Biology subjects

Kilroy, D.

Publications and source records attributed to Kilroy, D..

3 recordsLinked to original sources

bioRxiv2025

Assessment of pupillometry across different commercial systems of laying hens to validate its potential as an objective indicator of welfare

BackgroundReliable and non-invasive methods for assessing welfare in poultry are essential for improving evidence-based welfare monitoring and advancing management practices in commercial production systems. The iris-to-pupil (IP) ratio, previously validated by our group in primates and cattle, reflects autonomic nervous system balance and may serve as a physiological indicator of stress in laying hens. This study evaluated the utility of the IP ratio under field conditions across diverse commercial layer housing systems. Materials and Methods296 laying hens (Lohmann Brown, n = 269; White Leghorn, n = 27) were studied across four locations in Canada housed under different systems: Guelph (indoor; pen), Spring Island (outdoor and scratch; organic), Ottawa (outdoor, indoor and scratch; free-range), and Toronto (outdoor and hobby; free-range). High-resolution photographs of the eye were taken under ambient lighting. Light intensity was measured using the light meter app. The IP ratio was calculated using NIH ImageJ software. Statistical analysis included one-way ANOVA and linear regression using GraphPad Prism. ResultsBirds housed outdoors had the highest IP ratios, followed by those in scratch systems, while indoor and pen-housed birds had the lowest IP ratios (p < 0.001). Subgroup analyses of birds in Ottawa and Spring Island farms confirmed significantly higher IP ratios in outdoor environments compared to indoor and scratch systems (p < 0.001). IP ratio correlated weakly with ambient light intensity (r = 0.25) and age (r = 0.05), indicating minimal influence of these variables. Although White Leghorn hens showed lower IP ratios than Lohmann Browns, this difference was confounded by housing type; all White Leghorns were housed in pens. Thus, housing system but not breed was the primary driver of IP variation. ConclusionIP ratio is a robust, non-invasive physiological marker of welfare assessment in laying hens, sensitive to housing environment but minimally influenced by light or age. Its potential for integration with digital imaging technologies supports its use in scalable welfare assessment protocols.

physiology↗

bioRxiv2024

An arch worth revisiting: A study on the feline humeral supracondylar foramen and its evolutionary significance

The supracondylar foramen with a seemingly osseous peripheral arch noticed on the medio-distal feline humeri had remained disputed among anatomists. Some scholars have argued in favor of homology between this foramen and the supracondyloid foramen formed in the presence of the ligament of Struthers in humans. Other theories include its presence as a retinaculum holding the median nerve and brachial artery to their anatomical position in a flexed elbow. Unfortunately, these theories lack investigative rigor. The emergence of non-invasive imaging modalities, such as micro-computed tomography, has enabled researchers to inspect the internal anatomy of bones without dismantling. Thus, a micro-computed tomographic investigation was conducted on three feline humeri specimens while the internal anatomy of the supracondylar foramina was examined. Unlike the humerus, the thin peripheral arch of the feline supracondylar foramen failed to elicit any osseous trabeculae or foci of calcification. While adhering to the humeral periosteum at its origin, the non-osseous arch, typical of a muscular tendon or a ligament, inserts into a bony spur attached to the medial humeral epicondyle suggestive of a ligament or aponeurotic extension of a (vestigial) brachial muscle, with the coracobrachialis longus emerging to be the most likely candidate.

evolutionary biology↗

bioRxiv2023

Finding Expression of MUC1 and MUC4 in the Respiratory System of the Iraqi Common Quail (Coturnix coturnix)

BackgroundThis study focused on the major components of mucus, known as mucins, within the mucosal epithelium of the respiratory system in Iraqi Common Quail. Six quail were utilized in accordance with animal ethics guidelines from the College of Veterinary Medicine at the University of Al-Qadisiyah. Histological analysis, utilizing H&E staining, aimed to identify key respiratory system structures. PAS plus Alcian blue stains were employed to identify specific carbohydrates in the trachea, bronchi, and lungs. RT-qPCR was used to assess the gene expression levels of MUC1 and MUC4. ResultsThe trachea and bronchi encompassed four distinct layers: tunica mucosa, tunica submucosa, hyaline cartilage, and tunica adventitia. The mucosa consisted of pseudostratified epithelium that transitioned into simple columnar cells toward the primary and secondary bronchioles. This transition further progressed into simple cuboidal and squamous epithelium at smaller tertiary branches of the secondary bronchioles. Notably, the bronchial tunica submucosa was thinner than the trachea. While hyaline cartilage was prominently present in the trachea, it became fragmented in the bronchi and diminished towards the lungs and secondary bronchioles. Lung tissue was characterized by numerous lobules housing alveoli connected to alveolar ducts and sacs, alongside an intricate network of blood vessels. The respiratory tissues, including the trachea, bronchi, and lungs, exhibited a strong affinity for PAS-combined Alcian blue stains. This confirmed the substantial presence of both acidic and neutral mucins within the epithelial cells and glands. The trachea demonstrated significantly elevated levels of acidic mucins and a concentrated amount? of neutral mucins. Transcriptome analysis indicated the expression of both MUC1 and MUC4 genes. Importantly, MUC4 expression surpassed that of MUC1 in the trachea, bronchi, and lungs. ConclusionThis study highlights the similarity of histological structures in the trachea, bronchi, and lungs of quail to typical avian species. Moreover, it underscored the substantial presence of both acidic and neutral mucins, with MUC4 being the predominant mucin, potentially playing a pivotal role in regulating mucosal barrier functions and interacting with pathogens. Nonetheless, further investigation is warranted to elucidate MUC4s role in respiratory epithelial cells.

molecular biology↗