Polyphenol compounds in the chicken/animal diet: from the past to the future.

Animal feed provides a range of antioxidants that help the body building an integrated antioxidant system responsible for a prevention of damaging effects of free radicals and products of their metabolism. Vitamin E is considered to be the main chain-breaking antioxidant located in the membranes and effectively protecting them against lipid peroxidation. Recently, various polyphenol compounds, especially flavonoids, have received substantial attention because of their antioxidant activities in various in vitro systems. However, it was shown that flavonoid compounds are poorly absorbed in the gut and their concentrations in target tissues are too low to perform an effective antioxidant defences. The aim of the present paper is to review existing evidence about possible roles of various plant extracts provided with the diet in animal/poultry nutrition with a specific emphasis to their antioxidant activities.

Maternal effects and the evolution of brain size in birds: overlooked developmental constraints.

A central dogma for the evolution of brain size posits that the maintenance of large brains incurs developmental costs, because they need prolonged periods to grow during the early ontogeny. Such constraints are supported by the interspecific relationship between ontological differences and relative brain size in birds and mammals. Given that mothers can strongly influence the development of the offspring via maternal effects that potentially involve substances essential for growing brains, we argue that such effects may represent an important but overlooked component of developmental constraints on brain size. To demonstrate the importance of maternal effect on the evolution of brains, we investigated the interspecific relationship between relative brain size and maternal effects, as reflected by yolk testosterone, carotenoids, and vitamins A and E in a phylogenetic study of birds. Females of species with relatively large brains invested more in eggs in terms of testosterone and vitamin E than females of species with small brains. The effects of carotenoid and vitamin A levels on the evolution of relative brain size were weaker and non-significant. The association between relative brain size and yolk testosterone was curvilinear, suggesting that very high testosterone levels can be suppressive. However, at least in moderate physiological ranges, the positive relationship between components of maternal effects and relative brain size may imply one aspect of developmental costs of large brains. The relationship between vitamin E and relative brain size was weakened when we controlled for developmental mode, and thus the effect of this antioxidant may be indirect. Testosterone-enhanced neurogenesis and vitamin E-mediated defence against oxidative stress may have key functions when the brain of the embryo develops, with evolutionary consequences for relative brain size.

Effect of organic selenium on turkey semen quality during liquid storage.

The aim of the present study was to evaluate the effect of dietary organic selenium on the turkey semen during storage. Twenty males (BUT, Big 6, 40 weeks of age) were divided into control (n=10) and experimental group (n=10). The turkeys in the both groups were fed with a commercial diet containing 0.1 ppm Se in the form of sodium selenite. The experimental birds were additionally supplied with 0.3 ppm organic Se in the form Sel-Plex (Alltech, Inc.). After 30 days of feeding, the semen samples were collected twice a week for the 3 weeks of the study and diluted 1+1(v/v) with TUR-2 diluent, and stored in a water bath (+10 to 15 degrees C) for 6 h. The percentage of motile spermatozoa, the sperm viability (live/dead spermatozoa), total lipids, phospholipids and total cholesterol were assessed in fresh and stored semen. The fertilizing ability of semen was assessed by artificial insemination of 30 hens per group with dose containing 200x10(6) spermatozoa weekly. After 6 h of semen storage, the motility of spermatozoa decreased significantly in the control group (by 8.7 relative percent, P<0.05) and only by four relative percent (P>0.05) in experimental group reflecting a protective effect of dietary Se supplementation. The proportion of live spermatozoa was higher in fresh semen and significantly lower in stored semen. The positive effect of Se supplementation was observed on the lipid composition of stored semen: the concentration of the total lipids and phospholipids in the seminal plasma from control group significantly increased, while in the experimental group remained constant. Better semen integrity in the experimental group was associated with an improved fertilizing ability of spermatozoa: the fertility rate of stored spermatozoa in the control group was 88%, while in the experimental group was 90.5%.

Maternal organo-selenium compounds and polyunsaturated fatty acids affect progeny performance and levels of selenium and docosahexaenoic acid in the chick tissues.

