Impact of vitamin and mineral supplement withdrawal and wheat middling inclusion on finishing pig growth performance, fecal mineral concentration, carcass characteristics, and the nutrient content and oxidative stability of pork.

A study was conducted to determine if supplement withdrawal (omission of dietary vitamin and trace mineral premixes and a two-thirds reduction in dietary inorganic phosphorus) for 28 d preslaughter and the feeding of wheat middlings (dietary concentrations of 5, 15, and 30% from weaning to 16, 16 to 28, and 28 kg to slaughter, respectively) affect growth performance, carcass characteristics, and fecal mineral concentrations ofthe pig, as well as the nutrient content and oxidative stability of the longissimus dorsi muscle. Crossbred pigs (n = 64) were blocked by weight and assigned to one of four dietary treatments in a 2 x 2 factorial design (with or without supplement withdrawal, and with or without wheat middlings). Supplement withdrawal and wheat middling inclusion did not influence average daily gain (ADG), average daily feed intake, gain/feed, or carcass traits, except for a decrease (P < 0.01) in the ADG of pigs from 28 to 65 kg when fed wheat middlings. Supplement withdrawal decreased (P < 0.01) fecal Ca, P, Cu, Fe, Mn, and Zn concentrations. In diets containing full vitamin and mineral supplementation, wheat middling inclusion decreased (P < 0.01) fecal Ca, Cu, Fe, and Zn concentrations and increased (P < 0.01) fecal Mn. Supplement withdrawal decreased (P < 0.05) concentrations of riboflavin, niacin, and P in the longissimus dorsi muscle, but did not affect longissimus dorsi thiamin, vitamin E, Fe, Cu, Zn, and Ca concentrations. Inclusion of wheat middlings increased (P < 0.04) longissimus dorsi thiamin, niacin, riboflavin, and vitamin E concentrations and decreased (P < 0.04) Cu concentrations. However, wheat middling inclusion did not affect (P > 0.05) longissimus dorsi Ca, P, Fe, and Zn concentrations. Dietary treatment did not affect either Cu/Zn superoxide dismutase or glutathione peroxidase activity in the longissimus dorsi. The results from this study indicate that supplement withdrawal and dietary wheat middling inclusion alter pork nutrient content and fecal mineral concentration, but not the oxidative stability of pork.

Cyclooxygenase active bioflavonoids from Balaton tart cherry and their structure activity relationships.

Several flavonoids and isoflavonoids isolated from Balaton tart cherry were assayed for prostaglandin H endoperoxide synthase (PGHS-1) enzyme or cyclooxygenase isoform-1 (COX-1) activity. Genistein showed the highest COX-1 inhibitory activity among the isoflavonoids studied, with an IC50 value of 80 microM. Kaempferol gave the highest COX-1 inhibitory activity among the flavonoids tested, with an IC50 value of 180 microM. The structure-activity relationships of flavonoids and isoflavonoids revealed that hydroxyl groups at C4', C5 and C7 in isoflavonoids were essential for appreciable COX-1 inhibitory activity. Also, the C2-C3 double bond in flavonoids is important for COX-1 inhibitory activity. However, a hydroxyl group at the position decreased COX-1 inhibitory activity by flavonoids.

Antioxidant polyphenols from tart cherries (Prunus cerasus).

Montmorency and Balaton tart cherries were lyophilized and sequentially extracted with hexane, ethyl acetate, and methanol. Methanolic extracts of dried Balaton and Montmorency tart cherries (Prunus cerasus) inhibited lipid peroxidation induced by Fe(2+) at 25 ppm concentrations. Further partitioning of this methanol extract with EtOAc yielded a fraction that inhibited lipid peroxidation by 76% at 25 ppm. Purification of this EtOAc fraction afforded eight polyphenolic compounds, 5,7,4'-trihydroxyflavanone (1), 5,7, 4'-trihydroxyisoflavone (2), chlorogenic acid (3), 5,7,3', 4'-tetrahydroxyflavonol-3-rhamnoside (4), 5,7,4'-trihydroxyflavonol 3-rutinoside (5), 5,7,4'-trihydroxy-3'methoxyflavonol-3-rutinoside (6), 5,7,4'-trihydroxyisoflavone-7-glucoside (7), and 6, 7-dimethoxy-5,8,4'-trihydroxyflavone (8), as characterized by (1)H and (13)C NMR experiments. The antioxidant assays revealed that 7-dimethoxy-5,8,4'-trihydroxyflavone (8) is the most active, followed by quercetin 3-rhamnoside, genistein, chlorogenic acid, naringenin, and genistin, at 10 microM concentrations.

