Resumo -O objetivo deste trabalho foi avaliar o eugenol como anestésico para a tilápia-do-nilo. Para a concentração ideal, foram avaliados seis tratamentos (50, 75, 100, 150, 200 e 250 mg L -1 ), com dez peixes por tratamento, anestesiados individualmente, acompanhados durante a indução e recuperação. A toxicidade foi estimada pela submissão de 210 peixes a 7 concentrações de eugenol (50, 75, 100, 150, 200, 250, Eugenol as an anesthetic for Nile tilapiaAbstract -The objective of this work was to evaluate eugenol as anesthetic for Nile tilápia. For the best concentration of the anaesthetic, six treatments (50, 75, 100, 150, 200, and 250 mg L -1 ) were evaluated, with ten fi shes per treatment, anesthetised individually and monitored during the induction and recovery. Toxicity was estimated in 210 fi sh submitted to seven eugenol concentrations (50, 75, 100, 150, 200, 250, and 300 mg L -1 ) for 600 s; and for safety margin, 120 fi sh were submitted to 75 mg L -1 for fi ve time intervals (600, 1,200, 1,800, and 2,400 s). The effective concentrations were 50 and 75 mg L were recommended. The higher therapeutic concentration costs R$ 0.065 per liter. Eugenol was effective for euthanasia at 286.55 mg L -1 for 600 s.

Domestication is an evolutionary process during which we expect populations to progressively adapt to an environment controlled by humans. It is accompanied by genetic and presumably epigenetic changes potentially leading to modifications in the transcriptomic profile in various tissues. Reproduction is a key function often affected by this process in numerous species, regardless of the mechanism. The maternal mRNA in fish eggs is crucial for the proper embryogenesis. Our working hypothesis is that modifications of maternal mRNAs may reflect potential genetic and/or epigenetic modifications occurring during domestication and could have consequences during embryogenesis. Consequently, we investigated the trancriptomic profile of unfertilized eggs from two populations of Eurasian perch. These two populations differed by their domestication histories (F1 vs. F7+–at least seven generations of reproduction in captivity) and were genetically differentiated (FST = 0.1055, p<0.05). A broad follow up of the oogenesis progression failed to show significant differences during oogenesis between populations. However, the F1 population spawned earlier with embryos presenting an overall higher survivorship than those from the F7+ population. The transcriptomic profile of unfertilized eggs showed 358 differentially expressed genes between populations. In conclusion, our data suggests that the domestication process may influence the regulation of the maternal transcripts in fish eggs, which could in turn explain differences of developmental success.

RESUMO Objetivando avaliar o efeito da suplementação com megadoses de vitamina C na dieta de alevinos de Tilápia do Nilo ( Oreochromis niloticus), frente à infecção experimental por Edwardsiella tarda, foram realizados dois experimentos. Cada experimento foi composto por quatro grupos distintos: aqueles pertencentes aos grupos 1 e 4 receberam apenas ração comercial apresentando cerca de 300 mg de vitamina C por quilo de ração, enquanto os animais pertencentes aos grupos 2 e 3 receberam a mesma ração suplementada com 1.500 mg e 3.000 mg, respectivamente, de vitamina C (Lutavit® C Monophosphate – BASF) por quilo de ração. No primeiro experimento os animais receberam a dieta durante 14 dias consecutivos, sendo desafiados no 15º dia, enquanto no segundo experimento os animais só foram desafiados pela suspensão bacteriana após um intervalo de mais 14 dias findo o mesmo período de suplementação com vitamina C. Os resultados mostraram que, embora não haja diferença significativa (p > 0,05) com relação às concentrações de vitamina C, o intervalo entre o final do período de suplementação com megadoses de vitamina C na ração (Nutripeixe AL55 – PURINA) e a exposição à suspensão bacteriana apresentou diferença significativa (p < 0,05) sobre a infecção experimental com E. tarda em alevinos de Tilápia do Nilo (O. niloticus).