National University of Río Cuarto

Background and Aim: The increasing prevalence of antibiotic-resistant pathogens necessitates the exploration of alternatives to growth-promoting antibiotics (GPAs) in poultry production. This study evaluated a commercial additive containing plant extracts (carvacrol and cinnamaldehyde) as a potential replacement for GPAs in broiler chickens, focusing on productive parameters, cecal microbiota composition, cecal volatile fatty acid (VFA) concentration, and small intestinal histomorphology. Materials and Methods: The study involved 100 one-day-old Cobb 500 broiler chickens, divided into two treatment groups: Group 1 (control) received a basal diet (BD) with avilamycin (100 g/T), and Group 2 received a BD with a phytogenic feed additive (PFA) containing 10% carvacrol and 10% cinnamaldehyde (100 g/Tn). Over 42 days, the study measured total weight gain (TWG), feed intake, feed conversion ratio (FCR), carcass yield, digestive tract length, intestinal histomorphometry, VFA concentration, and cecal microbiota composition. Results: The PFA-treated group showed a 1.67% improvement in TWG and a 5.7% improvement in FCR compared to the control. The digestive tract length increased by 20 cm with PFA supplementation. While no significant differences were observed in cecal microbiota counts and VFA concentrations, a trend toward increased lactic acid bacteria and VFA levels was noted. Histomorphological analysis indicated enhanced villus height and a higher villus height-to-crypt depth ratio in the PFA group. Conclusion: The findings suggest that carvacrol and cinnamaldehyde-based PFAs may serve as viable alternatives to GPAs, promoting growth performance and gut health in broiler chickens. Further research is needed to elucidate the underlying mechanisms of action and confirm these preliminary results in larger-scale studies. Keywords: antibiotic alternatives, broiler chickens, carvacrol, cinnamaldehyde, gut health, phytogenic feed additives.

In this study, two new BOPHY-based derivatives were efficiently synthesized with high yields and characterized by using spectroscopic, electrochemical, and spectroelectrochemical techniques. The introduction of non-conjugated (carbazole (CBZ)) and conjugated (triphenylamine (TPA)) donor groups into the BOPHY macrocycle imparted different electrochemical and spectroscopic properties. Oxidation of BP-2CBZ led to the formation of unstable CBZ radical cations, which further reacted to generate dicarbazole (DCBZ) units, allowing the formation of a polymeric film during anodic cycling. In contrast, BP-2TPA exhibited a reversible oxidation process, generating stable BOPHY and TPA radical cations which inhibited the polymerization process. Spectroscopic differences were also observed, with BP-2CBZ displaying a high fluorescence quantum yield (f), while BP-2TPA emission was nearly quenched, exhibiting solvent-dependent fluorescence with a large Stokes shift (~160 nm). BP-2TPA also demonstrated aggregation-induced emission (AIE) properties, showing an increase in fluorescence intensity of around 12 times when the water content changes from 0 to 90%. These experimental findings were further corroborated by DFT and TDDFT calculations. The BP2CBZ polymer presented electrochromic properties, showing color changes upon oxidation. This work represents the first report of a BOPHY-based polymer synthesized through electrochemical methods.

Neonicotinoid are systemic insecticides used in agriculture. In particularly, imidacloprid (IM) and thiamethoxam (TM) have a selective toxicity to insects, and they have been implicated in the steep decline of...

