Plasma tocopherol, retinol, and carotenoid concentrations in free-ranging Humboldt penguins (Spheniscus humboldti) in Chile

Abstract

Plasma retinol and α‐tocopherol concentrations were measured in heparinized blood samples collected from 51 free‐ranging adult Humboldt penguins (Sphenicus humboldti) residing at two colonies off the Chilean coast. Thirty samples were collected in April 1992 from penguins inhabiting the Ex‐islote de los Pájaros Niños in Algarrobo, Chile. In September 1992, 21 samples were collected from birds inhabiting Isla de Cachagua, Chile. Samples were assayed for retinol, retinyl palmitate, α‐tocopherol, γ‐tocopherol, lutein, β‐cryptoxanthin, lycopene, α‐carotene, and β‐carotene. Retinol, α‐tocopherol, and lutein were detected in all samples, while lycopene and γ‐tocopherol were not detected in any. A significantly higher percentage of samples had detectable levels of retinyl palmitate and α‐carotene in April (P < 0.001): for β‐cryptoxanthin the percentage was higher in September (P < 0.001). Plasma concentrations of α‐tocopherol and lutein were higher in September. Alpha‐tocopherol concentrations were 1,877.1 ± 99.0 (SEM) μg/dl in April compared to 2.289 ± 122.3 μg/dl in September (P < 0.05); lutein concentrations were 4.16 ± 0.43 μg/dl in April vs. 10.68 ± 1.02 μg/dl in September (P < 0.001). Retinol concentrations were not significantly different (117 ± 8.0 μg/dl in April vs. 105.3 ± 7.6 μg/dl in September). Both physiologic changes associated with season, and the change in locale may have contributed to the differences seen in the assay means and the number of samples with detectable levels. © 1996 Wiley‐Liss, Inc.

Carotenoid availability in diet and phenotype of blue and great tit nestlings

“…Plasma carotenoid levels in wild birds are documented mainly for adults (e.g. Biard et al, 2005;Blount et al, 2002;Bortolotti et al, 2000;Hõrak et al, 2004;Ninni et al, 2004;Tella et al, 2004;Wallace et al, 1996). In our population, plasma carotenoid concentration in breeding great tit females was similar to that found in females of a rural population studied by Hõrak et al (Hõrak et al, 2004) (also our unpublished data).…”

Concentrations of retinol, 3,4‐didehydroretinol, and retinyl esters in plasma of free‐ranging birds of prey

“…Significant species‐specific differences were also observed in the adult birds. Retinol plasma concentrations comparable to our investigated common buzzard and northern goshawk nestlings were found in the plasma of black footed penguins ( Spheniscus demersus ) held in captivity and in free‐living individuals of other penguin species (Ghebremeskel et al., 1989, 1991, 1992; Wallace et al., 1996; Crissey et al., 1998). In contrast, the plasma of osprey and honey buzzard nestlings contained only small amounts of retinol.…”

“…Already Lederer and Rathmann (1938) assumed that the absence of vitamin A 2 in the liver of mammals and other terrestrial animals can be traced back to the lack of vitamin A 2 in nutrition. Interestingly, the presence of 3,4‐didehydroretinol is not mentioned in several studies about penguins (Gulland et al., 1988; Ghebremeskel et al., 1989, 1991, 1992; Monroe, 1993; Wallace et al., 1996; Crissey et al., 1998). This might be attributed to the fact that saltwater fish mostly store retinol (Lall and Parazo, 1995).…”

“…In contrast, the plasma of the likewise carnivorous owls contained only traces of retinyl esters. Retinyl esters were also detected in the plasma of Humboldt penguins (Wallace et al., 1996; Crissey et al., 1998). Wallace et al.…”

“…Retinyl esters were also detected in the plasma of Humboldt penguins (Wallace et al., 1996; Crissey et al., 1998). Wallace et al. (1996) investigated free‐living penguins in two different seasons and could only detect small amounts of retinyl esters during the breeding season, whereas no retinyl esters were found in September.…”