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Broiler farming and antibiotic use through an agency theory lens. A case study from West Bengal, India
Full text linkChicken meat (broiler) production is a rapidly growing livestock sector in India and one dominated by contract farming. Studies have reported high levels of antibiotic use in Indian broiler farms which is concerning given this is one of the driving forces for the development of antibiotic resistance. This study uses the economic lens of agency theory to examine strategic decisions which occur during contract broiler production and their potential impact on antibiotic use, using West Bengal as a case study. Agency theory focuses on the informational asymmetry and opportunism between service providers and seekers and the subsequent agency cost needed to avoid aberrant outcomes. Interviews were conducted with key informants (n=6) and stakeholders (n=20) associated with broiler production, and broiler farmers (17 contract and four non-contract), using online and face-to-face interviews. Data were analysed descriptively using manifest content analysis and interpretatively using reflexive thematic analysis. Contract farming in West Bengal exists within a series of inter-dependent relationships, many of which contain information asymmetry and can be subject to opportunism. Positioning contract companies as principals seeking labour from agents, we see how out-sourcing of production to distal farms leads to antibiotics being used as a risk mitigation strategy. This is further compounded by concerns about the Mycoplasma status of breeding stock resulting in use of antibiotics belonging to classes deemed critically important for human health. While antibiotic use decisions are predominately made by contract companies, they are dependent on the decisions farmers and breeding companies make concerning biosecurity and production practices. In turn, farmers’ decisions are shaped by factors such as access to financial and social capital. Thus, efforts to reduce antibiotic use in West Bengal’s broilers must not just focus on changing the behavior of individuals but more broadly consider the environment within which contracting exists
Computed tomography of the equine temporohyoid joint: Association between imaging changes and potential risk factors
No full textBackground: Temporohyoid osteoarthropathy (THO) is characterised by bone proliferation and cartilage ossification caused by infectious and degenerative conditions, amongst others. Objectives: To describe the variable appearance of the temporohyoid joint (THJ) on computed tomography (CT) and investigate associations between CT changes and potential risk factors. Study Design: Cross-sectional study. Methods: Head CT examinations were assessed. A grading system was developed for osseous proliferation (grade 0 [normal] to 3 [severe]) and tympanohyoid cartilage change (grade 0 [normal] to 3 [complete ossification]). Grades were also summed to create an overall sum grade. Ordinal logistic regression was performed to produce a multivariable model that assessed the association between THJ grade and signalment, presenting signs, CT features, and final diagnosis. Results: The horses included (n = 424) most commonly presented for dental and sinus disorders (37.7%). The most frequently observed (mode) bone grade, cartilage grade and overall grade were 2 (41.9%), 0 (52.6%) and 2 (27.0%), respectively. Bone proliferation was most common medially and caudally. Soft tissue swelling (OR 1.9, 95% CI 1.2-3.1, p < 0.05) and temporal bone fragmentation (OR 26.6, 95% CI 5.1-141.4, p < 0.05) were associated with increased bone grade. There was no correlation between increased grade and any presenting sign. Increased sum grade was significantly associated with increased age (OR per year 1.1, 95% CI 1.0-1.1, p < 0.05), Arabians (OR 4.2, 95% CI 1.3-14.0, p < 0.05) and Thoroughbreds (OR 2.9, 95% CI 1.5-5.4, p < 0.05) relative to Warmbloods. Main Limitations: Following training, a single observer evaluated images. Conclusions: Moderate caudomedial osseous proliferation of the THJ is common in horses presented for unrelated disease. Cartilage mineralisation, soft tissue swelling, and temporal bone fragmentation may serve as markers of disease. Thoroughbreds and Arabians are at increased risk of greater THJ remodelling. Increased THJ change was associated with age but not otitis, suggesting THO is predominantly degenerative
Study of dense granule proteins in Eimeria spp. identifies a limited repertoire with potential as vaccine candidates
