Effect of vitamin A on the antioxidant system of the chick during early postnatal development.

1. The effect of increasing vitamin A doses on the concentrations of vitamins A, E, ascorbic acid and carotenoids in the liver and blood plasma of the neonatal chick were investigated. 2. In the 1st experiment 75 d-old chickens were divided into 3 equal groups and in the 2nd experiment 100 d-old chickens were divided into 5 groups. Retinyl acetate in corn oil (1.72; 4.30; 8.60 or 17.2 mg) was intubated directly into the crop daily during the first 5 d after hatch. 3. The intubation of vitamin A increased its accumulation in the liver, with a plateau at about 6,000 microg/g, and was associated with inhibition of vitamin E and carotenoid utilisation from the liver during postnatal development. 4. Moderate amounts of vitamin A intubation increased ascorbic acid concentration in the liver, kidney, brain and plasma. A further increase in vitamin A intubation had an adverse effect on ascorbic acid concentrations in the plasma and brain. 5. The 2 highest inputs of vitamin A decreased glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities in the chicken liver and brain. 6. It is concluded that the effect of vitamin A on development of the antioxidant system in the neonatal chick is dose-dependent and an excess of vitamin A can compromise the antioxidant defence system.

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.

Antioxidant systems of the avian embryo: tissue-specific accumulation and distribution of vitamin E in the turkey embryo during development.

Tissue-specific accumulation of tocopherols and tocotrienols in turkey tissues during embryonic development and their susceptibility to lipid peroxidation were investigated. Fertile turkey eggs were incubated using standard commercial conditions. Embryonic tissues were collected at 16, 22, 25 d of incubation and from day-old poults (referred to as day 29) and alpha-; beta- + gamma- and delta-tocopherols and respective tocotrienols were analysed by HPLC. A turkey diet provided to the parent hens contained the complete range of tocopherols and tocotrienols. Between days 16 and 22 of embryo development, the alpha-tocopherol concentration in the liver remained constant and then increased significantly (P<0.01) reaching a maximum just after hatching. Similar changes were observed for the other tocopherols and tocotrienols. The accumulation of alpha-tocopherol in the yolk sac membrane (YSM) started after day 20 of development and at hatching the alpha-tocopherol concentration in the YSM was twice that of beta- + gamma-tocopherols and 15 times greater than that of alpha-tocotrienol. In the kidney, heart, lung, muscle and adipose tissues a gradual increase in tocopherol and tocotrienol concentrations took place between days 20 and 25 of development with a sharp increase in particular of alpha-tocopherol between days 25 and 29. There was a discrimination between tocopherols and tocotrienols during their assimilation from the diet by the parent hen and during metabolism by the developing turkey embryo. Tissue-specific features in the susceptibility to lipid peroxidation were found with the brain being the most susceptible to lipid peroxidation at day 25 and in day-old poults.

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 chick's brain can be normalised by supplementation of the parent hen with vitamin E.

The comparative roles of polyunsaturated fatty acids in pig neonatal development.

The present review focuses on the importance of polyunsaturated fatty acid (PUFA) provision for the normal development of the pig neonate. The review describes first the selected fatty acid composition of a range of porcine tissues including nervous tissues, muscle and adipose tissues, reproductive organs and immune-responsive organs and/or cells. The importance of PUFA to the functioning of the immune system of the neonate is considered briefly and is followed by an in-depth consideration of the sources of PUFA for the neonatal pig. The effects of different categories or specific types of fatty acid (i.e. non-essential, linoleic, alpha-linolenic, long-chain n-6 and n-3 PUFA) on various indices of pig neonatal growth are reviewed. The importance of n-3 PUFA supply to the fetal and early neonatal pig is underlined and evidence is presented for more attention to be given to the amounts available from maternal sources. Based on the material reviewed, recommendations are made on the dietary intake of PUFA in the gestating pig.

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, alpha-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.

Effect of supplementing the hen's diet with vitamin A on the accumulation of vitamins A and E, ascorbic acid and carotenoids in the egg yolk and in the embryonic liver.

