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Dogs can discriminate stressed from non-stressed human odour samples, but the effect on their cognition is unstudied. Using a cognitive bias task, we tested how human odours affect dogs' likelihood of approaching a food bowl placed at three ambiguous locations ("near-positive", "middle" and "near-negative") between trained "positive" (rewarded) and "negative" (unrewarded) locations. Using odour samples collected from three unfamiliar volunteers during stressful and relaxing activities, we tested eighteen dogs under three conditions: no odour, stress odour and relaxed odour, with the order of test odours counterbalanced across dogs. When exposed to stress odour during session three, dogs were significantly less likely to approach a bowl placed at one of the three ambiguous locations (near-negative) compared to no odour, indicating possible risk-reduction behaviours in response to the smell of human stress. Dogs' learning of trained positive and negative locations improved with repeated testing and was significant between sessions two and three only when exposed to stress odour during session three, suggesting odour influenced learning. This is the first study to show that without visual or auditory cues, olfactory cues of human stress may affect dogs' cognition and learning, which, if true, could have important consequences for dog welfare and working performance.
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Comportamento Animal , Cognição , Odorantes , Estresse Psicológico , Animais , Cães , Humanos , Cognição/fisiologia , Masculino , Feminino , Comportamento Animal/fisiologia , Olfato/fisiologia , Sinais (Psicologia) , Aprendizagem/fisiologiaRESUMO
Little is known about the simultaneous effects of non-pharmacological interventions (NPI) on healthy older adults' behavior and brain plasticity, as measured by psychometric instruments and magnetic resonance imaging (MRI). The purpose of this scoping review was to compile an extensive list of randomized controlled trials published from January 1, 2000, to August 31, 2023, of NPI for mitigating and countervailing age-related physical and cognitive decline and associated cerebral degeneration in healthy elderly populations with a mean age of 55 and over. After inventorying the NPI that met our criteria, we divided them into six classes: single-domain cognitive, multi-domain cognitive, physical aerobic, physical non-aerobic, combined cognitive and physical aerobic, and combined cognitive and physical non-aerobic. The ultimate purpose of these NPI was to enhance individual autonomy and well-being by bolstering functional capacity that might transfer to activities of daily living. The insights from this study can be a starting point for new research and inform social, public health, and economic policies. The PRISMA extension for scoping reviews (PRISMA-ScR) checklist served as the framework for this scoping review, which includes 70 studies. Results indicate that medium- and long-term interventions combining non-aerobic physical exercise and multi-domain cognitive interventions best stimulate neuroplasticity and protect against age-related decline and that outcomes may transfer to activities of daily living.
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Terbium-149 (T1/2 = 4.1 h, Eα = 3.98 MeV (16.7%), 28 µm range in tissue) is a radionuclide with potential for targeted alpha therapy. Due to the negligible emission of α-emitting daughter nuclides, toxicity to healthy tissue may be reduced in comparison with other α-particle emitters. In this study, terbium-149 was produced via 1.4 GeV proton irradiation of a tantalum target at the CERN-ISOLDE facility. The spallation products were mass separated and implanted on zinc-coated foils and, later, radiochemically processed. Terbium-149 was separated from the co-produced isobaric radioisotopes and the zinc coating from the implantation foil, using cation-exchange and extraction chromatographic techniques, respectively. At the end of separation, up to 260 MBq terbium-149 were obtained with > 99% radionuclidic purity. Radiolabeling experiments were performed with DOTATATE, achieving 50 MBq/nmol apparent molar activity with radiochemical purity > 99%. The chemical purity was determined by inductively coupled plasma-mass spectrometry measurements, which showed lead, copper, iron and zinc only at ppb level. The radiolabeling of the somatostatin analogue DOTATATE with [149Tb]TbCl3 and the subsequent in vivo PET/CT scans conducted in xenografted mice, showing good tumor uptake, further demonstrated product quality and its ability to be used in a preclinical setting.
