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.

The aim of the present study was to evaluate a novel probiotic Pediococcus pentosaceus RC007 used alone and convined with Saccharomyces cerevisiae var. boulardii RC009, as in-feed additives to substitute the non-therapeutic use of antibiotics, and evaluate the different structural characteristics of intestinal bacterial populations between groups, correlated with pig production performance. The in vivo study was conducted on post-weaning pigs, from 21 to 56 days-old. Three dietary treatments were included: T1- basal diet (BD - Control group); T2- BD with P. pentosaceus RC007; and T3- BD with a mix of P. pentosaceus RC007 and S. boulardii RC009. The weight gain increase of pigs consuming non-therapeutic antibiotics was similar to those that did not consume antibiotics during the study (p=0.0234), but had better health indicators. The use of a probiotic combination increased carcass weight and significantly reduced the lumbar fat thickness. In terms of taxonomic composition, there was a tendency to modify the abundance of Proteobacteria, Cyanobacteria, Enterobacteriaceae and Lactobacillaceae in pigs that consumed the additives. The genus Butyricicoccus, Collinsella and Ruminococcus tended to be more abundant in the microbiota of pigs at T3. For the first time, the results of the present study indicate that P. pentosaceus RC007 and S. boulardii RC009, a probiotic combination, could be a good substitute for antibiotics in improving pig production performance, while also contributing to a healthier gut microbiota, especially with the reduced abundance of Proteobacteria and Cyanobacteria.

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.