title: Influence of selenium sources on age-related and mild heat stress-related changes of blood and liver glutathione redox cycle in broiler chickens (Gallus domesticus).
abstract: Selenium is an essential trace element that up-regulates a major component of the antioxidant defense mechanism by controlling the body's glutathione (GSH) pool and its major Se-containing antioxidant enzyme, glutathione peroxidase (GPX). Evidence has emerged suggesting that organic selenium, natural seleno-amino acids found in plants, grains and selenized yeast, maintains the antioxidant defense system more efficiently than inorganic selenium. Inorganic selenium is a pro-oxidant, whereas organic selenium possesses antioxidant properties itself. As a pro-oxidant, inorganic selenium is not suitable for animals or humans. Therefore, we examined the GSH-GPX system in broiler chickens and determined that organic selenium was indeed more beneficial than inorganic selenium. Chickens fed the organic selenium as Sel-Plex, a selenized yeast, had elevated GPX activity in both blood and liver in a thermoneutral environment and after heat distress. More importantly, the ability to reduce the oxidized glutathione (GSSG to 2 GSH) was enhanced and facilitated by maintenance of glutathione reductase activity. Organic selenium-fed chickens were less affected by mild heat distress than inorganic selenium-fed chickens, and this assessment was based upon less induction of heat shock protein 70 (hsp70) in organic selenium-fed chickens. Our results clearly show that heat distress, a potent inducer of oxidative stress and hsp70, can be partially ameliorated by feeding organic selenium. We attribute this observation to an enhanced GSH-GPX antioxidant system in organic selenium-fed chickens.
authors.affiliation: Department of Animal Production, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan. kmahmoud@just.edu.jo
authors.forename: Kamel Z
authors.initials: KZ
authors.lastname: Mahmoud
authors.forename: F W
authors.initials: FW
authors.lastname: Edens
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002645:Chickens / Q000097:blood / Q000378:metabolism; D005978:Glutathione / Q000097:blood* / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018882:Heat Stress Disorders / Q000097:blood* / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D010084:Oxidation-Reduction; D012643:Selenium / Q000378:metabolism*; D018036:Selenium Compounds / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D018840:HSP70 Heat-Shock Proteins; D018036:Selenium Compounds; D005978:Glutathione; D012643:Selenium