Filiz Karadas

Effect of organic selenium in quail diet on its accumulation in tissues and transfer to the progeny

1. The aim of the present study was to investigate the effects on the eggs and hatchlings (up to 2 weeks post-hatch) of feeding a relatively large amount of so-called organic selenium to breeder quail. 2. Two groups of quail (3 families in each group consisting of 4 females and 1 male) were formed at the beginning of their reproductive period. The quail were fed on a commercial maize-based diet containing 0·096 mg/kg feed-derived selenium (Se), supplemented with 0·2 mg/kg selenite (control group) or 0·5 mg/kg organic selenium in the form of Sel-Plex™ (Alltech Ltd, USA) for 6 months. Eggs were collected at 6 months of age and Se in the egg yolk, egg white and shell was analysed. Five quail at 1, 7 and 14 d post-hatch were killed to provide samples of liver, brain, breast and leg muscles for Se analysis. After egg collection for analysis and incubation, adult quail were killed and liver, kidney, lung, brain, breast and leg muscles were collected for Se analyses. 3. Inclusion of high doses (0·5 mg/kg) of organic Se in the quail diet was associated with a significant increase in Se concentration in all tissues studied of adult quail as well as in egg yolk, egg albumin and eggshell. 4. Increased Se concentration in the quail egg was associated with increased Se concentration in the liver, breast and leg muscles and brain of newly hatched quail. This difference was shown to be significant for 2 weeks post-hatch. Therefore, it has been suggested that the maternal effect of dietary selenium can be seen beyond the hatching time and more emphasis should be given to this effect in future. 5. It was shown that it is possible to produce Se-enriched quail meat and eggs by adding organic selenium to the diet.

Maternal effects mediated by egg quality in the Yellow-legged Gull Larus michahellis in relation to laying order and embryo sex

BackgroundMaternal effects mediated by egg size and quality may profoundly affect offspring development and performance, and mothers may adjust egg traits according to environmental or social influences. In avian species, context-dependency of maternal effects may result in variation in egg composition, as well as in differential patterns of covariation among selected egg components, according to, for example, position in the laying sequence or offspring sex. We investigated variation in major classes of egg yolk components (carotenoids, vitamins and steroid hormones) in relation to egg size, position in the laying sequence and embryo sex in clutches of the Yellow-legged Gull (Larus michahellis). We also investigated their covariation, to highlight mutual adjustments, maternal constraints or trade-offs in egg allocation.ResultsLaying sequence-specific patterns of allocation emerged: concentration of carotenoids and vitamin E decreased, while concentrations of androgens increased. Vitamin A, estradiol and corticosterone did not show any change. There was no evidence of sex-specific allocation or covariation of yolk components. Concentrations of carotenoids and vitamins were positively correlated. Egg mass decreased along the laying sequence, and this decrease was negatively correlated with the mean concentrations of carotenoids in clutches, suggesting that nutritionally constrained females lay low quality clutches in terms of carotenoid content. Finally, clutches with smaller decline in antioxidants between first- and last-laid eggs had a larger increase in yolk corticosterone, suggesting that a smaller antioxidant depletion along the laying sequence may entail a cost for laying females in terms of increased stress levels.ConclusionsSince some of the analyzed yolk components (e.g. testosterone and lutein) are known to exert sex-specific phenotypic effects on the progeny in this species, the lack of sex-specific egg allocation by mothers may either result from trade-offs between contrasting effects of different egg components on male and female offspring, or indicate that sex-specific traits are controlled primarily by mechanisms of sexual differentiation, including endogenous hormone production or metabolism of exogenous antioxidants, during embryonic development.

Maternal Effects Mediated by Antioxidants and the Evolution of Carotenoid‐Based Signals in Birds

Bright yellow to red signals used in mate choice or intrasexual competition are based on carotenoid pigments that are hypothesized to be traded between physiological functions and coloration. These signals have recently been shown to be influenced by maternal effects. Indeed, yolk‐derived carotenoids are essential for embryos to develop efficient carotenoid metabolism in posthatching life. Maternal effects facilitate adaptation to environmental variability and influence the evolution of phenotypic traits such as secondary sexual signals. Here we propose that maternal investment in yolk carotenoids promotes the evolution of carotenoid‐based ornaments. We conducted a comparative analysis of lipid‐soluble antioxidants (carotenoids and vitamins A and E) in the eggs of 112 species of bird. Species with large clutch sizes deposited higher yolk concentrations of the three antioxidants. There was a significant positive relationship between yolk carotenoids and the expression of male carotenoid‐based signals, but not between yolk carotenoids and sexual dichromatism in these signals. These relationships were specific to carotenoids, as they were not found for vitamins A and E. This provides evidence consistent with the hypothesis that maternal effects mediated by yolk carotenoids play a role in the evolution of carotenoid‐based signals as a response to sexual selection, likely based on organizational effects of carotenoids during embryo development.

