VALORES MORFOMÉTRICOS EN LAR VAS DE YAMÚ BRYCON AMAZONICUS (PISCES: CHARACIDAE) OBTENIDAS CON SEMEN FRESCO Y CRIOCONSERVADO MORFOMETRIC VALUES IN YAMÚ BRYCON AMAZONICUS (PISCES: CHARACIDAE) LARVAE OBTAINED FROM FRESH AND CRIOPRESERVED SPERM

In order to evaluate the differences in the corporal growth, development and survival of yamu (Brycon amazonicus), larvae obtained from eggs fertilized with fresh (FS) and cryopreserved (CS) sperm were used. Males and females of yamu were hormonally stimulated with carp pituitary extract. The sperm obtained was evaluated and diluted in an egg yolk, glucose and dimethylsulfoxide solution and frozen in nitrogen vapours. Eggs from the same female were seminated in dry with fresh and cyopreserved sperm and the larvae obtained were evaluated from the hatching (0 hours) until 60 hours post-hatching (HPH). In each larva, the total length (TL), notocordal length (NL), yolk sac volume (YSV) and larvae survival from 35 to 60 HPH were determined. Significant differences in the TL were observed only at 42 and 54 HPH being the larvae from the CS the longest (6.5 ± 0.04 and 6.8 ± 0.04 mm, respectively). In terms of NL, the higher lengths were observed at 0, 3 and 54 HPH; larvae from FS was longer at 0 HPH (3.3 ± 0.02 mm) and larvae from CS were longer at 3 and 54 HPH (4.1 ± 0.05 and 6.6 ± 0.04 mm, respectively). The highest YSV was observed at 9 HPH in larvae from FS (0.6 ± 0.01 mm 3 ). No significant differences were observed in the survival between treatments. In conclusion, in the experimental condition above described, the corporal growth, development and survival of yamu larvae obtained from FS and CS did not change significantly in terms of LT, NL, and YSV until 60 HPH.