Abstract. Huda AN, Sabarudin A, Jayanegara A, Soetanto H. 2023. Fermentation parameters in the rumen of goats supplemented with polyphenol oxidase derived from Gliricidia sepium leaves under in vitro conditions. Biodiversitas 24: 3282-3290. The growing demand for healthy foods derived from ruminant products is restricted by the high content of saturated fatty acids in meat or milk due to the process of rumen biohydrogenation. Recent reports from intensive studies using polyphenol oxidase (PPO), an enzyme in plants’ secondary metabolism, as the inhibitor of rumen biohydrogenation cost doubt of ruminant products. PPO is assumed to increase the supply of UFA by reducing the rate of biohydrogenation due to rumen microbes’ activity. Microbes of the rumen, including species of bacteria and protozoa are responsible for rumen biohydrogenation. The present study investigated the effect of adding PPO derived from Gliricidia sepium leaves on fermentation parameters in the rumen, including protozoa density and diversity, fatty acid profile, volatile fatty acid profile, and the efficiency of microbial protein synthesis under in vitro conditions. The experiment was carried out through an in vitro rumen fermentation method, consisting of five treatments, i.e., negative control, positive control, the addition of 0.1 ml, 0.3 ml, and 0.5 ml PPO emulsion. The most dominant type of protozoa among all treatments was Entodinium spp. PPO emulsion increases the efficiency of microbial protein synthesis and volatile fatty acid concentration. 0.5 ml PPO emulsion increases linoleic acid. In conclusion, this finding poses a question on the role of rumen protozoa in lipid biohydrogenation in the rumen. A further experiment on the benefits of adding PPO regarding rumen biohydrogenation under in vivo conditions is warranted.

This study aimed to evaluate the antiprotozoal activity of potato peels and linseed oil. The material used were complete feed, potato peel and linseed which was experimented in vitro with four treatments and one control, T0; T1 (complete feed + linseed oil 0.15%); T2 (complete feed + 0.15% potato peel); T3 (complete feed + linseed oil 0.075% + potato peel 0.075%); T4 (complete feed). The results obtained showed a significantly different (P<0.01) on protozoa defaunation, total gas and degradable Dry Matter (DM), and Organic Matter (OM). The addition of potato peel and linseed had the same defaunation effect but tended to decrease, while the total gas production and DM and OM degradability differed. The addition of 0.075% potato peel and 0.075% linseed oil in the complete feed (T3) resulted in the most efficient treatment for gas production, DM, and OM degradability value. In conclusion, the use of plant bioactive compounds as biomarkers in the manipulation of rumen fermentation needs to consider several things, especially the condition of the rumen microflora, instead of focusing on the final results of the manipulation.