Development of antioxidant capacity in tissues of the chick embryo

Influence of in-ovo vitamin E and ascorbic acid injections on chick development, hatching performance and antioxidant content in different tissues of newly-hatched quail chicks

This study determined the influence of in ovo (IO) vitamin E and ascorbic acid injections on hatching performance, chick development, and antioxidant content of different tissues in day-old quail chicks. The experiment compared a control group (C: non-injection group) and injection groups, which had the yolk sac injected with 3.75 mg α- tocopherol (T1), or had the amniotic sac injected with 0.9% saline solution (T2), 2.5 mg ascorbic acid containing 0.9% saline solution (T3), and 2.5 mg ascorbic acid solution (T4), respectively.Mean relative asymmetry (RA) of bilateral lengths increased in the T2, T3 and T4 groups, whereas it decreased in the T1 group compared to C. The highest total carotene content in the residual yolk sac (RYS) was seen for the T1 group, which was significantly higher compared to T2, T3, and T4 groups. The highest total carotene concentration in liver was in the T1 group.The concentrations of delta-tocopherol, gamma-tocopherol and total vitamin E in RYS tissue were significantly higher in the T1 group than T2, T3, and T4 groups. Alpha-tocopherol and total vitamin E levels in the liver were significantly higher in the T2 and T4 groups than C.In ovo injections of vitamin E and ascorbic acid to different embryonic sacs caused antioxidant-specific effects on developmental stability of bilateral traits, RYS absorption, concentrations of total carotene and derivatives of vitamin E in newly-hatched quail chicks.

Proteomic analysis of liver tissues in chicken embryo at Day 16 and Day 20 reveals antioxidant mechanisms

To investigate the mechanisms of the defense system and antioxidant defense system during chicken embryo development, protein profiling of liver tissues in chicken embryo at Day 16 and Day 20 was conducted. TMT was used to analyze the liver tissues proteomes with significantly different activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in chicken embryo. PRM was operated to validate the target differentially abundant proteins (DAPs) using the same samples. The result showed a total of 34 DAPs were identified. Among these, 9 were upregulated and 25 were downregulated. The screened DAPs strictly related to regulation of oxidoreductase activity (DDO and GAS2L1), response to stress (ERAD2 and SAA), immune system process (GAL3 and PDCD4), and lipid regulation and metabolism (ETNPPL, APOV1, LIPM, and APOA4). These analyses indicated that the antioxidant enzyme activity of chicken embryo is regulated through different pathways. Correlation analysis revealed a linear relationship between mRNA and protein expression and 12 genes (ORM1, C8B, KPNA2, CA4, C1S, SULT1B, ETNPPL, ERCC6L, DDO, SERPINF1, VAT1L, and APOA4) were detected to be differently expressed both at mRNA and protein levels. In consequence, these findings are an important resource that can be used in future studies of antioxidant mechanisms in chicken embryo. BIOLOGICAL SIGNIFICANCE: The genetic mechanisms of antioxidant activity are still unclear in chicken embryo. In the article, the combined transcriptomic and proteomic analysis is used to further explore potential signaling pathways and differentially abundant proteins related to antioxidant activity. These findings will facilitate a better understanding of the mechanism and these DAPs can be further investigated as candidate markers to predict the activity of antioxidant enzymes.

Effects of maternal dietary vitamin E on the egg characteristics, hatchability and offspring quality of prolonged storage eggs of broiler breeder hens

This research aims to evaluate the effects of maternal vitamin E (VE) dietary supplementation on the egg characteristics, hatchability and antioxidant status of the embryo and newly hatched chicks of prolonged storage eggs. A total of 576 75-week-old Ross 308 breeder hens were randomly allocated into three dietary VE treatments (100, 200 and 400 mg/kg) with 6 replicates of 32 hens, for a 12-week feeding trial. At week 12, a total of 710 eggs were collected over a 5-day period, and eggs per treatment were attributed into 5 replicates and stored for 14 days until incubation. The egg yolk, trunk and head of 7-day-old embryo and the serum, liver, brain and yolk sac of newly hatched chicks were sampled for the evaluation of antioxidant status. Results showed that as maternal dietary VE levels increased, yolk α-tocopherol concentration increased (p < .05). Compared with 100 mg/kg VE, the use of 200 and 400 mg/kg VE increased the hatchability of set/fertile eggs and total antioxidant capacity (T-AOC) of liver and serum in chicks (p < .05), and decreased both the early embryonic mortality and the malondialdehyde (MDA) content of trunk and head in 7-day-old embryos (p < .05); moreover, 400 mg/kg VE increased the yolk T-AOC (p < .05) and decreased yolk and brain MDA content of chicks (p < .05). Brain T-AOC of chicks in 200 mg/kg VE group was improved compared to that of chicks in 100 mg/kg VE group (p < .05). In conclusion, maternal dietary VE at 200 or 400 mg/kg could increase hatchability by decreasing early embryonic mortality and increasing the antioxidant status of egg yolk, embryo and newly hatched chicks as breeder egg storage was prolonged to 14-18 days. The suitable VE level for the broiler breeder diet was 200 mg/kg as breeder egg storage was prolonged.

