Phables: from fragmented assemblies to high-quality bacteriophage genomes.

MOTIVATION: Microbial communities have a profound impact on both human health and various environments. Viruses infecting bacteria, known as bacteriophages or phages, play a key role in modulating bacterial communities within environments. High-quality phage genome sequences are essential for advancing our understanding of phage biology, enabling comparative genomics studies and developing phage-based diagnostic tools. Most available viral identification tools consider individual sequences to determine whether they are of viral origin. As a result of challenges in viral assembly, fragmentation of genomes can occur, and existing tools may recover incomplete genome fragments. Therefore, the identification and characterization of novel phage genomes remain a challenge, leading to the need of improved approaches for phage genome recovery. RESULTS: We introduce Phables, a new computational method to resolve phage genomes from fragmented viral metagenome assemblies. Phables identifies phage-like components in the assembly graph, models each component as a flow network, and uses graph algorithms and flow decomposition techniques to identify genomic paths. Experimental results of viral metagenomic samples obtained from different environments show that Phables recovers on average over 49% more high-quality phage genomes compared to existing viral identification tools. Furthermore, Phables can resolve variant phage genomes with over 99% average nucleotide identity, a distinction that existing tools are unable to make. AVAILABILITY AND IMPLEMENTATION: Phables is available on GitHub at https://github.com/Vini2/phables.

A new network analysis model in anorexia nervosa patients based on self-reported eating disorder symptoms, psychological distress, and cognitive flexibility.

OBJECTIVES: Cognitive flexibility and psychological distress, such as depression and anxiety, have been implicated in the aetiology of Anorexia Nervosa (AN). Despite the known associations between eating disorder (ED) symptoms, depression, anxiety, and cognitive flexibility, the specific pathways that connect these constructs are unclear. We therefore used network analysis to examine the relationship between these symptoms in an AN sample. METHODS: One hundred and ninety-three treatment-seeking individuals diagnosed with AN (95.6% female, M = 26.89 [SD = 9.45] years old) completed self-report measures assessing depression, anxiety, cognitive flexibility, and ED symptoms. To determine each symptom's influence in the network, we calculated the expected influence. RESULTS: The two relationships with the greatest edges were those between (1) weight/shape concerns and eating/dietary restraint and (2) weight/shape concerns and psychological distress (a measure that combined depression and anxiety). Cognitive flexibility was not connected to weight/shape concerns but had negative partial associations with eating concerns/dietary restraint and psychological distress. There was also a slight, non-zero connection between eating concerns/dietary restraint and psychological distress. CONCLUSIONS: The findings underscore the importance of weight/shape, eating/dietary concerns, and psychological distress in the AN network and suggest that addressing cognitive flexibility may be a useful target for eating concerns/dietary restraint and psychological distress. Future studies assessing the longitudinal course of psychopathology within the AN network structure may help in identifying whether specific symptoms function as risk factors or maintaining factors for this co-occurrence.

Striving to support the supporters: A mixed methods evaluation of the strive support groups for caregivers of individuals with an eating disorder.

This mixed-methods study evaluated a peer-led support group for ED caregivers; the Eating Disorders Families Australia strive support groups. Quantitatively, 110 past or current strive attendees completed an online survey assessing their own and their care recipients' demographic profiles, strive's impact on caregiving experiences, and caregivers' psychological distress, burden, caregiving skills and self-efficacy. Qualitative assessment comprised open-ended survey questions about caregivers' strive experiences, reinforced by in-depth focus group assessment of nine participants. Quantitative analyses revealed that participants felt more confident and supported, and less isolated in their caregiving since attending strive. Caregivers displayed mid-range psychological distress and caregiver burden, and moderate caregiver skills and self-efficacy. Qualitatively, the most helpful aspects of strive were the shared experience among participants, education, and support. The most difficult elements were emotional distress and overly dominant members. Reflections discussed the necessity of caregiver support and factors impacting strive attendance. Participants recommended resuming face-to-face contact and differentiating groups based on participant characteristics (e.g. care recipients' age/stage of illness). The current findings provide support for the importance and overall positive contribution of support groups led by caregivers, such as strive.