No full textEimeria species are obligate intracellular parasites that usually replicate in intestinal cells and can cause the disease coccidiosis. Coccidiosis of livestock and poultry incurs significant production losses and compromises animal welfare, with the greatest impact occurring in chicken production. Control of coccidiosis is challenging, requiring good husbandry and effective drug or live vaccine prophylaxis, and there is demand for more scalable and cost-effective vaccines. Proteins secreted from dense granules (GRAs) play crucial roles in intracellular survival in many apicomplexans, but knowledge of these organelles and their secreted proteins in Eimeria is extremely limited. In this study, we observed a reduced GRA protein repertoire encoded in Eimeria spp. genomes compared to Toxoplasma gondii (23 vs. 71) with just 12 orthologues identified in the Eimeria tenella genome. In silico analysis of three of these putative dense granule proteins - EtGRA9, EtGRA12a, and EtGRA12b - revealed the presence of signal peptides in EtGRA9 and EtGRA12b, while none was detected in EtGRA12a. Sequence analysis of E. tenella field isolates revealed a limited number of polymorphisms in the genes encoding these three proteins, suggesting purifying selection possibly related to their functional importance. In contrast, E. maxima showed greater variation, indicating relaxed selective pressure or diversifying selection. When expressed as recombinant proteins all three were recognised by sera from chickens previously infected with E. tenella. Their potential role in parasite intracellular niche formation and close interaction with the host cell makes them promising antigens for vaccine development. To evaluate this potential, EtGRA9 was expressed as a recombinant protein and used to vaccinate chickens prior to E. tenella challenge. Immunisation with recombinant EtGRA9 reduced parasite load in the caeca by 85.7%, comparable to immunisation with recombinant EtAMA1, an antigen previously shown to confer significant protection
Assessment of ante mortem welfare indicators and the pathophysiology of captive-bolt trauma in equids at slaughter - CORRIGENDUM
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Novel primers for the detection and differentiation of S. zooepidemicus and S. equi by PCR
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Increased susceptibility to diet-induced obesity in female mice impairs ovarian steroidogenesis: The role of elevated leptin signalling on nodal activity inhibition in theca cells
Full text linkObjectives Susceptibility to obesity in humans is driven by the intricate interplay of genetic, environmental and behavioural factors. Moreover, the mechanisms linking maternal obesity to infertility remain largely understudied. In this study, we investigated how variable susceptibility to obesity in mice affects ovarian steroidogenesis, with a particular focus on the leptin-mediated dysregulation of Nodal signalling pathway in theca cells (TC). Methods C56BL/6J (B6) and 129S1/SvlmJ (129) mice, models of maternal obesity (MO), were fed a chow diet (CD) and a high fat diet (HFD) for 16 weeks. To investigate the contrasting effects of leptin on ovarian steroidogenesis, B6 mice pharmacologically treated with leptin for 16 days on CD were used to model hyperleptinemia, while homozygous ob/ob (-/-) mice with genetic leptin deficiency, also on a CD, were used to examine the effects of obesity in the absence of leptin. Following the characterisation of the mouse phenotype, gonadal fat (GON), whole ovaries (WO), ovarian TC and granulosa cell (GC) fractions were collected for mRNA transcription and protein expression analysis. Finally, in vitro treated ovarian explants obtained from B6 mice were used to further elucidate the effects of Nodal on steroidogenesis. Results The significant gain in body weight (BW) and fat mass (FM) in HFD-fed B6 mice (p < 0.05), was associated with increased mRNA transcription of the adipose tissue expansion genes Polymerase I and transcript release factor (Cavin), Secreted frizzled-related protein 5 (Sfrp5) and Mesoderm specific transcript (Mest) in GON (p < 0.05). Furthermore, the HFD-fed B6 mice presented also impaired glucose metabolism and insulin sensitivity (p < 0.05). In contrast, the HFD-fed 129 mice exhibited no changes in BW and FM, maintaining glucose and insulin metabolism. At the ovarian level, decreased protein expression of Steroidogenic Acute Regulatory Protein (StAR) in WO obtained from HFD-fed B6 mice (p = 0.05), was followed by reduced transcription of key steroidogenic genes like