Effects of egg weight and in ovo injection of <i>α</i>-tocopherol on chick development, hatching performance, and lipid-soluble antioxidant concentrations in quail chick tissues

Abstract. Lipid-soluble antioxidants can be more effective for chick development when provided via in ovo (IO) injection than when supplemented to the maternal diet. This study was conducted to evaluate the effects of egg weight (EW) and IO injection of α-tocopherol on chick development, hatching performance and lipid-soluble antioxidant concentrations in residual yolk sac (RYS), liver and brain tissues of quail chicks. Eggs were obtained from quail breeders at days 72 and 128 of age and incubated at 37.8 ∘C and 60 % relative humidity. Each egg was numbered and weighed prior to incubation, and the average EW of all eggs was 11.76 ± 0.05 g. The eggs were divided into light (< 11.76 EW; EWL) and heavy (> 11.76 EW; EWH) groups (148 eggs per EW). Each EW group was divided into two IO groups: the control (non-injection) group and α-tocopherol group, in which 3.75 mg of α-tocopherol per egg was injected into the yolk sac followed by a 120 h incubation period. There were 64 eggs for each EW–IO treatment combination (16 eggs per EW per tray). The chick and RYS weights were significantly lower in the EWL group than in the EWH group. A significant EW by IO interaction suggested that IO increased the eggshell temperature of light quail eggs. The non-injected light eggs had a shorter hatching time due to the interaction of EW with IO. Hatchability, embryonic mortalities, and the cumulative hatching rate were not affected by EW or IO. The chick and middle toe lengths increased following IO administration (P < 0.05), which indicated that IO administration had positive effects on chick quality. However, shank length decreased following IO administration with an unchanged relative asymmetry (RA). IO significantly affected the absolute weights of the liver and heart and the relative weight of the heart, which was lower in the α-tocopherol group than in the control group. IO administration had no effect on total retinol and carotenoid concentrations in the RYS, liver and brain. Vitamin E, α-tocopherol and δ-tocopherol concentrations in the RYS, liver and brain were significantly higher in the α-tocopherol-treated chicks than in the control chicks. The highest brain α-tocopherol concentration was found in the α-tocopherol-treated chicks of the EWH group, indicating a significant interaction between EW and IO. The highest total lipid-soluble antioxidant concentrations were obtained following IO α-tocopherol treatment (P < 0.05), in the order brain < liver < RYS, but this pattern was not observed with δ-tocopherol. In conclusion, IO injection of α-tocopherol into the yolk sac affected the concentrations of tissue-specific lipid-soluble antioxidants in the RYS and tissues of newly hatched quail chicks, and EW had effects on various parameters.

Investigating the Mutagenicity of a Cold Argon-Plasma Jet in an HET-MN Model

OBJECTIVE

So-called cold physical plasmas for biomedical applications generate reactive oxygen and nitrogen species and the latter can trigger DNA damage at high concentrations. Therefore, the mutagenic risks of a certified atmospheric pressure argon plasma jet (kINPen MED) and its predecessor model (kINPen 09) were assessed.

METHODS

Inner egg membranes of fertilized chicken eggs received a single treatment with either the kINPen 09 (1.5, 2.0, or 2.5 min) or the kINPen MED (3, 4, 5, or 10 min). After three days of incubation, blood smears (panoptic May-Grünwald-Giemsa stain) were performed, and 1000 erythrocytes per egg were evaluated for the presence of polychromatic and normochromic nuclear staining as well as nuclear aberrations and binucleated cells (hen's egg test for micronuclei induction, HET-MN). At the same time, the embryo mortality was documented. For each experiment, positive controls (cyclophosphamide and methotrexate) and negative controls (NaCl-solution, argon gas) were included. Additionally, the antioxidant potential of the blood plasma was assessed by ascorbic acid oxidation assay after treatment.

RESULTS

For both plasma sources, there was no evidence of genotoxicity, although at the longest plasma exposure time of 10 min the mortality of the embryos exceeded 40%. The antioxidant potential in the egg's blood plasma was not significantly reduced immediately (p = 0.32) or 1 h (p = 0.19) post exposure to cold plasma.

CONCLUSION

The longest plasma treatment time with the kINPen MED was 5-10 fold above the recommended limit for treatment of chronic wounds in clinics. We did not find mutagenic effects for any plasma treatment time using the either kINPen 09 or kINPen MED. The data provided with the current study seem to confirm the lack of a genotoxic potential suggesting that a veterinary or clinical application of these argon plasma jets does not pose mutagenic risks.