Validating and developing a shortened version of the detail and flexibility (DFlex) questionnaire for eating disorders, anxiety and depression.

OBJECTIVE: To validate the original and a shortened version of the Detail and Flexibility (DFlex) Questionnaire. METHOD: Confirmatory factor analyses, internal consistency, and discriminant validity estimates were conducted within individuals with a diagnosis of an eating disorder (ED) (n = 124), an anxiety disorder and/or depression (n = 219), and a community sample (n = 852) (Part 1). Convergent validity of the DFlex through comparisons with the Autism Spectrum Quotient, Wisconsin Card Sorting Task, and Group Embedded Figures Task was undertaken within a combined ED and community sample (N = 68). Test-retest reliability of the DFlex was also examined across 2 years in a community sample (N = 85) (Part 2). RESULTS: The original factor structure of the DFlex was not supported. Hence, a shortened version, the DFlex-Revised, was developed. Good discriminant validity was obtained for the DFlex and DFlex-Revised, however, support for convergent validity was mixed. Finally, the 2-year test-retest reliability for the two DFlex versions was found to be low, suggesting potential malleability in construct over this timeframe. CONCLUSIONS: Further research is needed to validate the DFlex in clinical and non-clinical populations using different neurocognitive tests. Test-retest, using varied time intervals, should also be assessed.

Integrating human iPSC-derived macrophage progenitors into retinal organoids to generate a mature retinal microglial niche.

In the retina, microglia are resident immune cells that are essential for development and function. Retinal microglia play a central role in mediating pathological degeneration in diseases such as glaucoma, retinitis pigmentosa, age-related neurodegeneration, ischemic retinopathy, and diabetic retinopathy. Current models of mature human retinal organoids (ROs) derived from iPS cell (hiPSC) do not contain resident microglia integrated into retinal layers. Increasing cellular diversity in ROs by including resident microglia would more accurately represent the native retina and better model diseases in which microglia play a key role. In this study, we develop a new 3D in vitro tissue model of microglia-containing retinal organoids by co-culturing ROs and hiPSC-derived macrophage precursor cells (MPCs). We optimized the parameters for successful integration of MPCs into retinal organoids. We show that while in the ROs, MPCs migrate to the equivalent of the outer plexiform layer where retinal microglia cells reside in healthy retinal tissue. While there, they develop a mature morphology characterized by small cell bodies and long branching processes which is only observed in vivo. During this maturation process these MPCs cycle through an activated phase followed by a stable mature microglial phase as seen by the down regulation of pro-inflammatory cytokines and upregulation of anti-inflammatory cytokines. Finally, we characterized mature ROs with integrated MPCs using RNAseq showing an enrichment of cell-type specific microglia markers. We propose that this co-culture system may be useful for understanding the pathogenesis of retinal diseases involving retinal microglia and for drug discovery directly in human tissue.

Knowing and Naming: Phage Annotation and Nomenclature for Phage Therapy.

Bacteriophages, or phages, are viruses that infect bacteria shaping microbial communities and ecosystems. They have gained attention as potential agents against antibiotic resistance. In phage therapy, lytic phages are preferred for their bacteria killing ability, while temperate phages, which can transfer antibiotic resistance or toxin genes, are avoided. Selection relies on plaque morphology and genome sequencing. This review outlines annotating genomes, identifying critical genomic features, and assigning functional labels to protein-coding sequences. These annotations prevent the transfer of unwanted genes, such as antimicrobial resistance or toxin genes, during phage therapy. Additionally, it covers International Committee on Taxonomy of Viruses (ICTV)-an established phage nomenclature system for simplified classification and communication. Accurate phage genome annotation and nomenclature provide insights into phage-host interactions, replication strategies, and evolution, accelerating our understanding of the diversity and evolution of phages and facilitating the development of phage-based therapies.

"Can you see me?" Videoconferencing and eating disorder risk during COVID-19: Anxiety, impairment, and mediators.

