The objective of this research was to identify the most effective quantity for incorporating fish oil microcapsules that do not interfere with the degradation of nutrients and rumen fluid characteristics (pH, VFA, NH3) in vitro to produce livestock products that are high in omega-3 fatty acids. In this study, a randomized block design experimental method was employed, involving 7 distinct treatment conditions consisting of 3 rumen fluid collection groups. The seven treatments were A: control diet, B: control diet + 4% fish oil microcapsules (≈0.8% fish oil), C: control diet + 8% fish oil microcapsules (≈1.6% fish oil), D: Control ration + 12% fish oil microcapsules (≈2.4% fish oil), E: control ration + 0.8% fish oil, F: control ration + 1.6% fish oil, and G: control ration + 2.4 % Fish oil. Variables observed were: nutrient digestibility (dry matter, organic matter, crude fat, and crude fiber), digestibility of fiber fractions (NDF, ADF, cellulose, and hemicellulose), and fermentability of rumen fluid (pH, VFA and NH3). The findings indicated that the treatment did not have a significant impact (P>0.05) on the digestibility of dry matter, organic matter, crude fiber, NDF, ADF, cellulose, hemicellulose, pH, and NH3. However, there was a significant difference (P<0.05) observed in the digestibility of crude fat and VFA. The conclusions drawn from the research imply that the addition of fish oil microcapsules up to 12% in the ration does not interfere with nutrient digestibility, fiber fraction, and rumen fluid fermentability (pH, VFA, NH3).