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Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Melhoria de Qualidade , Térbio , Animais , Camundongos , Radioisótopos/uso terapêutico , ZincoRESUMO
While viscoelastic, adhesive contact rupture of simple indenters is well studied, contact formation has received much less attention. Here, we present simulations of the formation of contact between various power law indenters and an adhesive, viscoelastic foundation. For all investigated indenters, we find that the macroscopic relaxation time τ scales approximately with 1/ρ1.8, where ρ is the range of adhesion. The prolongation of contact formation with Tabor parameter is rationalized by the increased dissipation that short-range adhesion causes on a moving crack.
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The chemical composition of plant individuals can vary, leading to high intraspecific chemodiversity. Diversity of floral chemistry may impact the responses of flower-feeding insects. Tanacetum vulgare plants vary significantly in their leaf terpenoid composition, forming distinct chemotypes. We investigated the composition of terpenoids and nutrients of flower heads and pollen in plants belonging to three chemotypes - dominated either by ß-thujone (BThu), artemisia ketone (Keto) or a mixture of (Z)-myroxide, santolina triene, and artemisyl acetate (Myrox) - using different analytical platforms. We tested the effects of these differences on preferences, weight gain and performance of adults of the shining flower beetle, Olibrus aeneus. The terpenoid composition and diversity of flower heads and pollen significantly differed among individuals belonging to the above chemotypes, while total concentrations of pollen terpenoids, sugars, amino acids, and lipids did not differ. Beetles preferred BThu over the Myrox chemotype in both olfactory and contact choice assays, while the Keto chemotype was marginally repellent according to olfactory assays. The beetles gained the least weight within 48 h and their initial mortality was highest when feeding exclusively on floral tissues of the Myrox chemotype. Short-term weight gain and long-term performance were highest when feeding on the BThu chemotype. In conclusion, the beetles showed chemotype-specific responses towards different T. vulgare chemotypes, which may be attributed to the terpenoid composition in flower heads and pollen rather than to differences in nutrient profiles. Both richness and overall diversity are important factors when determining chemodiversity of individual plants and their consequences on interacting insects.
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Besouros , Tanacetum , Animais , Tanacetum/química , Tanacetum/metabolismo , Flores/química , Terpenos/metabolismo , Insetos , Plantas , Aumento de PesoRESUMO
Mycophenolate mofetil (MMF) is applied in proteinuric kidney diseases, but the exact mechanism of its effect on podocytes is still unknown. Our previous in vitro experiments suggested that MMF can ameliorate podocyte damage via restoration of the Ca2+-actin cytoskeleton axis. The goal of this study was to characterize podocyte biology during MMF treatment in nephrotoxic serum (NTS) nephritis (NTN). NTN was induced in three-week old wild-type mice. On day 3, half of the mice were treated with MMF (100 mg/kgBW/d p.o.) for one week. On day 10, we performed proteomic analysis of glomeruli as well as super-resolution imaging of the slit diaphragm. For multiphoton imaging of Ca2+ concentration ([Ca2+]i), the experimental design was repeated in mice expressing podocyte-specific Ca2+ sensor. MMF ameliorated the proteinuria and crescent formation induced by NTS. We identified significant changes in the abundance of proteins involved in Ca2+ signaling and actin cytoskeleton regulation, which was further confirmed by direct [Ca2+]i imaging in podocytes showing decreased Ca2+ levels after MMF treatment. This was associated with a tendency to restoration of podocyte foot process structure. Here, we provide evidence that MPA has a substantial direct effect on podocytes. MMF contributes to improvement of [Ca2+]i and amelioration of the disorganized actin cytoskeleton in podocytes. These data extend the knowledge of direct effects of immunosuppressants on podocytes that may contribute to a more effective treatment of proteinuric glomerulopathies with the least possible side effects.
