For both period and cumulative growth performance data, there were trends for increased feed intake and increased feed to gain ratios associated with increasing concentrations of dietary clinoptilolite. If, however, efficiency was expressed as daily intake of megacalories of metabolizable energy, there were no treatment effects. This lack of treatment response is illustrated by overall cumulative efficiencies of 4.39, 4.39, 4.40, and 4.31 Mcal. metabolizable energy/pound of weight gain for pigs fed diets containing 0, 2, 4, and 8% clinoptilolite.

The decreased carcass backfat and increased carcass lean content associated with increasing concentrations of dietary clinoptilolite are responses that were probably caused by the concomitant increases in dietary protein (amino acid) to metabolizable energy ratios.

Chemical analyses of feces for nitrogen and phosphorus revealed two relationships with dietary clinoptilolite concentration. First, both nitrogen and phosphorus concentrations in feces decreased with increasing dietary clinoptilolite concentrations. These responses likely resulted because the clinoptilolite increased the volume of feces. Second, the ratio of nitrogen to phosphorus increased with increasing dietary clinoptilolite concentration. This response probably resulted because ammonia nitrogen was sequestered by clinoptilolite because of its ion exchange properties.