Aline de Assis Lago

Performance and carcass traits in the diallel crossing of pacu and tambaqui

With the purpose of evaluating the changes and the degree of heterosis on performance and carcass traits of fish from the diallel crossing between Pacu and Tambaqui, four genetic groups were generated through hormonal induction: pacu, tambaqui, tambacu and paqui. For 196 days, 400 juveniles of each genetic group were stocked in a pond divided into four parts of equal size, one for each group. At the end of this period, when the fish weighed on average 1024 g (±115.52 g), 20 specimens of each genetic group were sampled, weighed, measured: head length; standard length; body height; and width; and also processed resulting in following body yield: viscera; carcass; head; fillet; rib; residue and skin yields. There was positive heterosis for body weight, viscera and skin yield and head measures and negative heterosis for carcass and filet yield and body width, indicating that the hybrids have better performance on weight gain, but are inferior in relation to the carcass conformation.

Deposition of bodily chemical components in the carcass of tilapia (oreochromis sp.) strains

The knowledge of how animals deposited chemical components as water, protein, fat and ash in the carcass is importance for the formulation of a balanced diet, allowing maximum performance with a low environmental impact. So, the study was carried out to evaluate the influence of different tilapia strains (Chitralada, Commercial, Red and Universidade Federal de Lavras [UFLA]) on the deposition of bodily chemical components in the carcass. The bodily components analyzed were water, protein, fat and ash. For the determination of the bodily chemical deposition curves by age, the exponential, Brody, logistic, Gompertz and von Bertalanffy models were adjusted. The Commercial and UFLA strains deposited water at a faster speed (P 0.05) for the logistic model parameter between Red, UFLA and Commercial strains for fat, which presented a maximum fat deposition (0.23 g) at 310 days of age. Regarding ash deposition, the Commercial strain presented a higher maximum deposition (0.10 g) at 337 days, occurring later than the other strains that presented maximum deposition (0.033g) at 254 days of age. Thus, it was concluded that the genetic strains evaluated differ in chemical deposition curves of water, protein, fat and ash.

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.