Maternally invested carotenoids compensate costly ectoparasitism in the hihi

Dietary ingested carotenoid biomolecules have been linked to both improved health and immunity in nestling birds. Here, we test whether maternally invested egg carotenoids can offset the cost of parasitism in developing nestling hihi (Notiomystis cincta) from the bloodsucking mite (Ornithonyssus bursa). Our results reveal clear negative effects of parasitism on nestlings, and that maternally derived carotenoids compensate this cost, resulting in growth parameters and ultimate mass achieved being similar to nonparasitized young. Our results offer an unique example of a direct positive relationship between enhanced maternal investment of carotenoids and an ability to cope with a specific and costly parasite in young birds. As O. bursa infestations reduce population viability in hihi, our findings also highlight the importance of key nutritional resources for endangered bird populations to better cope with common parasite infestations.

Dietary vitamin E (α-tocopherol acetate) and selenium supplementation from different sources: performance, ascites-related variables and antioxidant status in broilers reared at low and optimum temperatures

1. This study compared the effect of dietary supplementation with organic or inorganic selenium (Se) sources plus control amounts or large amounts of vitamin E (α-tocopherol acetate) in broilers raised at control (20 to 24°C) or low (14·5 to 16·8°C) temperatures after 2 weeks of age. 2. The following dietary treatments were used from one day old. Diet 1, the control diet, comprised a commercial diet containing 0·15 mg/kg inorganic Se and 50 mg vitamin E/kg feed. Diet 2 was the same as diet 1, supplemented with 0·15 mg/kg inorganic Se. Diet 3 was the same as diet 2 but was supplemented with 200 mg/kg vitamin E. Diet 4 was the same as diet 1, but inorganic Se was replaced with 0·30 mg/kg organic Se. Diet 5 was the same as diet 4, supplemented with 200 mg/kg vitamin E. 3. Low temperature reduced the growth rate of broilers; however, at 6 weeks, there were no differences in the body weights of birds fed on organic Se supplemented diets housed at low or control temperature. The feed conversion ratio was significantly affected by low temperature but not by diet. The heterophil/lymphocyte ratio was higher in chicks after one week in the cold, indicating mild stress. Blood triiodothyronine levels were significantly higher in birds after 1 and 4 weeks in the cold but thyroxin was not affected. 4. Organic Se supplementation increased relative lung weight at the control temperature, which might lead to greater respiratory capacity. Relative spleen weight significantly decreased in broilers fed diets supplemented with inorganic Se under cold conditions, a possible indication of chronic oxidative stress. 5. At the low temperature, supplementation with organic Se alone, or with inorganic Se and vitamin E increased glutathione peroxidase (GSHPx) activity and glutathione (GSH) concentration in the liver of broilers, which may indicate increased activity of birds’ antioxidant defence against suboptimal environments.

Levels of antioxidants in rural and urban birds and their consequences.

Numerous animals have successfully invaded urban habitats, although the factors associated with invasion success remain poorly understood. Urban areas are characterized by warmer microclimates, higher levels of primary productivity, longer breeding seasons and higher levels of pollutants. All these factors should cause oxidative stress, favoring invasion by species that have access to high levels of antioxidants. We analyzed concentrations of two categories of dietary, fat-soluble antioxidants (total carotenoids, total vitamin E) in the liver, the main storage organ in birds. Individuals killed by cats had lower levels of vitamin E than individuals that died for other reasons, showing natural selection on stored antioxidants. Bird species that had successfully colonized urban areas had significantly higher levels of vitamin E and total carotenoids than species that did not succeed, and rural populations had higher concentrations of vitamin E and total carotenoids than urban populations of the same species. Interspecific differences in concentrations of fat-soluble antioxidants, and differences between rural and urban populations of the same species, were accounted for by diet, but also by time since urbanization and number of generations since urbanization. These findings suggest that antioxidants, and by implication the ability to cope with oxidative stress, have contributed to successful invasion of urban areas by birds, and that the concentration of these antioxidants has changed in response to the urban environment.

A window on the past: male ornamental plumage reveals the quality of their early-life environment.