The effects of supplementing broiler breeder diets with polyunsaturated fatty acids (PUFA) and organo-Se compounds on the levels of Se and PUFA in chick tissues and on chick performance were assessed. Prepeak (23 wk) and peak (27 wk) production broiler breeders were fed 1 of 4 diets: a wheat-based commercial diet with soybean oil or fish oil but no added Se, and each diet with added Se as Sel-Plex (soybean oil + Se, fish oil + Se; Alltech Inc, Nicholasville, KY). The diets were designed to contain less than 0.1 mg of Se/kg and about 0.5 mg/kg for the nonsupplemented and the supplemented diets, respectively. As-hatched chicks from the 4 parental treatments were fed a nutritionally high quality diet (ME = 12.57 MJ/kg; CP = 228.7 g/kg) or a low quality diet (ME = 10.28 MJ/kg; CP = 182.8 g/kg), resulting in 8 dietary treatments. Performance was better and mortality lower in chicks from 27-wk-old breeders compared with those from 23-wk-old breeders. Fish oil in the maternal diet increased progeny mortality and reduced chick body mass at hatch. Body mass at 7 and 14 d posthatch was lower in chicks fed the low quality diet compared with chicks fed the high quality diet. At hatch, and for up to 14 d posthatch, chicks from hens fed diets high in PUFA had higher concentrations of docosahexaenoic acid (DHA) in the brain and liver compared with chicks hatched from hens fed diets low in PUFA. The DHA content of the tissues of chicks from breeders fed diets supplemented with Se was higher than that in chicks from breeders fed unsupplemented diets. Even after 14 d of being fed a diet with identical levels of Se, chicks hatched from parents fed diets high in Se had higher tissue Se concentrations than those hatched from parents fed diets low in Se. Supplementation of the maternal diet of chicks with organo-Se appears to enhance the DHA concentration of the chick brain, which may improve brain function.

Effects of supplementing broiler breeder diets with organoselenium compounds and polyunsaturated fatty acids on hatchability.

The effects of supplementing broiler breeder diets with polyunsaturated fatty acids (PUFA) and organoselenium compounds on fertility, hatchability, and the weight of 1-d-old chicks was assessed. Prepeak (23 wk) and peak (27 wk) production breeders were fed 1 of 4 diets: a wheat-based commercial breeder diet with 55 g/kg of either soybean oil (SO) or fish oil (FO), but no added Se (only that originating from feed ingredients), and each diet with added Se as Sel-Plex (SO + Se, FO + Se). The diets were designed to contain <0.1 mg/kg of Se and about 0.5 mg/kg of Se for the nonsupplemented (no added Se) and the supplemented diets, respectively. The Se concentration of the eggshell of the hatching egg was measured. The concentration of Se, PUFA, and total lipid content of the brain and liver of the 1-d-old chick was determined. The number of fertile eggs increased, embryonic mortality decreased, and hatchability increased as hen age increased from 23 to 27 wk. The Se concentration in the eggshell and the brain and liver of 1-d-old chicks was higher in the high-Se treatments com pared with the concentration in the low-Se treatments. Fish oil inclusion in the breeder diet increased embryonic mortality in wk 3 of incubation and reduced both hatchability and 1-d-old chick weight in hens of both ages. The addition of Se to the FO diets ameliorated some of these adverse effects, because chicks hatched from eggs laid by 23-wk-old breeders of the FO + Se treatment were heavier than those receiving the FO treatment. The Se concentration in the brain and liver of chicks from the FO hens was higher than that in chicks from the SO hens. The concentration of docosahexaenoic fatty acid was higher in the liver of chicks from the SO + Se treatment compared with that of chicks from the SO treatment, indicating possible protective effects of Se. Hatchability was decreased by increased PUFA and was higher in 27-wk-old compared with 23-wk-old breeders.

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+.

Antioxidants, radiation and mutation as revealed by sperm abnormality in barn swallows from Chernobyl.

