Effect of kisspeptin treatment on the chemical communication system of senegalese sole, both during puberty and breeding stages

• Autor(a) principal: Santos, Tomás Geraldes dos
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/15298
• topic: Kisspeptina; Linguado senegalês; Hormonas; Puberdade; Comunicação; Química; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

This thesis aimed to understand the effects of kisspeptin administration on the onset of puberty and chemical communication, of juvenile and adult Senegalese sole (Solea senegalensis), respectively. Senegalese sole is a highly valuable species for European aquaculture, currently facing problems regarding F1 breeders (born and reared in captivity) not reproducing naturally in captivity. Kisspeptin, a crucial hormone to the normal functioning of the reproductive axis, has been successively used as a treatment in other fish species, especially as a puberty accelerator. In a first trial, prepubertal Senegalese sole (approximately 1.5 year old), were treated with either single kisspeptin injection or PBS (control). Blood plasma was used for sex steroids determination (T, E2 and 11-KT) by ELISA, before, 4 hours, 2 and 4 days after treatment. Gonads were excised at 4 days post treatment, to determine gonadal maturation stage. Testosterone levels were found to be higher in both sexes with kisspeptin treatment, with treated females also having an estradiol increase trend, however without statistical significance. Histology analyses in males revealed increased spermatids and reduced spermatocyte numbers in the cortical region of treated fish indicating a more advanced stage of the gonad. These results evidence the positive effect of kisspeptin treatment on sole puberty, reinforced by studies on other species. A second experiment was conducted similarly to the first one, but with sole breeders, testing kisspeptin effect on their chemical communication. Urine samples from both groups were run to a LC-MS analysis to identify relevant compounds, and an EOG analysis, comparing their effect on sole olfactory epithelium. Two compounds were found in higher concentration in the treated sole’s urine, one undocumented hypothesized to have a steroid structure, and 3-hydroxyphenylacetic acid, both theorized to be pheromones, given that treated urine had increased potency on olfactory responses for both sexes.