No abstract

This review discusses different aspects of the uropygial gland of birds. The gland exhibits a striking morphological diversity in size, shape and presence/absence of tufts of feathers. It was shown that acidic mucins, neutral lipids, glycolipids and phospholipids are normal components of secretion. Several morphological and physiological aspects of the gland were studied on Rock Pigeon Columba livia Gmelin, 1879. The amount of the uropygial gland secretion, its lipid content and fatty acids profile were determined. The extracted lipid mixture contained of C14 to C20 fatty acids, mostly unsaturated; the saturated fatty acids were mainly 14:0, 16:0 and 18:0. No correlation was found between the size of the gland and the aquatic/terrestrial nature of the species. Ablation of the gland did not affect survival, body weight, feeding rate and serum cholesterol, total lipids or calcium levels after 32-120 days. The possible role of the gland in the protection against lipophilic compounds was discussed. The function of the gland is still a subject of controversy. It is accepted that its secretion confers water-repellent properties on the feather coat and maintain the suppleness of the feathers. Other physiological roles of the gland secretion may be associated to pheromone production, control of plumage hygiene, thermal insulation and defence against predators. Concerning the endocrine regulation of the uropygial function, there is scarce information presenting evidence for steroid regulated mechanisms.Keywords: Columba livia, preen gland, uropygial gland, uropygial physiology, chemistry of secretion. Aspectos fisiológicos e bioquímicos da glândula uropigial das aves ResumoEsta revisão discute diferentes aspectos da glândula uropigial das aves. A glândula exibe uma chamativa diversidade morfológica de tamanho, forma e presença/ausência de um tufo de penas. A glândula mostrou mucinas ácidas, lipídios neutros, glicolipídios e fosfolipídios como componentes normais de sua secreção. Diversos aspectos morfológicos e fisiológicos da glândula foram estudados na pomba doméstica Columba livia. Foi determinada a quantidade de secreção da glândula uropigial, seu conteúdo lipídico e o perfil de ácidos sebosos. A mistura lipídica extraída contém ácidos graxos C14 a C20, principalmente não saturados; os ácidos graxos saturados foram principalmente 14:0, 16:0 e 18:0. Não se encontrou correlação entre o tamanho da glândula e a natureza aquática/terrestre das espécies. A ablação da glândula não afetou a sobrevivência, peso corporal, alimentação e os níveis séricos de colesterol, lipídios totais ou cálcio depois de 32-120 dias. Discute-se o possível papel da glândula na proteção contra compostos lipofílicos. A função da glândula é ainda tema de controvérsia. Aceita-se que sua secreção confere às penas propriedades repelentes à água e as mantém flexíveis. Outras funções fisiológicas da secreção glandular podem estar associadas com a produção de feromonas, controle da higiene da plumagem, isolamento térmico e defesa contra predadore...

The toxic effect of sublethal concentrations (1, 17.5 and 35 mg L(-1)) of pure glyphosate was evaluated on acetylcholinesterase (AChE) activity in the fish species, Cnesterodon decemmaculatus. Acute bioassays (96 h) under laboratory conditions were conducted and homogenates for each specimen corresponding to the anterior, middle and posterior body sections were performed. Fish survival was 100%, even at the highest concentration tested (35 mg L(-1)), in accordance with the low lethal toxicity reported for glyphosate. However, a significant inhibitory effect on AChE activity was recorded even for the lowest herbicide concentration tested (1 mg L(-1)), in the homogenates corresponding to the anterior body section. The inhibition ranged from 23 to 36%. The analytical determination of glyphosate in assay media by ion chromatography, was used to verify its stability. These results indicate that AChE-a neurotoxicity biomarker-in C. decemmaculatus may be affected by exposure to environmentally relevant concentrations of glyphosate.