1. The effect of a range of supplementations of vitamin A to the laying hen on the concentration of vitamins A, E, ascorbic acid and carotenoids in the maternal liver, the egg yolk and the embryonic liver were investigated. 2. Four groups of 25 Rhode Island Red hens were fed on standard layer-breeder diets with concentrations of supplemented vitamin A ranging from 0 to 120 micrograms/g retinol equivalents from 28 weeks of age. After 3 months, the concentration of vitamin A in the maternal liver was found to be greatly enhanced in proportion to the increasing rates of supplementation with the vitamin. However, the concentration of vitamin E in the maternal liver was markedly reduced by high dietary contents of vitamin A. 3. The concentration of vitamin A in the yolk of the hens' eggs was markedly increased by the dietary supplementation. However, the concentration of both vitamin E and carotenoids in the yolks were significantly reduced by high dietary contents of vitamin A. 4. The concentration of vitamin A in the liver of the embryo and the day old chick was greatly increased by the high concentrations of maternal vitamin A provision. However, the concentration of vitamin E, carotenoids and ascorbic acid in the embryonic/neonatal liver were significantly reduced by high contents of vitamin A in the maternal diet. 5. The susceptibility of the embryonic/neonatal liver to lipid peroxidation was significantly increased as a result of high provisions of maternal vitamin A. 6. It is concluded that excessive provision of vitamin A to the laying hen results in an adverse effect on vitamin E, carotenoids and ascorbic acid in the embryonic/neonatal liver and can compromise the antioxidant status of the progeny.

The effect of temporary reductions in incubation temperature on growth characteristics and lipid utilisation in the chick embryo.

The effect(s) of finite exposure(s) to 22.0 degrees C on embryo weight gain, 3rd tarsus length, transfer of lipid from the yolk and uptake of specific lipid components by the liver, were measured in the chick embryo. Embryo growth was completely suspended over the period of temperature reduction, but resumed unimpaired when the optimum temperature of 37.5 degrees C was restored. Two successive periods of embryonic exposure to 22.0 degrees C (36 h at d 3 followed by 24 at d 10) were additive in their effect on growth retardation. Embryos subjected to temperature reductions on d 3 of incubation displayed significant changes in lipid concentrations and polyunsaturated fatty acid profiles within the liver when measured at d 18 of incubation. Yolk lipid uptake was significantly reduced but not suspended by embryonic exposure to 22.0 degrees C. It is suggested that the observed suspension of embryonic development was the result of a temperature dependent reduction in metabolism according to a Q10 approximately 2, which is typical of an ectothermic organism.

Relationship between spermatozoan lipid composition and fertility during aging of chickens.

Changes in the proportions of the various lipid components in spermatozoa were investigated throughout the reproductive period (24-72 wk of age) of male chickens. Sperm motility and in vivo fertility were also measured, and correlation coefficients with the lipid values were determined. The proportion of total phospholipid (PL) increased to reach a maximum value at 39 wk and decreased significantly thereafter. The relative content of free cholesterol and triacylglycerols showed no change in spermatozoa during aging or in relation to fertility values; free fatty acids and cholesterol esters increased continuously with age. Of the various PL classes, phosphatidylserine and phosphatidylcholine displayed a pattern of changes with age positively and negatively, respectively, in relation to the changes of fertility. The proportion of phosphatidylethanolamine had significantly decreased by the end of the reproductive period. The proportions of C16:0, C18:0, and C18:1n-9 within the PL of the spermatozoa increased with age, and those of C20:4n-6, C22:4n-6, and C22:6n-3 decreased. Positive correlations were found between fertility and total PLs, phosphatidylserine, and PL-bound C20:4n-6 and C22:4n-6; a negative correlation was found between fertility and phosphatidylcholine. Motility was positively correlated with the level of PL and negatively with that of free cholesterol; it was also positively correlated with the levels of C22:4n-6 and C22:6n-3 and negatively with those of C16:0, C18:0, and C18:1n-9. The results suggest that the lipid and fatty acid compositions of spermatozoa may be important predictors of fertility.

The relationship between the dietary provision of alpha-tocopherol and the concentration of this vitamin in the semen of chicken: effects on lipid composition and susceptibility to peroxidation.

This study is an attempt to enhance the resistance of chicken semen to peroxidative damage by supplementing the diet of cockerels with the major lipid-soluble antioxidant alpha-tocopherol. Cockerels at 6 months of age were fed for 8 weeks with feed containing 0, 20, 200 or 1000 mg alpha-tocopherol kg-1. Semen was collected during the final 2 weeks of the supplementation period and the concentrations of alpha-tocopherol in the spermatozoa and the seminal plasma were determined. The concentrations of alpha-tocopherol in whole semen, spermatozoa and seminal plasma were approximately twice as high when the supplementation was 200 mg kg-1 compared with when supplementation was 20 mg kg-1; however, supplementation at 1000 mg kg-1 did not achieve any further increase in these concentrations of alpha-tocopherol. Thus, the concentration of alpha-tocopherol in semen displays only a limited responsiveness to manipulation by dietary means. In contrast, the concentrations of the vitamin in the testes and liver were found to be much more amenable to dietary manipulation, exhibiting increases of six-seven-fold over the whole range of supplementation. However, the dietary-induced increase in the alpha-tocopherol content of semen did result in a significant reduction in the susceptibility of the semen to lipid peroxidation. A further effect of enhancing the concentration of this vitamin in the semen was a significant increase in the proportions of C20-22 polyunsaturated fatty acids in the sperm phospholipids. In addition, the proportion of phosphatidylethanolamine in the phospholipid was increased whereas that of sphingomyelin was reduced at the higher concentrations of alpha-tocopherol supplementation. Thus, an increased dietary intake of alpha-tocopherol does produce beneficial changes in the antioxidant capacity and lipid profile of semen, albeit to a relatively limited extent.

