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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

AvaliaÃÃo de desova induzida hormonalmente e qualidade dos ovos de ariacÃ, Lutjanus synagris (LINNAEUS, 1758) / Assessment of hormonally induced spawning and egg quality of ariacÃ, Lutjanus synagris (Linnaeus, 1758)

Oscar Pacheco Passos Neto 16 November 2010 (has links)
O presente estudo teve como objetivo avaliar a desova induzida hormonalmente e a qualidade dos ovos do ariacÃ, Lutjanus synagris. Foram avaliadas as fecundidades absoluta e relativa, o diÃmetro dos ovos e de suas respectivas gotÃculas de Ãleo, a porcentagem de ovos flutuantes, a taxa de fecundaÃÃo, a taxa de eclosÃo e sobrevivÃncia das larvas apÃs consumo da reserva vitelÃnica. O estudo foi desenvolvido no Centro de Estudos Ambientais Costeiros (CEAC) do Instituto de CiÃncias do Mar (LABOMAR) da Universidade Federal do Cearà (UFC). IndivÃduos juvenis foram capturados na natureza por meio de pesca com anzol, levados ao laboratÃrio e mantidos sob quarentena. Para finalizar o processo de maturaÃÃo gonadal os indivÃduos foram transferidos para o sistema interno, mantidos sob fotoperÃodo de 14 horas de claro e alimentados alternadamente com sardinha, camarÃo e lula. ApÃs a verificaÃÃo da maturaÃÃo gonadal foi iniciado o perÃodo de induÃÃo hormonal. Os animais foram capturados, anestesiados, medidos e pesados. O critÃrio de maturidade utilizado foi liberaÃÃo de sÃmen para os machos e diÃmetro mÃdio dos ovÃcitos maior que 400 μm para as fÃmeas. As induÃÃes ocorreram entre os meses de novembro de 2009 e marÃo de 2010 com injeÃÃes de gonadotrofina coriÃnica humana (hCG) na base da nadadeira peitoral. Foram utilizadas doses de 1.500 UI kg-1 e avaliados dois protocolos. No Protocolo 50/50 foram aplicadas duas injeÃÃes contendo 50% da dose total e no Protocolo 70/30 a primeira dose foi de 70% e a segunda de 30% da dose total. A segunda injeÃÃo foi aplicada 24 horas apÃs a primeira. Os machos receberam dose Ãnica de 750 UI de hCG kg-1 no momento da segunda injeÃÃo na fÃmea. A proporÃÃo sexual (fÃmea:macho) utilizada foi de 1:2. A porcentagem de ovos flutuantes apresentou diferenÃa significativa com valores mÃdios de 78,18  39,71% e 33,68  41,02% para os Protocolos 50/50 e 70/30, respectivamente. NÃo foi observada diferenÃa significativa para nenhum dos demais parÃmetros avaliados. Os valores mÃdios para fecundidade relativa foram de 306.815,10  135.218,18 Ãvulos kg-1 (Protocolo 50/50) 404.511,27  261.545,16 Ãvulos kg-1 (Protocolo 70/30). A fertilizaÃÃo dos ovos flutuantes variou entre 92 e 100% com diÃmetro mÃdio de 726,0  16,89 μm a 795,0  19,43 μm e da gotÃcula de Ãleo de 122,5  8,07 μm a 141,5  11,89 μm. A eclosÃo ocorreu em 16 horas sob temperatura mÃdia de 29,3  0,9oC. Ovos com mÃltiplas gotÃculas de Ãleo apresentaram eclosÃo e sobrevivÃncia similares Ãqueles com uma gotÃcula. O ariacà se mostrou uma espÃcie que se adapta bem ao cativeiro respondendo positivamente ao manejo e à induÃÃo hormonal. Os resultados positivos mostram que o hCG à eficaz na reproduÃÃo induzida desta espÃcie, contudo a variabilidade dos dados encontrados no presente estudo revela que a tÃcnica precisa ser aprimorada / The aim of this study was to evaluate the hormone induced spawn and egg quality of lane snapper, Lutjanus synagris. The absolute fecundity, relative fecundity, egg and oil globule diameter, percentage of floating eggs, percentage of fertilization, hatching rate and larval survival up to yolk consumption were assessed. The study was conducted at Centro de Estudos Ambientais Costeiros (CEAC) from Instituto de CiÃncias do Mar (LABOMAR) from the Universidade Federal do Cearà (UFC). Wild juveniles were captured by hook, took to the laboratory and held in a quarantine system. Fishes were transferred to the internal system to complete gonadal maturation under a 14h-light photoperiod and fed fish, shrimp and squid. After gonadal maturation, induced spawn period was started. Individuals were captured, anesthetized and measured. Maturity criteria were running milt for males and mean oocyte diameter greater than 400 μm for females. Induced spawns were attempted in the period between November 2009 and March 2010, by using human chorionic gonadotropin (hCG) injections at the base of the pectoral fin. Total doses of 1.500 IU kg-1 were used and two experimental protocols were evaluated. In the Protocol 50/50, injections of hCG were given in two doses of 50% of total dose while in the Protocol 70/30, the first dose was 70% and the second was 30% total dose. The second injection was given after 24 hours. Males received only one injection of 750 IU kg-1, at the time of the second injection to females. The sex ratio (female:male) was 1:2. The percentage of floating eggs was significantly different, with mean values of 78.18  39.71% and 33.68  41.02% for Protocols 50/50 and 70/30, respectively. There were no significant differences in any other evaluated parameters. The mean values of relative fecundity were 306,815.10  135,218.18 egg kg-1 (Protocol 50/50) and 404,511.27  261,545.16 egg kg-1 (Protocol 70/30). The percentage of fertilization in floating eggs ranged from 92 to 100% with mean egg diameters from 726.0  16.89 μm to 795.0  19.43 μm and oil globule diameters from 122.5  8.07 μm to 141.5  11.89 μm in Protocols 50/50 and 70/30. Hatching occurred 16 hours after spawning at mean temperature of 29.3  0.9oC. Spawns with eggs having multiple oil globules had a similar hatching rate and larval survival than those with simple oil globule. Lane snapper can successfully adapt to captivity conditions and positively respond to handling and induced spawn. The positive results show that hCG induced spawn is feasible, however the variability of the found data in the present study reveals that this technique needs to be improved

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