Reduced levels of antioxidants such as carotenoids and vitamins A and E can increase DNA damage caused by free radicals. Exposure to radiation has been proposed to reduce levels of antioxidants that are used for DNA repair and this reduction may be responsible for increased levels of mutation in radioactively contaminated areas. We test this hypothesis using field measures of antioxidants in blood, liver and eggs of the barn swallow Hirundo rustica while relating these to levels of mutation as reflected by the frequency of abnormal sperm. Antioxidant levels in blood, liver and eggs were reduced in Chernobyl, Ukraine, compared with an uncontaminated control area, and levels of antioxidants correlated negatively with levels of background radiation. The frequency of abnormal sperm was almost an order of magnitude higher in Chernobyl than in the control area and was negatively related to antioxidant levels in blood and liver. This is consistent with the hypothesis of a direct link between radiation and individual levels of antioxidants, suggesting that levels of mutation differ among individuals owing to individual differences in the abundance of antioxidants.

Effects of supplementing broiler breeder diets with organic selenium and polyunsaturated fatty acids on egg quality during storage.

We assessed the effects of supplementation of broiler breeder diets with polyunsaturated fatty acids (PUFA) and organic Se on hatching egg quality during storage. Broiler breeders (n = 352) were fed 1 of 4 diets: SO (soybean oil with no added Se), SO with Se (SO+Se), fish oil (FO), or FO and Se (FO+Se). Eggs from prepeak (23 wk) and peak production (27 wk) breeders were stored for 14 d under typical (15 degrees C, 78% RH) conditions. Eggs were analyzed for albumen Haugh units (HU) and pH, shell characteristics, egg component weight, Se content, and fatty acid (FA) profile. The efficiency of transfer of Se into the egg was greater in low Se treatments compared with in high Se treatments. The majority of Se from the low Se treatments was deposited in the yolk, whereas in high Se treatments, the Se was deposited evenly in the yolk and albumen. In the low Se treatments, the Se content of yolk and albumen was lower than in the high Se treatments and decreased as age increased. Albumen HU decreased with increased storage, although high Se treatments had greater HU compared with low Se treatments. Eggs from the FO treatment were smaller with thinner eggshells compared with the SO treatment, but addition of Se to the FO diets ameliorated some of these effects. The egg yolk FA profile from the SO+Se treatment was altered compared with that from the SO treatment, perhaps due to interactions between dietary PUFA and Se-dependent enzyme systems. Hatching egg quality during storage was affected by dietary PUFA and Se content, as well as broiler breeder age.

Designer egg evaluation in a controlled trial.

OBJECTIVE: To evaluate the ability of designer eggs enriched in vitamin E, lutein, selenium (Se) and docosahexaenoic acid (DHA) to deliver micronutrients to the human in a palatable and visually acceptable form. DESIGN: Double-blind, placebo-controlled trial, two treatment groups balanced for sex and age. SETTING: Department of Biochemistry and Nutrition, SAC, Scotland. SUBJECTS: Forty healthy adult volunteers completed the study. Volunteers were recruited among staff of the Scottish Agricultural College Interventions: Volunteers consumed, for 8 weeks, either a designer egg or a normal table egg per day. Fasting blood samples were taken before and at the end of the study. RESULTS: Consumption of designer eggs enriched in vitamin E, lutein, Se and DHA significantly increased the levels of alpha-tocopherol, lutein and DHA in plasma as compared to the changes found after consumption of normal table eggs, with the largest increases found in plasma lutein (1.88-fold increase). The proportion of DHA was increased in all the main lipid classes of the plasma including triacylglycerol (2.3-fold), free fatty acids (1. 6-fold), cholesteryl ester (1.4-fold) and phospholipid (1.3-fold). Egg consumption did not change Se concentration in plasma, blood pressure, total plasma lipid concentrations or the concentrations of total cholesterol and HDL-cholesterol in plasma. CONCLUSION: Consumption of designer eggs enriched in vitamin E, lutein, DHA and Se as part of normal diet for 8 weeks effectively increased the blood levels of alpha-tocopherol, lutein and DHA. SPONSORSHIP: Scottish Office Agriculture, Environment, and Fisheries Department.

Selective excretion of yolk-derived tocotrienols into the bile of the chick embryo.

