Ana Luiza de Freitas dos Santos

Colonial cheese production represents a valuable cultural and economic activity in southern Brazil. This study evaluated the effect of oral supplementation of dairy cows with an essential oil blend (EOB)—a combination of eucalyptus oil, peppermint oil, and menthol crystals—on the chemical composition and quality parameters of Colonial cheese during 21 days of ripening. Nine dairy cows were randomly assigned to three groups: control, EOB3.6 (3.6 g/cow/day), and EOB7.2 (7.2 g/cow/day). Milk from each treatment was used to produce Colonial cheeses, which were analyzed for physicochemical composition, texture, color, lipid profile, thiobarbituric acid reactive substances (TBARS), and microbiological quality at different ripening stages. Data were analyzed by analysis of variance (ANOVA) using SAS^® software, following verification of normality and homogeneity of variances. When assumptions were met, repeated-measures ANOVA was applied, and means were compared using Tukey’s test (p < 0.05). Sensory data were evaluated by ANOVA using XLSTAT^® (Addinsoft, Paris, France). EOB supplementation maintained the physicochemical integrity of the cheeses, with a gradual increase in fat content during maturation (40 g/100 g at 21 days, p < 0.05). At seven days, the EOB7.2 treatment showed lower lipid oxidation (TBARS = 0.063, p < 0.05), indicating antioxidant potential. Significant interactions between treatment and maturation were observed for color parameters and polyunsaturated fatty acids (PUFA) (p < 0.05). Cheeses from EOB7.2 presented higher saturated fatty acids (SFA) and lower unsaturated fatty acids (UFA) compared with the control (p < 0.05). No Salmonella spp. or Staphylococcal enterotoxins were detected. Counts of coagulase-positive Staphylococcus, molds, and yeasts remained stable, while Escherichia coli counts were lower in EOB-supplemented cheeses throughout ripening. Overall, EOB supplementation improved oxidative stability and microbiological safety without compromising the technological or compositional quality of Colonial cheese.

Wheat silage is an underexplored forage in ruminant nutrition that offers potential benefits due to its high crude protein content and capacity to mitigate methane emissions. However, little is known about its interaction with feed additives. This study evaluated the effects of monensin (25 ppm) and narasin (13 ppm) on the in vitro ruminal fermentation of wheat silage using a randomized complete block design with three treatments and seven replicates per incubation. Gas production was recorded over 48 h, and fermentation parameters, including pH, in vitro organic matter digestibility (IVOMD), metabolizable energy (ME), ammonia nitrogen (NH₃-N), and volatile fatty acid (VFA) profiles, were determined. Both ionophores maintained a higher ruminal pH compared to the control (p < 0.01) and reduced total gas production, ME, and IVOMD (p < 0.01), without significant differences between monensin and narasin. No effects were observed on total VFA production, acetate-to-propionate ratio, or ammonia concentration, although isobutyrate was reduced (p < 0.01). Fermentation kinetics revealed decreased gas production and digestion rates in the slowly degradable fraction, particularly with monensin. In conclusion, ionophores modulated fermentation but did not improve digestibility or energy availability, suggesting limited nutritional benefits when wheat silage is used as the sole forage source.