[18O]-Labeled Singlet Oxygen as a Tool for Mechanistic Studies of 8-Oxo-7,8-Dihydroguanine Oxidative Damage: Detection of Spiroiminodihydantoin, Imidazolone and Oxazolone Derivatives

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Vitamina E no desempenho, características de carcaça e qualidade do presunto cozido de suínos Vitamin E on performance, carcass characteristics and quality of pig's cooked ham

O objetivo deste trabalho foi avaliar o efeito da vitamina E sobre o desempenho, características de carcaça e qualidade do presunto. Noventa e seis suínos foram submetidos aos seguintes tratamentos: controle, 100, 200 e 400 mg de vitamina E por kg de ração, fornecidas a partir de 116 dias antes do abate. Após o abate, as carcaças foram avaliadas, resfriadas, desossadas e o pernil foi removido para fabricação de presunto cozido. Análises dos teores de vitamina E e ácido tiobarbitúrico (TBARS) foram realizadas em amostras de pernil e de presunto. A média do ganho de peso foi 789,81 g por dia, do consumo 2.418 g por dia e da conversão alimentar 3,06. Os animais apresentaram 113,57 kg de peso vivo; 85,90 kg de peso de carcaça; 75,62% de rendimento de carcaça; 61,28 mm de profundidade de lombo; 23,16 mm de espessura de toucinho e 49,28% de carne magra. Amostras de presunto com suplementação de vitamina E apresentaram de 0,61 a 1,19 mg kg-1 de TBARS, contra 1,77 a 3,91 mg kg-1 de TBARS do controle. Dietas com 200 mg vitamina E por kg de ração reduziram os níveis de oxidação em 70% no presunto cozido e diminuíram a espessura de toucinho.<br>The objective of this work was to evaluate the effect of vitamin E on performance, carcass characteristics and cooked ham quality. Ninety-six pigs were submitted to the following treatments: control; 100, 200 and 400 mg of vitamin E per kg of diet; during 116 days before slaughter. After slaughter, pig carcasses were measured, chilled, deboned and ham sections were removed to produce the cooked ham. Samples of frozen and cooked ham were analysed in relation to vitamin E and thiobarbituric acid (TBARS) contents. Growth rate mean was 789.81 g per day, feed intake mean was 2,418 g per day and feed:gain ratio was 3.06. The carcass showed the following mean: 113.57 kg alive weight; 85.90 kg carcass weight; 75.62% carcass yield; 61.28 mm ham depth; 23.16 mm backfat thickness and 49.28% lean meat. The cooked ham samples with the best levels of vitamin E showed 0.61 to 1.19 mg kg-1 TBARS, against 1.77 to 3.91 mg kg-1 TBARS for the control. Levels of supplementation of 200 mg vitamin E per kg of diet reduce the oxidation levels up to 70% in cooked ham and decrease backfat thickness

<a name="home"></a>Lycopene and ß-carotene protect in vivo iron-induced oxidative stress damage in rat prostate

It has been suggested that iron overload may be carcinogenic. In the present study, we evaluated the effect of plasma and prostate carotenoid concentration on oxidative DNA damage in 12-week-old Wistar rats treated with intraperitoneal (ip) ferric nitrilotriacetate (Fe-NTA) (10 mg Fe/kg). Plasma ß-carotene and lycopene concentrations were measured as a function of time after ip injection of carotenoids (10 mg kg-1 day-1 ß-carotene or lycopene) in rats. The highest total plasma concentration was reached 3 and 6 h after ip injection of lycopene or ß-carotene, respectively. After 5 days of carotenoid treatment, lycopene and ß-carotene were present in the 0.10-0.51 nmol/g wet tissue range in the prostate. Using a sensitive method to detected 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) by HPLC/EC, the level of 8-oxodGuo in rat prostate DNA was significantly higher (6.3 ± 0.6 residues/10(6) dGuo) 3 h after Fe-NTA injection compared with control rats (1.7 ± 0.3 residues/10(6) dGuo). Rats supplemented with lycopene or ß-carotene for 5 days prior to Fe-NTA treatment showed a reduction of about 70% in 8-oxodGuo levels to almost control levels. Compared with control rats, the prostate of Fe-NTA-treated animals showed a 78% increase in malondialdehyde accumulation. Lycopene or ß-carotene pre-treatment almost completely prevented lipid damage. Epidemiological studies have suggested a lower risk of prostate cancer in men reporting a higher consumption of tomato products. However, before associating this effect with tomato sauce constituents, more information is required. The results described here may contribute to the understanding of the protective effects of carotenoids against iron-induced oxidative stress