In this work, alginate nanoparticles (ALG-NPs) were synthesized using reverse micelles (RMs) as nanoreactors to investigate how interfacial charge influences their structure, size, and encapsulation properties. Three types of RMs were employed: (i) anionic RMs formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in isopropyl myristate, (ii) cationic RMs formed by benzyl-hexadecyl-dimethylammonium chloride (BHDC) in toluene, and (iii) nonionic RMs formed by 2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol (TX-100) in cyclohexane. ALG-NPs were synthesized at varying water contents (W0 = [H2O]/[surfactant]) and resuspended in water at pH 6.5 for characterization. Dynamic light scattering revealed that nanoparticle size is highly dependent on the RM template. ALG-NPs synthesized in AOT RMs were the smallest, with their size increasing as W0 increased, a trend also observed for TX-100 RMs. In contrast, the opposite behavior was observed in BHDC RMs, where nanoparticle size decreased with increasing W0. This difference reflects the degree of crosslinking with Ca²⁺ ions as influenced by interfacial charge. Using N,N-dimethyl-6-propionyl-2-naphthylamine (PRODAN) and curcumin, we found that AOT-based ALG-NPs were the most compact and rigid, offering prolonged protection for curcumin against degradation under ambient conditions. This study underscores the potential of tailoring ALG-NPs through precise control of interfacial environments, offering new opportunities for applications in food technology, nutraceuticals, and biotechnology. By stabilizing bioactive compounds and enhancing bioavailability, these findings pave the way for innovative functional formulations.

This study evaluated the effects of EO administered via intramammary inoculation in dairy cows during the drying-off period and its impact on milk quality in the subsequent lactation. Ten pregnant Holstein cows, free of mastitis, were selected from an organic dairy farm in Córdoba, Argentina. Twenty-four quarters were inoculated with EO: eight received 0.25 g, eight received 0.50 g, and eight received 1.00 g. Control groups included uninoculated quarters and quarters treated with cephapirin. Milk samples were collected before treatment and within 4 days after calving to assess microbial count and somatic cell counts (SCC). The expression of TNF-α, IL-6, and IL-10 was quantified using qPCR and malondialdehyde (MDA) levels were also measured. Blood samples were collected before treatment and within 4 days after calving to determine serum IL-6 and IL-4 levels using ELISA. No significant effects were observed on milk’s physical-chemical properties following EO or cephapirin treatment. EO at 1.00 g significantly reduced microbial load (p < 0.05), comparable to cephapirin. SCC increased with all EO doses (p < 0.01, p < 0.05, p < 0.05, respectively). Differential cell counts showed an increase in macrophages after 1.00 g EO treatment. The relative expression of TNF-α, IL-6, and IL-10 decreased without statistical significance. MDA levels significantly increased with cephapirin (p < 0.001), but EO had no effect. Serum IL-6 and IL-4 levels remained unchanged. In conclusion, intramammary EO inoculation enhanced immune response, reduced microbial load, and did not induce lipid peroxidation, suggesting its potential as a preventive treatment for mastitis.

Aims A key challenge in applied vegetation science is understanding the impact of herbivory on plant communities. Herbivores often reduce dominant species' abundance (biomass, cover), making resources available for new species and increasing plant diversity. This understanding is crucial in systems undergoing ecological restoration through trophic rewilding. In Iberá National Park, Argentina, jaguars ( Panthera onca ) are being reintroduced after a 70‐year absence, and it is critical to assess the role of herbivores in shaping plant communities for evaluating future potential trophic cascades. Capybaras ( Hydrochoerus hydrochaeris ), the park's most abundant herbivore and an important prey for jaguars, likely exert significant pressure on vegetation. This study aims to investigate how capybara herbivory affects vegetation height, biomass, diversity, and composition, providing insights into how jaguar reintroduction might indirectly influence plant communities and restore ecosystem functionality through capybaras' demographic or behavioral responses. Location Iberá National Park, Corrientes, Argentina. Methods We simulated the absence of capybara foraging pressure by establishing 10 3 m x 3 m herbivore exclosures with adjacent unfenced control plots in the capybara's grazing lawns. Vegetation attributes—height, biomass, plant diversity, and species composition—were monitored over 4 years to assess the impact of capybara exclusion on plant communities. Results Excluding capybaras significantly increased vegetation height and biomass, which, in turn, altered plant diversity and species composition. The exclosures' vegetation height and biomass were consistently higher than those in control plots. A decrease in species diversity accompanied this shift, as the abundance of common species declined and the dominance of a few species increased, generating new communities. Conclusions Capybaras significantly influence vegetation dynamics, demonstrating their role in shaping plant communities. Excluding capybaras leads to species composition and structural shifts, highlighting herbivory's importance in maintaining ecosystem heterogeneity. These findings provide critical baseline data for understanding the potential indirect impacts of the jaguar's reintroduction on plant communities and ecosystem processes. This study contributes valuable insights into the ecological mechanisms underlying plant–herbivore interactions, which are essential for guiding restoration practices and rewilding strategies.

