Six gilts and six barrows are used in a 2 x 2 experiment with two phase feeding versus multiphase feeding and celite addition versus clinoptilolite addition. Nitrogen and ammonia concentration in the slurry on dry matter basis was reduced by 30% and 35% respectively by multiphase feeding, together with a decreased ratio of ammonia over nitrogen. Ammonia fixation in pig slurry by clinoptilolite increased from 21% after 14 days of supplementation upto 35% at 8 weeks after the supplementation period.