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Integridade cromatínica e morfometria das cabeças espermáticas e suas relações com a concepção em éguas

2026-08-25T06:22:48Z

Title: Integridade cromatínica e morfometria das cabeças espermáticas e suas relações com a concepção em éguas Abstract: The evaluation of sperm chromatin and morphometry has gained relevance for diagnosing subfertility in stallions, especially when conventional seminal parameters do not explain reproductive failures. This study investigated whether changes in chromatin compaction, detected by Toluidine Blue, Feulgen Reaction, and Acridine Orange, as well as computational sperm head morphometric variables, correlate with conception in mares inseminated with fresh or cooled semen. Additionally, sperm morphometry was compared between Quarter Horse and Mangalarga stallions in order to evaluated possible differences between breeds and whether there was a correlation with conception. Ninety-seven semen samples used for artificial insemination were analyzed, and at least 150 sperm heads per sample were examined for chromatin compaction and morphometric variables. Chromatin characteristics evaluated showed no significant correlation with conception, indicating low sensitivity of these smear methods to predict reproductive performance when ejaculates meet minimum quality standards. In contrast, morphometric variables showed a significant correlation, with the width/length ratio (r= -0,226; p= 0,0398) and ellipticity (r= 0,226; p= 0,0400) standing out, in addition to a moderate correlation for form factor (r= -0,211; p= 0,0556) and Fourier 0 (r= 0,172; p= 0,1210). Significant differences were also observed between breeds, although these did not impact conception rates. The results indicate that, while the evaluated chromatin methods are not effective predictors, computational sperm head morphometry shows potential as a complementary objective tool for estimating stallion fertility.

Avaliação otológica canina e sua relação com endocrinopatias: aspectos técnicos, micológicos e bacterianos

2026-08-25T06:20:38Z

Title: Avaliação otológica canina e sua relação com endocrinopatias: aspectos técnicos, micológicos e bacterianos Abstract: Accurate assessment of canine otological microbiota is essential for proper diagnosis and management of otitis externa, one of the most common conditions in small animal practice. This thesis investigated technical, mycological, and bacterial aspects of canine otological microbiota, with emphasis on their relationship with endocrinopathies. Eighty dogs were evaluated, including 40 with hypothyroidism or hypercortisolism and 40 healthy controls, matched by age, sex, and breed. Animals underwent complete otological evaluation including otoscopy, auricular cytology, bacterial and fungal culture. For mycological analysis, hair samples were collected by manual traction or sterile vaginal cervical brush and inoculated in DTM medium for dermatophyte identification. Quantification of Malassezia spp. was performed by cytological evaluation, and bacterial samples were identified by MALDI-TOF, subjected to antimicrobial susceptibility testing using the VITEK system, biofilm formation capacity assessment by crystal violet method followed by microbiological counting of the sessile form, and ultrastructural analysis by scanning electron microscopy. Additionally, commercial and compounded propolis-based products were tested for antibiofilm efficacy. The prevalence of Malassezia spp. was significantly higher in endocrinopathic dogs (37.5%) compared to controls (10.0%; p<0.01), with dogs with otological malasseziosis presenting a 5.4-fold higher risk of being endocrinopathic (OR = 5.40; 95% CI: 1.60-18.20). Positive fungal culture for dermatophytes was identified exclusively in endocrinopathic dogs (5.0%). Different Staphylococcus strains were isolated, with all S. pseudintermedius strains demonstrating biofilm formation capacity (BFI>1.10) and variable antimicrobial resistance profiles. Results demonstrate strong association between endocrinopathies and opportunistic fungal infections, emphasizing the importance of endocrine investigation in recurrent otitis cases, and highlight the role of bacterial biofilms in persistence of otological infections.

Economic values for fertility, growth, carcass, and meat quality traits for seedstock and cow-calf operations in the Southeastern United States

2026-08-12T06:28:43Z

Title: Economic values for fertility, growth, carcass, and meat quality traits for seedstock and cow-calf operations in the Southeastern United States Abstract: This study aimed to estimate trait-specific economic values for use as weights in economic selection indexes for Brahman and Angus–Brahman beef cattle operations. Economic values (EVs) were derived for fertility, growth, and carcass traits using the UF Purebred Brahman and the UF Multibreed Angus–Brahman (MAB) herds as a reference population. Bioeconomic models were developed using herd variable costs, revenues, and management data collected from February 2024 to May 2025. The BRA herd is a seedstock production operation focused on the breeding and marketing of registered, genetically superior purebred animals, providing genetic material to support the long-term sustainability of the beef cattle industry. In addition to the BRA herd, a simulated scenario was developed to represent a broader range of seedstock operations in the Southeastern United States. Offspring from the BRA herd and the seedstock scenario were either sold at weaning or yearling, retained as replacements, slaughtered for carcass evaluation, or sold for breeding purposes. The MAB herd is a cow-calf operation that focuses on breeding cows to produce one healthy, marketable calf per cow per year, supplying the beef industry with enough and high-quality meat. In addition to the MAB herd, three simulated scenarios were developed to represent a broader range of cow–calf operations in the Southeastern United States. Offspring from the MAB herd and from the simulated scenarios were either sold at weaning or yearling, retained as replacements, or marketed to a meat processor. EVs were estimated as the expected change in profitability resulting from a one-unit change in performance of a specific trait, while holding all other traits constant. EVs were estimated for calving success-to-sale (CSS), age at first pregnancy (AFP), weaning weight (WW), yearling weight (WY), weight at 15 months of age (W15), weight at 18 months of age (W18), dressing percentage (DP), USDA quality grade (QG), and USDA yield grade (YG). In the BRA herd and the simulated seedstock scenario, calving success-to-sale was the most economically important trait, followed by AFP, DP, QG, WY, YG, W15, and WW. In the MAB herd and the three simulated scenarios, calving success-to-sale was also the most highly valued trait, followed by AFP, DP, QG, YG, and growth traits. The relative importance of growth traits in the MAB herd and simulated scenarios varied by marketing endpoint, highlighting the need to align selection for growth traits with revenue-generating sale strategies. In conclusion, trait specific economic values enable selection strategies for improving the efficiency of genetic progress. Overall, the results support data-driven breeding decisions to optimize productivity, profitability, and genetic progress through multiple-trait selection.

