Carlos Cicinato Vieira Melo

SELÊNIO E VITAMINA EM DIETAS PARA TILÁPIAS Oreochromis niloticus

Dentre as especies de peixes que demonstram potencial para o cultivo no Brasil, a tilapia do Nilo (Oreochromis niloticus) e considerada a especie mais produtiva. Essa especie apresenta diversas vantagens, entre elas: rapido crescimento, maior rendimento de file, resistencia a baixa qualidade de agua e boa aceitacao no mercado consumidor. Na nutricao de peixes varios sao os aspectos a serem avaliados em uma racao. O selenio e a vitamina E fazem parte de um sistema de defesa antioxidante multicomponente. Este sistema protege as celulas contra os efeitos adversos das especies reativas de oxigenio e outros radicais livres que iniciam a oxidacao. Alem disso a suplementacao de Vitamina E na dieta proporciona um maior desempenho produtivo, efeitos positivos nos parâmetros imunologicos dos peixes e resistencia ao estresse. O selenio e um elemento que possui margem estreita entre os niveis de exigencia e toxidez. As exigencias sao baixas, mas se nao atingida, podem comprometer o sistema antioxidante e causar graves consequencias para o metabolismo do animal. A capacidade do peixe em acumular selenio nos tecidos pode tornar a carne de pescado um interessante alimento funcional para a nutricao humana, especialmente como boa fonte de selenio. A especie tilapia do Nilo tem um nivel de exigencia especifica de selenio e vitamina E que nao pode ser satisfeito somente pelo ambiente aquatico. Desta forma uma correta suplementacao na dieta de minerais e vitaminas podera garantir um maior desempenho, proporcionando uma melhor qualidade de carne e melhor aceitacao no mercado.

Influential Factors of Quality of Fish Gametes for Use of In Vitro Fertilization

Aquaculture is the fastest growing livestock activity in Brazil, producing important sources of protein for human consumption. Most Brazilian fish farms that work with native species perform in vitro reproduction, given that these migrating species cannot release gametes without hormonal induction. To succeed with in vitro reproduction, the evaluation of reproductive parameters of both genders is necessary. The objective of this review is to describe the main reproductive parameters of fish, which must be evaluated for in vitro reproduction.

Influência do horário de aplicação e da variedade genética em fêmeas de tilápias Oreochromis niloticus submetidas à indução hormonal com hCG

The aim of this work was to evaluate the influence of the application time and genetic variability of females submitted to hormonal induction with hCG. The experiment was performed in the months of July and August 2012. We used a completely randomized design, with a 2x4x2 (two varieties, four application times, with or without hCG) factorial scheme, with four replicates for the control treatments and six replicated for those with hCG induction. Forty females of the GIFT and UFLA varieties, with microchips, were housed in a water recirculation system. Four application times were used: 6; 12; 18 and 24 hours. The hCG dosage was 5UI/gram of fish, divided into two applications. Oocyte extrusion was performed 720 hours after the last application, observing the number of animals in each treatment which presented spawning. The obtained data were submitted to variance analysis and the means compared by the SNK test at 5% significance. The induction with hCG provided better (P 0.05), while GIFT presented higher SI (P<0.05) when the hormonal induction was performed at 24 h in relation to the application performed at 18 h. The diameter of the oocytes of the UFLA variety was larger than that of the GIFT variety (P<0.05). Observing the control group, the UFLA variety presented a higher percentage of oocytes with peripheral position of the germinal vesicle (P<0.05) in relation to GIFT. The hormonal induction with hCG was influenced by the variety and the time of application.