Blanco Guillermo, Hornero-Méndez Dámaso
Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006 Madrid, Spain.
Departament of Food Phytochemistry, Instituto de la Grasa (CSIC), Campus Universidad Pablo de Olavide, 41013 Seville, Spain.
Curr Zool. 2022 Nov 12;69(6):658-669. doi: 10.1093/cz/zoac090. eCollection 2023 Dec.
Carotenoids are diet-based micronutrients important in health and coloration signaling. Related species with similar diets can differ in the kinds and levels of circulating carotenoids, which suggests specific physiological mechanisms to efficiently utilize these micronutrients, regardless of their availability. We explored whether diet and parental provisioning of unusual sources of carotenoids (fresh vegetal matter and vertebrate feces) can explain the occurrence and concentrations of carotenoids in the cinereous vulture , griffon vulture , and Egyptian vulture nestlings, even when these pigments appear to not be deposited in their integumentary system. A greater diversity of wild prey in diet could be behind the profile of higher concentrations of carotenoids in the Egyptian vulture, the species with carotenoid-dependent coloration during adulthood, while differences in diet composition between cinereous and griffon vultures do not translate to different carotenoid profiles. The carotenoid profile appears to not be related to the ingestion of unusual matter rich in these compounds, although the infrequent occurrence of lycopene and unidentified γ-carotene-like compounds suggest that these vultures may be exploiting vegetal matter that left no identifiable unconsumed remains in the nest of Egyptian vultures. The consumption of green plant material by griffon vultures does not result in especially high levels of carotenoids when compared to the carotenoids found in cinereous vultures, which do not consume green plant material. Ungulate feces were not provisioned to Egyptian vulture nestlings, despite the fact they contain carotenoids that adults need for appropriate coloration. Overall, this study indicates that diet differences alone appear insufficient to explain contrasting interspecific carotenoid profiles, especially since all types of food consumed are considered to be poor in carotenoids, except vegetable matter. We suggest that nestling Egyptian vultures are comparatively efficient in uptaking carotenoids present in low concentrations in food when these compounds are not deposited in their integument, which suggests allocation to other functions.
类胡萝卜素是基于饮食的微量营养素，对健康和颜色信号传导很重要。具有相似饮食的相关物种在循环类胡萝卜素的种类和水平上可能存在差异，这表明存在特定的生理机制来有效利用这些微量营养素，而不管它们的可获得性如何。我们探讨了饮食以及父母提供不寻常的类胡萝卜素来源（新鲜植物物质和脊椎动物粪便）是否可以解释秃鹫、兀鹫和埃及秃鹫雏鸟体内类胡萝卜素的出现和浓度，即使这些色素似乎并未沉积在它们的体表系统中。饮食中野生猎物种类的多样性可能是埃及秃鹫体内类胡萝卜素浓度较高的原因，埃及秃鹫在成年期具有依赖类胡萝卜素的体色，而秃鹫和兀鹫之间饮食组成的差异并未转化为不同的类胡萝卜素特征。类胡萝卜素特征似乎与摄入富含这些化合物的不寻常物质无关，尽管番茄红素和未鉴定的γ-胡萝卜素样化合物的罕见出现表明，这些秃鹫可能正在利用在埃及秃鹫巢穴中没有留下可识别未消耗残骸的植物物质。与不食用绿色植物物质的秃鹫相比，兀鹫食用绿色植物材料并不会导致类胡萝卜素水平特别高。尽管有蹄类动物粪便中含有成年秃鹫适当体色所需的类胡萝卜素，但并未给埃及秃鹫雏鸟提供。总体而言，这项研究表明，仅饮食差异似乎不足以解释种间类胡萝卜素特征的差异，特别是因为除了植物物质外，所有消耗的食物类型都被认为类胡萝卜素含量低。我们认为，当这些化合物未沉积在体表时，埃及秃鹫雏鸟在摄取食物中低浓度存在的类胡萝卜素方面相对高效，这表明这些类胡萝卜素被分配到了其他功能。
