Características do desenvolvimento inicial de duas linhagens de tilápia Oreochromis niloticus e uma linhagem híbrida de Oreochromis sp

• Autor(a) principal: Neumann, Erika [UNESP]
• Data de Publicação: 2004
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/144148; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/12-09-2016/000220696.pdf
• topic: Peixe; Peixe - Reprodução; Linhagem (Genética); Tilapia (Peixe); Morfologia (Animais); Fishes

The study of fish morphology allied to the morphometric discrimination of growth's fish, allows it to observe correlated changes during the species ontogenesis. Aiming to determine intraspecific variations of tilapias submitted to sex reversal and to contribute to rearing improvement programs, in this study were described the initial stages of development characteristics of two tilapia strains of Orechromis niloticus (common Nile and Thaichiltralada) and one hybrid strain of Oreochromis sp (Red tilapia). For the description of the initial development and the effectiveness of the sexual reversion, larvae were fed from the hatch to thirty days of life with 17-alpha-methyltestosterone incorporated to the ration (60mg/kg). The three tilapia strains were analyzed considering three treatments and six repetitions. The experimental delineation used was completely randomized. The strain Thaichiltralada has shown the best result to fecundity per lot, thought it has not differed from common Nile for relative fecundity, which had the lowest average in Red. The strain common Nile overtopped as for medium diameter of eggs, consequently, for the size of the larvae at hatching and the yolk sac. Also, were observed differences for the head length, which had the highest increase in Thai-chiltralada; for pigmentation pattern on vertical stripes, that occurred first in common Nile compared to Thai-chiltralada; and for the fin formation, which was late in Thai-chiltralada. At 90 days of life, the survival rate in common Nile has surpassed Thai-chiltralada on 40,00% and Red on 24,00%, while the instantaneous growth rate was similar in common Nile and Thai-chiltralada, and slightly lower in Red, which has presented the highest condition factor value. The decreasing percentual of males was on the order common Nile, Thai-chiltralada and Red (98.73%, 96.23% and 89.46% respectively, P<0.05). Considering all the analyzed ...