The aim of this study was to investigate the possibility of biodiscrimination between different forms of vitamin E during the development of the chick embryo. The vitamin E present in the initial yolk consisted of alpha-tocopherol (90%), (beta + gamma)-tocopherol (8%), alpha-tocotrienol (0.3%) and (beta + gamma)-tocotrienol (1.3%). In marked contrast, the vitamin E recovered from the bile of the day-16 embryo contained much higher proportions of alpha-tocotrienol (10%) and especially of (beta + gamma)-tocotrienol (42%). By the time of hatching, 56% of the vitamin E present in the bile was in the form of (beta + gamma)-tocotrienol. The residual yolk of the newly-hatched chick contained far greater proportions of alpha-tocotrienol (2.6%) and (beta + gamma)-tocotrienol (10%) than were present in the initial yolk. The results suggest that the liver of the embryo may selectively excrete tocotrienols as components of bile, whilst retaining the tocopherols within the hepatocytes. The increased proportions of tocotrienols in the residual yolk may result from the recycling of bile from the gall bladder to the yolk. The liver of the day-old chick contained alpha-tocopherol as the main form of vitamin E (90%) with only a small proportion (0.2%) of (beta + gamma)-tocotrienol. The alpha-tocopherol form was also the main vitamin E component in the brain (85%), heart (79%), lung (82%) and adipose tissue (91%) of the day-old chick. The present study suggests the occurrence of a high degree of biodiscrimination between tocopherols and tocotrienols during the development of the chick embryo.

Fatty acid composition, glutathione peroxidase and superoxide dismutase activity and total antioxidant activity of avian semen.

This work demonstrates that spermatozoa from five avian species (chicken, turkey, guinea fowl, duck and goose) are all characterised by high proportions of polyunsaturated fatty acids, from 46 (turkey) to 55% (duck) of total. For each of the species, the most abundant fatty acids were arachidonic (20:4n-6) and docosatetraenoic (22:4n-6) acids, representing between 22 (turkey) and 40% (chicken) of total. Significant activities of the major isozymes of superoxide dismutase and glutathione peroxidase, which protect against the peroxidation associated with high degree of fatty acid unsaturation, were found in spermatozoa from all species. The seminal plasma also had these activities and showed additional mechanisms for protecting spermatozoa from peroxidation. In general terms, these lipid and enzyme proteins were similar between the five avian species and different from those reported for mammalian sperm.

Carotenoid discrimination by the avian embryo: a lesson from wild birds.

The concentrations (microg/g wet yolk) of total carotenoids in eggs of the common moorhen (Gallinula chloropus), American coot (Fulica americana) and lesser black-backed gull (Larus fuscus), collected in the wild, were 47.5, 131.0 and 71.6, respectively. In contrast to data for eggs of the domestic chicken, beta-carotene was a significant component in the yolks of these three wild species, forming 25-29% by wt. of the total carotenoids present. The concentration of total carotenoids in the livers of the newly-hatched chicks was 5-10 times higher than in the other tissues and beta-carotene was again a major component, forming 37-58% of the hepatic carotenoids. In the newly-hatched gull, the proportions of both lutein and zeaxanthin were very low in the liver but high in the heart and muscle when compared with the yolk. By contrast canthaxanthin, echinenone and beta-carotene were very minor constituents of heart and muscle when compared with their proportions in the yolk of the gull. The proportions of lutein and zeaxanthin in the liver of the newly-hatched coot and moorhen were also far lower than in the yolk whereas the liver was relatively enriched with beta-cryptoxanthin, beta-carotene and (in the moorhen) echinenone. The results indicate that avian embryos discriminate between different carotenoids during their distribution from the yolk to the various tissues.

Fatty acid composition of the adipose tissue and yolk lipids of a bird with a marine-based diet, the emperor penguin (Aptenodytes forsteri).

