Bioavailability of Iron in Cottonseed Meal, Ferric Sulfate, and Two Ferrous Sulfate By-Products of the Galvanizing Industry

Stephanie D. Boling, Hardy M. Edwards, Jason L. Emmert, Robert R. Biehl, David H. Baker

Research output: Contribution to journalArticlepeer-review


Iron depletion-repletion assays were carried out with young chicks to establish Fe bioavailability values for Fe2(SO4)3·7H2O (22.7% Fe), FeZnSO4·H2O (20.2% Fe, 13.0% Zn), Zn-FeSO4·H2O (20.2% Zn, 14.2% Fe), and cottonseed meal (200 mg Fe/kg). Standard hemoglobin response curves were established using feed-grade FeSO4·H2O (28.8% Fe) or reagent-grade FeSO4·TH2O (20.1% Fe) as standards such that relative bioavailability (RBV) could be assessed for the experimental sources of Fe. Weight gain, hemoglobin, and hematocrit responded linearly (P < 0.05) to Fe supplementation in all assays. Using hemoglobin as the response criterion, slope-ratio calculations established Fe RBV values of 126% for Fe-ZnSO4·H2O and 93% for ZnFeSO4·H2O. The 126% value for Fe-ZnSO4·H2O was greater (P < 0.05) than the FeSO4·H2O standard (100%), but the 93% value for Zn-FeSO4·H2O was not different (P > 0.10) from the standard. However, evaluation of all criteria of response (hemoglobin, hematocrit, weight gain) suggested that neither Fe-ZnSO4·H2O nor Zn-FeSO4·H2O had different Fe RBV values than FeSO4·H2O. Standard-curve calculations were used for assessment of Fe RBV in Fe2(SO4)3·TH2O and cottonseed meal, as only a single level of Fe addition was studied for each of these products. Iron RBV in Fe2(SO4)3·TH2O was estimated to be 37%, whereas Fe RBV in cottonseed meal was found to be 56%. Both of these values were lower (P < 0.05) than the FeSO4 standard. The data suggest that the two new products, representing combinations of FeSO4·H2O and ZnSO4·H2O by-products of the galvanizing industry, are excellent sources of bioavailable Fe, whereas ferric sulfate and cottonseed meal are relatively poor sources of usable Fe.

Original languageEnglish (US)
Pages (from-to)1388-1392
Number of pages5
JournalPoultry science
Issue number9
StatePublished - Sep 1998


  • Bioavailability
  • Cottonseed meal
  • Ferric sulfate
  • Ferrous sulfate
  • Iron

ASJC Scopus subject areas

  • Animal Science and Zoology


Dive into the research topics of 'Bioavailability of Iron in Cottonseed Meal, Ferric Sulfate, and Two Ferrous Sulfate By-Products of the Galvanizing Industry'. Together they form a unique fingerprint.

Cite this