Nutrient requirements of poultry

OXIDATIVE STRESS . . . . . . . . . . . . . .. . . . . .... . . . . .. . . . . .. . . . ... .. . . . . .... . . .. .. . . . . . ... . 84 RESPONSE OF SOD TO ENVIRONMENTAL STRESS . . . . . . . . . . . . . . . .. . . . .... . . .... . . . . . . 87 Photoinhibition . . . . . . . . . . .. . ... . . .. . . . .. . . . . ..... . . . , ... ", , ... ,' , ... . ,., . . . "" . .. . ,'.' . . ,' . . . . , ., 87 Paraquat and Other Herbicides . . .. , . . .... , ..... , . . . . ... . . . .. . . . . . . . . . . . . ,.. 91 Atmospheric Pollutants . . " .... , .... , " .... " , , . . , .... , ' 94 Waterlogging and Drought .. ", . . ... , . . . . . . , .. "", . . ", . . . . . ", . . . .. ", . . .. , . . . ... """", . . " 97 The Defense Response to Pathogens . ... . . . . "" ... "" .... " ...... " ,."" .... . , 98 The Phenomenon of Cross-Tolerance . . . , , .. . . . . ...... . . , . . . . . . , . . .... , .. . . . . . . . .. .. 101 The Mechanism of SOD Regulation ........ , , ...... , " 102 GENETIC ENGINEERING OF SOD IN PLANTS .. ' ...... ' . . . . . . . . . . . . . . . . . . . . . . . .. . . . , .... ' 104 Cu/ZnSOD and MnSOD Overexpression . . . . . .. . . . . . , . . . . . . .. . . . . . .. . . . . . , .... . . . . .. . . ,.... . . 105 Prospects for Stress Tolerance through Genetic Engineering of SOD . . . . ,,, .. , . . . . . . . 106

Superoxide dismutase and stress tolerance

This article is a review of the fundamental chemistry of the tocopherols and tocotrienols relevant to their antioxidant action. Despite the general agreement that α-tocopherol is the most efficient antioxidant and vitamin E homologuein vivo, there was always a considerable discrepancy in its “absolute” and “relative” antioxidant effectivenessin vitro, especially when compared to γ-tocopherol. Many chemical, physical, biochemical, physicochemical, and other factors seem responsible for the observed discrepancy between the relative antioxidant potencies of the tocopherolsin vivo andin vitro. This paper aims at highlighting some possible reasons for the observed differences between the tocopherols (α-, β-, γ-, and δ-) in relation to their interactions with the important chemical species involved in lipid peroxidation, specifically trace metal ions, singlet oxygen, nitrogen oxides, and antioxidant synergists. Although literature reports related to the chemistry of the tocotrienols are quite meager, they also were included in the discussion in virtue of their structural and functional resemblance to the tocopherols.

The chemistry and antioxidant properties of tocopherols and tocotrienols

Inhibition of oxidation of human low-density lipoprotein by phenolic substances in red wine

Pigments are present in all living matter and provide attractive colors and play basic roles in the development of organisms. Human beings, like most animals, come in contact with their surroundings through color, and things can or cannot be acceptable based on their color characteristics. This review presents the basic information about pigments focusing attention on the natural ones; it emphasizes the principal plant pigments: carotenoids, anthocyanins, and betalains. Special considerations are given to their salient characteristics; to their biosynthesis, taking into account the biochemical and molecular biology information generated in their elucidation; and to the processing and stability properties of these compounds as food colorants.

Natural Pigments: Carotenoids, Anthocyanins, and Betalains — Characteristics, Biosynthesis, Processing, and Stability

The interacting effects of ascorbic acid and metal ions on carotene oxidation were studied in an aqueous carotene-linoleate solution at pH 7. Ascorbic acid at concentrations up to 10—3 M was a prooxidant. Fe3+ and, to a lesser extent Co2+, acted synergistically with ascorbic acid, the prooxidant effect increasing with metal concentration. Cu2+ formed a prooxidant system with ascorbic acid only at low metal concentration, but as the copper concentration was raised, inversion of activity occurred and the copper-ascorbic acid system exerted a stabilizing action on carotene. Prooxidant effects were enhanced and antioxidant effects weakened in the presence of added lmoleate hydroperoxides. The latter were unstable in the presence of ascorbic acid and especially ascorbic acid + Cu2+. Ascorbic acid itself became unstable in the presence of Cu2+. Oxygen depletion, brought about by the rapid oxidation of ascorbic acid, may be partly responsible for the carotene-stabilizing effect of the Cu*+-ascorbic acid couple. It is postulated that additional stabilization results from the radical-scavenging properties of copper or of a copper chelate formed by ascorbic and/or dehydro-ascorbic acid.

PROOXIDANT AND ANTIOXIDANT EFFECTS OF ASCORBIC ACID AND METAL SALTS IN A β‐CAROTENE‐LINOLEATE MODEL SYSTEM

Absorption and Secretion of Fatty Acids and Bile Acids in the Intestine of the Laying Fowl

Fat Digestion and Absorption in Chicks Fed Raw or Heated Soybean Meal

Factors relating to photo-oxidative damage in tomatoes were investigated during maturation of the fruit and upon induction of sunscald. Superoxide dismutase (SOD) activity passed through a minimum at the mature-green and breaker stages of ripening and availability of zinc and copper did not appear to be a limiting factor in the synthesis of the enzyme. Iron levels were maximal and total carotenoid concentrations were lowest during the same mature-green and breaker stages of maturation, while chlorophyll was starting to decrease but was still present in large amounts. Peroxidase activity decreased steadily during ripening. Artificial induction of tolerance to photodynamic damage by controlled heat treatment was accompanied by an increase in SOD activity, while carotenoid levels and peroxidase activity did not change. These findings support the thesis that the previously reported susceptibility of tomatoes to photodynamic damage, i.e. sunscald, during the mature-green and breaker stages of maturation is related to enhanced formation of superoxide ions, at a time when chloroplast structure begins to break down. SOD, by scavenging the superoxide, appears to supplement the protective action of carotenoids against photo-oxidative injury.

P. Budowski

Papers

PROOXIDANT AND ANTIOXIDANT EFFECTS OF ASCORBIC ACID AND METAL SALTS IN A β‐CAROTENE‐LINOLEATE MODEL SYSTEM

Absorption and Secretion of Fatty Acids and Bile Acids in the Intestine of the Laying Fowl

Fat Digestion and Absorption in Chicks Fed Raw or Heated Soybean Meal

Photo‐oxidative damage in the ripening tomato fruit: Protective role of superoxide dismutase

The Effect of Dietary Fat and Tocopherol on Lipolysis and Oxidation in Turkey Meat Stored at Different Temperatures