Vitamin A

Pitt, G. A. J.

doi:10.1007/978-3-0348-5831-1_10

Cited by 23 publications

(7 citation statements)

References 141 publications

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“…Astaxanthin has been suggested to enhance fish growth owing to its status of pro‐vitamin A (Pitt 1971). Our experiment, as well as a previous work on rainbow trout (Choubert et al .…”

Section: Discussionmentioning

confidence: 99%

Pigmentation of gilthead seabream, Sparus aurata (L. 1875), using Chlorella vulgaris (Chlorophyta, Volvocales) microalga

Gouveia

Choubert

Pereira

et al. 2002

Aquaculture Research

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A feeding experiment was conducted over 9 weeks with seven groups of 30 (fish per group) unpigmented gilthead seabream, Sparus aurata (L. 1875) (initial mean weight = 145.2 ± 12.3 g). Three experimental diets were prepared by adding to a basal diet free of carotenoid (final pigment content of around 40 mg per kg feed): (i) a biomass of the carotenogenic Chlorella vulgaris (Chlorophyta, Volvocales); (ii) a synthetic astaxanthin; and (iii) a mixture (1:1) of microalgal biomass and synthetic astaxanthin. At 3‐week intervals, five fish were sampled from each tank for total carotenoids analysis in skin and muscle. The carotenoid pigments (total amount = 0.4%) identified in the carotenogenic alga were lutein (0.3%), β‐carotene (1.2%), canthaxanthin (36.2%), astaxanthin, free and esterified forms (55.0%), and other pigments (7.3%). Carotenoid pigments were significantly deposited in the four skin zones studied during the feeding trial: the forefront between the eyes, the opercule, along the dorsal fin and in the abdominal area. In the muscle, regardless of the astaxanthin source, the amount of carotenoids measured was very low (less than 1 mg kg−1) and differences not significant. Moreover, no muscle pigmentation was evident, and there was no variation in the amount of carotenoid analysed in skin tissue, through the trial, for each treatment. It was concluded that supplementing the feed with C. vulgaris would be an acceptable practice in aquaculture to improve the market appeal of the gilthead seabream.

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“…Astaxanthin has been suggested to enhance fish growth owing to its status of pro‐vitamin A (Pitt 1971). Our experiment, as well as a previous work on rainbow trout (Choubert et al .…”

Section: Discussionmentioning

confidence: 99%

Pigmentation of gilthead seabream, Sparus aurata (L. 1875), using Chlorella vulgaris (Chlorophyta, Volvocales) microalga

Gouveia

Choubert

Pereira

et al. 2002

Aquaculture Research

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“…In particular, carotenoid pigments obtained from plants, algae, some bacteria and fungi (Gray 1996) perform important biological functions in animal tissues, such as the development of the intense pigmentation of many sexual ornamentations, or the enhancement of the antioxidant activity and the immune system (Aguilera & Amat 2007;Fitze et al 2007). Moreover, carotenoids are the essential precursors of vitamin A (Pitt 1971), which is involved in many vital functions as growth, vision, cell differentiation and spermatogenesis (Dennert 1984;Underwood 1984;Dierenfeld et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Do Hermann's tortoises (Testudo hermanni) discriminate colours? An experiment with natural and artificial stimuli

Pellitteri‐Rosa

Sacchi

Galeotti

et al. 2010

Italian Journal of Zoology

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Many animals use chemical and visual cues to obtain reliable information about potential food resources. Most reptiles have evolved highly specialized chemosensory and visual capacities, in particular colour vision, to accomplish this task. By presenting animals with flowers and coloured cardboard discs in two-choice experiments, we examined whether both male and female Hermann's tortoises (Testudo hermanni) were able to distinguish between different colours, and show some preference for certain colours. We found that both sexes responded and discriminated equally between different colours, with some differences between flowers and discs. In particular, the red was preferred in the disc experiment, mainly by males, but was disregarded by both sexes in the flower experiment, where red was represented by poppy, Papaver rhoeas. This suggests that Hermann's tortoise probably relies on a mixed system of olfactory and visual abilities to detect food in order to optimize the intake of essential nutrients as minerals or carotenoids. Our results demonstrate that the most preferred colour by tortoises was the yellow, which might reflect carotenoid content, and we discuss the potential implications of this finding.

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“…Both are found in ornamental plumage and can be highly variable in hue within and across species. In addition to ornamental functions, melanins provide structural support to feathers (Burtt 1981), and carotenoid pigments are essential vitamin A precursors (Pitt 1971;Underwood 1984). In contrast to pigment-based colours, blue, purple, green, ultraviolet colours and iridescence are produced when physical structures in the re£ective keratin of the feather scatter incident light and re£ect the shortest wavelengths (Finger 1995;Finger & Burkhardt 1992;Fox 1976;Greenewalt et al 1960).…”

Section: Introductionmentioning

confidence: 99%

Condition–dependent variation in the blue–ultraviolet coloration of a structurally based plumage ornament

Keyser

Hill

1999

Proc. R. Soc. Lond. B

218

171

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After years of investigation into the function of sexually dimorphic ornamental traits, researchers are beginning to understand how bright plumage colour in birds acts as an intraspeci¢c signal. This work has focused primarily on pigment-based ornaments because they are highly variable in patch size, hue and brightness for some species. In contrast, structurally based ornaments have been little studied, in part because they do not appear to be as variable as pigment-based ornaments. We investigated a structurally based plumage ornament in a wild population of blue grosbeaks (Guiraca caerulea), a sexually dimorphic passerine. We report plumage variation that extends into the ultraviolet region of the spectrum. The pattern of covariation between four out of ¢ve elements of plumage variation suggests that structurally based ornamentation is pushed towards extreme expression of the trait as predicted by the sexual selection theory. The`bluest' birds have the highest percentage of blue feathers on the body. These ornamental feathers re£ect light maximally at the shortest wavelengths (ultraviolet), with the greatest intensity and the greatest contrast. Age may have some e¡ect on expression of blueness. In addition, plumage variables are correlated with growth bars in tail feathers (a record of nutritional condition during moult in a nonornamental trait). This suggests that the ornament is partially condition dependent. Thus, blue plumage in male grosbeaks may serve as an honest indicator of age and quality.

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Vitamin A

Cited by 23 publications

References 141 publications

Pigmentation of gilthead seabream, Sparus aurata (L. 1875), using Chlorella vulgaris (Chlorophyta, Volvocales) microalga

Pigmentation of gilthead seabream, Sparus aurata (L. 1875), using Chlorella vulgaris (Chlorophyta, Volvocales) microalga

Do Hermann's tortoises (Testudo hermanni) discriminate colours? An experiment with natural and artificial stimuli

Condition–dependent variation in the blue–ultraviolet coloration of a structurally based plumage ornament

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