The emperor penguin (Aptenodytes forsteri) is an Antarctic seabird feeding mainly on fish and therefore has a high dietary intake of n-3 polyunsaturated fatty acids. The yolk is accumulated in the developing oocyte while the females are fasting, and a large proportion of the fatty acid components of the yolk lipids are derived by mobilization from the female's adipose tissue. The fatty acid composition of the total lipid of the yolk was characterized by high levels of n-3 polyunsaturated fatty acids. However, it differed in several respects from that of the maternal adipose tissue. For example, the proportions of 14:0, 16:1n-7, 20:1n-9, 22:1n-9, 20:5n-3, and 22:6n-3 were significantly greater in adipose tissue than in yolk. Thus adipose tissue lipids contained 7.6+/-0.3% and 8.0+/-0.3% (wt% of total fatty acids; mean +/- SE; n = 5) of 20:5n-3 and 22:6n-3, respectively, whereas the yolk total lipid contained 1.6+/-0.1 and 5.5+/-0.3% of these respective fatty acids. The proportions of 16:0, 18:0, 18:1n-9, 18:2n-6, and 20:4n-6 were significantly lower in the adipose tissue than in the yolk lipids. The proportions of triacylglycerol, phospholipid, free cholesterol, and cholesteryl ester in the yolk lipid were, respectively, 67.0+/-0.2, 25.4+/-0.3, 5.3+/-0.2, and 1.8+/-0.2% (wt% of total yolk lipid). The proportions of 20:4n-6, 20:5n-3, 22:5n-3, and 22:6n-3 were, respectively, 5.7+/-0.3, 2.8+/-0.2, 1.4+/-0.1, and 11.7+/-0.5% in phospholipid and 0.4+/-0.0, 1.2+/-0.1, 0.8+/-0.1 and 3.6+/-0.3% in triacylglycerol. About 95% of the total vitamin E in the yolks was in the form of alpha-tocopherol with gamma-tocopherol forming the remainder. Two species of carotenoids, one identified as lutein, were present.

Transfer of Vitamins E and A from yolk to embryo during development of the king penguin (Aptenodytes patagonicus).

Since the yolk lipids of the king penguin (Aptenodytes patagonicus) are rich in n-3 fatty acids, which are potentially susceptible to peroxidative damage, the yolk contents and yolk-to-embryo transfer of antioxidants and lipid-soluble vitamins were investigated under conditions of natural incubation in the wild. The concentration of vitamin E in the unincubated egg was 155 microg/g wet yolk, of which 88% was alpha-tocopherol and the rest was gamma-tocopherol. Vitamin A (2.9 microg/g) was present in the yolk entirely as retinol; no retinyl esters were detected. Throughout the latter half of the incubation period, vitamins E and A were taken up from the yolk into the yolk sac membrane (YSM) and later accumulated in the liver, with vitamin A being transferred in advance of vitamin E. In the YSM, vitamin A was present almost entirely as retinyl ester, indicating that the free retinol of the yolk is rapidly esterified following uptake. Retinyl esters were also the predominant form in the liver. The retinyl esters of the liver and YSM displayed different fatty acid profiles. At hatching, the brain contained relatively little vitamin E (4.7 microg/g) compared to the much higher concentration in the liver (482.9 microg/g) at this stage. Ascorbic acid was not detected in the yolk but was present at a high concentration in the brain at day 27 (404.6 microg/g), decreasing to less than half this value by the time of hatching. This report is the first to delineate the yolk-to-embryo transfer of lipid-soluble vitamins for a free-living avian species. The yolk fatty acids of the king penguin provide an extreme example of potential oxidative susceptibility, forming a basis for comparative studies on embryonic antioxidant requirements among species of birds whose yolk lipids differ in their degree of unsaturation.

Captivity diets alter egg yolk lipids of a bird of prey (the American kestrel) and of a galliforme (the red-legged partridge).

The salient feature of the fatty acid profile of kestrel eggs collected in the wild was the very high proportion of arachidonic acid (15.2%+/-0.7% of fatty acid mass, n=5) in the phospholipid fraction of the yolk. Kestrels in captivity fed on day-old chickens produced eggs that differed from those of the wild birds in a number of compositional features: the proportion of linoleic acid was increased in all the lipid fractions; the proportion of arachidonic acid was increased in yolk phospholipid and cholesteryl ester; the proportion of alpha-linolenic acid was decreased in all lipid classes, and that of docosahexaenoic acid was decreased in phospholipid and cholesteryl ester. Partridge eggs from the wild contained linoleic acid as the main polyunsaturate of all the yolk lipid fractions. Captive partridges maintained on a formulated diet very rich in linoleic acid produced eggs with increased levels of linoleic, arachidonic, and n-6 docosapentaenoic acids in the phospholipid fraction; reduced proportions of alpha-linolenic acid were observed in all lipid classes, and the proportion of docosahexaenoic acid was markedly reduced in the phospholipid fraction. Thus, captive breeding of both the kestrel and the partridge increases the n-6/n-3 polyunsaturate ratio of the yolk lipids.

