Impact of thermal processing on trace element status of formula fed infant rhesus monkeys

The infant rhesus monkey is an excellent animal model for studying the effect of various infant formulas on trace element absorption and status. Infant monkeys fed regular, powdered infant formula exclusively from birth to 6 mo of age exhibit normal growth and have blood parameters similar to those of breast-fed monkeys. Moreover, breast-fed monkeys and monkeys fed formula with different levels of iron have hematological indices similar to those of human infants. In this study, we explored the effect of feeding infant monkeys different whey-dominant ready-to-feed formulas: Formula in cans at 12 mg Fe/L available in U.S. (C), and formula in glass bottles: UHT process (12 mg Fe/L) and standard thermal process (STP) at either 8 (STP8) or 12 mg Fe/L (STP 12). Growth and indices of Fe status, (hemoglobin, MCV and serum ferritin) were similar in all groups. However, infants fed can-formula showed a progressive and significant decline in serum Cu [5 mo C:0.44±0.02; UHT:1.32±0.19; STP8:0.94±0.17; STP 12:0.73±0.18 mg/L] and RBC Cu, Zn-superoxide dismutase activity during the 5 mo study. Moreover, coat color changed dramatically from the normal brown to a silvery-white color. UHT and STP fed monkeys did not exhibit changes in Cu status or coat color. These data suggest that formula processing conditions affect Cu status.