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Ácido Micofenólico , Nefrite , Podócitos , Ácido Micofenólico/administração & dosagem , Animais , Camundongos , Podócitos/efeitos dos fármacos , Nefrite/tratamento farmacológico , Nefrite/patologia , Camundongos Endogâmicos C57BL , Glomérulos Renais/química , Glomérulos Renais/patologia , Proteoma/efeitos dos fármacos , Citoesqueleto de Actina/efeitos dos fármacosRESUMO
BACKGROUND: We report our initial experience with intrathoracic negative pressure therapy (ITNPT) in the stage-adjusted treatment of pleural empyema (PE) based on a case series. MATERIALS AND METHODS: ITNPT represents a further development for intrathoracic use. After thoracic surgical open debridement, an intrathoracic negative pressure dressing was inserted. The drainage elements were a thin open-pore double-layer drainage film (OF) with open-pore polyurethane foams (PUF). Only the OF was placed in direct contact with the lung parenchyma. Negative pressure was generated using an electronic pump (continuous suction, -75â¯mmâ¯Hg). In revision thoracotomies, ITNPT was stopped or continued depending on local findings. RESULTS: In total, 31 patients with stage II and III pleural empyema underwent ITNPT, which was administered during the primary procedure (nâ¯= 17) or at revision (nâ¯= 14). Treatment duration was a mean of 10 days (2-18 days) with a mean change interval of 4 days (2-6 days). Intrathoracic negative pressure dressings were applied a mean of 3.5 (1-6) times. The empyema cavity continuously reduced in size and was cleansed by the suction. The OF has a minimum intrinsic volume with maximum absorption surface. Once negative pressure is established, there is no intrathoracic dead volume and the parenchyma can expand. The protective material properties of OF make ITNPT suitable for the treatment of pleural empyema. Targeted local intrathoracic drainage of the septic focus is a possible adjunct to surgery. The surgical dressings must be changed repeatedly. The method is suitable for the treatment of complex stage II and III pleural empyemas. CONCLUSION: The OF can be used as an intrathoracic drainage element for ITNPT in pleural empyema. This new application option expands the range of indications for negative pressure therapy.
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Empiema Pleural , Tratamento de Ferimentos com Pressão Negativa , Humanos , Empiema Pleural/cirurgia , Drenagem/métodos , Tratamento de Ferimentos com Pressão Negativa/métodos , Sucção , ToracotomiaRESUMO
BACKGROUND: Up to a quarter of inpatients in high-income countries (HICs) self-report beta-lactam allergy (BLA), which if incorrect,increases the use of alternative antibiotics, worsening individual health outcomes and driving bacterial resistance. In HICs, up to 95% ofself-reported BLAs are incorrect. The epidemiology of BLA in low- and middle-income African countries is unknown. OBJECTIVES: To describe the epidemiology and de-labelling outcomes of self-reported BLA in hospitalised South African (SA) patients. METHODS: Point-prevalence surveys were conducted at seven hospitals (adult, paediatric, government and privately funded, district andtertiary level) in Cape Town, SA, between April 2019 and June 2021. Ward prescription records and in-person interviews were conductedto identify and risk-stratify BLA patients using the validated PEN-FAST tool. De-labelling was attempted at the tertiary allergy clinic atGroote Schuur Hospital. RESULTS: A total of 1 486 hospital inpatients were surveyed (1 166 adults and 320 children). Only 48 patients (3.2%) self-reported a BLA,with a higher rate in private than in government-funded hospitals (6.3% v. 2.8%; p=0.014). Using the PEN-FAST tool, only 10.4% (n=5/48)of self-reported BLA patients were classified as high risk for true penicillin hypersensitivity. Antibiotics were prescribed to 70.8% (n=34/48)of self-reported BLA patients, with 64.7% (n=22/34) receiving a beta-lactam. Despite three attempts to contact patients for de-labelling atthe allergy clinic, only 3/36 underwent in vivo testing, with no positive results, and 1 patient proceeded to a negative oral challenge. CONCLUSION: Unlike HICs, self-reported BLA is low among inpatients in SA. The majority of those who self-reported BLA were low risk fortype 1 hypersensitivity, but outpatient de-labelling efforts were largely unsuccessful.
