Misleni Ricarte de Lima

Crescimento e sobrevivência da tilápia chitralada submetida a diferentes fotoperíodos

The objective of this work was to assess the effect of photoperiod in the growth and survival of tilapia chitralada, Oreochromis niloticus, during and after the sexual reversion. The work was carried out in 2006 and 2007, and divided into two experiments. In the first experiment, post-larvae of 0.031±0.0058 g and 1.24±0.096 cm were used, at the density of 1.5 post-larva L-1. The post-larvae were submitted to the following photoperiods: 0, 8, 12, 16, 24 hours of light and 12.5 hours of natural light, during 28 days. The fishes were fed with 45% crude protein balanced food, containing androgen hormone, at 20% of the total biomass, divided into four meals. Sampling was done at the beginning and at the end of the experiment. In the second experiment, sex reverted fingerlings of 0.38±0.16 g and 2.81±0.40 cm were used. The experiment protocols were the same as in the former experiment, except for the stock density (0.33 fish L-1), food ratio (10% of the total biomass) and the experimental period (46 days). Sampling was done every fifteen days. The photoperiod interfered more intensively in the survival of the tilapia post-larvae, and the natural light was the recommended photoperiod during the sexual reversion. The best survival rate of the fingerlings occurred in the 0-hour light group; regarding fingerling growth, however, better results in bodyweight and length were found in the other photoperiod groups. It seems that the photoperiod responses to survival and growth are related to fish age.

Crescimento heterogêneo de tilápia do Nilo alimentados com resíduo de biscoito na dieta

O objetivo deste trabalho foi avaliar o efeito de quatro niveis da adicao de residuo de biscoito (0, 7.0, 14.0 e 21.0%) na dieta de juvenis de tilapia do Nilo sobre o crescimento heterogeneo, com peso inicial medio de 3,0±0,5g em um delineamento experimental inteiramente casualisado (DIC) com quatro tratamentos e cinco repeticoes, foram utilizados 100 animais peso medio inicial de 3,0±0,5g distribuidos em 20 aquarios experimentais de 130L cada onde permaneceram por 60 dias, foram alimentados tres vezes ao dia ate a aparente saciedade. Os peixes alimentados com 14% de residuo de biscoito apresentaram melhor crescimento homogeneo.