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1.
Comp Biochem Physiol B Biochem Mol Biol ; 135(2): 325-35, 2003 Jun.
Article in English | MEDLINE | ID: mdl-12798942

ABSTRACT

Urate oxidase is not present in birds yet allantoin, a product of this enzyme, has been measured in birds. Studies were designed to compare the concentrations of plasma purine derivatives in chickens and turkeys fed inosine-supplemented diets. The first study consisted of 12 male chicks that were fed diets supplemented with 0.6 mol inosine or hypoxanthine per kilogram diet from 3- to 6-week-old. Study 2 consisted of 12 turkey poults (toms) fed inosine-supplemented diets (0.7 mol/kg) from 6- to 8-week-old. Plasma allantoin and oxypurines concentrations were measured weekly using high performance liquid chromatography. Plasma uric acid (PUA) in chickens fed inosine-supplemented diets increased from 0.31 to 1.34 mM (P<0.05) at the end of week 2. In turkeys, those fed control diet had 0.17 mM PUA concentration compared to 0.3 mM in those fed the inosine diet at week 2 (P<0.05). Allantoin concentration increased in chickens from week 1 to 2 while a decrease was observed in turkeys (P<0.005) for both treatments. These data show that allantoin is present in turkey and chicken plasma. The presence of allantoin in avian plasma is consistent with uric acid acting as an antioxidant in these species.


Subject(s)
Allantoin/blood , Chickens/blood , Turkeys/blood , Animals , Hypoxanthine/pharmacology , Inosine/pharmacology , Male , Oxidation-Reduction , Oxidative Stress , Urate Oxidase/metabolism , Uric Acid/blood , Uric Acid/metabolism
2.
Am J Physiol Regul Integr Comp Physiol ; 282(3): R791-6, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11832400

ABSTRACT

Birds have high metabolic rates, body temperatures, and plasma glucose concentrations yet physiologically age at a rate slower than comparably sized mammals. These studies were designed to test the hypothesis that the antioxidant uric acid protects birds against oxidative stress. Mixed sex broiler chicks (3 wk old) were fed diets supplemented or not with purines (0.6 mol hypoxanthine or inosine). Study 1 consisted of 18 female Cobb x Cobb broilers that were fed purines for 7 days, whereas study 2 consisted of 12 males in a 21-day trial. Study 3 involved 30 mixed sex broilers that were fed 40 or 50 mg allopurinol/kg body mass (BM) for 21 days, a drug that lowers plasma uric acid (PUA). PUA and leukocyte oxidative activity (LOA) were determined weekly for all studies. For study 2, pectoralis major shear force, relative kidney and liver sizes (RKS and RLS), and plasma glucose concentrations were also determined. In study 1, PUA concentration was increased three- and twofold (P < 0.001) in birds fed inosine or hypoxanthine, respectively, compared with control birds. LOA of birds supplemented with inosine was lower (P < 0.05) than that of control or hypoxanthine birds. In study 2, PUA concentrations were increased fivefold (P < 0.001) in birds fed inosine and twofold (P < 0.001) in birds fed hypoxanthine compared with control birds at day 21. RKS (g/kg BM) was greater (P < 0.001) for chicks fed purine diets compared with control chicks. Muscle shear value was lower (P < 0.05) in chicks fed purine diets. PUA concentration was decreased (P < 0.001) in birds consuming allopurinol diets, whereas LOA was increased (P < 0.01) in study 3. These studies show that PUA concentrations can be related to oxidative stress in birds, which can be linked to tissue aging.


Subject(s)
Animals, Newborn/blood , Chickens/blood , Leukocytes/metabolism , Uric Acid/blood , Animals , Animals, Newborn/anatomy & histology , Chickens/anatomy & histology , Diet , Female , Hypoxanthine/administration & dosage , Hypoxanthine/pharmacology , Inosine/administration & dosage , Inosine/pharmacology , Kidney/anatomy & histology , Liver/anatomy & histology , Male , Organ Size , Osmolar Concentration , Oxidation-Reduction/drug effects , Pectoralis Muscles/drug effects , Pectoralis Muscles/physiology
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