نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه بیماری های داخلی دام های بزرگ دانشکده دامپزشکی دانشگاه ارومیه ارومیه ایران
2 گروه علوم دامی دانشکده کشاورزی دانشگاه ارومیه
3 گروه بیماری های داخلی دام های بزرگ دانشکده دامپزشکی دانشگاه رازی کرمانشاه ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective:Rumen acidosis is one of the most important nutritional disorders in ruminants, characterized by a decline in ruminal pH, epithelial damage, disruption of fermentative pathways, reduced nutrient absorption, and increased methane emissions. Subacute ruminal acidosis (SARA) is highly prevalent in dairy and feedlot cattle and results in significant economic losses due to reduced milk yield, poor growth performance, veterinary costs, and energy lost through inefficient fermentation. With increasing restrictions on the use of antibiotic feed additives, plant-based additives such as Glycyrrhiza glabra (licorice) have gained attention due to their antimicrobial, anti-inflammatory, and fermentation-modulating properties. However, many plant extracts have limitations such as low solubility, instability, and poor bioavailability. Nanoliposome technology offers a promising strategy to improve stability, controlled release, and bioefficacy of bioactive compounds. This study aimed to evaluate the effects of free and nanoliposome-encapsulated licorice extract on ruminal fermentation parameters, methane production, protozoal population, and pH stabilization under normal and acidosis-induced conditions.
Materials and Methods:This in vitro study was conducted using rumen fluid collected from fistulated Holstein bulls. Nanoliposomes were synthesized via thin-film hydration and loaded with standardized commercial licorice extract containing 19–24% glycyrrhizin. A basal diet with a forage-to-concentrate ratio of 70:30 was used, with three treatments: basal diet alone, basal diet plus free licorice extract, and basal diet plus nanoliposome-encapsulated extract. Buffered rumen fluid was incubated at 39 °C under continuous CO₂. Gas production was recorded at multiple intervals up to 120 h. After 24 h of incubation, ruminal pH, protozoal counts, volatile fatty acids (VFA), methane production, digestibility, fermentable organic matter, and metabolizable energy were measured. An acidosis challenge test was performed by adding dextrose to induce rapid fermentation. Data were analyzed using the mixed model procedure of SAS and Tukey’s test for mean comparison.
Findings:Nanoliposomes exhibited a uniform spherical morphology with a hydrodynamic diameter of 122.2 nm and a low PDI (0.013), indicating high stability and homogeneity. Both free and nanoliposome licorice extract reduced lag time and increased early-stage fermentation rate, while decreasing gas production during late fermentation (48–120 h). Treatments increased butyrate concentration while decreasing acetate and propionate, resulting in a lower total VFA concentration and reduced methane production. The nanoliposome treatment caused a greater reduction in protozoal population compared with free extract and maintained a significantly higher ruminal pH, particularly under acidosis-induced conditions. Ammonia-nitrogen concentrations and substrate degradability remained within optimal ranges, indicating no adverse effects on overall microbial activity. In the acidosis challenge, nanoliposome licorice extract more effectively prevented severe pH decline and showed superior buffering and stabilization capacity, while supporting adequate microbial fermentation.
Conclusion:Encapsulation of licorice extract in nanoliposomes enhanced its functionality in modulating rumen fermentation, reducing methane emission, lowering protozoal counts, and maintaining ruminal pH during acidosis. Controlled release and improved stability of the encapsulated extract provided more sustained biological effects compared with the free form. These findings suggest that nanoliposome-encapsulated licorice extract can serve as an effective natural additive for mitigating SARA, improving nutrient utilization, enhancing environmental sustainability, and potentially reducing reliance on antibiotic feed additives in ruminant nutrition.
کلیدواژهها [English]
)