Effects of experimental calcium availability and anthropogenic metal pollution on eggshell characteristics and yolk carotenoid and vitamin levels in two passerine birds

The maternal investment into egg quality depends on the condition of the female, the quality of the mate, and the quality of the environment. In that sense, availability of nutrients and exposure to pollutants are essential parameters to consider. The main aim of this study is to assess the effects of calcium (Ca) availability and anthropogenic metal pollution on early-stage reproduction in two passerine species, great tits (Parus major) and pied flycatchers (Ficedula hypoleuca), inhabiting a Ca-poor and metal-polluted area in SW Finland. Both species were able to obtain sufficient Ca for eggshell formation, and metal pollution was below the level of having negative effects in the egg size and eggshell characteristics. However, metal polluted environment negatively affected yolk lutein and vitamin D3 levels in both species, probably because of a lower access to carotenoid-rich diet and higher metal interference with vitamin D3 metabolism. The higher levels of vitamin D3 in yolks in the unpolluted zone could also be due to upregulated D3 levels as a response to the lower natural Ca availability. Yolk carotenoids and vitamin D3 were positively associated with nestling growth and size, supporting their importance for the appropriate chick development. The interspecific differences in yolk nutrient concentrations possibly reflect the different growth rate of these species. Pied flycatchers are likely adapted to low Ca availability through an efficient vitamin D3 metabolism, but their Ca intake could be close to a deficient level.

Effect of dietary canthaxanthin and 25-hydroxycholecalciferol supplementation on the performance of duck breeders under two different vitamin regimens

BACKGROUND

Dietary canthaxanthin (CX), 25-hydroxycholecalciferol (25-OH-D 3 ) and vitamins have been widely reported to be involved in productive and reproductive performance of broiler breeders. However, limited information is available for duck breeders. In this study, a total of 1,560 Cherry Valley SM3 duck breeder females and 312 males were used to assess if the addition of CX and 25-OH-D3 could increase the performance of duck breeders under two different dietary vitamin regimens. Four diets were used under a 2 × 2 factorial arrangement with 2 kinds of vitamin premixes (REGULAR and HIGH; HIGH premix had higher levels of all vitamins except K3 than REGULAR premix), and with or without the supplementation of the mixture of CX (6 mg/kg) and 25-OH-D3 (0.069 mg/kg). The ducks were fed ad libitum with pelleted diets based on corn-soybean meal from 38 to 77 wk of age.

RESULTS

HIGH vitamin premix decreased malondialdehyde (MDA) level (P < 0.001) of egg yolk, increased hatchability of fertile eggs (P = 0.029), increased hatchability of total eggs (P = 0.029), and decreased serum protein carbonyl level (P = 0.037) of breeder males. The mixture of CX and 25-OH-D3 increased serum calcium of breeder females (P = 0.010), decreased the cracked egg rate (P = 0.001), increased the pigmentation of egg yolk (P < 0.001) and male bill (P < 0.001), and decreased MDA level of egg yolk (P < 0.001) and male serum (P = 0.034). Interactive effects were observed in cracked egg rate (P = 0.038), shell thickness (P = 0.011) and serum phosphorus (P = 0.026) of breeder females. HIGH vitamin premix together with the mixture of CX and 25-OH-D3 decreased cracked egg rate and increased shell thickness of duck breeders. Serum phosphorus was decreased in duck breeder females fed REGULAR vitamin premix without the addition of the CX and 25-OH-D3 mixture.

CONCLUSIONS

Dietary HIGH vitamin premix increased antioxidant status of eggs and breeder males, and increased hatchability. The mixture of CX and 25-OH-D3 enhanced egg shell quality, and promoted pigmentation and antioxidant status of eggs and breeder males.

The effects of maternal dietary vitamin premixes, canthaxanthin, and 25-hydroxycholecalciferol on the performance of progeny ducklings

This trial studied the effects of maternal dietary vitamin premixes, and the mixture of canthaxanthin (CX) and 25-hydroxycholecalciferol (25-OH-D3) on the performance of progeny ducklings. Four maternal diets were used under a 2 × 2 factorial arrangement with 2 kinds of vitamin premixes (Regular and High; High premix had higher levels of all vitamins except K3 than the Regular premix), and with or without the addition of the mixture of CX (6 mg/kg) and 25-OH-D3 (0.069 mg/kg). Cherry Valley duck breeders (38-wk-old) were fed with corn-wheat flour-soybean meal-based diets for 8 wk, and then eggs were collected and hatched. Healthy ducklings (equal number of female and male) from each maternal group were randomly selected and received the same commercial starter (1 to 14 d) and grower (15 to 35 d) pellet diet for 35 d. Maternal High vitamin premix increased shank pigmentation (1 d, P = 0.001), BW (1 d, P < 0.001 and 14 d, P = 0.006), BW gain (1 to 14 d, P = 0.008), G:F ratio (1 to 14 d, P = 0.007), superoxide dismutase (SOD; 1 d liver, P = 0.027 and 14 d serum, P = 0.031), and total antioxidant capacity (1 d liver, P < 0.001); and decreased protein carbonyl (14 d serum, P = 0.011) of ducklings. The mixture of CX and 25-OH-D3 increased yolk pigmentation (P < 0.001); increased shank pigmentation (1 d, P < 0.001 and 14 d, P < 0.001), BW (1 d, P < 0.001), feed intake (15-35 d, P = 0.014), SOD (1 d liver, P = 0.032), and tibia ash (14 d, P = 0.010) of ducklings; and decreased malondialdehyde (P < 0.001) and protein carbonyl (P = 0.044) of yolks, and malondialdehyde (14 d serum, P < 0.001) of ducklings. In conclusion, either maternal High vitamin premix or maternal supplementation of the CX and 25-OH-D3 mixture improves growth performance and antioxidant status of ducklings.

