The effect of combination of protected and non-protected soybean oil (<i>Glycine max</i> L.) supplementation on <i>in vitro</i> nutrient digestibility

This study aims to determine the effect of the combination of protected (PSO) and non-protected (SO) soybean oil supplementation on nutrient digestibility in vitro. Fatty acid protection using rejected milk and formaldehyde. Feed substrate consists of 60% elephant grass and 40% bran pollard, then supplemented with PSO and SO with various levels of balance, namely T1 (0%:5%), T2 (1.25%:3.75%), T3 (2.5%:2.5%), T4 (3.75%:1, 25%), and T5 (5%:0%) based on dry matter (DM). This study consisted of three replications. In vitro, the digestibility of dry matter (IVDMD), organic matter (IVOMD), crude protein (IVCPD), and crude fiber (IVCFD) was determined using a two-stage in vitro technique (Tilley and Terry 1963, modified by Utomo 2012). Data were analyzed using one-way ANOVA, followed by Duncan’s test. Results revealed that supplementation with PSO and SO at T4 and T5 significantly increased total and rumen IVDMD and total IVOMD (P&lt;0.05), decreased rumen IVCPD, and had no effect on rumen IVOMD, total IVCPD, and both rumen and total IVCFD. In conclusion, 5% PSO supplementation did not negatively affect IVDMD, IVOMD, and IVCFD but reduced IVCPD in ruminants.