Effects of dietary supplementation with alpha-linolenic acid on the phospholipid fatty acid composition and quality of spermatozoa in cockerel from 24 to 72 weeks of age.

The aim of this study was to investigate the effects of supplementing the diet of the male chicken with alpha-linolenic acid (18:3n-3) on the phospholipid fatty acid composition, motility and fertilizing ability of chicken spermatozoa. The birds in the control group received a diet supplemented with soybean oil rich in linoleic acid (18:2n-6) whereas those in the test group were supplemented with linseed oil rich in alpha-linolenic acid. A number of age-related changes in the lipid parameters of the spermatozoa were observed in control birds. Between 24 and 72 weeks of age the amount of total lipid in the spermatozoa of control birds increased by approximately 2.4 times and the proportions of cholesterol and free fatty acid also increased significantly, whereas the proportions of phospholipid and triacylglycerol decreased. In addition, the proportion of phosphatidylcholine in the total phospholipid increased, whereas the proportion of phosphatidylserine decreased during the same period. The proportion of docosatetraenoic acid (22:4n-6) in the phospholipid decreased significantly between 24 and 72 weeks of age. The concentration of spermatozoa in the semen of control birds increased to a maximum at week 39 and had decreased significantly by week 72. Supplementation with alpha-linolenic acid had little or no effect on the proportion of docosahexaenoic acid (22:6n-3) in the phospholipid profile of the spermatozoa. However, supplementation with alpha-linolenic acid did produce a significant but small increase in the proportion of docosapentaenoic acid (22:5n-3) recorded at 39 and 54 weeks. Thus, this study shows that the fatty acid composition of the sperm phospholipid demonstrates a marked resistance to dietary manipulation. Supplementation with alpha-linolenic acid significantly enhanced semen fertility at week 39. The results suggest that the small increase in the proportion of n-3 fatty acids in the sperm phospholipids induced by enriching the diet with alpha-linolenic acid is associated with a significant improvement in semen quality at 39 weeks of age.

The preferential mobilisation of C20 and C22 polyunsaturated fatty acids from the adipose tissue of the chick embryo: potential implications regarding the provision of essential fatty acids for neural development.

The aim of this study was to determine the relative mobilisation of the different fatty acyl components of the triacylglycerol (TAG) of the chick embryo's adipose tissue in the light of the specific requirements of the developing neural tissues of the embryo for C20-22 polyunsaturated fatty acids. Pieces of adipose tissue, obtained from embryos at various developmental stages, were incubated in vitro in Dulbecco's Medium containing serum albumen. The fatty acid compositions of the initial tissue TAG and of the free fatty acid (FFA) mobilised from the tissue during 1 h of incubation were determined and compared. The composition of the FFA released into the medium under conditions of basal (i.e., unstimulated) lipolysis was markedly different in several respects from that of the TAG from which it originated. The polyunsaturated fatty acids, 20:4n-6, 20:5n-3, 22:5n-3 and 22:6n-3, were consistently found to be preferentially released into the medium, whereas the major fatty acyl constituents of the tissue, 16:0 and 18:1n-9, were selectively retained in the TAG. For example, at day 18 of development, the proportions (% w/w of fatty acids) of 20:5n-3 and 22:6n-3 released into the incubation medium were respectively 6.5 and 7.5 times higher than in the original tissue TAG. Glucagon stimulated the overall rate of mobilisation by approx. 2-fold and also partially suppressed the preferential mobilisation of C20-22 polyunsaturates. These results may be relevant to the elucidation of the means by which essential polyunsaturates are delivered from the yolk to the neural tissues of the embryo, with the implication of a mediatory role for the embryonic adipose tissue in this transfer.

The effect of dietary oil containing (n-3) fatty acids on the fatty acid, physicochemical, and organoleptic characteristics of pig meat and fat.