The objective of this work was to obtain postbiotics derived from the cell wall of Saccharomyces cerevisiae RC016 by applying different strategies and to characterize them in terms of their antitoxin capacity in vitro and their in vivo impact on intestinal integrity, evaluating the modulation of the microbiota and the histomorphometry of the intestine. Moreover, the impact of dried strategies on chemical groups related to food toxin adsorption was analyzed. Nine mechanical and enzymatic cell disruption treatments were assayed using S. cerevisiae RC016 biomass to obtain the postbiotic under study. Then, postbiotics were characterized using high-resolution optical microscopy and assayed for in vitro studies related to their antitoxin activity (adsorption and degradation of aflatoxin B1). Postbiotics were dried using freeze-dried and spray-dried methods and subjected to FT-IR spectroscopy. Finally, the postbiotic efficacy was determined on an in vivo study conducted on 16 male and female BALB/c mice, divided into two experimental groups, each experimental group (n = 8) separated by sex in different cages (four females and four males): untreated (control) and yeast wall treated (YW); (a) female control; (b) male control; (c) female control + YW; (d) male control + YW. The intestinal microbiota showed significant differences in the counts of LAB and enterobacteria between male and female animals. The histomorphometric analysis showed a significant increase in villi height and width, as well as crypt depth, compared to the control group in male mice with the addition of the postbiotic solution of S. cerevisiae. These findings open new avenues for further optimizing postbiotics’ production processes and evaluating their efficacy across diverse conditions and populations.

El bosque de caldén se ubica en la región centro de Argentina y su principal actividad económica es la ganadería bovina, donde el pastoreo continuo conduce a una acumulación de material herbáceo senescente que aumentan el riesgo de incendios, principal causa de degradación del bosque. Para su restauración y/o expansión de la superficie boscosa, es crucial desarrollar métodos de propagación eficientes en vivero. El siguiente trabajo tuvo por objetivo evaluar la influencia de dos sustratos (suelo/arena/lombricompuesto y turba/perlita/lombricompuesto), dos tamaños de envases (15×6 y 25×7 cm) y dos ambientes (vivero e invernadero) sobre el crecimiento y calidad de plantín de Neltuma caldenia. Se registró diámetro a la altura de cuello, altura total, relación entre parte aérea y radical, índice de esbeltez e Índice de Dickson. En esta experiencia la mejor combinación en cuanto a parámetros de crecimiento y calidad del plantín fue sustrato suelo/arena/lombricompuesto, empleando un contenedor profundo y en cancha de cría. Estos resultados son alentadores ya que, con materiales de bajo costo y una baja infraestructura de vivero, es factible lograr plantines de N. caldenia de calidad.

