A rumen defaunation trial was conducted using Leucaena leucocephala forage as defaunating agent. Defaunation was performed by supplementing fresh L. leucocephala forage at two levels and frequencies as follows: T1 = 0.75% of BW, DM basis + 1 follow-up administration in a month), T2 = 0.75% BW + 2 follow-up administration in a month, T3 = 1.25% BW + 1 follow-up administration in a month, T4 = 1.25% BW + 2 follow-up administration in a month and T5 = control treatment, without defaunating agents added. The experiment was set up in a Randomized Complete Block Design (RCBD) having age and sex of the animals as basis for blocking. Rumen fluid was collected in each animal through stomach tubing before and after the experiment for bacterial and protozoal counting. Results revealed that L. leucocephala was significantly (P<0.001) effective in reducing protozoal numbers and increasing the bacterial population in all levels and frequencies as compared to the control. However, T2 and T4 appeared to be the best treatments in reducing protozoal numbers with a corresponding greater increase in bacterial counts. Therefore, L. leucocephala can effectively manipulate the rumen environment by reducing the protozoa without negative effects on bacteria. At any level of feeding, its use as defaunating agent must have two (2) follow-ups administration in a month. 

Plant secondary metabolites appeared to have some effects on rumen fermentation pattern, microbial population, feed intake and digestibility. An experiment was conducted to identify forage species with potential in defaunating (killing protozoal population) the reticulo-rumen in goats. There were five forage species tested: Robles (Cassia siamea), Desmodium (Desmodium heterophyllum), Kakawate (Gliricidia sepium), Centro (Centrosema pubescens) and Ipil-ipil (Leucaena leucocephala) with sodium lauryl sulfate (SLS) as the control treatment. The forages of the different species were homogenized using a blender to extract the juice.The extracts were then drenched down into the reticulo-rumen of goats through stomach tubing at 1% of their body weight (BW). Froth analysis for saponin content showed higher values in Robles followed by Ipil-ipil, with Kakawate as the lowest. Ipil-ipil and Robles had comparable defaunating effects with that of the SLS which significantly reduced (p<0.01) the protozoal numbers as compared to the other forages tested. However, Ipil-ipil and Desmodium appeared to have significantly higher (p<0.01) dry matter (DM) intake p of the basal Napier grass (Pennisetum purpureum) diet as compared to the other forages tested. Bacterial population also decreased but differences among treatments were not significant. Therefore, forage extracts containing high amounts of saponin are effective in reducing protozoal population, comparable to that of SLS. The use of Ipil-ipil forage extract for defaunating the rumen is recommended as it is organic, unlike SLS, and also promotes higher dietary DM intake.