Antioxidant systems in chick embryo development. Part 1. Vitamin E, carotenoids and selenium

Chick viability is known to be an important factor determining profitability of the poultry industry. Chick embryo tissues contain a high proportion of highly polyunsaturated fatty acids in the lipid fraction and therefore need antioxidant defence. The antioxidant system of the developing embryo and newly hatched chick includes the antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase), water-soluble antioxidants (ascorbic acid, taurine, carnitine, glutathione, etc.), fat-soluble antioxidants (vitamin E, carotenoids, coenzyme Q) as well as selenium (Se). In fact, the high levels of endogenous antioxidants within the egg and embryonic tissues can clearly serve as a major adaptive mechanism for the protection of the tissue during the oxidative stress experienced at hatching. It has been shown that among different nutrients in the maternal diet which could significantly affect chick embryo development and their viability in the early posthatch life, natural antioxidants have been suggested to play a central role. Our data indicate that increased supplementation of the maternal diet can substantially increase concentrations of vitamin E, carotenoids (especially canthaxanthin) and Se in developing chick tissues and significantly decrease susceptibility to lipid peroxidation being effective nutritional tools to deal with various commercial stresses in poultry production.

Influence of dietary selenomethionine supplementation on performance and selenium status of broiler breeders and their subsequent progeny

The study was conducted to investigate the effects of dietary maternal selenomethionine or sodium selenite supplementation on performance and selenium status of broiler breeders and their next generation. Two hundred and forty 39-week-old Lingnan yellow broiler breeders were allocated randomly into two treatments, each of which included three replicates of 40 birds. Pretreatment period was 2 weeks, and the experiment lasted 8 weeks. The groups were fed the same basal diet supplemented with 0.30 mg selenium/kg of sodium selenite or selenomethionine. After incubation, 180 chicks from the same parental treatment group were randomly divided into three replicates, with 60 birds per replicate. All the offspring were fed the same diet containing 0.04 mg selenium/kg, and the experiment also lasted 8 weeks. Birth rate was greater (p < 0.05) in hens fed with selenomethionine than that in hens fed with sodium selenite. The selenium concentration in serum, liver, kidney, and breast muscle of broiler breeders, selenium deposition in the yolk, and albumen and tissues' (liver, kidney, breast muscle) selenium concentrations of 1-day-old chicks were significantly (p < 0.01) increased by maternal selenomethionine supplementation compared with maternal sodium selenite supplementation. The antioxidant status of 1-day-old chicks was greatly improved by maternal selenomethionine intake in comparison with maternal sodium selenite intake and was evidenced by the increased glutathione peroxidase activity in breast muscle (p < 0.05), superoxide dismutase activity in breast muscle and kidney (p < 0.05), glutathione concentration in kidney (p < 0.01), total antioxidant capability in breast muscle and liver (p < 0.05), and decreased malondialdehyde concentration in liver and pancreas (p < 0.05) of 1-day-old chicks. Feed utilization was better (p < 0.05), and mortality was lower (p < 0.05) in the progeny from hens fed with selenomethionine throughout the 8-week growing period compared with those from hens fed with sodium selenite. In summary, we concluded that maternal selenomethionine supplementation increased birth rate and Se deposition in serum and tissues of broiler breeders as well as in egg yolk and egg albumen more than maternal sodium selenite supplementation. Furthermore, maternal selenomethionine intake was also superior to maternal sodium selenite intake in improving the tissues Se deposition and antioxidant status of 1-day-old chicks and increasing the performance of the progeny during 8 weeks of post-hatch life.

Methionine and selenium yeast supplementation of the maternal diets affects antioxidant activity of breeding eggs