Star and Cytochrome P450 17a1 (Cyp17a) in TC (p < 0.05). Furthermore, the transcription of Nodal and its receptors was downregulated (p < 0.05), whereas mRNA levels of Suppressor of cytokine signalling 3 (Socs3) and SMAD family member 7 (Smad7) were upregulated in TC obtained from HFD-fed B6 mice (p < 0.05). No changes were seen in the genes regulating steroidogenesis, Nodal signalling, or Socs3 and Smad7 activity in the ovaries of HFD-fed 129 mice. Importantly, the pharmacological treatment of lean mice with leptin, upregulated the ovarian transcription of Socs3 and Smad7, while downregulating Nodal and its receptors (p < 0.05). Finally, in vitro pharmacological inhibition of Nodal signalling pathway in ovarian explants isolated from CD-fed B6 mice decreased the transcription of Star and Cyp17a in TC (p < 0.05), whereas Nodal treatment of explants obtained from HFD-fed B6 mice restored the transcription of both genes (p < 0.05). Conclusions Increased susceptibility to obesity in MO is associated with systemic hyperleptinemia and hypoestrogenism due to compromised ovarian steroidogenesis, largely driven by the inhibitory effects of leptin-Smad7 pathway on Nodal signalling activity in the TC compartment of ovarian follicles. (c) 2024 The Authors. Published by Elsevier GmbH. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Identification of a global gene expression signature associated with the genetic risk of catastrophic fracture in iPSC-derived osteoblasts from Thoroughbred horses
Full text linkBone fractures are a significant problem in Thoroughbred racehorses. The risk of fracture is influenced by both genetic and environmental factors. To determine the biological processes that are affected in genetically susceptible horses, we utilised polygenic risk scoring to establish induced pluripotent stem cells (iPSCs) from horses at high and low genetic risk. RNA-sequencing on iPSC-derivedosteoblasts revealed 112 genes that were significantly differentiallyexpressed. Forty-three of these genes have known roles in bone, 27 are not yet annotated in the equine genome and 42 currently have no described role in bone. However, many of the proteins encoded by the known and unknown genes have reported interactions. Functional enrichment analyses revealed that the differentially expressed genes were overrepresented in processes regulating the extracellular matrix and pathways known to be involved in bone remodellingand bone diseases. Gene set enrichment analysis also detected numerous biological processes and pathways involved in glycolysis with the associated genes having a higher expression in the iPSC-osteoblasts from horses with low polygenic risk scores for fracture. Therefore, the differentially expressed genes may be relevant for maintaining bone homeostasis and contribute to fracture risk. A deeper understanding of the consequences of mis-regulationof these genes and the identification of the DNA variants which underpin their differential expression may reveal more about the molecular mechanisms which are involved in equine bone health and fracture risk
Development and Progression of Bovine Respiratory Disease Measured Using Clinical Respiratory Scoring and Thoracic Ultrasonography in Preweaned Calves on Dairy Farms in the United Kingdom: A Prospective Cohort Study
No full textThe respiratory health of preweaned calves is an important determinant of their health, welfare, and future performance. This prospective cohort study measured bovine respiratory disease (BRD) on 16 dairy farms, including 476 calves in South-west England. Wisconsin and California respiratory scoring and thoracic ultrasonography were performed repeatedly at 7 ± 0.89 day intervals (mean ± SD) at 0–56 days of age (n = 3344 examinations). Cases were localized to the upper or lower respiratory tract, or both, and classified as new, repeat, or chronic. Prevalence and incidence were calculated. Multivariate modeling of factors associated with repeated measurements was performed. Increasing age (OR = 1.05, 95% CI 1.04–1.06) and fecal score (Score 2, OR = 1.78, 95% CI 1.14–2.77) were associated with a lower odds of a healthy BRD subtype, whereas increasing serum total protein (OR = 0.97, 95% CI 0.96–0.99) was protective. Older (OR 1.08, 95% CI 1.06–1.09), male (OR 1.69, 95% CI 1.01–2.84) calves with elevated Wisconsin respiratory scores (≥5, OR 5.61, 95% CI 3.38–9.30) were more likely to have elevated thoracic ultrasound scores. BRD remains common in calves born in UK dairy herds, requiring precise identification and management if preweaning health is to be optimized