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Avian Medicine and Surgery

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    ABSTRACT: The purpose of this study was to investigate for the first time the prevalence and pathology of spontaneous atherosclerosis in free – living pigeons in Mosul, Iraq. A hundred apparently healthy, 1-1.5 year old both sex pigeons of local breed free – living used. Effects of factors such as weight, sex, age and health status on prevalence of the condition were also studied. Prevalence of naturally occurring atherosclerosis was 10%. Grossly, the heart was hypertrophied and of firm consistency, aorta and coronary arteries were prominent and cordlike with thickened walls. Microscopically, lipid – laden "foam cells" were seen throughout the thickened tunica media and intima. Damage of the elastic lamellae and hypertrophy of the smooth muscle cells were also noted. Spontaneous atherosclerosis occurred more frequently in old pigeons. No effect was found for sex, weight, and health status of the pigeons on prevalence and pathology of spontaneous atherosclerosis. It was concluded that spontaneous atherosclerosis is fairly common in local pigeons and it occurred more commonly in old pigeons. Sex, weight, and health status of the pigeons did not constitute risk factors for the occurrence of spontaneous atherosclerosis.
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    ABSTRACT: The endangered, endemic Yellow-eyed penguin (Megadyptes antipodes) is one of the flagship species for New Zealand's wildlife tourism, and recently concern has been raised that tourism-related pressures may be becoming too great. We compared two neighbouring breeding areas exposed to different levels of human disturbance. Penguins at the site exposed to unregulated tourism showed significantly lower breeding success and fledging weights than those in an area visited infrequently for monitoring purposes only. High parental baseline corticosterone concentrations correlated with lower fledgling weights at both sites. Stress-induced corticosterone concentrations were significantly higher at the tourist-exposed site, suggesting birds have been sensitized by frequent disturbance. Consequences are likely to include reduced juvenile survival and recruitment to the tourist site, while the changed hormonal stress responses may ultimately have an effect on adult fitness and survival. For maintenance of attractive Yellow-eyed penguin-viewing destinations we recommend that tourists stay out of breeding areas and disturbance at penguin landing beaches is reduced.
    General and Comparative Endocrinology 05/2007; 152(1):54-63. DOI:10.1016/j.ygcen.2007.02.022 · 2.67 Impact Factor
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    ABSTRACT: Carotenoids are biologically active pigments of crucial importance for the development of avian embryos and nestlings. Thus parental ability to provide nestlings with a carotenoid-rich diet may enhance offspring fitness. However, very little is known about the possible effects of carotenoid availability in the diet on growing nestlings in natural populations. We experimentally manipulated dietary intake of carotenoids by nestlings of two closely related passerine species, the great tit Parus major and the blue tit Parus caeruleus, and measured nestling antioxidants, body condition, immunity and plumage colour. There was no detectable increase in plasma carotenoids after treatment in carotenoid-fed nestlings of either species despite regular supply of dietary carotenoids. However, in carotenoid-fed blue tit nestlings, plasma vitamin E concentration increased with plasma carotenoid concentration, while that was not the case for control nestlings. In both species, there was no significant effect of carotenoid supply on immune function. Carotenoid supplementation enhanced yellow feather colour in great tit nestlings only. In both species a strong effect of carotenoid supply was found on body condition with an increase in body mass for small carotenoid-fed nestlings compared to similarly sized control nestlings. Dietary availability of carotenoids may thus have important fitness consequences for tits. We hypothesise that the difference in effect of dietary carotenoids on the two species is due to relatively larger clutch size and higher growth rates of blue tits compared to great tits, leading to blue tit nestlings being more in need of carotenoids for antioxidant function than great tit nestlings.
    Journal of Experimental Biology 04/2006; 209(Pt 6):1004-15. DOI:10.1242/jeb.02089 · 3.00 Impact Factor

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