OBJECTIVE: The use of videoconferencing has increased during the pandemic, creating prolonged exposure to self-image. This research aimed to investigate whether eating disorder (ED) risk was associated with videoconferencing performance for work or study and to explore whether the use of safety behaviors and self-focused attention mediated the relationship between ED risk and perceived control over performance anxiety, impaired engagement, or avoidance of videoconferencing for work or study. METHOD: In 2020, an online survey was distributed within Australia to those aged over 18 years via academic and social networks, measuring: use of videoconferencing for work/study, demographics, ED risk, safety behaviors for appearance concerns, self-focused attention, perceived control over performance anxiety, perceived engagement impairment, and avoidance of videoconferencing. A total of 640 participants (77.3% female, Mage  = 26.2 years) returned complete data and were included in analyses. RESULTS: 245 participants (38.7%) were considered at-risk for EDs (SCOFF > 2). Those at-risk reported significantly more safety behaviors, self-focused attention, impaired engagement, and avoidance, plus lower perceived control over performance anxiety than those not at-risk. Multiple mediation models found the effects of ED risk on control over performance anxiety, impaired engagement, and avoidance were partially mediated by safety behaviors and self-focused attention. DISCUSSION: Our cross-sectional findings suggest videoconferencing for work/study-related purposes is associated with performance anxiety, impaired engagement, and avoidance among individuals at-risk for EDs. Poorer videoconferencing outcomes appear more strongly related to social anxiety variables than ED status. Clinicians and educators may need to provide extra support for those using videoconferencing. PUBLIC SIGNIFICANCE: Because videoconferencing often involves seeing your own image (via self-view) we wondered whether the appearance concerns experienced by those with eating disorders (EDs) might interfere with the ability to focus on or to contribute to work/study videoconferencing meetings. We found that although those with EDs experience more impairments in their videoconferencing engagement/contribution, these were linked just as strongly to social anxiety as they were to appearance concerns.

Tonight, I'm disordered eating: The effects of food delivery app use, loneliness, and mood on daily body dissatisfaction and disordered eating urges.

With the recent proliferation of food delivery applications ('apps'; FDAs), accessing a meal is more convenient and immediate than ever. However, these apps may foster dysregulated eating behaviours, including maladaptive eating to cope with negative emotional states. Using ecological momentary assessment (EMA), the current study assessed whether FDA use at baseline predicted levels of EMA-assessed disordered eating urges and body dissatisfaction, whether negative mood and loneliness impacted disordered eating urges and body dissatisfaction at the state level, and whether the latter relationships were moderated by FDA usage frequency. Participants (N = 483; 78.7% women; 20.1% men; 1.2% other) completed a baseline questionnaire and were characterised as current FDA users (49.3%) or non-users (50.7%). Participants then completed a smartphone-facilitated investigation into their experiences of loneliness, negative mood, body dissatisfaction, and disordered eating urges, six times per day for 7-days. Across the entire sample, current FDA users at baseline reported greater EMA-assessed urges to overeat. At the state level, loneliness and negative mood predicted greater body dissatisfaction, with the latter also predicting greater urges for restrictive eating and overeating. Among current FDA users at baseline, at the state level, loneliness predicted greater body dissatisfaction, and negative mood predicted greater body dissatisfaction and urges for overeating. No moderating effects were observed for baseline FDA usage frequency. These results elucidate FDA use and daily experiences of loneliness and negative mood as factors elevating eating disorder (ED)-related risk. Further extensions of this research with nuanced measures of state FDA use are required.

Deletion of Tgfß signal in activated microglia prolongs hypoxia-induced retinal neovascularization enhancing Igf1 expression and retinal leukostasis.