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Hipersensibilidade a Drogas , Hipersensibilidade , Adulto , Humanos , Criança , beta-Lactamas/efeitos adversos , Autorrelato , África do Sul/epidemiologia , Testes Cutâneos/métodos , Antibacterianos/efeitos adversos , Penicilinas , Hipersensibilidade a Drogas/epidemiologia , Hospitais Públicos , Hospitais Privados , GovernoRESUMO
Healthy aging leads to poorer performance in upper limb (UL) daily living movements. Understanding the neural correlates linked with UL functional movements may help to better understand how healthy aging affects motor control. Two non-invasive neuroimaging methods allow for monitoring the movement-related brain activity: functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG), respectively based on the hemodynamic response and electrical activity of brain regions. Coupled, they provide a better spatiotemporal mapping. The aim of this study was to evaluate the effect of healthy aging on the bilateral sensorimotor (SM1) activation patterns of functional proximal UL movements. Twenty-one young and 21 old healthy participants realized two unilateral proximal UL movements during: i) a paced reaching target task and ii) a circular steering task to capture the speed-accuracy trade-off. Combined fNIRS-EEG system was synchronised with movement capture system to record SM1 activation while moving. The circular steering task performance was significantly lower for the older group. The rate of increase in hemodynamic response was longer in the older group with no difference on the amplitude of fNIRS signal for the two tasks. The EEG results showed aging related reduction of the alpha-beta rhythms synchronisation but no desynchronisation modification. In conclusion, this study uncovers the age-related changes in brain electrical and hemodynamic response patterns in the bilateral sensorimotor network during two functional proximal UL movements using two complementary neuroimaging methods. This opens up the possibility to utilise combined fNIRS-EEG for monitoring the movement-related neuroplasticity in clinical practice.
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Espectroscopia de Luz Próxima ao Infravermelho , Extremidade Superior , Humanos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Envelhecimento , Eletroencefalografia/métodos , HemodinâmicaRESUMO
In advanced stages of Kienböck's disease, the lunate is no longer conservable. One of the surgical options is to resect the lunate and replace it with a prosthesis. The procedure consisted in lunate resection and interposition of a free APSI® or Pi2® pyrocarbon implant through a dorsal approach. Follow-up was clinical and radiological on QuickDASH and PRWE scores. At a median follow-up of 3 years, 12 patients were reviewed, with a median age of 56 years. Flexion significantly decreased from 42° to 28° (p < 0.01). Extension and pronation-supination were conserved. Strength was 94% compared to the opposite side, with no significant difference from the preoperative measurement. Median QuickDASH and PRWE scores were 15.9 and 23.5 respectively and had significantly improved. One patient underwent scaphocapitate fusion because she was still in pain; the other patients were pain-free. No patients had to change jobs because of their wrist. Radiographically, there was no carpal collapse and carpal height was conserved. Radioscaphoid angle and ulnar translation were stable. There was 1 case of asymptomatic implant dislocation. Interposition of a pyrocarbon implant after lunate resection in advanced Kienböck's disease is a motion-conserving procedure that provides pain relief and functional recovery in the short and medium term. LEVEL OF EVIDENCE: IV.
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Membros Artificiais , Ossos do Carpo , Osso Semilunar , Osteonecrose , Feminino , Humanos , Pessoa de Meia-Idade , Osso Semilunar/cirurgia , Ossos do Carpo/cirurgia , Osteonecrose/cirurgiaRESUMO
The synthesis and the first structural characterization of the halogenated pyridinium salts [C5 F5 NH]+ , [C5 F4 ClNH]+ , [(C5 F5 N)2 H]+ , [(C5 Cl5 N)2 H]+ of the weakly coordinating anion (WCA) [Al(OTeF5 )4 ]- , showing noncovalent interactions in the solid state, are presented. The salts were characterized by the multinuclear NMR and IR spectroscopy as well as X-ray diffraction. Hirshfeld surface analysis and solid state structures reveal various intermolecular anion-π and σ-hole interactions between the corresponding halogenated pyridinium cations and the anion [Al(OTeF5 )4 ]- .