Four hundred fifty 52-wk-old Langshan layer hens (dual-purpose type, an indigenous poultry breed of China) were randomly divided into 9 treatments with 5 replicates in each treatment. Birds were fed corn-soybean diets (0.13 mg of Se/kg) supplemented with 0, 0.30, and 0.60 mg/kg of Se from Se yeast and 3.2, 4.0, and 5.4 g of dl-Met/kg, respectively. Increasing Se yeast supplementation significantly increased Se concentration in the egg yolk (P < 0.01) and the Se concentration of the 3.2 g of Met/kg treatment was higher than those of the 4.0 and 5.4 g of Met/kg treatments. Adding 0.3 mg of Se/kg to the diet significantly increased glutathione peroxidase (GSH-Px) activity in the egg yolk compared with 0 and 0.6 mg of Se/kg (P < 0.01) and increasing Se yeast supplementation significantly increased the GSH-Px activity in the egg albumen (P < 0.01). Increasing Met supplementation significantly decreased the GSH-Px activity in both the yolk and the albumen of the eggs (P < 0.01). Methionine supplemented at 3.2 and 4.0 g/kg significantly increased glutathione concentration in the egg yolk compared with 5.4 g of Met/kg (P < 0.01) and increasing Met supplementation increased the glutathione concentration in the egg albumen. Increasing Met supplementation significantly decreased malondialdehyde concentration in the egg yolk (P < 0.01) and Se supplemented at 0 and 0.6 mg/kg increased the malondialdehyde concentrations in the egg yolk compared with 0.3 mg of Se/kg (P < 0.01). Methionine supplemented at 4.0 and 5.4 g/kg significantly decreased carbonyl concentration compared with 3.2 g of Met/kg. The conclusion was drawn that Se yeast and Met supplementation of the maternal diets could enhance antioxidant activity of breeding eggs.

Detrimental effects of carotenoid pigments: the dark side of bright coloration

Carotenoid pigments produce yellow, orange, and red integumentary color displays that can serve as reliable signals of health and condition. In many birds and fish, individuals gain competitive or mating advantages by ingesting and utilizing large quantities of carotenoid pigments. Carotenoid pigments serve as antioxidants, performing important functions as free-radical scavengers. The beneficial effects of carotenoid pigments are well documented, but rarely have researchers considered potential detrimental effects of high-level accumulation of carotenoids. We maintained American goldfinches (Carduelis tristis) on high- or low-carotenoid diets through molt and tested for damage to the liver and skeletal muscle. High intake of carotenoids had no measurable effect on liver enzymes but caused an increase in creatine kinase, an indicator of skeletal muscle breakdown, and a reduction in vertical flight performance, a measure of skeletal muscle integrity. The detrimental effects of high-level carotenoid accumulation were approximately equivalent to the negative effects of removing carotenoids from the diet. The adverse effects observed in this study have important implications for theories of the function and evolution of colorful plumage.

Effect of higher dietary vitamin E concentrations on physical and biochemical characteristics of semen in Kadaknath cockerels

1. This experiment was to investigate the effects of increasing dietary vitamin E on physical and biochemical characteristics of semen in Indian reared Kadaknath (KN) cockerels. DL-alpha-Tocopherol acetate was used as the source of vitamin E. 2. A total of 135 one-day-old male KN chicks were randomly selected and divided into 9 groups with 15 chicks in each group (3 dietary treatments x 3 replicates). 3. The basal diet contained 15 IU (10 mg) vitamin E/kg and the two experimental diets were supplemented with 150 IU (100 mg) and 300 IU (200 mg) vitamin E/kg (diets T(2) and T(3), respectively). 4. Physical characteristics in terms of semen volume, sperm concentration, sperm motility and percentage live sperm did not differ significantly, whereas proportion of abnormal and dead spermatozoa were significantly lower and fertility higher in the T(2) group. 5. Biochemical characteristics in term of quantities of protein and nitric oxide (NO) did not differ significantly, whereas the quantity of glucose, acid phosphatase (ACP) and vitamin E were significantly higher in the T(2) group. 6. In contrast, the quantities of alkaline phosphatase (ALP), glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) were significantly lower in T(2) group and higher in the T(1) (control) group. 7. From this study it can be concluded that moderate supplementation of dietary vitamin E may be beneficial for physical and biochemical characteristics of semen in Indian reared KN cock.

Yolk Antioxidants Vary with Male Attractiveness and Female Condition in the House Finch (Carpodacus mexicanus)

The manipulation of egg content is one of the few ways by which female birds can alter offspring quality before hatch. Lipid-soluble vitamins and carotenoids are potent antioxidants. Female birds deposit these antioxidants into eggs in variable amounts according to environmental and social conditions, and the quantities deposited into eggs can have effects on offspring health and immunological condition. Allocation theory posits that females will alter the distribution of resources according to mate quality, sometimes allocating resources according to the differential allocation hypothesis (DAH), investing more in offspring sired by better-quality males, and other times allocating resources according to a compensatory strategy, enhancing the quality of offspring sired by lower-quality males. It is unknown, however, whether antioxidants are deposited into eggs according to the DAH or a compensatory strategy. We examined deposition patterns of yolk antioxidants (including vitamin E and three carotenoids) in relation to laying order, mate attractiveness, female condition, and yolk androgen content in the house finch (Carpodacus mexicanus). Female house finches deposited significantly more total antioxidants into eggs sired by less attractive males. Additionally, yolk antioxidant content was significantly positively correlated with female condition, which suggests a cost associated with the deposition of antioxidants into eggs. Finally, concentrations of antioxidants in egg yolks were positively correlated with total yolk androgen content. We suggest that yolk antioxidants are deposited according to a compensatory deposition strategy, enabling females to improve the quality of young produced with less attractive males. Additionally, yolk antioxidants may act to counter some of the detrimental effects associated with high levels of yolk androgens in eggs and, thus, may exert a complementary effect to yolk androgens.

