Raymond C. Noble

Tissue-specific differences in antioxidant distribution and susceptibility to lipid peroxidation during development of the chick embryo

The purpose of this study was to determine the tissue-specific acquisition of antioxidant capacity during chick embryo development and to assess the effectiveness of this process in the prevention of lipid peroxidation. The transfer of alpha-tocopherol, carotenoids and ascorbic acid from the yolk/yolk sac membrane (YSM) to the developing chick embryo and the distribution of these antioxidant compounds between the embryonic tissues were investigated. The concentrations of alpha-tocopherol and carotenoids in the yolk decreased between day 15 of development and hatching at day 21, concomitant with an increase in the levels of these antioxidants in the YSM. The concentration of both these lipid-soluble antioxidants in the liver increased dramatically between day 18 of embryonic development and day 1 after hatching. The adipose tissue content of alpha-tocopherol also increased markedly during the late embryonic/early neonatal period. However, the levels of alpha-tocopherol in the liver were far higher than in any other tissue with particularly low levels observed for the brain. Also, carotenoids were undetectable in the developing brain. Ascorbic acid was not present in the initial yolk but high levels of this water-soluble antioxidant were detected in the YSM, particularly at the early stages of development. The concentration of ascorbic acid in the embryonic brain was far higher than in any other tissue. Homogenates of brain tissue were extremely susceptible to lipid peroxidation during incubation in vitro whereas extracts of liver, yolk and YSM were relatively resistant to lipid peroxidation, particularly in the absence of exogenous Fe2+.

Viability, susceptibility to peroxidation and fatty acid composition of boar semen during liquid storage

The changes in viability, susceptibility to peroxidation and fatty acid composition of total phospholipid were studied in boar spermatozoa during 5 day liquid storage in a standard or alpha-tocopherol (alphaT) enriched diluent. The sperm rich fraction of the ejaculates was collected from 6-month old boars. Sperm viability progressively decreased during storage and alphaT inclusion into the diluent significantly inhibited this trend. alphaT inclusion also decreased significantly peroxidation (TBARS production of spermatozoa). Spermatozoa stored in the treatment diluent became rapidly enriched in alphaT with a concomitant decrease of alphaT content in the medium. The proportion of polyunsaturates, mainly 22:6n-3, decreased with a complementary increase in the content of the saturates, mainly 18:0. The inclusion of alphaT into the diluent was effective in totally preventing the significant decrease of 22:6n-3 observed in sperm phospholipid in the control samples during the storage period. It is concluded that the alphaT inclusion in the boar semen diluent increased cell viability through its prevention of an oxidative reduction in the levels of the major polyunsaturated fatty acids, namely 22:6n-3.

Evaluation in vitro of plant essential oils as natural antioxidants

ABSTRACT Five essential oils, geranium, monarda, nutmeg, oregano and thyme, were evaluated for their antioxidant properties at final concentrations of 0.75 ppm to 100 ppm. Thiobarbituric acid reactive substances (TBARS) were measured in three avian assay systems based on egg yolk, one-day old chicken livers and muscle from mature chickens. All the oils demonstrated extensive antioxidant capacities. The egg yolk TBARS assay showed monarda, nutmeg and thyme essential oils to be the most effective while the chick liver assay revealed nutmeg oil to be the most active. The chicken muscle assay demonstrated equal activity for the oils of monarda, nutmeg, oregano and thyme. Based on this assay technique, oils demonstrating the most effective antioxidant capacities will be chosen for feeding trials to demonstrate their effectiveness in vivo upon polyunsaturated fatty acid (PUFA) metabolism during vital periods of the lifespan, in particular, the foetal/neonate and aging periods.

Effect of Vitamin E and Selenium Supplementation of Cockerel Diets on Glutathione Peroxidase Activity and Lipid Peroxidation Susceptibility in Sperm, Testes, and Liver

The phospholipids of avian spermatozoa are characterized by high proportions of arachidonic (20:4n-6) and docosatetraenoic (22:4n-6) fatty acids and are therefore sensitive to lipid peroxidation. α-Tocopherol and glutathione peroxidase [GSH-Px] are believed to be the primary components of the antioxidant system of the spermatozoa. The present study evaluates the effect of vitamin E and vitamin E plus Se supplementation of the cockerel diet on GSH-Px activity, vitamin E accumulation, and lipid peroxidation in the spermatozoa, testes, and liver. At the beginning of the experiment 75 Rhode Island Red cockerels were divided into five groups, kept in individual cages, and fed a wheat-barley-based ration balanced in all nutrients. Supplements fed to the different groups were as follows: vitamin E, 0, 20, 200, 20, and 200 mg/kg to groups 1–5, respectively, with groups 4 and 5 also receiving 0. 3 mg Se/kg. The vitamin E supplementation produced increased levels of α-tocopherol in semen, testes, and liver. The inclusion of the Se into the cock diet had a significant (P < 0.01) stimulating effect on GSH-Px activity in seminal plasma, spermatozoa, testes, and liver. The increased vitamin E concentration in the spermatozoa was associated with a reduction in their susceptibility to lipid peroxidation. Similarly, the increased GSH-Px activity provided enhanced protection against lipid peroxidation.