An investigation was made to alter the fatty acid composition of pork and a pork product in line with human dietary advice while not adversely affecting factors controlling consumer acceptability. Pigs (n = 150) were assigned to three dietary treatments with 25 intact male-female pairs per treatment. Diet A (control) contained 3% of a 4:1 (wt/ wt) tallow-soybean oil mixture. Diets B and C contained 2% rapeseed oil plus 1% fish oil. Diets A, B, and C were supplemented with 100, 100, and 250 mg of all-rac-alpha-tocopheryl acetate/kg of diet, respectively. Pigs were given ad libitum access to feed from 52 kg live weight until 95 kg (slaughter). Sausages were prepared from the resulting cuts. Tissues of pigs were evaluated in terms of fat firmness, color, fatty acid composition, and contents of alpha-tocopherol and thiobarbituric acid-reactive substances (TBARS). Organoleptic characteristics of chops and sausages were evaluated by a trained taste panel. Pigs fed Diets B and C had improved feed conversion ratios (P < .05) and ADG compared with control pigs. The levels of n-3 (omega-3) polyunsaturates were significantly increased in the tissues and sausage from pigs fed Diets B and C with associated alterations in n-6 to n-3 fatty acid ratios that accorded with contemporary human dietary recommendations. Levels of alpha-tocopherol and TBARS were significantly altered in the tissues. There were no appreciable differences between treatments in carcass characteristics, including color. The overall organoleptic acceptability of chops and sausages was not different between the treatments.

Illustrations and implications of current models of HIV health service provision in rural areas.

Despite recent evidence of faster than average increases in HIV/AIDS cases in rural areas across the U.S., there is still a generally poor understanding of successful models of rural HIV/AIDS health-care delivery. Past research in rural Kentucky suggested several barriers to care resulting in most rural HIV-positive patients traveling from rural to urban areas for care. Patients sought urban areas for care for reasons including patient confidentiality, a perceived lack of expertise on the part of rural physicians in caring for HIV-positive patients, and outright referral from rural to urban areas. Case histories are used to illustrate a variety of models of care used by rural HIV-positive patients. These include splitting and sharing care between rural primary care physicians and urban medical specialists, as well as patients receiving all their care in urban areas. Implications of these models for quality of care are discussed.

Lipid and antioxidant changes in spermatozoa and seminal plasma throughout the reproductive period of bulls.

The lipid compositions and associated antioxidant capacities of spermatozoa and seminal plasma from bulls were examined at the beginning, middle and end of their reproductive period. The reduction in concentration and motility of spermatozoa associated with ageing was accompanied by a large decrease in lipid concentrations within the seminal plasma; this change in lipid concentration was accompanied by an increase in the proportion of phospholipid. By contrast, the proportion of phospholipids in the spermatozoa was significantly reduced. The major phospholipid fractions within both the spermatozoa and seminal plasma were phosphatidyl choline and phosphatidyl ethanolamine. With increasing age there was a large decrease in the proportion of phosphatidyl ethanolamine and a commensurate increase in that of phosphatidyl choline within the spermatozoa and seminal plasma. These major changes in phospholipids were accompanied by a decrease in the amount of phosphatidyl inositol and an increase in that of cardiolipin in both spermatozoa and seminal plasma. The reductions in the proportions of phosphatidyl ethanolamine were accompanied by extensive reductions in the content of the major polyunsaturated fatty acids, arachidonic 20:4 (n-6) and docosahexaenoic 22:6 (n-3); there was a decrease also in the concentration of 22:6 (n-3) in phosphatidyl choline. The changes in lipid composition owing to ageing were associated with a marked reduction within the seminal plasma of the major antioxidant enzyme systems, glutathione peroxidase and superoxide dismutase.

The effects of dietary supplementation with docosahexaenoic acid on the phospholipid fatty acid composition of avian spermatozoa.

This study represents an attempt at the dietary manipulation of the fatty acid composition of chicken spermatozoa in order to enhance the levels of n-3 polyunsaturates at the expense of the n-6 fatty acids, which normally predominate in the lipids of avian semen. Male chickens were provided with either a control diet supplemented with maize oil or the test diet supplemented with fish oil (Tuna Orbital Oil) from 10 weeks of age. Semen samples were collected from the birds after 30 and 48 weeks of supplementation. The fish oil diet induced a significant but limited increase in the proportion of 22:6n-3 in the spermatozoan phospholipid in parallel with an equivalent decrease in the proportions of 20:4n-6 and 22:4n-6. However, since the maximal level of 22:6n-3 in the phospholipid that was achieved by fish oil feeding was less than 10% (wt/wt of fatty acids), these changes fell far short of representing a switch from the typical avian pattern to that more characteristic of the n-3 enriched mammalian semen. Analysis of the fatty acid compositions of the constituent classes of phospholipid in the spermatozoa indicated that, in both dietary states, the phosphatidylethanolamine fraction contained much greater proportions of n-6 and n-3 C20-22 polyunsaturates than the phosphatidylcholine fraction. The results indicate that the typical fatty acid profile of the spermatozoa of domesticated poultry, characterised by the predominance of C20-22 n-6 polyunsaturates, displays a considerable degree of resistance to manipulation by dietary means and does not adopt the "mammalian" type of profile following supplementation with n-3 fatty acids.