Selenium distribution in eggs of avian species

We studied the effect of egg mass of eight different avian species on Se distribution between egg components and the effect of incubation on Se accumulation by chicken eggshell and shell membrane. Eight groups of birds received a diet without Se supplementation. Unfertile eggs were collected after 35 days of feeding; yolk, albumen, shell and shell membrane were assayed separately for Se. All avian species studied showed identical Se concentration in yolk-albumen complex equal to 38.7 microg Se/100 g, reflecting a linear correlation between yolk-albumen mass and Se content. Shells and shell membrane Se accumulation showed quadratic correlation with the appropriate mass thus explaining unusually high Se concentration in ostrich shell and shell membrane, that reached values 1785 and 1904 microg Se/kg respectively. Incubation of fertile eggs decreased eggshell Se content, the effect being more expressed in eggs from hens fed sodium selenite compared to organic Se utilization (Sel-Plex). It was concluded that shell might be an additional Se source for an embryo.

Cadmium induces reactive oxygen species generation and lipid peroxidation in cortical neurons in culture

Cadmium is a toxic agent that it is also an environmental contaminant. Cadmium exposure may be implicated in some humans disorders related to hyperactivity and increased aggressiveness. This study presents data indicating that cadmium induces cellular death in cortical neurons in culture. This death could be mediated by an apoptotic and a necrotic mechanism. The apoptotic death may be mediated by oxidative stress with reactive oxygen species (ROS) formation which could be induced by mitochondrial membrane dysfunction since this cation produces: (a) depletion of mitochondrial membrane potential and (b) diminution of ATP levels with ATP release. Necrotic death could be mediated by lipid peroxidation induced by cadmium through an indirect mechanism (ROS formation). On the other hand, 40% of the cells survive cadmium action. This survival seems to be mediated by the ability of these cells to activate antioxidant defense systems, since cadmium reduced the intracellular glutathione levels and induced catalase and SOD activation in these cells.

Free radicals, lipid peroxidation and the antioxidant system in the blood of cows and newborn calves around calving

The oxidative stress of birth in cattle (Bos taurus) was evaluated by measuring steady state concentration of free radicals in whole blood, rate of lipid peroxidation and activity of antioxidant enzymes in erythrocytes, antioxidant capacity of blood plasma in 14 calves at birth and four times after birth until 3 weeks of age and also in their mothers at calving. The same parameters were also measured in 58 dairy cows before calving, at parturition and after calving. Free radical concentration in the blood of newborn calves was higher than in cows confirming that birth means oxidative stress for calves. Red blood cell malondialdehyde in calves was the highest at birth and following the first solid feed intake at the third week. Superoxide dismutase activity increased in calves during the first three weeks of life. Ferric reducing ability of plasma was higher in calves at birth than in cows and decreased thereafter. Higher superoxide dismutase activity in red blood cells and lower ferric reducing ability of plasma in dairy cows was found at calving compared to the average of all pre- and post-calving results. We conclude that the blood of newborn calves is well prepared to deal with the oxidative stress of birth, and that such a stress is present even when some fingerprint markers of redox imbalance show no apparent alterations. Stress of calving has minor effects on the antioxidant system of cows.

Interspecies variation in yolk selenium concentrations among eggs of free-living birds: The effect of phylogeny

Birds deposit the trace element selenium (Se) into their eggs because an adequate supply of this micronutrient is essential for embryonic development. Although there is considerable interest in egg Se with regard to topics as diverse as poultry nutrition and environmental pollution, data on the natural levels of Se in eggs of free-living avian species are currently very limited. To address this lack of information, we measured the yolk Se concentrations in eggs of 14 avian species collected in the wild. The concentrations (ng/g wet yolk) varied from 394 to 2238, with a mean value of 1040. Values (means+/-SD) for eggs from the UK, Canada and New Zealand were, respectively, 522+/-192 (3 species), 1194+/-584 (8 species) and 1147+/-200 (3 species). However, analysis by appropriate statistical models indicates that the effect of phylogenetic relatedness among these species is so significant that it removes any effect of geographical location. In particular, species belonging to the order Passeriformes displayed significantly higher yolk Se levels than Non-Passeriforme species. In marked contrast to the free-living species, our previously published data indicate that the Se concentration in egg yolk of the domestic chicken is only about 100 ng/g wet yolk when the birds are maintained on a basal commercial diet without supplementary Se. The results reveal an extensive interspecies variation in yolk Se (across a 6-fold range) for eggs collected from the wild. Nevertheless, the Se concentrations in the yolks of all the free-living species were far higher (4-21-fold) than that achieved in the yolk of the domestic chicken consuming a standard basal diet.

