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Bursa of Fabricius (BF) is a primary lymphoid organ in birds, crucial for lymphocyte development and immune function. This study investigates age‐related alterations in the histomorphology and ultrastructure of the bursal tissue in green‐winged teal (Anas crecca) at 8th and 24th weeks of age. Twenty ducks were examined, and the sample tissues were collected post‐euthanasia for histological and scanning electron microscopy (SEM) analyses. At the 8th week, the histological sections exhibited normal lymphocyte distribution and structural organization, characterized by a well‐developed muscular layer and plicae. In contrast, by the 24th week, significant involution was observed, marked by reduced bursal weight, diminished muscular layer and increased fibrosis. Histological changes included necrosis and depletion of lymphocytes, alongside alterations in the follicular‐associated epithelium. SEM revealed collagen fibre spreading and loss of microvilli, indicating advanced involution. This study highlights the developmental and involutionary stages of the organ in A. crecca, providing essential insights into the age‐dependent changes in this critical immune organ. This is the first report detailing these histomorphometric and ultrastructural alterations in A. crecca, highlighting the age‐dependent nature of these changes, besides contributing to our understanding of avian immunology. This scientific diagram illustrates age‐related changes in the Bursa of Fabricius (BF) of green‐winged teal (Anas crecca) ducks at two developmental stages. In the 8th week, the BF shows maximum maturation with peak morphometric measurements (body weight, bursal dimensions), the thickness of cortex and medulla layers and well‐developed ultrastructure, including microvilli and regular borders. By the 24th week, the BF undergoes involution with decreased measurements, reduced tissue thickness and structural deterioration, including absent microvilli, irregular borders and collagen fibre deposition. The study demonstrates the natural developmental progression from functional maturity to age‐related regression in this important immune organ of waterfowl.

[Abstract] The aim of this study was to evaluate the correlation between resonance frequency analysis (RFA) values and the histomorphometric bone-implant contact (BIC) immediately after insertion of the implant. Additionally, it was examined to define which extent peak insertion torque (PIT) was correlated with the latter measurements. 15 Xive(R) S plus root from dental implants were inserted in fresh porcine frontal bones. The insertion torque was measured with the Kavo Intrasurg 300 surgical unit. RFA connector was coupled to the implants and the mean value of 20 consecutive RFA measurements was calculated via Osstell(R) ISQ device. The implants were removed with the adjacent bone with a band saw. The blocks were processed for undecalcified histology. Two perpendicular longitudinal middle sections of the implant were made and stained with toluidine blue and the BIC was assessed by histomorphometry. The correlation coefficient (Spearman) between RFA and BIC was R=0.579 (p=0.026, F test). The correlation between PIT and BIC (0.33, p>0.05) and PIT and RFA (0.153, p>0.05) was not statistically significant. The present data confirmed a moderate and statistically positive correlation between RFA and BIC. No correlation between BIC and PIT and PIT and RFA was observed. Further studies considering different bone qualities would be beneficial in understanding the relation between RFA and BIC.

This study aims to evaluate the grid of Merz and ImageJ methods for histometric quantification, verifying which is more reliable and defining which is most suitable based on the time required to perform. Thirty histological samples of maxillary sinuses grafted with xenografts were evaluated using an optical light microscope attached to an image capture camera and connected to a microcomputer. The images were digitalized and recorded as a TIFF image, and the new bone formation was evaluated using the grid of Merz and ImageJ. The Bland–Altman analysis was used to identify the agreement between the methods and determine suitable future research options. The timing of the quantification was also performed to identify a possible advantage. The mean value for the quantification analysis timing for the grid of Merz was 194.9 ± 72.0 s and for ImageJ was 871.7 ± 264.4, with statistical significance between the groups (p = 0.0001). The Bland–Altman analysis demonstrated a concordance between the methods, due to the bias being next to the maximum concordance (−1.25) in addition to the graphic showing the scattering points next to the mean of differences and inside of limits of agreement. Thus, it was demonstrated that the grid of Merz presents reliable outcomes and advantages over the ImageJ methodology regarding the time spent to contour the areas of interest.