Effect of supplementation with saponins from Yucca schidigera on ruminal methane production by Pelibuey sheep fed Pennisetum purpureum grass

TheaimoftheworkwastodeterminetheeffectofincreasingconcentrationsofsaponinsfromYuccaschidigera in the diet on voluntary intake, rumen fermentation and methane (CH4) production in Pelibuey sheep fed a tropical grass Pennisetum purpureum. Five male sheep (32.2 1.1 kg liveweight) were fed chopped P. purpureum grass in a 5 · 5 Latin square design. Sheep were supplemented with 0.0, 1.5, 3.0, 4.5 or 6.0 g per day of saponins from Y. schidigera mixed with ground corn, before the grass was offered. Feed intake, feed refusal and total faecal output were recorded for 20 days of the adaptationperiodand5daysoftheexperimentalperiod.Apparentdigestibilityofdrymatter(DMD),organicmatter(OMD), neutraldetergent fibre(NDFD)andaciddetergent fibre(ADFD)weredetermined.Ruminalmethaneemissionwasestimated using stoichiometric balance and the molar proportion of volatile fatty acids was determined by gas chromatography. Voluntary intake, DMD, OMD, NDFD, ADFD, volatile fatty acids and CH4 emission were not affected (P > 0.05) by increasinginclusionlevelsofsaponinsintherationofsheep.Nonetheless,CH4productionincreasedasthevoluntaryintake of NDF augmented. Addition of6g ofsaponins per dayas a supplementtoPelibuey sheep fed atropical grass didnot affect voluntary intake and digestibility of DM, OM, NDF and ADF, or ruminal methane production.