It is well established that the expression of many ornamental traits is dependent on the current condition of the bearer. However, conditions experienced in early life are also known to be important for an individuals subsequent fitness and therefore, directly or indirectly, for the fitness of their mate. Specifically, a recent hypothesis suggests that sexually selected traits might be sensitive to conditions experienced during early-life development and thereby function as honest indicators of developmental history. Whether this applies to colourful male plumage, however, is largely unknown. We tested this idea with a field experiment by manipulating neonatal nutrition in a sexually dichromatic passerine, the hihi (Notymystis cincta). We found that carotenoid supplementation increased nestling plasma carotenoid concentration, which was in turn correlated with increased yellow saturation in male breeding plumage after moulting. We also found that the post-moult luminance (lightness) of the white ear-tufts tended to be reduced in males that had received an all-round nutritional supplement as nestlings. Black breeding plumage was not affected by neonatal nutritional treatment. Although the mechanisms that generate colourful plumage are evidently diverse, our results show that at least some parts of this display are accurate indicators of environmental conditions during development.

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.

Photoperiodic lighting (16 hours of light:8 hours of dark) programs during incubation: 1. Effects on growth and circadian physiological traits of embryos and early stress response of broiler chickens

This study was conducted to evaluate the effect of a 16L:8D photoperiod during incubation, either during the whole incubation period (Inc(0-21d)) or the last week of incubation (Inc(14-21d)), on embryo growth, incubation performance, and light:dark rhythm of plasma melatonin and corticosterone in relation to early stress responses of newly hatched chicks to the posthatching environment. A dark incubation condition (Inc(Dark)) served as control. Three batches of eggs (n = 1,080, 1,320, 720) from Ross 308 broiler breeders were used in the experiment. Embryos from Inc(0-21d) presented a daily rhythm of melatonin at internal pipping and hatching, but Inc(Dark) embryos did not. The Inc(14-21d) group had rhythmic plasma melatonin at hatching only. A L:D rhythm of corticosterone was apparent at hatching. A significant incubation × sampling time interaction suggested that a lower increment in blood corticosterone level in Inc(0-21d) at 8 h posthatching (light period), as compared with hatching (dark period) values, might be associated with probable changes in the hypothalamic-pituitary-adrenal axis in Inc(0-21d) through incubation lighting. This finding may also suggest improved adaptation to the posthatching environment. Incubation lighting did not consistently affect brain malondialdehyde concentration; the only difference between groups was higher concentrations at hatching in Inc(14-21d), whereas incubation groups at the internal pipping stage had similar values. Mean relative asymmetry (RA) did not differ with incubation lighting. The malondialdehyde and RA results indicate that neither lighting nor darkness during the overall incubation exacerbated embryo oxidative and developmental stress. An increased breast muscle weight was observed at hatching only in Inc(14-21d). The Inc(0-21d) group had increased embryo weights relative to egg weight and decreased residual yolk but had no effect on chick weight, relative heart and liver (% of embryo weight), hatchability, embryo mortality, incubation time, oxidative stress, or mean RA. In conclusion, these results provide further evidence that photoperiodic lighting during incubation (Inc(0-21d)) may improve adaptation of chicks to a novel environment at hatching, possibly giving birds a better start for early posthatching development.

Dietary essential oils improve the hepatic antioxidative status of broiler chickens

Abstract 1. A total of 200 male Ross 308 chickens were used to evaluate the effects of a standardised combination of essential oils including 5% carvacrol, 3% cinnamaldehyde and 2% capsicum oleoresin (XT 6930; Pancosma S.A., Geneva, Switzerland) on their performance, hepatic antioxidant concentration and caecal tonsils morphometry. 2. Two diets were offered to broiler chickens from d old to 21 d of age. The control diet (C) was slightly lower in metabolisable energy (12.13 MJ/kg ME) and crude protein (215 g/kg CP) than breeders’ recommendation. The second diet, made as XT 6930, was added on the top of the control diet at 100 mg/kg. Each diet was offered ad libitum to birds housed in one of 10 floor pens in a randomised complete block design. The birds were housed in 20 floor pens, 10 birds in each pen, and were allocated to 10 replicates of the two dietary treatments. 3. The concentration of antioxidants in the liver of the birds was determined using high-performance liquid chromatography (HPLC) at 21 d of age. Birds fed control diet only had lower weight and converted less efficiently feed to gain compared to birds fed essential oils-supplemented diet. Feed consumption was not affected by dietary treatments. The antioxidant data showed that supplemented essential oils improved the hepatic concentration of carotenoids and coenzyme Q10 when fed to broiler chickens. The morphometry of the caecal tonsils of the birds was not influenced by dietary treatments. 4. It can be concluded that that dietary combination of essential oils, including carvacrol, cinnamaldehyde and capsicum oleoresin, improved growth, feed efficiency and the hepatic concentration of carotenoids and coenzyme Q10 when fed to broiler chickens.