title: Determination of Dietary Iron Requirements by Full Expression of Iron-Containing Enzymes in Various Tissues of Broilers.
abstract: BACKGROUND
  The current dietary iron requirement (80 mg/kg) of broilers is mainly based on growth, hemoglobin concentration, or hematocrit data obtained in a few early studies; however, expressions of iron-containing enzymes might be more sensitive novel criteria to evaluate dietary iron requirements.
  
  
  OBJECTIVE
  The objective of this study was to determine dietary iron requirements of broilers for the full expression of succinate dehydrogenase (SDH), catalase, and cytochrome c oxidase (COX) in various tissues.
  
  
  METHODS
  A total of 336 1-d-old Arbor Acres male chicks were randomly assigned to 1 of 7 treatments with 6 replicates and fed a basal corn and soybean-meal diet (control, containing 67 mg Fe/kg) and the basal diet supplemented with 20, 40, 60, 80, 100, or 120 mg Fe/kg from FeSO4⋅ 7H2O for 21 d. Regression analysis was performed to estimate the optimal dietary iron concentration with the use of broken-line or quadratic models.
  
  
  RESULTS
  SDH activity in the liver and heart, COX and catalase activity in the liver, Sdh mRNA levels in the liver, and Cox mRNA levels in the liver and heart of broilers were affected (P < 0.027) by supplemental iron concentration, and increased quadratically (P < 0.004) as dietary iron concentration increased. Dietary iron requirements estimated on the basis of fitted broken-line or quadratic-curve models (P < 0.005) of the above indexes were 97-136 mg/kg.
  
  
  CONCLUSIONS
  SDH activity in the liver and heart, COX and catalase activity in the liver, Sdh mRNA levels in the liver, and Cox mRNA levels in the liver and heart are, to our knowledge, new and sensitive criteria to evaluate the dietary iron requirements of broilers, and the dietary iron requirements would be 97-136 mg/kg to support the full expression of the above iron-containing enzymes in various tissues of broiler chicks from 1 to 21 d of age, which are higher than the current NRC iron requirement.
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China.|Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, China; and.
authors.forename: Xinyan
authors.initials: X
authors.lastname: Ma
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China.
authors.forename: Xiudong
authors.initials: X
authors.lastname: Liao
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
authors.affiliation: Department of Animal Science, Hebei Normal University of Science and Technology, Qinhuangdao, China.
authors.forename: Sufen
authors.initials: S
authors.lastname: Li
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China.
authors.forename: Liyang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, State Key Laboratory of Animal Nutrition, Beijing, China; wlysz@263.net.
authors.forename: Xugang
authors.initials: X
authors.lastname: Luo
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D002645:Chickens; D004032:Diet / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D019266:Iron, Dietary / Q000008:administration & dosage / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology; D008297:Male; D009206:Myocardium / Q000201:enzymology; D009751:Nutritional Requirements; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D019266:Iron, Dietary; D012333:RNA, Messenger; D002374:Catalase; D013385:Succinate Dehydrogenase; D003576:Electron Transport Complex IV
keywords: broilers; gene expression; iron; iron-containing enzymes; requirements