Influência do fotoperíodo no crescimento do pacamã

Abstract

The objective of this study was to evaluate the effect of photoperiod on the performance of pacamã Lophiosilurus alexandri. We used juvenile weight (4.20 ± 0.05 g) and length (8.20 ± 0.06 cm), distributed in 16 boxes, 10 animals per cage. The animals were adapted to laboratory conditions for 10 days with photoperiod (12:12 Light/Dark). After this period, the animals were subjected to the experimental phase. The treatments were 24 light (24L); 12:12 Light/Dark fed during the light (12:12L/D a); 12:12 Light/Dark fed during the dark (12:12L/D b) and 24 Dark (24D), totaling four treatments and four replications. The animals were fed with 48% crude protein, twice daily for 60 days. Feeding was performed by automatic feeders programmed manually to dispense 5% of the biomass. Consumption was measured daily by the difference in weight of the food dispensed by the feeder and the remains collected daily. The remains were dried in an oven with forced ventilation for 24 hours. The weight to 24D treatment were performed with the aid of red Light Emitting Diodes (LED). Biometrics was held every fifteen days. The results revealed that there was no difference in weight and length after 60 days of experiment. There was no difference in the percentage of weight gain, weight gain and specific survival. The treatments (24L) and (12:12L/D a) were statistically different between themselves and the other treatments. Consumption was lower for treatment (12:12L/D b) and (24D) compared with other treatments, with averages of 1,55 and 1,86g/100g body weight, with no statistical difference between these. It is concluded that the photoperiod is suitable for the species of 12:12L/D with food at night.