Retinal neovascularization (NV) is the major cause of severe visual impairment in patients with ischemic eye diseases. While it is known that retinal microglia contribute to both physiological and pathological angiogenesis, the molecular mechanisms by which these glia regulate pathological NV have not been fully elucidated. In this study, we utilized a retinal microglia-specific Transforming Growth Factor-ß (Tgfß) receptor knock out mouse model and human iPSC-derived microglia to examine the role of Tgfß signaling in activated microglia during retinal NV. Using a tamoxifen-inducible, microglia-specific Tgfß receptor type 2 (Tgfßr2) knockout mouse [Tgfßr2 KO (ΔMG)] we show that Tgfß signaling in microglia actively represses leukostasis in retinal vessels. Furthermore, we show that Tgfß signaling represses expression of the pro-angiogenic factor, Insulin-like growth factor 1 (Igf1), independent of Vegf regulation. Using the mouse model of oxygen-induced retinopathy (OIR) we show that Tgfß signaling in activated microglia plays a role in hypoxia-induced NV where a loss in Tgfß signaling microglia exacerbates and prolongs retinal NV in OIR. Using human iPSC-derived microglia cells in an in vitro assay, we validate the role of Transforming Growth Factor-ß1 (Tgfß1) in regulating Igf1 expression in hypoxic conditions. Finally, we show that Tgfß signaling in microglia is essential for microglial homeostasis and that the disruption of Tgfß signaling in microglia exacerbates retinal NV in OIR by promoting leukostasis and Igf1 expression.

Serine and Lipid Metabolism in Macular Disease and Peripheral Neuropathy.

BACKGROUND: Identifying mechanisms of diseases with complex inheritance patterns, such as macular telangiectasia type 2, is challenging. A link between macular telangiectasia type 2 and altered serine metabolism has been established previously. METHODS: Through exome sequence analysis of a patient with macular telangiectasia type 2 and his family members, we identified a variant in SPTLC1 encoding a subunit of serine palmitoyltransferase (SPT). Because mutations affecting SPT are known to cause hereditary sensory and autonomic neuropathy type 1 (HSAN1), we examined 10 additional persons with HSAN1 for ophthalmologic disease. We assayed serum amino acid and sphingoid base levels, including levels of deoxysphingolipids, in patients who had macular telangiectasia type 2 but did not have HSAN1 or pathogenic variants affecting SPT. We characterized mice with low serine levels and tested the effects of deoxysphingolipids on human retinal organoids. RESULTS: Two variants known to cause HSAN1 were identified as causal for macular telangiectasia type 2: of 11 patients with HSAN1, 9 also had macular telangiectasia type 2. Circulating deoxysphingolipid levels were 84.2% higher among 125 patients with macular telangiectasia type 2 who did not have pathogenic variants affecting SPT than among 94 unaffected controls. Deoxysphingolipid levels were negatively correlated with serine levels, which were 20.6% lower than among controls. Reduction of serine levels in mice led to increases in levels of retinal deoxysphingolipids and compromised visual function. Deoxysphingolipids caused photoreceptor-cell death in retinal organoids, but not in the presence of regulators of lipid metabolism. CONCLUSIONS: Elevated levels of atypical deoxysphingolipids, caused by variant SPTLC1 or SPTLC2 or by low serine levels, were risk factors for macular telangiectasia type 2, as well as for peripheral neuropathy. (Funded by the Lowy Medical Research Institute and others.).

Where does purging disorder lie on the symptomatologic and personality continuum when compared to other eating disorder subtypes? Implications for the DSM.

OBJECTIVES: To assess the clinical significance and distinctiveness of purging disorder (PD) from other eating disorder (ED) diagnoses. METHOD: Participants included 3127 women consecutively admitted to an ED treatment centre (246 PD, 465 anorexia nervosa restrictive [AN-R], 327 AN-binge purging [AN-BP], 1436 bulimia nervosa [BN], 360 binge eating disorder [BED], 177 atypical AN and 116 unspecified feeding or eating disorder [UFED]) who were diagnosed according to DSM-5 criteria. Additionally, 822 control participants were recruited from the community. All participants completed measures assessing ED symptoms (EDI-2), general psychopathology (SCL-90-R) and personality (TCI-R). RESULTS: Patients with PD, when compared to controls, scored significantly higher on the EDI-2 and SCL-90-R, and most TCI-R dimensions. Most of the significant differences between PD and the other ED diagnoses emerged between PD and AN-R, followed by Atypical-AN, UFED, AN-BP and BED, with patients with PD typically reporting higher scores on the EDI-2 and SCL-90-R subscales. Significant differences between PD and BN were also present, but to a lesser extent. The findings for personality varied amongst the different ED diagnoses. CONCLUSIONS: PD is a clinically significant disorder, which seems to be more similar to BN than it is to AN and the other ED subtypes.