Novel antioxidant compounds from tart cherries (Prunus cerasus).

As indicated by an Fe(II)-induced liposome peroxidation bioassay, the EtOAc extract of tart cherries (Prunus cerasus) was found to have strong antioxidant activity. Purification of this extract afforded chlorogenic acid methyl ester (1) and three novel compounds, 2-hydroxy-3-(o-hydroxyphenyl) propanoic acid (2); 1-(3', 4'-dihydroxycinnamoyl)-cyclopenta-2,5-diol (3), and 1-(3', 4'-dihydroxycinnamoyl)-cyclopenta-2,3-diol (4), as determined by their spectral data. At a 20-microM concentration, the antioxidant activities of compounds 3 and 4 were comparable to the antioxidant activities of caffeic acid, whereas compound 1 showed activity similar to chlorogenic acid. Also, these compounds showed antioxidant activities similar to the commercial antioxidants tert-butylhydroquinone and butylated hydroxytoluene. However, compound 2 was not active when tested at a 100-microM concentration.

Improved oxidative stability of veal lipids and cholesterol through dietary vitamin E supplementation.

The influence of dietary vitamin E supplementation on the α-tocopherol content of muscle membranes and on the resultant oxidative stability of veal was investigated. Daily supplementation of veal calves with 500 mg vitamin E in the form of α-tocopherol acetate for 12 weeks after birth increased muscle and membranal α-tocopherol concentrations approximately 6-fold over those of control animals. Oxidative stability of mitochondrial and microsomal lipids was enhanced by dietary supplementation as indicated by the results of an oxidative assay using hydrogen peroxide-activated metmyoglobin as the catalyst of oxidation. Muscle lipid and cholesterol stability was also improved by supplementation.

Influence of oxidised dietary oil and antioxidant supplementation on membrane-bound lipid stability in broiler meat.

1. The effects of oxidised oil, dietary alpha-tocopherol and BHA/BHT-supplementation on the fatty acid composition of mitochondrial, microsomal and soluble protein fractions of broiler muscles, and on their lability to metmyoglobin/hydrogen peroxide-catalysed peroxidation were investigated. 2. Oxidised oil in the broiler diets induced rapid oxidation of the membrane-bound lipids and decreased their stability towards metmyoglobin-hydrogen peroxide-catalysed peroxidation. 3. Supplementation of the broiler diets with alpha-tocopherol increased the alpha-tocopherol concentrations in the microsomal and soluble protein fractions of the dark meat as well as the soluble protein fraction of the white meat. This, in turn, stabilised the membrane-bound lipids against metmyoglobin/hydrogen peroxide-initiated peroxidative changes.

Effects of oxidised dietary oil and antioxidant supplementation on broiler growth and meat stability.

1. Broilers were fed on diets containing oxidised sunflower oil, sunflower oil and sunflower oil supplemented with alpha-tocopherol, butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT). 2. Oxidised oil caused a significant reduction in broiler body and carcase weights, whereas alpha-tocopherol and BHA/BHT supplementation improved growth. 3. Meat samples from these broilers were stored at 4 degrees C and -20 degrees C and their oxidative stability evaluated. Feeding oxidised oil to broilers resulted in meat that underwent rapid oxidative changes during refrigerated and frozen storage. 4. On the other hand, dietary alpha-tocopherol and BHA/BHT supplementation increased alpha-tocopherol and BHA/BHT concentrations in meat and significantly (P less than 0.05) improved the oxidative stability of meat during refrigerated and frozen storage.

Further factors influencing N-nitrosamine formation in bacon.

The possible relationship of unsaturated fatty acids in adipose tissue to the formation of N-nitrosamines in bacon was evaluated by trials in which pigs were fed regular (control), tallow-, coconut fat- and corn oil-supplemented diets. Bacon prepared from pigs fed corn oil-supplemented diets contained significantly higher levels of N-nitrosopyrrolidine and N-nitrosodimethylamine than did control bacon samples; however, bacon produced from pigs fed a coconut fat-supplemented diet contained significantly lower levels of N-nitrosopyrrolidine. Fatty acid analyses of the adipose tissue of the bacon samples indicated that N-nitrosopyrrolidine levels in bacon correlated well with the degree of unsaturation of the adipose tissue. N-nitrosothiazolidine was detected in both brine-cured and dry-cured bacon at levels generally below 4 micrograms/kg. However, its formation was greatly reduced by the inclusion of alpha-tocopherol in the cure. The role of woodsmoke in N-nitrosothiazolidine formation in bacon is discussed.