Effects of dietary inclusion of a zeolite (clinoptilolite) on performance and protein metabolism of young growing pigs

The aim of the study was to investigate the influence of dietary inclusion of the clay mineral Klinofeed on performance and protein metabolism of growing pigs (30–50 kg body weight). The major content of Klinofeed is clinoptilolite (70%), a natural clay mineral with the ability to bind ammonium and other ions. The study was conducted with ten litters, each consisting of four female pigs. The pigs were fed two basal diets, A and B. In vitro studies on ileal digestibility of protein and hindgut fermentation indicated that the ileal digestibility of protein was similar, while hindgut fermentation was 30% higher in diet A than in diet B. Within each diet, 0 or 3% of the feed was replaced by Klinofeed. The gross energy content of the basal diets was identical, and addition of Klinofeed resulted in a general reduction in the energy content. As the pigs did not compensate for this energy-reducing effect by increasing the feed intake or improving the feed:gain ratio, this resulted in a reduction in daily gain. Klinofeed elevated nitrogen excretion in faeces and lowered nitrogen excretion in urine. These changes were most pronounced when feeding diet A, perhaps because of a higher production of ammonia and an increased binding of nitrogen to Klinofeed in the hindgut. Protein retention was not significantly influenced by Klinofeed. It was concluded that dietary inclusion of Klinofeed for young growing pigs changed the excretion pattern of nitrogen towards increased excretion in the faeces and decreased excretion in the urine without altering protein deposition.