Desempenho produtivo e tolerância térmica de juvenis de acará-bandeira (Pterophyllum scalare) alimentados com diferentes fontes de lipídeos / Productive performance and thermal tolerance of juvenile freshwater angelfish (Pterophyllum scalare) fed with different lipid sources

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The present study was conducted to evaluate the influence of diets with different fatty acids composition, on the productive performance, as well as cold and heat tolerance of juvenile freshwater angelfish (Pterophyllum scalare). The experiment was accomplished in three phases. During phase one, the productive performance of freshwater angelfish was evaluated in an entirely randomized design with four treatments (canola, linseed, olive and soy oils) and four replications. Fish (n=192) of medium standard length of 2.56 0.16cm and medium weight of 0.72 0.21g were distributed in 8-L aquariums (35 x 30 x 14cm), maintained with aeration, filtering and controlled temperature through heater and thermostat (27 0.5 C), in a stoking density of 12 fish/aquarium. Fish were fed ad libitum, three times a day. At the end of 50 days, the following parameters were evaluated: survival, weight gain, length gain, feed intake, feed conversion ratio, specific growth rate and condition factor. During the second phase, cold tolerance was evaluated in juvenile freshwater angelfish. An entirely randomized design was used with four treatments: canola, linseed, olive and soy oils and three replications. Seventy two juvenile of freshwater angelfish, coming from the phase one were distributed in 3-L aquariums (30x20x08cm), maintained with aeration, in a stocking density of 6 fish/aquarium. Fish were fed with diets used in the phase one at 11:00 a.m. The aquariums were maintained in acclimatized camera (B.O.D.) equipped with a fluorescent lamp (40W), maintained lit from 6:00 a.m. to 6:00 p.m. (photoperiod of 12:00 light) controlled through timer. For a period of 3 days B.O.D. was set at 27C for fish adaptation. After that, temperature was reduced 1C per day, always at 12:00a.m., until the observation of 100% of fish mortality. In the phase three, the heat tolerance was evaluated in juvenile freshwater angelfish. The accomplished procedures were similar to those on phase two, except for temperature variation, that was elevated 1C per day. Comparison among treatments for cold and heat tolerance was made for the temperature values in which there was fish mortality equal or superior to 50%. Data of productive performance and cold and heat tolerance were submitted to the analysis of variance. Significant differences (P>0.05) were not observed for any parameters evaluated. Thus, it was concluded that the vegetal oils addition, with different fatty acids compositions, showed no one influence in the productive performance and on cold and heat tolerance of juvenile freshwater angelfish.

ASSUNTO(S)

desempenho produtivo fatty acids nutrition piscicultura Ácidos graxos ornamental fish productive performance nutrição peixes ornamentais

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