Complexos de Paládio(II) e Platina(II) ligados a β-dicetonas como estratégia de controle Campylobacter jejuni na indústria avícola

2026-08-11T06:29:07Z

Title: Complexos de Paládio(II) e Platina(II) ligados a β-dicetonas como estratégia de controle Campylobacter jejuni na indústria avícola Abstract: Campylobacter jejuni is the main etiological agent responsible for bacterial gastroenteritis worldwide. Campylobacteriosis is frequently associated with the consumption of contaminated foods, especially chicken meat. Factors such as the ability to colonize different environments, form biofilms, and exhibit increasing resistance to antibiotics represent a major challenge for controlling this pathogen in the food production chain and for public health. In this context, the search for new antimicrobial agents has intensified, with particular emphasis on metal-based compounds with potential biological activity. Metal complexes containing β-diketone ligands have attracted interest due to their structural stability, chemical versatility, and potential to interact with biological systems. This thesis was structured into three chapters. The first chapter is dedicated to general considerations and the theoretical background of the topics addressed in the subsequent chapters. The second chapter aimed to evaluate the efficacy of palladium metal complexes bound to β-diketonates and dimethyl sulfoxide (DMSO), with the formulas [Pd²⁺Cl₂(4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione)(DMSO)] (PdDMSOTTA) and [Pd²⁺Cl₂(4,4,4-trifluoro-1-phenyl-1,3-butanedione)(DMSO)] (PdDMSOBTA). The third chapter aimed to investigate the activity of platinum complexes bound to β-diketones, with the formulas [Pt²⁺Cl₂(4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione)(DMSO)] (PtDMSOTTA) and [Pt²⁺Cl₂(4,4,4-trifluoro-1-phenyl-1,3-butanedione)(DMSO)] (PtDMSOBTA). The tests were conducted on six C. jejuni strains resistant to erythromycin and ciprofloxacin, evaluated in both planktonic and sessile forms. The bactericidal activity of the complexes was determined through the minimum bactericidal concentration (MBC). All strains were classified according to the biofilm formation index (BFI) as non-producers, weak, moderate, or strong biofilm producers, while antibiofilm activity was evaluated through mature biofilm eradication assays. The ultrastructure of the biofilms was analyzed by scanning electron microscopy, the metabolomic profile by gas chromatography coupled with mass spectrometry (GC–MS), and cytotoxicity in differentiated Caco-2 cells by the resazurin reduction assay. The tests presented in Chapter Two show the results for palladium complexes coordinated to β-diketones. The PdDMSOBTA complex exhibited greater bactericidal activity against planktonic cells, with an average MBC of 15.36 µg/mL, eliminating all strains at concentrations < 50 µg/mL, whereas PdDMSOTTA showed lower efficacy. In biofilms, PdDMSOBTA promoted complete elimination at concentrations < 400 µg/mL and significantly reduced the adhered biomass, with an average reduction of approximately 75% in the biofilm formation index. Metabolomic analysis revealed alterations in metabolic pathways related to amino acid metabolism, purine metabolism, and cellular stress response. The viability of Caco-2 cells remained above 80–90% after exposure to the compounds, indicating low cytotoxicity. In Chapter Three, the antimicrobial potential of platinum(II) β-diketonate complexes, PtDMSOBTA and PtDMSOTTA, was investigated against the same six resistant strains of C. jejuni. The PtDMSOBTA complex showed higher bactericidal activity in the planktonic form, with an average MBC of 12.76 µg/mL, while PtDMSOTTA showed lower efficacy. In biofilms, PtDMSOBTA eliminated all isolates at concentrations < 200 µg/mL and significantly reduced biofilm biomass, whereas PtDMSOTTA showed a moderate effect. Scanning electron microscopy revealed structural disorganization of the biofilms and reduction of the extracellular matrix. Metabolomic analysis identified alterations in pathways related to amino acid metabolism, redox balance, and tryptophan metabolism. Both complexes showed low cytotoxicity, with cell viability between 80 and 100%. The study allowed the conclusion that palladium(II) and platinum(II) β-diketonate complexes, especially PdDMSOBTA and PtDMSOBTA, containing the ligand 4,4,4-trifluoro-1-phenyl-1,3-butanedione, exhibit significant antimicrobial activity against C. jejuni in both planktonic and sessile forms. planktonic cells, concentrations up to 100 µg/mL were sufficient to eliminate the microorganism, possibly due to metabolic alterations associated with the induction of cellular stress. In addition, the compounds showed low cytotoxicity in eukaryotic cells, indicating an initial profile of biological safety. Regarding the sessile form, higher concentrations were required for biofilm eradication, and additional cytotoxicity studies are still necessary to confirm safety under these conditions. Overall, the results obtained highlight the potential of these metal complexes as promising alternatives for the control of C. jejuni, especially in strategies aimed at reducing contamination in environments related to food production and processing.