Antioxidants in the egg yolk of a wild passerine: differences between breeding seasons

Carotenoids and fat-soluble vitamins play crucial roles in several physiological processes. Yolk carotenoid composition may be influenced by the bird's dietary intake and by the possible discrimination during carotenoid metabolism. Information regarding the pigment composition of passerine eggs is very limited. In the present 2-year study, we determined the carotenoid and vitamin concentrations and the percentage profile of carotenoid components in collared flycatcher (Ficedula albicollis) eggs. The major carotenoid was lutein in both years, followed by cis-lutein, zeaxanthin and beta-carotene as other significant components. Carotenoid concentration was higher in 2000 than in 2001. As caterpillar abundance and ambient temperature was lower in 2001 than in 2000, we suggest that the decreased availability of carotenoid-rich resources and the elevated antioxidant demand of the female restricted the carotenoid allocation to the eggs. Our study is the first to indicate that the concentration and profile of yolk carotenoids may considerably vary in the same wild bird population between breeding seasons with different environmental conditions. Compared to other birds, the yolk of this species was relatively rich in vitamins A and E. Vitamin E concentration was positively correlated with total carotenoid concentration, which may be beneficial for the nestlings as these antioxidants synergistically provide better protection.

The selenium intake of the female chicken influences the selenium status of her progeny

The primary purpose of this study is to determine the extent to which the effects of dietary supplementation of the female chicken with selenium (Se) continue into the next generation. An additional aim is to compare the relative effectiveness of pre-hatch (from the hen's diet) with that of post-hatch (from the progeny's diet) supplementation with Se on the Se status of the chick during the first 4 weeks of post-hatch life. Hens were maintained on control or Se-supplemented diets, respectively containing 0.027 and 0.419 mug Se/g of feed. The high-Se diet elevated the Se content of the hens' eggs by 7.1-fold. At hatch, the concentrations of Se in the liver, breast muscle and whole blood of the chicks originating from the high-Se parents were, respectively, 5.4-, 4.3- and 7.7-fold higher than the values in the chicks of the low-Se parents. When the offspring from the two parental groups were both maintained on the low-Se progeny diet, the tissue Se concentrations in chicks originating from the high-Se hens remained significantly higher for 3-4 weeks after hatching, compared with the values in chicks from the low-Se hens. Similarly, tissue glutathione peroxidase activity remained significantly higher in chicks from the high-Se hens for 2-4 weeks post-hatch. Thus, the effects of maternal Se supplementation persist in the progeny for several weeks after hatching. However, when chicks hatching from low-Se eggs were placed on a high Se diet, their tissue Se concentrations at 7 days of age were markedly higher than the values in chicks from high-Se eggs placed on the low-Se diet.

Kinetic studies on the glutathione peroxidase activity of selenium-containing glutathione transferase

Selenium-containing glutathione transferase (seleno-GST) was generated by biologically incorporating selenocysteine into the active site of glutathione transferase (GST) from a blowfly Lucilia cuprina (Diptera: Calliphoridae). Seleno-GST mimicked the antioxidant enzyme glutathione peroxidase (GPx) and catalyzed the reduction of structurally different hydroperoxides by glutathione. Kinetic investigations reveal a ping-pong kinetic mechanism in analogy with that of the natural GPx cycle as opposed to the sequential one of the wild type GST. This difference of the mechanisms might result from the intrinsic chemical properties of the incorporated residue selenocysteine, and the selenium-dependent mechanism is suggested to contribute to enhancement of the enzymatic efficiency.

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.

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.

Thiols prevent H2O2-mediated loss of sperm motility in cryopreserved bull semen

We previously showed that cryopreservation of bull spermatozoa in egg yolk Tris extender (EYTG) significantly reduced the intracellular level of thiols. Other studies showed the beneficial effects of adding antioxidants to cryopreserved bull spermatozoa. These studies led us to investigate the effects of various thiols, an important class of antioxidants, on sperm motility of cryopreserved bull semen in a commonly used extender, EYTG. Sperm motility was analyzed by computer-assisted semen analysis (CASA). After thawing, a diluted pool of bull semen was incubated at 38.5 degrees C in airtight tubes with the following thiols for 6 hours: glutathione (GSH/GSSG), cysteine, N-acetyl-L-cysteine (NAC) and 2-mercaptoethanol in the presence or absence of oxidative stress. The oxidative stress was caused by adding H2O2 (100 microM) to diluted semen. Incubation of diluted bull semen in EYTG at 38.5 degrees C over a period of 6 h decreased sperm motility by approximately 9 fold from the start (72 +/- 3, mean +/- SEM, n=4) to the end (9 +/- 4, n=4) of the incubation. We found that all thiols to a concentration above 0.5 mM maintained high sperm motility for 6 h in the absence of an external source of oxidative stress (52 +/- 4, for 4 thiols). However, one mM of each thiol was required to efficiently protect sperm motility in the presence of 100 microM of H2O2 for 6 h. We also found that the GSH concentration in diluted semen was too low (microM) to adequately supply exogenous addition of 72 U/mL of glutathione peroxidase (GPx), an enzyme that detoxifies H2O2 and hydroperoxides using GSH as a cofactor. In fact, a better protection of sperm motility could be achieved with only 5 U/mL of GPx and 0.1 mM of GSH added to diluted semen. Our results also demonstrated that added GSSG (0.5 mM) in diluted semen was not regenerated efficiently to GSH over 6 h. The latter result indicated in the extender that the glutathione redox-cycle was deficient. Therefore, deleterious effects sperm motility after cryopreservation in EYTG can be counteracted by adding various thiols at mM concentration.