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Sais , Ânions , Ressonância Magnética Nuclear Biomolecular , Difração de Raios XRESUMO
PURPOSE: In this work, we present a subsystem of a robotic circulating nurse, that produces recommendations for the next supplied sterile item based on incomplete requests from the sterile OR staff, the current situation, predefined knowledge and experience from previous surgeries. We describe a structure to store and query the underlying information in terms of entities and their relationships of varying strength. METHODS: For the implementation, the graph database Neo4j is used as a core component together with its querying language Cypher. We outline a specific structure of nodes and relationships, i.e., a graph. Primarily, it allows to represent entities like surgeons, surgery types and items, as well as their complex interconnectivity. In addition, it enables to match given situations and partial requests in the OR with corresponding subgraphs. The subgraphs provide suitable sterile items and allow to prioritize them according to their utilization frequency. RESULTS: The graph database was populated with existing data from 854 surgeries describing the intraoperative use of sterile items. A test scenario is evaluated in which a request for "Prolene" is made during a cholecystectomy. The software identifies a specific "Prolene" suture material as the most probable requested sterile item, because of its utilization frequency from over 95%. Other "Prolene" suture materials were used in less than 15% of the cholecystectomies. CONCLUSION: We have proposed a graph database for the selection of sterile items in the operating room. The example shows how the partial information from different sources can be easily integrated in a query, leading to an unique result. Eventually, we propose possible enhancements to further improve the quality of the recommendations. In the next step, the recommendations of the software will be evaluated in real time during surgeries.
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Software , Humanos , Bases de Dados FactuaisRESUMO
Morbid obesity and prolonged pregnancy are independently associated with adverse delivery and perinatal outcomes. We conducted a retrospective observational study on otherwise uncomplicated women with a body mass index (BMI) ≥ 40 kg/m2 where, having reached term, induction of labour (IOL) was planned, to prevent prolonged pregnancy. The primary aim was to describe delivery outcomes and short-term maternal and perinatal adverse events. Of 117 cases included, 69 (59%) laboured spontaneously before the induction date, while 48 (41%) required an IOL. Of 48 patients that underwent an IOL, 22 (45.8%) achieved vaginal delivery, compared to 55 (79.7%) who laboured spontaneously (p = <.001). Twenty-two (18.8%) of the 117 babies weighed more than 4000 g, with 13 of these delivered vaginally. Overall, term patients with morbid obesity who laboured spontaneously before requiring induction, had a high rate of vaginal delivery. However, when IOL was required, the rate of caesarean delivery rose dramatically.Impact statementWhat is already known on this subject? Morbid obesity and prolonged pregnancy are independently associated with adverse delivery and perinatal outcomes. Induction of labour (IOL) increases the workload in busy units.What do the results of this study add? These results help inform accurate counselling on delivery outcomes, which is integral to respectful care, for the continuously increasing numbers of morbidly obese pregnant women.What the implications are of these findings for clinical practice and/or further research? It is preferable to avoid semi- or urgent caesarean deliveries in morbidly obese women after IOL. The outcomes of earlier induction of labour from 39- or 40-weeks' gestation requires investigation. Earlier induction may reduce the numbers of caesarean deliveries for abnormal cardiotocograph during the process.
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Trabalho de Parto Induzido , Obesidade Mórbida , Gravidez Prolongada , Feminino , Humanos , Lactente , Gravidez , Parto Obstétrico/métodos , Trabalho de Parto Induzido/métodos , Resultado da Gravidez , Gravidez Prolongada/prevenção & controle , Estudos RetrospectivosRESUMO
Natural compounds may bear promising therapeutic benefits against metabolic diseases such as type 2 diabetes mellitus (T2DM), which are characterized by a state of insulin resistance and mitochondrial dysfunction. Here, we examined the cellular mechanisms by which aspalathin, a dihydrochalcone C-glucoside unique to rooibos, may ameliorate palmitate-induced insulin resistance and mitochondrial dysfunction in cultured C2C12 myotubules. This current study demonstrated that aspalathin remains effective in improving glucose uptake in insulin-resistant skeletal muscle cells, supported by the upregulation of insulin-dependent signaling that involves the activation of insulin receptor (IR) and direct phosphorylation of protein kinase B (AKT). Interestingly, aspalathin also improved mitochondrial respiration and function, which was evident by an increased expression of carnitine palmitoyltransferase 1 (Cpt1), fatty acid transport protein 1 (Fatp1), sirtuin 1 (Sirt1), nuclear respiratory factor 1 (Nrf1), and transcription factor A, mitochondrial (Tfam). Importantly, our results showed that aspalathin treatment was effective in ameliorating the devastating outcomes of insulin resistance and mitochondrial dysfunction that are linked with an undesired pro-inflammatory response, by reducing the levels of well-known pro-inflammatory markers such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and protein kinase C-theta (PKC-theta). Thus, beyond improving glucose uptake and insulin signaling, the current study brings a new perspective in the therapeutic benefits of aspalathin in improving mitochondrial respiration and blocking inflammation to attenuate the detrimental effect of palmitate in skeletal muscle cells.
