Elsevier

The Journal of Nutrition

Volume 146, Issue 11, November 2016, Pages 2267-2273
The Journal of Nutrition

Determination of Dietary Iron Requirements by Full Expression of Iron-Containing Enzymes in Various Tissues of Broilers123

https://doi.org/10.3945/jn.116.237750Get rights and content
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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.

Keywords

iron
iron-containing enzymes
gene expression
requirements
broilers

Abbreviations

COX
cytochrome c oxidase
PI
plasma iron
ROS
reactive oxygen species
SDH
succinate dehydrogenase
TIBC
total iron-binding capacity
TS
transferrin saturation.

Cited by (0)

1

Supported by the Agricultural Science and Technology Innovation Program (ASTIP-IAS08), the China Agriculture Research System (project no. CARS-42), the Program of the National Natural Science Foundation of China (project no. 31672440), and the Research Program of the Key Laboratory of Animal Nutrition (project no. 2004DA125184G1606).

2

Author disclosures: X Ma, X Liao, L Lu, S Li, L Zhang, and X Luo, no conflicts of interest.

3

Supplemental Tables 1 and 2 are available from the “Online Supporting Material” link in the online posting of the article and from the same link in the online table of contents at http://jn.nutrition.org.

7

These authors contributed equally to this work.

Copyright © 2016 American Society of Nutrition. Published by Elsevier Inc. All rights reserved.