Bridging of childhood obsessive-compulsive personality disorder traits and adult eating disorder symptoms: A network analysis approach.

OBJECTIVES: Obsessive-compulsive personality disorder (OCDP) traits are commonly associated with eating disorders (EDs), with evidence demonstrating that these traits predispose and exacerbate the ED illness course. However, limited research has examined the symptomatic interplay between ED and OCDP traits. We used network analysis to (1) identify the most central symptoms in a network comprised of OCPD traits retrospectively assessed in childhood and ED symptoms and (2) to identify symptoms which bridged OCPD traits and ED symptoms. METHODS: Participants were 320 females with an ED (anorexia nervosa n = 227, bulimia nervosa n = 93), who completed the semi-structured EATATE interview and the Eating Disorder Inventory-2. Expected influence (EI) was computed to determine each symptom's influence in the network. Bridge symptoms were identified by computing bridge EI. RESULTS: A regularised partial correlation network showed that ascetism, social insecurity, ineffectiveness, and impulsivity had the highest EI in the OCPD and ED network. With respect to bridging symptoms, interpersonal distrust emerged as a possible bridging node between the OCPD and ED trait/symptom clusters. DISCUSSION: These findings highlight the centrality of non-specific ED symptoms in the ED symptom network and suggest that interpersonal distrust may play a functional role through which childhood OCPD traits and ED symptoms are connected.

Do orthorexia and intolerance of uncertainty mediate the relationship between autism spectrum traits and disordered eating symptoms?

PURPOSE: Autism spectrum disorder traits have been implicated in the psychopathology of eating disorders and may also be relevant for the development of orthorexia symptoms. Further, intolerance of uncertainty (IUS) may indirectly contribute to the development of disordered eating, as the displacement of anxiety onto food may help achieve a sense of control and maximise certainty. We examined a new cognitive model of eating pathology which assessed the role of IU and orthorexia symptoms as potential mediators of the relationship between autistic traits and disordered eating in a community sample. METHODS: Three-hundred-and-ninety-six female participants (M = 20.07, SD = 4.52 years old) completed an online self-report questionnaire which assessed the variables of interest. RESULTS: Despite finding significant bivariate correlations, our model results showed that autistic traits did not directly predict disordered eating or orthorexia symptoms. Significant indirect relationships were found between autistic traits and eating disorder symptoms through both IU and orthorexia symptoms. CONCLUSION: The findings provide partial support for our proposed model suggesting that autistic traits may increase the vulnerability for disordered eating, not directly, but through their associations with mechanisms such as IU and the development of problematic eating behaviours typical of orthorexia. Future research should focus on whether targeting IU may assist in preventing the development of disordered eating. LEVEL OF EVIDENCE: Level V, cross-sectional descriptive study.

The cognitive-interpersonal model of disordered eating: A test of the mediating role of alexithymia.

OBJECTIVE: The cognitive-interpersonal model proposes that high levels of attention to detail and cognitive rigidity confer risk for the development of eating disorders (EDs) and that socioemotional deficits, such as alexithymia, contribute to their maintenance. However, no studies have examined the direct and indirect relationships of these constructs. We investigated the mediating role of specific alexithymia traits (difficulties describing feelings, difficulties identifying feelings, and externally oriented thinking) on the relationship between attention to detail, cognitive rigidity, and ED symptoms while controlling for anxiety and depression symptoms. METHOD: Four hundred and one nonclinical female participants (M = 20.57, SD = 4.99 years old) completed self-report measures assessing the variables of interest. RESULTS: Path analyses revealed that difficulties identifying feelings was the only significant mediator between attention to detail and cognitive rigidity to ED symptoms. However, these mediation effects became nonsignificant after controlling for anxiety and depression. CONCLUSIONS: Difficulties identifying feelings may in part underlie the relationship between attention to detail and cognitive rigidity and ED symptoms, providing support for the cognitive-interpersonal model. However, these relationships are heavily influenced by anxiety and depression symptoms. Enhancing individual's ability to identify emotional states may help to decrease ED symptoms for individuals who report high levels of attention to detail and cognitive rigidity.