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Diabetes Mellitus Tipo 2 , Resistência à Insulina , Humanos , Resistência à Insulina/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Insulina/farmacologia , Músculo Esquelético/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Palmitatos , Glucose/metabolismo , Mitocôndrias/metabolismoAssuntos
Condroma , Diáfises , Condroma/diagnóstico por imagem , Condroma/cirurgia , Humanos , Rádio (Anatomia)RESUMO
BACKGROUND: Sacral neuromodulation (SNM) is a common treatment for patients with urinary and faecal incontinence. A close contact of the tined lead electrode with the targeted nerve is likely to improve functional outcome. The aim of this study was to compare the position of the SNM lead in relation to the sacral nerve by comparing different implantation techniques. METHODS: This cadaver study was conducted at the Division of Anatomy of Vienna's Medical University in October 2020. We dissected 10 cadavers after bilateral SNM lead implantation (n = 20), using two different standardized implantation techniques. The cadavers were categorized as group A (n = 10), representing the conventional guided implantation group and group B (n = 10), where SNM implantation was conducted with the novel fluoroscopy-guided "H"-technique. The primary goal was to assess the distance between the sacral nerve and the lead placement. RESULTS: The electrodes were inserted at a median angle of 58.5° (46-65°) in group A and 60° (50-65°) in group B, without reaching statistical significance. In 8 cadavers, the lead entered the S3 foramen successfully. The median distance of the lead to the nerve did not show a significant difference between both groups (E0: Group A: 0.0 mm vs. Group B: 0.0 mm, p = 0.969; E1: Group A: 0.0 mm vs. Group B: 0.5 mm p = 0.754; E2: Group A: 2.5 mm vs. Group B: 2.5 mm p = 1.000; E3: Group A: 3.5 mm vs. Group B: 4.0 mm p = 0.675). In 2 cases (20%) of the conventional group A, the lead was misplaced and located at the gluteal muscle. Perforation of the presacral fascia was observed in one lead placement in group A and in two placements in group B. CONCLUSIONS: Both standardized implantation techniques may ensure close electrode proximity to the targeted nerve. Misplacement of the electrode was more often observed with the conventional implantation technique.
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Terapia por Estimulação Elétrica , Plexo Lombossacral , Cadáver , Terapia por Estimulação Elétrica/métodos , Eletrodos Implantados , Humanos , Sacro/inervação , Sacro/cirurgia , Resultado do TratamentoRESUMO
BACKGROUND: Children and adolescents with intellectual disabilities (ID) are at increased risk of developing challenging behaviour. Challenging behaviour may be partially explained by low individual communicative competences. However, communication involves at least two partners, thus outcomes may also vary according to each interaction partners' abilities. We therefore investigated the degree to which the interplay between individual and classmates' communication skills predicts changes in challenging behaviour among students with ID. METHODS: This study used a longitudinal design with two measurement points across one school year. Challenging behaviour and communication skills were measured by teacher reports in 1125 students with ID attending special needs schools. Applying a multilevel approach, we investigated (1) whether higher individual communication skills at the first measurement were related to a subsequent decrease in challenging behaviour and (2) whether this effect was moderated by classmates' levels of communication skills. In addition, we examined (3) if classroom communication skills were indirectly related to a decrease in challenging behaviour by influencing individual communicative abilities. RESULTS: Higher individual communication skills at the first measurement were significantly related to a decrease in general challenging behaviour over the school year. This effect was not moderated by classroom-level communication skills. However, classmates' communication skills exerted an indirect influence by enhancing individual communicative abilities. Further analyses suggested classroom contextual effects related to a decrease in several sub-domains of challenging behaviour. CONCLUSIONS: The study results suggest that both individual communicative competences and those of the classroom context are relevant to understanding challenging behaviour development in ID. Perspectives for counteracting such behaviour in light of the present findings are discussed.
