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

2026-01-22T00:00:00Z

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

2026-03-26T00:00:00Z

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.

Desenvolvimento de sistemas biopoliméricos ativos incorporando óleo essencial de cravo para preservação de alimentos

2026-06-26T00:00:00Z

Title: Desenvolvimento de sistemas biopoliméricos ativos incorporando óleo essencial de cravo para preservação de alimentos Abstract: The search for safer, natural, and sustainable foods has driven the advancement of technologies aimed at food preservation and the replacement of conventional packaging. In this context, this thesis aimed to develop two distinct active packaging systems using clove essential oil (CEO) as the active compound combined with biodegradable polymers, in order to evaluate their ability to inhibit different bacterial species. The thesis was organized into three chapters: the first dedicated to a literature review, and the following two chapters presented in the form of scientific articles. In Chapter 2, a bioactive chitosan film containing 1% chitosan and clove essential oil at concentrations of 1% and 1.5% was developed. Successful entrapment of CEO within the chitosan polymer matrix was observed. The film containing 1% CEO exhibited a uniform microstructure, improved flexibility, and adequate thermal stability. The film containing 1.5% CEO showed microphase separation. Both films were able to inhibit the growth of Escherichia coli, Salmonella Enteritidis, and Staphylococcus aureus. Refrigerated strawberries, cherry tomatoes, and Fuji apples were coated using the dipping technique, and the formulation containing 1% CEO was able to extend the shelf life of refrigerated strawberries by 8 days. The developed film proposes a simpler clean-label packaging approach, highlighting its potential application as active packaging. In Chapter 3, CEO was encapsulated using cellulose nanocrystals (CNC), producing a Pickering emulsion (PE-CEO) for incorporation into hydroxypropyl methylcellulose (HPMC). Stable emulsions were produced and maintained for at least 90 days using 1.5% CNC. The emulsions demonstrated antibacterial activity against E. coli ATCC 25922, S. Enteritidis 13076, K. pneumoniae, and S. aureus 25923, as well as multidrug-resistant and ESBL-producing strains, including E. coli ESBL, S. diarizonae ESBL, K. pneumoniae, and S. aureus. HPMC films containing different concentrations of PE-CEO (1.5, 3.0, 6.25, and 12.5%) were then produced. These films exhibited a homogeneous microstructure, transparency of up to 59.2%, appropriate viscoelastic behavior, and a significant reduction in bacterial counts after 24 hours for all tested strains, particularly at the higher concentrations (6.25 and 12.5%). Overall, the results demonstrate that the developed films represent a promising and sustainable approach, aligned with the clean-label concept for the development of active packaging.

Exploring Copper (II) and Nickel (II) complexes for the control of antimicrobial-resistant Campylobacter jejuni and Escherichia coli

2026-02-26T00:00:00Z

Title: Exploring Copper (II) and Nickel (II) complexes for the control of antimicrobial-resistant Campylobacter jejuni and Escherichia coli Abstract: Campylobacter jejuni and Escherichia coli are among the main pathogens associated with foodborne diseases, particularly those originating from poultry. The dissemination of multidrug-resistant strains and their ability to form biofilms favor the persistence of these microorganisms in industrial environments and reduce the effectiveness of conventional antimicrobials and sanitizers. In this context, this thesis aimed to evaluate the potential of two copper(II) complexes, [Cu(tta)(bipy)NO₃] and [Cu(tta)(phen)NO₃], and two nickel(II) complexes, [Ni(η²-NO₃)(bta)(phen)] and [Ni(η²-NO₃)(btacl)(phen)], as alternatives for the control of antimicrobial-resistant C. jejuni and E. coli, integrating phenotypic, genomic, and structural approaches. The thesis was organized into three chapters, with Chapter 1 dedicated to the theoretical framework and Chapters 2 and 3 structured as scientific articles. In Chapter 2, four metal complexes were evaluated against five resistant Campylobacter jejuni isolates. All isolates were classified as strong biofilm formers and exhibited a broad genomic repertoire, including 134 virulence genes and multiple determinants associated with resistance to antimicrobials, metals, and biocides. The complexes significantly reduced bacterial viability and biofilm formation, with particular emphasis on the [Ni(η²NO₃)(bta)(phen)] complex, which showed the lowest minimum bactericidal concentration (6.25 µg/mL) and promoted pronounced disruption of the extracellular matrix. Metabolomic analysis identified 408 compounds belonging to 14 chemical classes, revealing alterations consistent with oxidative stress, metabolic imbalance, and impairment of cellular integrity. In Chapter 3, ten Escherichia coli isolates from the poultry production chain were evaluated. Four isolates (40%) were classified as strong biofilm formers, and all exhibited a multidrug-resistant profile, with seven distinct resistance phenotypes. Genomic characterization revealed 28 antimicrobial resistance determinants, 280 virulence genes, 168 genes associated with resistance to metals and biocides, as well as 13 plasmid replicons. The complexes showed bactericidal activity against both planktonic (1.56–100 µg/mL) and sessile cells (25–400 µg/mL), again with superior performance of the [Ni(η²NO₃)(bta)(phen)] complex. Overall, the results demonstrate that metal complexes, particularly nickel(II)-based compounds, have high potential for the control of resistant bacteria associated with biofilms, contributing to the development of innovative strategies within the One Health framework.