,for genome-scale R-gene mining

In crop improvement, the isolation, cloning and transfer of disease resistance genes (R-genes) is an ultimate goal usually starting from tentative R-gene analogs (RGAs) that are identified on the basis of their structure. For bread wheat, recent advances in genome sequencing are supporting the efforts of wheat geneticists worldwide. Among wheat R-genes, nucleotide-binding site (NBS)-encoding ones represent a major class. In this study, we have used a polymerase chain reaction-based approach to amplify and clone NBS-type RGAs from a bread wheat cultivar, ‘Salambo 80.’ Four novel complete ORF sequences showing similarities to previously reported R-genes/RGAs were used for in silico analyses. In a first step, where analyses were focused on the NBS domain, these sequences were phylogenetically assigned to two distinct groups: a first group close to leaf rust Lr21 resistance proteins; and a second one similar to cyst nematode resistance proteins. In a second step, sequences were used as initial seeds to walk up and downstream the NBS domain. This procedure enabled identifying 8 loci ranging in size between 2,115 and 7,653 bp. Ab initio gene prediction identified 8 gene models, among which two had complete ORFs. While GenBank survey confirmed the belonging of sequences to two groups, subsequent characterization using IWGSC genomic and proteomic data showed that the 8 gene models, reported in this study, were unique and their loci matched scaffolds on chromosome arms 1AS, 1BS, 4BS and 1DS. The gene model located on 1DS is a pseudo-Lr21 that was shown to have an NBS-LRR domain structure, while the potential association of the RGAs, here reported, is discussed. This study has produced novel R-gene-like loci and models in the wheat genome and provides the first steps toward further elucidation of their role in wheat disease resistance.     

Microbial metabolic exchange in 3D

Mono- and multispecies microbial populations alter the chemistry of their surrounding environments during colony development thereby influencing multicellular behavior and interspecies interactions of neighboring microbes. Here we present a methodology that enables the creation of three-dimensional (3D) models of a microbial chemotype that can be correlated to the colony phenotype through multimodal imaging analysis. These models are generated by performing matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) imaging mass spectrometry (IMS) on serial cross-sections of microbial colonies grown on 8 mm deep agar, registering data sets of each serial section in MATLAB to create a model, and then superimposing the model with a photograph of the colonies themselves. As proof-of-principle, 3D models were used to visualize metabolic exchange during microbial interactions between Bacillus subtilis and Streptomyces coelicolor, as well as, Candida albicans and Pseudomonas aeruginosa. The resulting models were able to capture the depth profile of secreted metabolites within the agar medium and revealed properties of certain mass signals that were previously not observable using two-dimensional MALDI-TOF IMS. Most significantly, the 3D models were capable of mapping previously unobserved chemical distributions within the array of sub-surface hyphae of C. albicans and how this chemistry is altered by the presence of P. aeruginosa, an opportunistic pathogen known to alter virulence of C. albicans. It was determined that the presence of C. albicans triggered increased rhamnolipid production by P. aeruginosa, which in turn was capable of inhibiting embedded hyphal growth produced beneath the C. albicans colony at ambient temperature.     

Isolation and antioxidant activities of polysaccharides extracted from the shoots of Phyllostachys edulis (Carr.)

Polysaccharides extracted from Phyllostachys edulis (Carr.) are a group of hetero polysaccharides, and their antioxidant activities were investigated employing various established in vitro systems. Available data obtained with in vitro models suggested that among the three samples, B1 (extraction with water) showed significant inhibitory effects on superoxide radical and hydroxyl radical; its reducing power was also the strongest among the three samples. These results clearly establish the possibility that polysaccharides extracted from P. edulis could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress. However, comprehensive studies need to be conducted in experimental animal models.     

Kinetic modeling using S-systems and lin-log approaches

We analyze the growth dynamics and production of an industrially interesting amino acid in a recombinant Escherichia coli strain, using in parallel two alternative modeling frameworks, namely S-systems and lin-log models. These models have identical steady-state solutions, but differ in their representation of transients. The models were parameterized with data from two bioprocesses that differed in their initial culture concentrations and then used to predict responses under yet a different initial culture regimen. Among the S-system models, several alternatives representing slightly different pathway structures, were tested. All were found to be capable of capturing the dynamics of all variables in the test systems and also of predicting the dynamic responses under new conditions. The lin-log models also captured the dynamics, but not as well as the S-system models. A probable reason for the inferior performance of lin-log models is their intrinsic property of not representing situations well where variable concentrations are moderately small.     

Moving in and out of Poverty: The Within-Individual Association between Socioeconomic Status and Juvenile Delinquency

A family’s SES can be changeable over time. This study was the first to investigate if such within-individual changes in family SES are associated with parallel fluctuations in boys’ delinquent behavior from childhood to adolescence. Participants were a community sample of boys and their caregivers (N = 503) who were assessed annually for ten consecutive years spanning ages 7–18. Fixed effects models revealed that changes in familial SES were related to changes in delinquency: Youths were more likely to offend during years in which their parents’ SES was lower than during years in which their parents’ SES was higher. Contrary to expectations, we found no evidence that this association was accounted for by families moving to different neighborhoods or by changes in parenting. Since within-individual models provide a stricter test of causality than between-individual models, these findings support claims that impacting familial SES may have a direct effect on youths’ delinquency.