Lipid composition, fatty acid profiles, and lipid-soluble antioxidants of eggs of the Hermann's tortoise (Testudo hermanni boettgeri)

The major lipid classes, their fatty acid profiles, and the amounts of the lipid-soluble components, vitamin E, vitamin A, and carotenoids, were determined for egg yolks of the Hermann's tortoise (Testudo hermanni boettgeri) with the aim of identifying any features that may potentially impair the adaptation of this endangered species to deteriorations in habitat. Total lipid formed 16% (wt/wt) of the fresh yolk and consisted of (wt/wt) 74.4% triacylglycerol, 18.1% phospholipid, 3.0% cholesteryl ester, and 3.4% free cholesterol. Despite a diet based on green plants, contributing alpha-linolenic acid as the main polyunsaturate, this fatty acid formed only 3.8% of the total mass of fatty acid of the total lipid. The main acyl component of the yolk lipids was the monounsaturated fatty acid, oleic acid, which formed 45.6% of the total. The most striking feature of the yolk composition was the almost complete lack of two nutrients, docosahexaenoic acid and vitamin A, which are essential for the developing embryo. Although it is feasible that the embryo synthesizes docosahexaenoic acid from yolk-derived alpha-linolenic acid and also converts yolk-derived beta-carotene to vitamin A, the yolk is poorly endowed with both these precursors. The stringencies displayed by the yolk composition in this species may limit the flexibility to adapt to changes in the availability of food items when the habitat is threatened. Zoo Biol 20:75-87, 2001. Copyright 2001 Wiley-Liss, Inc.

Role of oxidative stress and antioxidant defense in 3,3',4,4',5-pentachlorobiphenyl-induced toxicity and species-differential sensitivity in chicken and duck embryos

The role of oxidative stress and antioxidant defense in 3,3',4,4',5-pentachlorobiphenyl (PCB 126)-induced toxicity and species-specific sensitivity was examined in White Leghorn chicken (Gallus domesticus) and Pekin duck (Anas platyrhynchos) embryos. Eggs were injected into the air cell with 0.4-1.6 microgram PCB 126/kg egg in corn oil prior to incubation. Lipid peroxidation measured by thiobarbituric acid reactive substances (TBARS), the GSSG:GSH ratio, and glutathione peroxidase (GPox) activities were determined in liver and adipose tissue of day 19 chicken and day 26 duck embryos. In chicken embryos, PCB 126 increased mortality and the incidence of edema and liver lesions, decreased embryo size, increased eye and head malformations, and markedly reduced fat storage. In contrast, no effects on the endpoints were observed in duck embryos even at the highest dose used in chicken embryos. PCB 126 increased hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity in a dose-dependent manner in chicken but not duck embryos. PCB 126 significantly increased TBARS levels in liver and to a greater degree in adipose tissue of chicken embryos, indicating that adipose tissue is a sensitive target for this compound. Increases in lipid peroxidation by PCB 126 were associated with significant decreases in GPox activity in these tissues. These biochemical changes support oxidative stress playing a role in PCB 126-induced embryo toxicity while antioxidant defenses provided protection against oxidative damage induced by this compound. Ducks, the less-sensitive species, showed higher basal levels of hepatic GPox than chickens, suggesting that this antioxidant enzyme may contribute to the differences in sensitivity to this compound between the two species.

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.

Tissue-specific changes in the activities of antioxidant enzymes during the development of the chicken embryo

1. Tissue-specific profiles of the expression of the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) and the concentrations of reduced glutathione (GSH) during the development of the chick embryo were investigated. 2. The liver, brain, yolk sac membrane (YSM), kidney, lung, heart and skeletal muscles were collected at the following days of embryo development: 10, 11, 13, 15, 17, 19, 21 and 22 (day-old chicks). 3. The different tissues of the embryo displayed distinct development strategies with regard to the acquisition of antioxidant capacity. In the liver the specific activity of SOD increased between days 10 and 11 of development, then significantly decreased up to day 15 and remained at the same value during the rest of the developmental period. GSH-Px specific activity increased through the time of development. CAT had 2 peaks of specific activity at day 10 of the development and in day-old chicks. 4. The brain was characterised by comparatively high SOD-specific activity especially during the last days of incubation. The specific activities of GSH-Px and CAT were low throughout development. 5. In the YSM maximal GSH-Px and CAT-specific activities were found on day 15 of incubation. In the kidney and heart GSH-Px-specific activity increased at hatching time. CAT-specific activity in the kidney increased just after hatching. 6. It is concluded that each tissue studied expressed a profile of antioxidant defence mechanisms to deal with oxidative stress at hatching time.

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.

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.

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.

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.