Effect of different concentrations of oregano (<i>Origanum vulgare</i>) extract on rumen digestion <i>in vitro</i>

Abstract

Residual antimicrobial substances resulting from the overuse of growth-promoting antibiotics in animal feed pose an emerging threat to human health and the environment. Plant extracts containing essential oils in general, and in particular Origanum vulgare extract, are a potential alternative to feed antibiotics, contributing to the growth of productive potential, due to their antimicrobial and antioxidant properties. They can inhibit the reproduction of pathogenic microorganisms, causing conformational changes in cell membranes. In this regard, the purpose of the study was to study the effect of different dosages of O. vulgare extract on the digestibility of diet components and the composition of volatile fatty acids in the rumen content under in vitro conditions. Three dosages of the oregano extract were tested in the experiment: 0.5; 1; 10 ml/l. The results of the present study indicate that small doses of O. vulgare extract do not lead to metabolic shifts in the rumen digestion. High dose (10 ml/l), on the contrary, reduces the total number of protozoa. The average dose load of 1 ml/l leads to an increase in digestibility to 72.63% and the concentration of infusoria to 555.56 thousand pcs/ml. Thus, based on the results obtained, it follows that the inclusion of the O. vulgare extract in a dose of 1 ml/l enhances metabolic processes in the rumen, leading to better digestion of feed. The dosage of 10 ml/l, the maximum of the tested, provided an increase in the concentration of the volatile fatty acids. However, when using 1 ml/l of O. vulgare, the most significant changes in the concentration of the volatile fatty acids occurred.