Aim We investigated the effects of habitat destruction and hunting on the functional decline of top predators, specifically jaguar and puma, in the Gran Chaco. Location The 1.1 million km² South American Gran Chaco. Methods We used spatially explicit, individual‐based models for jaguars and pumas, incorporating detailed information on habitat suitability and hunting pressure. We parameterized our models with literature data and calibrated them through a Delphi expert‐elicitation process. We simulated population trajectories under a hypothetical, threat‐free, baseline versus different threat scenarios. Results Under combined threats of hunting and habitat loss, jaguar and puma populations declined by 88% and 80%, respectively, compared to range contractions of 48% and 35%, respectively. Both species remained regionally viable, particularly due to large protected areas, which acted as population sources but were surrounded by strong sinks. We observed a widespread weakening of the top carnivore guild function, with at least one species extirpated across 67% of the Chaco and strong declines (> 80%; considered here as functional loss) for both species concurrently across 61% of their area of historical co‐occurrence. Hunting was a much stronger driver of population declines (88% and 77% for jaguars and pumas, respectively) compared to habitat destruction (26% and 22%). Main Conclusions Large predators play key functional roles in ecosystems. Our findings reveal that these functions can be lost over vast areas due to the combined effects of habitat destruction and hunting, with functional loss extending far beyond the areas of species' extirpation. Very large protected areas, like Kaa‐Iya in Bolivia, are crucial for maintaining viable populations of top predators, highlighting the pressing need for increased protection and connectivity in the Chaco to prevent further trophic downgrading. More generally, our research underscores the value of spatially detailed, mechanistic models for disentangling the complex dynamics of multiple threats on ecological functioning at broad scales.

In the rhizosphere ecosystem, the tomato develops associated with a diversity of microorganisms and/or organisms, many of which can be beneficial or pathogenic for this plant. Plant-parasitic nematodes (PPN) produce significant economic losses in tomato crops. Nacobbus sp. is one of the most frequent and abundant PPN in Argentina. Management of this nematode through biological strategies constitutes an eco-compatible alternative to ensure the sustainability of the horticultural system. In this work, the potential of the combined application of broccoli aqueous extract (BAE—12%) and Purpureocillium lilacinum SR14 (1 × 10⁶ conidia g⁻¹) for the control of N. aberrans s.l. in tomato (Solanum lycopersicum cv. Platense) plants were evaluated. The chamber test was conducted with sterile horticultural soil, artificially infested with J2, while naturally infested horticultural soil was employed for the greenhouse test. The antagonist activities of P. lilacinum SR14, BAE and SR14 + BAE against the N. aberrans s.l. population were evaluated in the two assays. Results showed that the combined treatment (P. lilacinum SR14 + BAE) significantly reduced the PPN population, both in chamber (22%) and greenhouse (98%) grown plants. Furthermore, it was demonstrated that both strategies were compatible with each other, the host crop and the soil microbiome. Therefore, this type of agroecological practice, could be a plausible alternative to be adopted by horticultural producers in Argentina for the control of the phytonematode, N. aberrans s.l.

In 1963, Eduardo Lissi and Juan Grotewold started a chemical kinetics and photochemistry group at the School of Sciences at the University of Buenos Aires (Facultad de Ciencias Exactas y Naturales, FCEN, UBA). Political circumstances in Argentina and in Chile were a great determinant of the evolution, dispersion, and re‐encounters of the group members. The initial graduate students in the group developed their own research groups working in various Countries and on a variety of projects. We relate the story of the strong interactions with each other of the original group as well as the cooperations and synergy (Intersystem Crossings) of Lissi and Grotewold and of their descendants with other research groups, mainly (but not only) in Latin America. A strong network of partnerships, friendships, and fruitful collaborations between the kineticists, photochemists, and photobiologists in Argentina, Chile and Brazil has evolved from the initial steps in the 1960s.