Relationship between vitamin E content and susceptibility to lipid peroxidation in tissues of the newly hatched chick

1. The effect of supplementing the diet of the parent hen with vitamin E on the vitamin E content of the yolk and of embryonic and neonatal tissues was evaluated and the effects of elevated tissue concentrations of vitamin E on peroxidation susceptibility was examined. 2. Laying hens (Ross 1 broiler-breeder strain) were maintained on diets containing either 147 (control diet) or 365 (high vitamin E diet) microg vitamin E/g feed. 3. In the day-16 embryo, the concentrations of of vitamin E in the yolk sac membrane, liver, brain and lung were respectively 5.0, 4.3, 1.7 and 5.6 times greater for those derived from the hens on the high vitamin E diet compared with those from the control group. 4. In the day-old chick, the concentrations of vitamin E in the yolk sac membrane, liver, brain and lung were respectively 14.8, 2.8, 3.0 and 5.1 times greater for those derived from hens on the high vitamin E diet compared with those from the control group. 5. Homogenates of tissues from the day-old chick were incubated in the absence and presence of Fe2+ in order to determine the extent of spontaneous and iron-stimulated peroxidation as measured by the generation of thiobarbituric acid reacting substances. For the chicks derived from hens on the control diet, the brain was markedly more susceptible to both spontaneous and iron-stimulated peroxidation than were the other tissues. Tissues from the chicks derived from the hens on the high vitamin E diet exhibited significantly reduced susceptibilities to peroxidation. In particular, the susceptibility of the brain was reduced to the same level as that of the other tissues. 6. It is concluded that the high peroxidative susceptibility of the chicks brain can be normalised by supplementation of the parent hen with vitamin E.

Tissue-specific antioxidant profiles and susceptibility to lipid peroxidation of the newly hatched chick.

The hatching process is characterized by a range of adaptive changes, and a newly hatched chick is considered as an intermediate stage between prenatal and postnatal development. The aim of the present study was to evaluate the characteristic relationships between tissue-specific fatty acid composition and antioxidant protection in newly hatched chicks. Liver, yolk sac membrane, heart, kidney, lung, and four brain regions (cerebrum, cerebellum, stem, and optic lobes) were collected. Fatty acid composition of total lipids and phosphoglycerides, α-tocopherol, lutein, ascorbic acid, reduced glutathione, and the activities of Mn-and Cu,Zn-superoxide dismutase (SOD) and Se-dependent and non-Se-glutathione peroxidase (GSH-Px), and catalase (CAT) were determined. The levels of Fe, Cu, Zn, and Mn as well as tissue susceptibility to lipid peroxidation were also studied. The tissues of the newly hatched chick showed distinctive features in fatty acid profiles, antioxidant accumulation, and susceptibility to lipid peroxidation. The brain clearly displayed the greatest susceptibility to spontaneous and Fe-stimulated lipid peroxidation, was highly unsaturated and contained very low levels of vitamin E, no detectable carotenoids, low GSH-Px, and low CAT activity. At the same time, the brain was characterized by high ascorbic acid concentration and comparatively high SOD activity. It was suggested that in postnatal development, antioxidant enzymes presumably play the major role in antioxidant protection of the chick tissues.

The relationship between the levels of α-tocopherol and carotenoids in the maternal feed, yolk and neonatal tissues : Comparison between the chicken, turkey, duck and goose

The relationship between the levels of the lipid-soluble antioxidants, a-tocopherol and carotenoids, in the parental diet, the yolk and the neonatal tissues was investigated for four avian species of commercial importance. The chicken displayed a much greater efficiency in incorporating a-tocopherol from the parental diet into the yolk in comparison with the turkey, duck and goose. Thus, in spite of similar concentrations in the respective diets, the resultant con- centration of a-tocopherol in the yolk of the chicken egg was four to -ve times greater than observed for the other three species. A similar but less dramatic picture was observed for carotenoids: identical dietary provision of carotenoids in the maternal feeds resulted in the chicken eggs displaying between 1E4 and 1E9 times the concentration in the yolk than was observed for the other three species. These di†erences between the species regarding the levels of a-tocopherol and carotenoids in the yolk were closely reNected in the subsequent concentrations of these components in the livers of the hatchlings. Thus, the concentrations of a-tocopherol and carotenoids in the liver of the day-old chicken were respectively about three and two times greater than in the livers of the other three species. Although the water-soluble antioxidant, ascorbic acid, is synthesised by the embryo as opposed to provision via the maternal diet and the yolk, the concen- tration of this component in the brain of the day-old chicken was approximately 50% greater than in the brains of the other three species. Thus, it is possible that the antioxidant capacity of the developing turkey, duck and goose may be com- promised under conditions of commercial production. All four species displayed a rapid depletion of a-tocopherol and carotenoids from the livers during the -rst 9 days after hatching. 1998 SCI. (