A cluster analysis of purging disorder: Validation analyses with eating disorder symptoms, general psychopathology and personality.

OBJECTIVES: To assess the natural grouping of Purging Disorder (PD) patients based on purging symptomatology and to evaluate the derived classes (a) against each other and (b) to a control group on a range of clinical and psychological measures. METHOD: Participants included 223 PD women consecutively admitted to a tertiary ED treatment centre and 822 controls. Purging behaviours (self-induced vomiting, laxative and diuretic use) were used as indicators, while the EDI-2 (ED symptoms), the SCL-90-R (general psychopathology), and the TCI-R (personality traits) were used as validators. RESULTS: Three distinct PD clusters emerged: Cluster 1 (only self-induced vomiting), Cluster 2 (self-induced vomiting and laxative use) and Cluster 3 (all purging methods). Significant differences between Cluster 1 and Cluster 3 were found for the EDI-2 drive for thinness and perfectionism subscales, and the TCI-persistence scale. All clusters differed significantly from the controls on all the EDI-2 and the SCL-90-R scales, but findings for the TCI-R scales were less consistent. CONCLUSIONS: This study adds to a growing literature on the validity and distinctiveness of PD and provides evidence of dimensional symptom differences amongst PD clusters.

Development of the Halifax Visual Scanning Test: A New Measure of Visual-Spatial Neglect for Personal, Peripersonal, and Extrapersonal Space.

OBJECTIVES: Visual-spatial neglect is a common attentional disorder after right-hemisphere stroke and is associated with poor rehabilitation outcomes. The presence of neglect symptoms has been reported to vary across personal, peripersonal, and extrapersonal space. Currently, no measure is available to assess neglect severity equally across these spatial regions and may be missing subsets of symptoms or patients with neglect entirely. We sought to provide initial construct validity for a novel assessment tool that measures neglect symptoms equally for these spatial regions: the Halifax Visual Scanning Test (HVST). METHODS: In Study I, the HVST was compared to conventional measures of neglect and functional outcome scores (wheelchair navigation) in 15 stroke inpatients and 14 healthy controls. In Study II, 19 additional controls were combined with the control data from Study I to establish cutoffs for impairment. Patterns of neglect in the stroke group were examined. RESULTS: In Study I, performance on all HVST subtests were correlated with the majority of conventional subtests and wheelchair navigation outcomes. In Study II, neglect-related deficits in visual scanning showed dissociations across spatial regions. Four inpatients exhibited symptoms of neglect on the HVST that were not detected on conventional measures, one of which showed symptoms in personal and extrapersonal space exclusively. CONCLUSIONS: The HVST appears a useful measure of neglect symptoms in different spatial regions that may not be detected with conventional measures and that correlates with functional wheelchair performance. Preliminary control data are presented and further research to add to this normative database appears warranted.

Identification of genes essential for pellicle formation in Acinetobacter baumannii.

BACKGROUND: Acinetobacter baumannii is an opportunistic pathogen, which has the ability to persist in the clinical environment, causing acute and chronic infections. A possible mechanism contributing to survival of A. baumannii is its ability to form a biofilm-like structure at the air/liquid interface, known as a pellicle. This study aimed to identify and characterise the molecular mechanisms required for pellicle formation in A. baumannii and to assess a broad range of clinical A. baumannii strains for their ability to form these multicellular structures. RESULTS: Random transposon mutagenesis was undertaken on a previously identified hyper-motile variant of A. baumannii ATCC 17978 designated 17978hm. In total three genes critical for pellicle formation were identified; cpdA, a phosphodiesterase required for degradation of cyclic adenosine monophosphate (cAMP), and A1S_0112 and A1S_0115 which are involved in the production of a secondary metabolite. While motility of the A1S_0112::Tn and A1S_0115::Tn mutant strains was abolished, the cpdA::Tn mutant strain displayed a minor alteration in its motility pattern. Determination of cAMP levels in the cpdA::Tn strain revealed a ~24-fold increase in cellular cAMP, confirming the role CpdA plays in catabolising this secondary messenger molecule. Interestingly, transcriptional analysis of the cpdA::Tn strain showed significant down-regulation of the operon harboring the A1S_0112 and A1S_0115 genes, revealing a link between these three genes and pellicle formation. Examination of our collection of 54 clinical A. baumannii strains revealed that eight formed a measurable pellicle; all of these strains were motile. CONCLUSIONS: This study shows that pellicle formation is a rare trait in A. baumannii and that a limited number of genes are essential for the expression of this phenotype. Additionally, an association between pellicle formation and motility was identified. The level of the signalling molecule cAMP was found to be controlled, in part, by the cpdA gene product, in addition to playing a critical role in pellicle formation, cellular hydrophobicity and motility. Furthermore, cAMP was identified as a novel regulator of the operon A1S_0112-0118.