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Deficiência Intelectual , Adolescente , Criança , Comunicação , Humanos , Instituições Acadêmicas , EstudantesRESUMO
BACKGROUND: Free faecal liquid (FFL) is a condition in horses characterised by two-phase (one solid and one liquid) separation of faeces. Causes of the condition are unknown, but disturbed hindgut fermentation has been suggested as it may alter biochemical composition and appearance of faeces in equines. However, information on faecal composition in horses with FFL is scarce. Faecal chemical composition (dry matter, osmolality, ash, macro minerals, short-chain fatty acids (SCFA) and pH) and physical characteristics (free liquid, sand, water holding capacity and particle size distribution) were compared in horses with (case) and without (control) FFL in two sub-studies. In sub-study I, faeces from 50 case-control horse pairs in Sweden and Norway were sampled in three sampling periods (SP1-SP3). In sub-study II, faeces from 32 case-control horse pairs in Germany were sampled on one occasion. RESULTS: In sub-study I, faecal concentration and proportion of lactic acid (of total short-chain fatty acids, SCFA) and water holding capacity was lower in case compared to control horses. Other variables (content of dry matter, ash, sodium, calcium, phosphorous, magnesium, sulphur, and concentrations of i-butyric, n-valeric and total SCFA, ammonia-N as proportion of total N, and pH) were similar in faeces from case and control horses. In sub-study II, all analysed variables were similar in faecal samples from case and control horses. Faecal particle size distribution was similar in case and control horses, but the proportion of larger particles (2 and 1 mm) were lower and proportion of smaller particles (< 1 mm) was higher in sub-study I compared to in sub-study II. CONCLUSIONS: To the authors' knowledge, this is the first study to investigate faecal chemical composition and physical characteristics in horses with FFL. Case and control horses had similar total SCFA, pH and osmolality, indicating that hindgut fermentation was similar. However, small differences in concentration and proportion (of total SCFA) of lactic acid and water holding capacity of faeces were shown and are of interest for further studies of horses with FFL.
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Fezes/química , Cavalos , Ração Animal , Animais , Estudos de Casos e Controles , Dieta/veterinária , Ácidos Graxos Voláteis/análise , Alemanha , Ácido Láctico/análise , Água/análiseRESUMO
Many insect herbivores engage in apparent competition whereby two species interact through shared natural enemies. Upon insect attack, plants release volatile blends that attract natural enemies, but whether these volatiles mediate apparent competition between herbivores is not yet known. We investigate the role of volatiles that are emitted by bean plants upon infestation by Acyrthosiphon pisum aphids on the population dynamics and fitness of Sitobion avenae aphids, and on wheat phloem sap metabolites. In a field experiment, the dynamics of S. avenae aphids on wheat were studied by crossing two treatments: exposure of aphid colonies to A. pisum-induced bean volatiles and exclusion of natural enemies. Glasshouse experiments and analyses of primary metabolites in wheat phloem exudates were performed to better understand the results from the field experiment. In the field, bean volatiles did not affect S. avenae dynamics or survival when aphids were exposed to natural enemies. When protected from them, however, volatiles led to larger aphid colonies. In agreement with this observation, in glasshouse experiments, aphid-induced bean volatiles increased the survival of S. avenae aphids on wheat plants, but not on an artificial diet. This suggests that volatiles may benefit S. avenae colonies via metabolic changes in wheat plants, although we did not find any effect on wheat phloem exudate composition. We report a potential case of associational susceptibility whereby plant volatiles weaken the defences of receiving plants, thus leading to increased herbivore performance.