An altogether 15 months-trial with diets containing 12%, 18%, and 24% protein (Trial I) was followed by another one, where a 6% protein-diet was fed for 12 weeks after an adaptation period with a 18% protein-diet (Trial II). Blood samplings, performed at the end (Trials I and II) and several times during the test period (Trial II), did not show differences in relevant parameters between the dietary groups, except a decrease in WBC in the period with 6% dietary protein, with no other clinical symptoms. Feed consumption did not alter with dietary protein and reproduction data were not conclusive regarding the protein supply. Although cases of death occurred, mainly caused by infections, no dependance on the dietary protein level is detectable.

It can be concluded, that the protein requirement of Callithricidae is not as high as supposed, and that a supply of 2.8 g protein/kg body weight is enough forSaguinus fuscicollis.