Assessing the seasonal prevalence and risk factors for nuchal crest adiposity in domestic horses and ponies using the Cresty Neck Score.

BACKGROUND: Nuchal crest adiposity in horses and ponies has been associated with an enhanced risk of metabolic health problems. However, there is no current information on the prevalence of, and risk factors specific to, nuchal crest adiposity in horses and ponies. In addition, the cresty neck score has not previously been utilised across different seasons within a UK leisure population, it is not know whether nuchal crest adiposity shows the same seasonal trends as general obesity. RESULTS: A Cresty Neck Score (CNS, 0-5) was given to 96 horses with access to pasture (>6 h per day) at the end of winter and at the end of summer in order to obtain two prevalence estimates. Risk factors were assessed using the single outcome cresty neck/no cresty neck in either season (binary), from owner questionnaires and analysed using a mixed effects logistic regression model (outcome variable CNS <3 or CNS ≥3/5). Agreement between winter and summer scores was assessed using weighted Kappa methods. Winter CNS values were significantly higher than summer CNS values (p = 0.002) indicating a systematic bias. The prevalence of a CNS ≥ 3/5 was 45.83% at the end of winter, falling to 33.33% at the end of summer and was higher in ponies (<14.2 hh) than horses (≥14.2 hh) in both seasons. This may reflect a real winter increase in regional fat deposition, or an increased difficulty in obtaining an accurate estimate of regional adiposity in winter months. Breed was the strongest risk factor for CNS ≥3/5 in both seasons, with native UK breeds appearing to be most at risk (p < 0.001). In a separate, small validation study, the CNS showed good inter-observer reliability. CONCLUSIONS: The prevalence of a CNS ≥3/5 was higher at the end of winter than at the end of summer, which was the opposite pattern seasonal variation to that observed for general obesity. Further studies are required to investigate the potential influence of time of year upon CNS interpretation and studies utilising the CNS should consider potential seasonal variability in nuchal crest adiposity.

Dominance rank is associated with body condition in outdoor-living domestic horses (Equus caballus).

The aim of our study was to explore the association between dominance rank and body condition in outdoor group-living domestic horses, Equus caballus. Social interactions were recorded using a video camera during a feeding test, applied to 203 horses in 42 herds. Dominance rank was assigned to 194 individuals. The outcome variable body condition score (BCS) was recorded using a 9-point scale. The variables age and height were recorded and considered as potential confounders or effect modifiers. Results were analysed using multivariable linear and logistic regression techniques, controlling for herd group as a random effect. More dominant (p = 0.001) individuals generally had a higher body condition score (p = 0.001) and this association was entirely independent of age and height. In addition, a greater proportion of dominant individuals fell into the obese category (BCS ≥ 7/9, p = 0.005). There were more displacement encounters and a greater level of interactivity in herds that had less variation in age and height, lending strength to the hypothesis that phenotypic variation may aid cohesion in group-living species. In addition there was a strong quadratic relationship between age and dominance rank (p < 0.001), where middle-aged individuals were most likely to be dominant. These results are the first to link behavioural predictors to body condition and obesity status in horses and should prompt the future consideration of behavioural and social factors when evaluating clinical disease risk in group-living animals.