Níveis iônicos no plasma e no conteúdo do trato gastrintestinal de teleósteos coletados em diferentes salinidades

Detalhes bibliográficos
Ano de defesa: 2008
Autor(a) principal: Becker, Alexssandro Geferson
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Santa Maria
BR
Ciências Biológicas
UFSM
Programa de Pós-Graduação em Biodiversidade Animal
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://repositorio.ufsm.br/handle/1/5267
Resumo: Seawater teleost fish are hyposmotic to their environment and as a consequence must deal with a constant diffusive loss of water and a net gain of salts. In contrast to living in seawater, teleosts fish in a freshwater environment are faced with the opposite dilemma, a constant osmotic influx of water and depletion of salts. Between these environments there are estuarine regions, which are habitats of several species. The purpose of this study was to investigate Na+, Cl-, K+, Ca2+, and Mg2+ levels in the fluid phase and total amount of the contents of the segments of the gastrointestinal tract and plasma of freshwater and estuarine teleosts collected in different salinities (0 to 34 ) in the São Gonçalo channel in Pelotas, southern Brazil. Moreover, a possible relationship between the ion levels and salinity was investigated. After capture of the fishes, blood was collected and specimens were sacrificed for removal gastrointestinal tract segments: stomach, pyloric ceca/anterior intestine, mid- and posterior intestine. The results showed that there was no relationship between ion levels in the plasma, in the fluid phase and in the total amount of the segments of the gastrointestinal tract with salinity when considering all species together, but species (Micropogonias furnieri and Netuma barba) collected in three or more salinities demonstrated significant relationship of these parameters with salinity. The ion levels in the fluid phase and total amount of the most species showed significantly higher values in the anterior intestine than stomach. Moreover, ion levels showed a variation throughout the gastrointestinal tract suggesting possible ion absorption. These results suggest that the change of salinity affected ion levels in the plasma and in the content of the gastrointestinal tract of Micropogonias furnieri and Netuma barba, indicating that this system might be related with osmoregulation of these species.