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.

Phospholipid fatty acid composition, vitamin E content and susceptibility to lipid peroxidation of duck spermatozoa.

Recent studies on chicken semen have suggested that the lipid and fatty acid composition of spermatozoa may be important determinants of fertility. Phospholipid fatty acid composition, vitamin E content and in vitro susceptibility to lipid peroxidation of duck spermatozoa were investigated using GC-MS and HPLC based methods. The total phospholipid fraction of duck spermatozoa was characterized by high proportions of the n-6 polyunsaturated fatty acids arachidonic (20:4n-6), docosatetraenoic (22:4n-6) and docosapentaenoic (22:5n-6) acids but a substantial proportion of the n-3 fatty acid docosahexaenoic (22:6n-3) acid was also present. Palmitic (16:0) and stearic (18:0) fatty acids were the major saturates in sperm phospholipids. Among the phospholipid classes, phosphatidylserine (PS) had the highest degree of unsaturation due to very high proportions of 22:6n-3, 22:5n-6, 22:4n-6 and 20:4n-6, comprising together more than 75% of total fatty acids in this fraction. Phosphatidylethanolamine (PE) also contained high proportions of these four C(20-22) polyunsaturates, which together formed 60% of total fatty acids in this phospholipid. Spermatozoa and seminal plasma of duck semen were characterized by unexpectedly low content of vitamin E, being more than 4-fold lower than in chicken semen. In duck semen the major proportion of the vitamin E (>70%) was located in the spermatozoa. The very high proportion of 22:6n-3 in PS and PE fractions of duck sperm lipids and the comparatively low levels of vitamin E could predispose semen to lipid peroxidation. Nevertheless the in vitro susceptibilities to Fe2+-stimulated lipid peroxidation of duck and chicken spermatozoa were very similar. The results of the study suggest that increased superoxide dismutase and glutathione peroxidase activity and increased antioxidant activity of seminal plasma may compensate for the low levels of vitamin E to help protect the membranes of duck spermatozoa, which exhibit a high degree of unsaturation from oxidative stress.

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. Alpha-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 alpha-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.

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.

Tissue-specific fatty acid and alpha-tocopherol profiles in male chickens depending on dietary tuna oil and vitamin E provision.

The beneficial health-promoting effects of the long-chain polyunsaturated fatty acids (PUFA) of the n-3 series make them important constituents of human and animal diets. The effects of tuna oil or a combination of tuna oil with an increased level of vitamin E on the fatty acid profile and vitamin E distribution in tissues taken from cockerels were studied. Male chickens (Ross broiler breeders), penned on white wood shavings, were allocated into one of three groups with 12 birds per group and were fed from 10 wk of age on a commercial diet supplemented with 3% corn oil (control) or with 3% Tuna orbital oil (TO). Vitamin E was added at the rate of 40 mg/ kg, except in the third group in which the birds received a diet containing TO (3%) supplemented with 160 mg/kg vitamin E (TO+E). At 72 wk of age, the cockerels were killed, and tissues (liver, testes, heart, lung, kidney, spleen, thigh muscle, pancreas, internal fat, cerebellum, and cerebrum) were dissected for lipid and vitamin E analyses. Inclusion of TO in the cockerel diets significantly (P < 0.01) increased docosahexanoic acid (DHA) proportions in the major lipid fractions of the tissues with the brain being more resistant to lipid manipulation compared with the other tissues. Tissue enrichment with DHA took place at the expense of a decrease of n-6 PUFA. In the DHA-enriched tissues, vitamin E level decreased (P < 0.05), and susceptibility to peroxidation (TBARS accumulation) significantly (P < 0.01) increased. High vitamin E supplementation (160 mg/kg) in combination with TO prevented decrease of alpha-tocopherol concentration in the tissues and normalized or even increased their resistance to lipid peroxidation. There was tissue-specificity in response to dietary vitamin E supplementation; the liver was most responsive and the cerebellum was most resistant to vitamin E manipulation.