Post-weaning diarrhea (PWD) is a major concern for pig producers, as stress and early weaning increase susceptibility to enteropathogens like enterotoxigenic Escherichia coli (ETEC) and Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium). This study explores the immunomodulatory and antimicrobial properties of lipopeptide extracts (LPEs) from Bacillus strains which contain surfactin (SF) - an immunomodulatory lipopeptide - and their potential in mitigating PWD. Pre-incubation with LPEs from B. subtilis TC12, containing 1, 40 and 60 µg/ml SF, stimulated TNF-α production significantly (p < 0.05) in LPS-challenged RAW 264.7 cells. In contrast, B. velezensis MFF 2.2 LPE, containing 0.1 and 1 µg/ml SF, reduced TNF-α production by macrophages after LPS-challenge. The production of IFN-γ by these cells was not affected by pre-incubation with any of the extracts. On the other hand, all treatments significantly decreased (p < 0.05) IL-10 production. LPEs significantly reduced (p < 0.05) NO production; however, neither TC12 nor MFF 2.2 LPEs affected macrophage phagocytic activity or bactericidal capacity and, in addition, LPEs showed bacteriostatic activity towards S. Typhimurium and ETEC. Also, LPEs did not affect RAW 264.7 viability (> 90%) in concentrations up to 60 µg/ml SF for TC 12 and 1 µg/ml for MFF 2.2. These findings suggest that LPEs from native Bacillus possess immunomodulatory and antimicrobial properties, which could help control inflammation and inhibit pathogen growth during piglet weaning. According to preliminary in vivo studies, LPEs might offer a promising alternative to reduce antibiotic usage in pig husbandry.

Background Several epidemiological studies have been carried out using Multiple-Locus Variable-number tandem repeat Analysis (MLVA) for M. hyopneumoniae typing. However, a global perspective on the implications of the genetic diversity of this pathogen is lacking. Objective This study aimed to determine and to analyze the genetic structure of M. hyopneumoniae based on the p97R1-p146R3 MLVA typing scheme and to characterize, analyze and compare MLVA types among countries where the information was publicly available. Methods A set of 797 publicly available data of M. hyopneumoniae p97R1-p146R3 MLVA genetic types from six different countries were analyzed using Genalex 6.41 software to characterize loci polymorphism and using Structure 2.3.4 software in order to identify the genetic structure. Results A total of 185 MLVA types were identified among the analyzed data. For the p97R1 and p146R3 loci, most of the molecular variation in M. hyopneumoniae populations was identified within countries. Three genetic clusters and their recombinations were identified globally. Conclusion M. hyopneumoniae is a genetically diverse pathogen with limited clonality and three well-defined clusters and their combinations were identified in this investigation. The greatest genetic variation of M. hyopneumoniae was observed within countries.

Barley (Hordeum vulgare L.) is the second winter crop in Argentina. In the national market, grains are mainly destined to produce malt for beer manufacture. Fusarium species are common, causing Fusarium Head Blight (FHB) in barley, which generates yield and quality losses, as well as mycotoxin occurrence. The aims of this study were to determine (a) the incidence of the main species causing FHB in different locations of the barley-growing region of Argentina, (b) their ability to produce mycotoxins, and (c) the levels of deoxynivalenol (DON) and nivalenol (NIV) natural occurrence in grains at the harvest stage. Additionally, a strain of Bacillus velezensis was studied as a biocontrol agent in order to control F. graminearum sensu stricto and mycotoxin accumulation during the malting process, with the final objective being to reduce DON contamination in the beer manufacture chain. Fusarium graminearum ss was the most prevalent species causing FHB, with Fusarium poae being less distributed. Both species produced several mycotoxins, including NX-2 and NX-3, which is the first report of their production by strains isolated from barley in Argentina. Deoxynivalenol contamination was found in 95% of barley grains during the 2016 harvest season (mean: 0.4 mg/kg), while NIV contamination was present in 29% of samples (mean: 0.49 mg/kg). In the 2017 harvest season, 53.6% of grains were contaminated with DON (mean: 0.42 mg/kg), and 21% with NIV (mean: 0.8 mg/kg). Quantification of F. graminearum ss by real-time PCR during the micro-malting process showed that application of the biocontrol agent before the germination stage was the most effective treatment, with a 45% reduction in fungal DNA levels. Reduction in DON contamination (69.3–100%) in artificially infected grains with F. graminearum ss, was also observed. The present work contributes to the knowledge of FHB in Argentina and to the development of a strategy to control this disease and mycotoxin contamination in barley, promoting at the same time food security.