Development of antioxidant capacity in tissues of the chick embryo

Abstract The concentrations of vitamin E, vitamin A, selenium, reduced glutathione and the activities of glutathione peroxidase and superoxide dismutase were determined in the yolk, yolk sac membrane, liver and brain of the developing chick embryo. The changes in the concentrations of vitamins E and A in the yolk and liver during development were consistent with the occurrence of a preferential transfer of vitamin A from the yolk to the embryo before day 14 of incubation, whereas the main period of vitamin E transfer occurred later, during the last week of incubation. The concentrations of reduced glutathione in the yolk sac membrane, liver and brain were similar at all developmental stages studied. However, the levels of the other measured antioxidant systems were very much higher in the liver than in the brain. Thus, in the newly hatched chick, the levels of vitamin E, vitamin A, selenium, glutathione peroxidase and superoxide dismutase were, respectively, 58.0-, 174.7-, 3.6-, 4.0- and 4.7- fold higher in the liver than in the brain when expressed on the basis of tissue fresh weight.

Effect of long-term supplementation with arachidonic or docosahexaenoic acids on sperm production in the broiler chicken.

The possibility was investigated that dietary supplementation of the male chicken with long-chain polyunsaturated fatty acids of the n-6 and n-3 series may prevent the decrease in sperm output that normally occurs by 60 weeks of age. From 26 weeks of age, birds were raised on wheat-based diets supplemented with either maize oil (rich in linoleic acid, 18:2n-6), arasco oil (rich in arachidonic acid, 20:4n-6) or tuna orbital oil (rich in docosahexaenoic acid, 22:6n-3). The effects of the last two oils were investigated at two levels of vitamin E supplementation (40 and 200 mg kg(-1) feed). By 60 weeks of age, there was a small increase in the proportion of the main polyunsaturate of chicken sperm phospholipid, docosatetraenoic acid 22:4n-6, in chickens fed arasco oil diet compared with chickens given the maize oil diet, an effect that was potentiated at the higher dietary intake of vitamin E. Supplementation with tuna orbital oil significantly reduced the proportions of 20:4n-6 and 22:4n-6 in the sperm phospholipid and increased the proportion of 22:6n-3. The diet supplemented with tuna orbital oil and the lower level of vitamin E markedly depleted vitamin E from the tissues of the birds and decreased the concentration of vitamin E in the semen; these effects were largely prevented by the higher level of vitamin E in the diet. The susceptibility of semen to lipid peroxidation in vitro was increased in chickens fed arasco and tuna orbital oils with 40 mg vitamin E kg(-1) feed, but was reduced when 200 mg vitamin E kg(-1) feed was provided in the diet. The number of spermatozoa per ejaculate decreased by 50% between 26 weeks and 60 weeks of age in the birds fed the maize oil diet. This age-related decrease in the number of spermatozoa was almost completely prevented by feeding the birds with the oils enriched in either 20:4n-6 or 22:6n-3. Testis mass at 60 weeks of age was approximately 1.5 times greater in birds given of the arasco and tuna orbital oil diets compared with those given the maize oil diet.

The fatty acid composition of brain phospholipids from chicken and duck embryos

The effects of differences in the fatty acid composition of the lipids of egg yolk on the subsequent levels of arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3) in the total phospholipids and in the isolated phospholipid classes of the embryonic brain were investigated by a comparison of two domesticated avain species, the chicken and the duck. The yolk phospholipids of chicken eggs contained similar proportions of 20:4n-6 and 22:6n-3 (approx. 6% wt/wt of total fatty acids). In marked contrast, the yolk phospholipids of commercially produced duck eggs contained an overwhelming preponderance of 20:4n-6 over 22:6n-3 (approx. 10% cf.1%). These differences between the yolks of the two species were only partly reflected in the fatty acid compositions of the total phospholipids of the embryonic brains at equivalent developmental stages. Typically, the chicken brain phospholipids contained approximate proportions of 20:4n-6 and 22:6n-3 of 8% and 17%, respectively, whereas both these polyunsaturates were present at approx. 11% in the duck samples. The brain phospholipids were resolved into their component phospholipid classes by high performance liquid chromatography. In both species, phosphatidylcholine contained only low levels of 20:4n-6 and 22:6n-3, whereas phosphatidylethanolamine displayed a high content of 22:6n-3. Phosphatidylserine was also rich in 22:6n-3 whereas phosphatidylinositol exhibited a high proportion of 20:4n-6. The results suggest that the relatively low level of 22:6n-3 in the yolk of duck eggs is partly compensated for by an enhanced efficiency in the incorporation of this fatty acid into the brain phospholipids, in comparison with the chicken.